CN203135724U - Switch converter and slope compensation circuit thereof - Google Patents

Abstract

A switching converter and a slope compensation circuit thereof are disclosed. The slope compensation circuit comprises a first voltage unit for providing a first voltage signal; a first operation unit that provides a current control signal based on an operation result of the first voltage signal and the second voltage signal; a first switch, a first end of which is coupled to a first end of the first voltage unit; a first capacitor, wherein a first end is coupled to the second end of the first switch, and a second end is coupled to the second end of the first voltage unit; a first switch, a first end of which is coupled to the first end of the first capacitor; and a first current unit, wherein a first end is coupled to the second end of the second switch, a second end is coupled to the second end of the first capacitor, and a control end is coupled to the output end of the first arithmetic unit and provides a first current signal based on the current control signal. In this way, the transient response, the linear regulation rate or the load regulation rate of the switching converter are improved by adjusting the slope of the slope compensation signal according to the input voltage or the load state.

Description

Switch converters and slope compensation circuit thereof

Technical field

Embodiment of the present utility model relates to electronic circuit, relates in particular to a kind of switch converters and is used for the slope compensation circuit of switch converters.

Background technology

Because advantages such as high conversion efficiency and simple internal construction, switch converters has obtained using widely in field of power supplies.Switch converters has the various control pattern, for example constant ON time control, peak current control, Average Current Control etc.Constant ON time control has superior load transient response, simple internal construction and level and smooth mode of operation switches, and has obtained good application in switch converters.

Fig. 1 illustrates the schematic circuit diagram of the switch converters 100 of the constant ON time control of existing employing.Switch converters 100 comprises ON time control unit 101, comparing unit 102, logical block 103 and switching circuit 104.Switching circuit 104 comprises at least one switching tube, and the conducting by this at least one switching tube is converted to output voltage VO UT with input voltage VIN with turn-offing.ON time control unit 101 produces ON time signal COT, with the conducting duration of one or more switching tubes in the control switch circuit 104.Comparing unit 102 is coupled to the output of switching circuit 104, output voltage VO UT and voltage reference signal VREF is compared, to produce comparison signal SET.Logical block 103 is coupled to the output of ON time control unit 101 and comparing unit 102, produces control signal CTRL according to ON time signal COT and comparison signal SET, with conducting and the shutoff of at least one switching tube in the control switch circuit 104.

In switching circuit 104 the equivalent series resistance value of output capacitor hour, output voltage VO UT may produce subharmonic oscillation, causes switch converters 100 job insecurities.In order to prevent the generation of this subharmonic oscillation, switch converters 100 also comprises slope compensation unit 105 usually.Slope compensation unit 105 produces slope compensation signal VSLOPE and it is provided to comparing unit 102.Comparing unit 102 produces control signal CTRL according to voltage reference signal VREF, output voltage VO UT and slope compensation signal VSLOPE.

In order to guarantee that switch converters all can keep stable under various states, the slope of slope compensation signal VSLOPE must be enough big, for example greater than a critical value that is determined by switching frequency, duty ratio and output capacitor.Yet the slope compensation signal VSLOPE of high slope can cause adverse effect to the transient response of switch converters.Simultaneously, after load current IOUT or input voltage VIN change, if the slope of slope compensation signal VSLOPE remains unchanged, output voltage VO UT also will change with load current IOUT or input voltage VIN, and then influence load regulation (output voltage VO UT is with the variation of load current IOUT) and line regulation (output voltage VO UT is with the variation of input voltage VIN).For this reason, how realizing adjusting according to switching frequency or duty ratio (ON time or turn-off time) or output capacitor or input voltage VIN or output voltage VO UT or load current IOUT etc. slope compensation circuit or the control circuit of the slope of slope compensation signal VSLOPE, is the difficult problem that those skilled in the art face.

The utility model content

For addressing the above problem, the utility model provides a kind of switch converters and is used for slope compensation circuit and the control circuit of switch converters.

A kind of slope compensation circuit for switch converters according to the utility model embodiment comprises: first voltage cell, have first end and second end, and first voltage signal is provided; First arithmetic element provides current controling signal based on the operation result of described first voltage signal and second voltage signal at its output; First switch has first end and second end, and its first end is coupled to first end of described first voltage cell; First electric capacity has first end and second end, and its first end is coupled to second end of described first switch, and its second end is coupled to second end of described first voltage cell; Second switch has first end and second end, and its first end is coupled to first end of described first electric capacity; And first current unit, have first end, second end and control end, its first end is coupled to second end of described second switch, its second end is coupled to second end of described first electric capacity, its control end is coupled to the output of described first arithmetic element, provides first current signal based on described current controling signal.

According to embodiment of the present utility model, described switch converters comprises the input that receives input voltage, output and at least one device for power switching of output voltage are provided, control the turn-on and turn-off of described device for power switching by a control signal, described switch converters is transformed to described output voltage with described input voltage, and described second voltage signal reflects the variation of the turn-off time of the ON time of the load current of the output voltage of the input voltage of described switch converters or described switch converters or described switch converters or described device for power switching or described device for power switching.

According to embodiment of the present utility model, when the input voltage of described switch converters reduces or the load current of described switch converters increases or turn-off time of described device for power switching when reducing, described first current signal increases.

According to embodiment of the present utility model, described computing is addition or subtraction or multiplication or division.

According to embodiment of the present utility model, described first voltage cell comprises: first resistance, have first end and second end, and its first end is configured to first end of described first voltage cell, and its second end is configured to second end of described first voltage cell; And first current source, having first end and second end, its first end or second end are coupled to first end or second end of described first resistance.

According to embodiment of the present utility model, described first arithmetic element has first input end, described slope compensation circuit also comprises first testing circuit, have first input end, second input and output, its first input end and second input are coupled to the two ends of first voltage cell, and its output is coupled to the first input end of described first arithmetic element so that first detection signal that is ratio with first voltage signal to be provided.

According to embodiment of the present utility model, described first arithmetic element has second input, described slope compensation circuit also comprises second detecting unit, have input and output, its input receives reflection switching tube conducting or first status signal of turn-off time, and its output is coupled to second input of described first arithmetic element so that described second voltage signal to be provided, described second detecting unit comprises, second current unit has first end and second end, and second current signal is provided; The 3rd switch has first end and second end, and its first end is coupled to first end of described second current unit, conducting or shutoff under the control of described first status signal; Second electric capacity has first end and second end, and its first end is coupled to second end of described the 3rd switch, and its second end is coupled to second end of described second current unit; The 4th switch has first end and second end, and its first end is coupled to first end of described second electric capacity, and its second end is coupled to second end of described second electric capacity; And sampling hold circuit, having input and output, its input is coupled to first end of described second electric capacity, and its output provides the sampling inhibit signal as described second voltage signal.

According to embodiment of the present utility model, described sampling hold circuit is exported the voltage peak in previous cycle.

According to embodiment of the present utility model, second detecting unit comprises that also described second current unit has first end, second end and control end, provides second electric current based on the tertiary voltage signal; Described sampling hold circuit has input and output, and its input is coupled to first end of described second electric capacity, and its output provides adopts guarantor's signal; And division circuit, having first input end, second input and output, its first input end receives described tertiary voltage signal, and its second input receives the described guarantor's signal of adopting, and its output provides the division signal as described second voltage signal.

According to embodiment of the present utility model, described division circuit provides described division signal based on described tertiary voltage signal and the described merchant who adopts guarantor's signal; Described first arithmetic element provides described current controling signal based on amassing at its output of described first voltage signal and described second voltage signal.

According to embodiment of the present utility model, described division circuit provides described division signal based on the described merchant who adopts guarantor's signal and described tertiary voltage signal; Described first arithmetic element based on described first voltage signal and second voltage signal the merchant provide described current controling signal at its output.

According to embodiment of the present utility model, be proportionate relationship or linear relationship between described first current signal and the described current controling signal.

According to embodiment of the present utility model, be proportionate relationship or linear relationship between described second current signal and the described tertiary voltage signal.

According to embodiment of the present utility model, have first electricity between described first current signal and the described current controling signal and lead the factor; Have second electricity between described second current signal and the described tertiary voltage signal and lead the factor; The product that described first electricity is led the factor and described second electric capacity equals the product that described second electricity is led the factor and described first electric capacity.

A kind of switch converters road according to the utility model embodiment comprises: switching circuit has the input, the output that output voltage is provided and at least one device for power switching that receive input voltage; The ON time control unit produces the ON time signal; Slope compensation circuit produces slope compensation signal, comprising: first voltage cell, have first end and second end, and first voltage signal is provided; First arithmetic element provides current controling signal based on the operation result of described first voltage signal and second voltage signal at its output; First switch has first end and second end, and its first end is coupled to first end of described first voltage cell; First electric capacity has first end and second end, and its first end is coupled to second end of described first switch, and its second end is coupled to second end of described first voltage cell; Second switch has first end and second end, and its first end is coupled to first end of described first electric capacity; And first current unit, have first end, second end and control end, its first end is coupled to second end of described second switch, its second end is coupled to second end of described first electric capacity, its control end is coupled to the output of described first arithmetic element, provides first current signal based on described current controling signal; Comparing unit is coupled to slope compensation unit and switching circuit, based on the output voltage generation comparison signal of slope compensation signal, reference signal and switching circuit; And logical block, be coupled to ON time control unit and comparing unit, produce control signal according to ON time signal and comparison signal, with conducting and the shutoff of controlling described device for power switching device for power switching.

According to embodiment of the present utility model, described control signal comprises first control signal and second control signal, described switching circuit comprises: first device for power switching, have first end, second end and control end, its first termination is received described input voltage, and its control end is coupled to described logical block to receive described first control signal; Second device for power switching has first end, second end and control end, and its first end is coupled to second end of first device for power switching, its second end ground connection, and its control end is coupled to logical block to receive described second control signal; Inductor has first end and second end, and wherein first end is coupled to second end of described first device for power switching and first end of described second device for power switching; And output capacitor, be coupled between second end and ground of described inductor.

According to embodiment of the present utility model, described comparing unit comprises comparator, described comparator has first input end, second input and output, its first input end receives the poor of described reference signal and described slope compensation signal, its second input is coupled to the output of described switch converters to receive the feedback signal of output voltage or sign output voltage, and its output provides comparison signal.

According to embodiment of the present utility model, described comparing unit comprises comparator, described comparator has first input end, second input and output, its first input end receives described reference signal, its second input receives feedback signal and the described slope compensation signal sum that characterizes described output voltage, and its output provides comparison signal.

A kind of switch converters road according to the utility model embodiment comprises: switching circuit has the input, the output that output voltage is provided and at least one device for power switching that receive input voltage; The ON time control unit produces the ON time signal; Slope compensation circuit produces slope compensation signal; Comparing unit is coupled to slope compensation unit and switching circuit, based on the output voltage generation comparison signal of slope compensation signal, reference signal and switching circuit; And logical block, be coupled to ON time control unit and comparing unit, produce control signal according to ON time signal and comparison signal, with conducting and the shutoff of at least one device for power switching in the control switch circuit; Wherein, when input voltage reduces or load current when increasing, the slope of described slope compensation signal increases to improve line regulation or the load regulation of described switch converters.

According to embodiment of the present utility model, if the turn-off time of described device for power switching reduces, the input voltage that then is considered as described switch converters reduces or the load current increase.

According to embodiment of the present utility model, described control signal comprises first control signal and second control signal, described switching circuit comprises: first device for power switching, have first end, second end and control end, its first termination is received described input voltage, and its control end is coupled to described logical block to receive described first control signal; Second device for power switching has first end, second end and control end, and its first end is coupled to second end of first device for power switching, its second end ground connection, and its control end is coupled to logical block to receive described second control signal; Inductor has first end and second end, and wherein first end is coupled to second end of described first device for power switching and first end of described second device for power switching; And output capacitor, be coupled between second end and ground of described inductor.

According to embodiment of the present utility model, slope compensation circuit is regulated the slope of slope compensation signal according to input voltage or load condition, has improved transient response, load regulation and the line regulation of switch converters.

Description of drawings

Fig. 1 is the schematic circuit diagram of the switch converters 100 of the constant ON time control of existing employing;

Fig. 2 is the schematic circuit diagram according to the slope compensation circuit 200 of the utility model one embodiment;

Fig. 3 is slope compensation circuit shown in Figure 2 200 working waveform figures according to the utility model one embodiment;

Fig. 4 is the schematic circuit diagram according to the slope compensation circuit 400 of the utility model one embodiment;

Fig. 5 is the schematic circuit diagram according to the slope compensation circuit 500 of the utility model one embodiment;

Fig. 6 is the schematic circuit diagram according to the slope compensation circuit 600 of the utility model one embodiment;

Fig. 7 is the schematic circuit diagram according to the slope compensation circuit 700 of the utility model one embodiment;

Fig. 8 is the schematic circuit diagram according to the slope compensation circuit 800 of the utility model one embodiment;

Fig. 9 is the working waveform figure according to second testing circuit 801 shown in Figure 8 of the utility model one embodiment;

Figure 10 is the schematic circuit diagram according to the slope compensation circuit 1000 of the utility model one embodiment;

Figure 11 is the schematic circuit diagram according to the switch converters 1100 of the utility model one embodiment;

Figure 12 is the schematic circuit diagram according to the switch converters 1200 of the utility model one embodiment;

Figure 13 is the working waveform figure according to the switch converters 1200 of the utility model one embodiment;

Figure 14 is the working waveform figure according to the switch converters 1200 of the utility model one embodiment;

Figure 15 reduces for input voltage VIN or the working waveform figure of load current IOUT existing switch converters when increasing; With

Figure 16 reduces for input voltage VIN or the working waveform figure of load current IOUT switch converters 1200 when increasing.

Embodiment

To describe specific embodiment of the utility model in detail below, should be noted that the embodiments described herein only is used for illustrating, be not limited to the utility model.In the following description, in order to provide thorough understanding of the present utility model, a large amount of specific detail have been set forth.Yet, it is evident that for those of ordinary skills: needn't adopt these specific detail to carry out the utility model.In other examples, for fear of obscuring the utility model, do not specifically describe known circuit, material or method.

In whole specification, " embodiment ", " embodiment ", " example " or mentioning of " example " are meaned: special characteristic, structure or characteristic in conjunction with this embodiment or example description are comprised among at least one embodiment of the utility model.Therefore, differ to establish a capital in each local phrase " in one embodiment ", " in an embodiment ", " example " or " example " that occurs of whole specification and refer to same embodiment or example.In addition, can with any suitable combination and or sub-portfolio with specific feature, structure or property combination in one or more embodiment or example.In addition, it should be understood by one skilled in the art that at this accompanying drawing that provides all be for illustrative purposes, and accompanying drawing is drawn in proportion not necessarily.Should be appreciated that when claiming " element " " to be connected to " or " coupling " during to another element it can be directly to connect or be couple to another element or can have intermediary element.On the contrary, when claiming element " to be directly connected to " or during " being directly coupled to " another element, not having intermediary element.Identical Reference numeral indication components identical.Term used herein " and/or " comprise any and all combinations of one or more relevant projects of listing.

Fig. 2 is the schematic circuit diagram according to the slope compensation circuit 200 that is used for switch converters of the utility model one embodiment.Slope compensation circuit 200 can be used for multiple switch converters, for example be used for switch converters 100 shown in Figure 1 and switch converters 1100 shown in Figure 11, can also be used for the switch converters of peak current control, Average Current Control and other control models.These switch converters generally comprise input, the output that output voltage VO UT is provided and at least one device for power switching that receives input voltage VIN, by the turn-on and turn-off of switching signal control device for power switching, switch converters is transformed to output voltage VO UT with input voltage VIN.

According to some embodiment, slope compensation circuit 200 comprises: first voltage cell 201, have first end and second end, and the first voltage signal V1 is provided; First arithmetic element 202 provides current controling signal VCTL based on the operation result of the first voltage signal V1 and the second voltage signal V2 at its output; First switch 203 has first end and second end, and its first end is coupled to first end of first voltage cell 201; First electric capacity 204 has first end and second end, and its first end is coupled to second end of first switch 203, and its second end is coupled to second end of first voltage cell 201; Second switch 205 has first end and second end, and its first end is coupled to first end of first electric capacity 204; And first current unit 206, have first end, second end and control end, its first end is coupled to second end of second switch 205, its second end is coupled to second end of first electric capacity 204, its control end is coupled to the output of arithmetic element 202, provides the first current signal I1 based on current controling signal VCTL.Slope compensation circuit 200 can be adjusted the first current signal I1 with the slope of adjustment slope compensation signal according to the operation result of the first voltage signal V1 and the second voltage signal V2, and then improves transient response, load regulation and the line regulation of switch converters.

Those skilled in the art can reasonably arrange the second voltage signal V2 according to different applied environments, switch converters is made different adjustment.In one embodiment, the second voltage V2 can be the variation of the turn-off time TOFF of the ON time TON of the load current IOUT of the output voltage VO UT of the reflection input voltage VIN of switch converters or switch converters or switch converters or switching tube or switching tube.Correspondingly, slope compensation circuit 200 can be adjusted the slope of slope compensation signal according to the variation of the turn-off time TOFF of the ON time TON of the load current IOUT of the output voltage VO UT of input voltage VIN or switch converters or switch converters or switching tube or switching tube.

Those skilled in the art can reasonably arrange the operation relation of the first voltage signal V1 and the second voltage signal V2 according to different applied environments, and these operation relations comprise addition, subtraction, multiplication, division, integration, differential etc.Especially, in one embodiment, first arithmetic element 202, based on the first voltage signal V1 and the second voltage signal V2 long-pending (be V1 * V2) or merchant's (being V1/V2) provide current controling signal VCTL at its output, the first current signal I1 that first current unit 206 produces is directly proportional or linear relationship with current controling signal VCTL.Because the first current signal I1 and the first voltage signal V1 are directly proportional or linear relationship, when the first voltage signal V1 changed, do not change the discharge time of first electric capacity 204 substantially.

In one embodiment, first end of first voltage cell 201 is its anode (positive poles), and second end is its negative electrode (negative pole), and first electric current I 1 flows to second end by first end of first current unit 206.Under the control of switching signal 301, very first time section P1,203 conductings of first switch, second switch 205 ends, and first voltage cell 201 is 204 quick charges of first electric capacity.At the second time period P2, first switch 203 ends, second switch 205 conductings, and first current unit 206 is 204 discharges of first electric capacity, first electric capacity, 204 both end voltage reduce, signal 302 as shown in Figure 3.In another embodiment, first end of first voltage cell 201 is its negative electrode (negative poles), and second end is its anode (positive pole), and first electric current I 1 flows to first end by second end of first current unit 206.At very first time section P1,203 conductings of first switch, second switch 205 ends, and first voltage cell 201 is first electric capacity, 204 repid discharges (perhaps being called reverse charging).At the second time period P2, first switch 203 ends, second switch 205 conductings, and first current unit 206 is 204 chargings of first electric capacity, first electric capacity, 204 both end voltage raise, signal 303 as shown in Figure 3.Those skilled in the art can also be according to the actual needs of circuit, the negative electrode (negative pole) and anode (positive pole) of first voltage cell 201 reasonably are set, and/or the flow direction of first electric current I 1, and/or first switch 203, second switch 205 conducting with deadline section to produce different signals at first electric capacity, 204 two ends.

In one embodiment, can directly use the voltage signal VDIF (first voltage difference) at first electric capacity, 204 two ends as slope compensation signal.In other embodiment, can also select the voltage signal of first electric capacity, 204 first ends as slope compensation signal, perhaps the signal VDIF (first voltage difference) to first electric capacity, 204 two ends amplifies, handles the back as slope compensation signal.Second end of first voltage cell 201 or first electric capacity, 204 second ends can be coupled to earth potential or other electromotive forces.For example, as shown in Figure 4, in one embodiment, second end of first voltage cell 201 and first electric capacity, 204 second ends are coupled to the first reference voltage VREF1, thereby first end at first electric capacity 204 obtains the first voltage difference VDIF and the first reference voltage VREF1 sum (VREF1+VDIF), namely realizes slope compensation signal and the first reference voltage VREF1 addition.First end of first voltage cell 201 or first electric capacity, 204 first ends can be coupled to earth potential or other electromotive forces.For example, as shown in Figure 5, in one embodiment, first electric capacity, 204 first ends are coupled to the second reference voltage VREF2, thereby obtain the second reference voltage VREF2 and the first voltage difference VDIF poor (VREF2-VDIF) at second end of first electric capacity 204, realize that namely the second reference voltage VREF1 and slope compensation signal subtract each other.

First voltage cell 201 can adopt realizations such as voltage follower, amplifier, buffer, can adopt diode, zener or resistance to realize.Fig. 6 illustrates the schematic circuit diagram according to the slope compensation circuit 600 of the utility model one embodiment.Slope compensation circuit 600 comprises first voltage cell 601, first voltage cell 601 has first end and second end, comprises first resistance 602, has first end and second end, its first end is configured to first end of first voltage cell, and its second end is configured to second end of first voltage cell 601; First current source 603 has first end and second end, and its first end or second end are coupled to first end or second end of first resistance 602, and its other end is coupled to reference power source VSup.The current direction of first current source 603 and determined the polarity (negative electrode (negative pole) or anode (positive pole)) of first end and second end of first voltage cell 601 with the annexation of first resistance 602.For example, as shown in Figure 6, when the electric current of first current source 603 flowed into first end of first resistance 602 by reference power source VSup, first end of first voltage cell 601 was anode (positive pole); When the electric current of first current source 603 flowed into reference power source VSup by first end of first resistance 602, first end of first voltage cell 601 was negative electrode.Because the resistance of first resistance 602 and the current capacity of first current source 603, first voltage cell 601 provides the ability of the first voltage signal V1 to be restricted.For example; in waveform shown in Figure 3; because first voltage cell 601 provides the ability of the first voltage signal V1 to be restricted; begin or P2 time period when finishing in the P1 time period; signal 302 and signal 303 can not be transient changing rapidly; but the process that a charging is arranged or discharge, i.e. slowly variation, this all is not break away from the utility model protection range.In part embodiment, first switch 203 is coupled to first end of first voltage cell 601 by a little current-limiting resistance, damages first switch 203 or first voltage cell 601 to prevent excessive electric current.

First arithmetic element 202 has first input end and second input.In one embodiment, the first input end of first arithmetic element 202 is coupled to first end of first voltage cell 201 or second end to receive the first voltage signal V1.In another embodiment, the first input end of first arithmetic element 202 is coupled to first end and/or second end of first voltage cell 201 by first detecting unit 701.

Fig. 7 is the schematic circuit diagram according to the slope compensation circuit 700 that is used for switch converters of the utility model one embodiment.Compare with slope compensation circuit 200 shown in Figure 2, slope compensation circuit 700 further comprises first detecting unit 701.First detecting unit 701 has first end, second end and output, and its first end and second end couple first end and second end of first voltage cell 201 respectively, and its output provides the first detection signal VD1 relevant with the first voltage signal V1.Signal correction comprises between two signals and being directly proportional or ratio or linear relationship etc.Wherein, direct ratio represents that a signal (quantitatively) increases with the increase of another one signal, and ratio represents that the merchant of the two is constant within the specific limits.

In another embodiment, as shown in Figure 6, first testing circuit 610 comprises second resistance 611, has first end and second end, its first end is coupled to the first input end of first arithmetic element 202 so that first detection signal 613 to be provided, and its second end is coupled to earth potential; Second current source 612 has first end and second end, and its first end is coupled to reference power source VSup, and its second end is coupled to first end of second resistance 611, and second current source 612 has and first current source, 603 proportional electric currents.For this reason, first detection signal 613 and the first voltage signal V1 are linear.Those skilled in the art also can regard second resistance 611 and second current source 612 as the part of first voltage cell 601.That is, first voltage cell 601 directly provides proportional first detection signal 613 with the first voltage signal V1 to the first input end of first arithmetic element 202.For this reason, " first arithmetic element 202; operation result based on the first voltage V1 and the second voltage V2 provides current controling signal ICTL at its output " also do not mean that first arithmetic element 202 must be directly or receive indirectly or use the first voltage signal V1 to carry out computing, receives or uses the signal (for example first detection signal 613) of relevant with the first voltage signal V1 (for example essence is equal or proportional or linear relationship) can reach the purpose of this utility model yet.

In one embodiment, second input of first arithmetic element 202 directly is coupled to the input of switch converters or the output of switch converters.At this moment, input voltage VIN or output voltage VO UT namely can be configured to the second voltage signal V2.In one embodiment, second input of first arithmetic element 202 is coupled to the input of switch converters or the output of switch converters by voltage detecting circuit.Voltage detecting circuit provides the second voltage signal V2 based on (for example be directly proportional, inverse ratio, ratio, linear relationship etc.) input voltage VIN or output voltage VO UT.In another embodiment, second input of first arithmetic element 202 detects the variation of load current IOUT by current detection circuit.Current detection circuit provides the second voltage signal V2 based on load current IOUT.

Fig. 8 illustrates the schematic circuit diagram according to the slope compensation circuit 800 that is used for switch converters of the utility model one embodiment.Compare with slope compensation circuit 200 shown in Figure 2, slope compensation circuit 800 shown in Figure 8 further comprises second testing circuit 801.Second testing circuit 801 has input and output, and its input receives reflection switching tube conducting or first status signal 802 of turn-off time, and its output provides the second voltage signal V2.

Second testing circuit 801 comprises, second current unit 8011 has first end and second end, and second electric current I 2 is provided; The 3rd switch 8012 has first end and second end, and its first end is coupled to first end of second current unit 8011; Second electric capacity 8013 has first end and second end, and its first end is coupled to second end of the 3rd switch 8012, and its second end is coupled to second end of second current unit 8011; The 4th switch 8014 has first end and second end, and its first end is coupled to first end of second electric capacity 8013, and its second end is coupled to second end of second electric capacity 8013; Sampling hold circuit 8015 has input and output, and its input is coupled to first end of second electric capacity 8013, and its output provides to adopt protects signal 8016, and its output is coupled to or is configured to the output of second detecting unit 801.Adopt guarantor's signal 8016 and be configured to voltage signal V2.

Suppose that first status signal 802 is signals of reflection device for power switching turn-off time.Fig. 9 illustrates the working waveform figure according to second testing circuit 900 of the utility model one embodiment.In one embodiment, can directly adopt the switching signal 901 of control device for power switching switch as first status signal.In another embodiment, can be added or deduct a time period the actual turn-off time of device for power switching to obtain as shown in Figure 9 first status signal 902, wherein low level time section P4 represents the turn-off time.Especially, in constant ON time control, because ON time is constant, can directly use the switch periods of device for power switching to deduct a set time, for example minimum ON time obtains first status signal.In one embodiment, the 3rd switch 8012 and the 4th switch 8014 conducting and ending under the control of first status signal 902.At the 3rd time period P3,8014 conductings of the 4th switch, the 3rd switch 8012 ends, and second electric capacity, 8013 both end voltage differences are zero.At the 4th time period P4, the 4th switch 8014 ends, 8012 conductings of the 3rd switch, it is 8013 chargings of second electric capacity that second current unit 8011 begins, second electric capacity, 8013 both end voltage begin linear the increase, and the amplitude of second electric capacity, 8013 both end voltage is relevant with second electric current I 2 and the 4th time period P4.Reference numeral 903 illustrates second electric capacity, 8013 both end voltage to be changed.In one embodiment, first status signal 902 is controlled the conducting of the 3rd switch 8012 and is ended, and the 4th switch 8014 is by reset signal control (for example forcing conducting the 4th switch 8014 at P4 or the P5 end of term in week).

In one embodiment, sampling hold circuit 8015, the peak information of second electric capacity, 8013 both end voltage of sampling, and export this peak information as the second voltage signal V2 at one-period.For example, obtain the peak information of cycle P5, and export this peak information in the P6 cycle.In another embodiment, sampling hold circuit 8015 can also be exported average, higher value of the peak information in several cycles etc.For example in the average of the peak value of the peak value of cycle P7 output cycle P5 and cycle P6.And for example bigger one in the peak value of the peak value of cycle P7 output cycle P5 and cycle P6.

According to above-mentioned instruction, those skilled in the art can use second testing circuit to obtain the variation of the ON time TON of switching tube.For example, use signal controlling the 3rd switch 8012 conductings of reflection device for power switching ON time.

Figure 10 is the schematic circuit diagram according to the slope compensation circuit 1000 of the utility model one embodiment.Compare with slope compensation circuit 800 shown in Figure 8, use second testing circuit 1001 to replace second testing circuit 801.Second testing circuit 1001 that Figure 10 shows comprises: second current unit 1002 has been replaced second current source, 8011, the second current units 1002 and has been had first end, second end and control end, provides second electric current I 2 based on tertiary voltage signal V3; In one embodiment, second electric current I 2 and the proportional relation of tertiary voltage signal V3, it is K2 that its electricity is led the factor, namely

I2＝IB+K2×V3 (1)

Wherein IB is second initial current value.When IB was set to zero, second electric current I 2 was proportionate relationship with tertiary voltage signal V3.When K2 was constant, second electric current I 2 was linear with tertiary voltage signal V3.

Division circuit 1003, have first input end, second input and output, its first input end receives tertiary voltage signal V3, its second input is coupled to the output of sampling hold circuit 8015 and adopts guarantor's signal 8016 with reception, provides division signal 1003 based on tertiary voltage signal V3 and the merchant's (being V3/V8016) who adopts guarantor's signal 8016 at output.Division signal 1003 for tertiary voltage signal V3 when adopting the merchant who protects signal 8016, division signal 1003 and turn-off time are inversely proportional to.Division signal 1003 is when adopting the merchant who protects signal 8016 and tertiary voltage signal V3, and division signal 1003 was directly proportional with the turn-off time.In one embodiment, division signal 1003 is configured to the output signal (the second voltage signal V2) of second detecting unit 1000.First arithmetic element 202 provides current controling signal VCTL based on the operation result of the first voltage V1 and the second voltage signal V2 at its output.

First current unit 206 provides first electric current I 1 based on current controling signal VCTL.In one example, first electric current I 1 and the proportional relation of current controling signal VCTL, it is K2 that its electricity is led the factor, namely

I1＝IA+K1×VCTL (2)

Wherein IA is first initial current value.When IA was set to zero, first electric current I 1 was proportionate relationship with current controling signal VCTL.When K1 was constant, first electric current I 1 was linear with current controling signal VCTL.

Especially, in one embodiment, second electric current I 2 is proportionate relationship with tertiary voltage signal V3, and the output signal of sampling hold circuit 8015 is the peak value of electric capacity 8013 both end voltage, then adopt guarantor's signal VPEAK to be,

$\mathrm{VPEAK}=\frac{K2\×V3\×\mathrm{TP}4}{C8013}---\left(3\right)$

Wherein, the time of the P4 time period that TP4 is shown in Figure 9, i.e. the conducting duration of the 3rd switch 8012; C8013 is the capacitance of second electric capacity 8013.Division circuit 1003 provides division signal 1004 based on the merchant of tertiary voltage signal V3 and sampled signal 8016 at output, namely

$\mathrm{<figure-callout\; id="1003"\; label="V"\; filenames="HDA00002865859200051.png"\; state="\{\{state\}\}">V</figure-callout>}1003=\frac{V3}{\mathrm{VPEAK}}=\frac{C8013}{K2\&times;\mathrm{TP}4}---\left(4\right)$

The introducing of division circuit 1003 makes second detecting unit 1001 that normalized output signal can be provided.First computing circuit 202 is based on first voltage signal and the long-pending current controling signal VCTL that provides of division signal 1004 (being configured to the second voltage signal V2), and first electric current I 1 is proportionate relationship with current controling signal VCTL, namely

$I1=\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HDA00002865859200022.png,HDA00002865859200032.png"\; state="\{\{state\}\}">K</figure-callout>}1\&times;\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="HDA00002865859200022.png,HDA00002865859200032.png"\; state="\{\{state\}\}">V</figure-callout>}1\&times;\mathrm{<figure-callout\; id="1003"\; label="V"\; filenames="HDA00002865859200051.png"\; state="\{\{state\}\}">V</figure-callout>}1003=\frac{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HDA00002865859200022.png,HDA00002865859200032.png"\; state="\{\{state\}\}">K</figure-callout>}1\&times;\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="HDA00002865859200022.png,HDA00002865859200032.png"\; state="\{\{state\}\}">V</figure-callout>}1\&times;C8013}{K2\&times;\mathrm{TP}4}---\left(5\right)$

Can be known that by formula (5) first current signal depends on circuit parameter (K1, K2, C8013), the first voltage signal V1 and turn-off time TP4.When first electric current I 1 and the first voltage signal V1 proportionate relationship changed the voltage signal V1 that wins, first electric current I 1 ratio thereupon changed, and avoids influencing the turn-off time.The proportionate relationship of the inverse of first electric current I 1 and turn-off time TP4 made when the turn-off time, TP4 changed that first electric current I 1 ratio thereupon changes.According to,

$\frac{\mathrm{dv}}{\mathrm{dt}}=\frac{I1}{C204}=\frac{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HDA00002865859200022.png,HDA00002865859200032.png"\; state="\{\{state\}\}">K</figure-callout>}1\&times;\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="HDA00002865859200022.png,HDA00002865859200032.png"\; state="\{\{state\}\}">V</figure-callout>}1\&times;C8013}{\mathrm{<figure-callout\; id="204"\; label="C"\; filenames="HDA00002865859200012.png,HDA00002865859200022.png"\; state="\{\{state\}\}">C</figure-callout>}204\&times;K2\&times;\mathrm{TP}4}---\left(6\right)$

Long-pending and second electricity that first electricity is led factor K 1 and second electric capacity 8013 leads that factor K 2 and first electric capacity 204 are to be amassed when equating, the slope of slope compensation signal and " merchant of the first voltage signal V1 and turn-off time TP4 " are simple linear relationship, the slope of adjusting slope compensation signal that can be convenient.Those skilled in the art can know that division circuit 1003 also can provide division signal 1004 at output based on merchant's (being V8016/V3) of sampled signal 8016 and tertiary voltage signal V3.At this moment, only need first computing circuit 202 to provide current controling signal VCTL based on the merchant (but not long-pending) of the first voltage signal V1 and division signal 1004, can obtain the first current signal I1 shown in the formula (5).Simultaneously, those skilled in the art also can know, above-described embodiment usage ratio relation and multiplication relation is in order to obtain optimized effect, if be directly proportional based on negative feedback or the relation of inverse ratio, first computing circuit 202 can use the addition relation to replace the multiplication relation, and the subtraction relation is replaced division relation etc.

Figure 11 is the schematic circuit diagram that illustrates according to the switch converters 1100 of the utility model one embodiment, comprises control circuit and switching circuit 1104.Switching circuit 1104 comprises at least one switching tube, and the conducting by this at least one switching tube is converted to output voltage VO UT with input voltage VIN with turn-offing.Switching circuit 1104 can adopt any DC-DC or ac/dc transformation topology structure, for example synchronous or asynchronously boost, buck converter, and normal shock, anti exciting converter etc.Switching tube in the switching circuit 1104 can be any controllable semiconductor switch device, for example mos field effect transistor (MOSFET), igbt (IGBT) etc.

The control circuit circuit comprises ON time control unit 1101, comparing unit 1102, logical block 1103, slope compensation unit 200.ON time control unit 1101 produces ON time signal COT, with the conducting duration of switching tube in the control switch circuit 1104.Slope compensation unit 200 produces slope compensation signal VSLOPE.Comparing unit 1102 is coupled to slope compensation unit 11205 and switching circuit 1104, based on the output voltage VO UT of slope compensation signal VSLOPE, voltage reference signal VREF and switching circuit, produces comparison signal SET.Logical block 1103 is coupled to ON time control unit 1101 and comparing unit 1102, produces control signal CTRL according to ON time signal COT and comparison signal SET, with conducting and the shutoff of at least one switching tube in the control switch circuit 1104.

Those skilled in the art can know that the slope compensation circuit after above-mentioned various distortion to slope compensation circuit 200, the improvement can be used for switch converters 1100 equally.

In one embodiment, when input voltage VIN reduced, slope compensation circuit 200 increased the slope of ramp signal VSLOPE.For example, second input that ramp signal produces first arithmetic element 202 of circuit 200 is coupled to input voltage VIN, arithmetic element based on the merchant of the first voltage V1 and input voltage VIN or difference current controling signal VCTRL is provided.When input voltage VIN reduced, current controling signal VCTRL increased, and first electric current I 1 increases, thereby had increased the slope of slope compensation signal VSLOPE, and then had improved transient response and line regulation.

In one embodiment, when load current IOUT increased, slope compensation circuit 200 increased the slope of ramp signal VSLOPE.Second input that ramp signal produces first arithmetic element 202 of circuit 100 detects load current IOUT by load detecting circuit, arithmetic element based on the merchant of the first voltage V1 and input voltage VIN or difference current controling signal VCTRL is provided.When load current IOUT increased, current controling signal VCTRL increased, and first electric current I 1 increases, thereby had increased the slope of slope compensation signal VSLOPE, and then had improved transient response and load regulation.

In another embodiment, switch converters 1100 can also comprise feedback circuit 1107.Feedback circuit 1107 has input and output, wherein input be coupled to switching circuit 1104 output to receive output voltage VO UT, output is coupled to comparing unit 1102 so that the feedback signal FB that represents output voltage VO UT to be provided.Comparing unit 1102 produces comparison signal SET based on slope compensation signal VSLOPE, voltage reference signal VREF and feedback signal FB.In one embodiment, feedback circuit 1107 comprises resitstance voltage divider.

Figure 12 is the circuit theory diagrams according to the switch converters 1200 of the utility model one embodiment.The structural similarity of the structure of switch converters 1200 and switch converters shown in Figure 11 1100.Wherein switching circuit 1204 adopts the synchronous buck transformation topology, comprises switching tube S1, S2, inductor L and output capacitor COUT.Switching circuit 1204 is converted to output voltage VO UT by conducting and the shutoff of switching tube S1 and S2 with input voltage VIN.Switching tube S1 has first end, second end and control end, and wherein first termination is received input voltage VIN.Switching tube S2 has first end, second end and control end, and wherein first end is coupled to second end of switching tube S1, the second end ground connection.Inductor L has first end and second end, and wherein first end is coupled to second end of switching tube S1 and first end of switching tube S2.Output capacitor COUT is coupled between second end and ground of inductor L.The voltage at output capacitor COUT two ends is output voltage VO UT.In another embodiment, switching tube S2 can be replaced by diode.Especially, switch converters 1200 has slope compensation circuit shown in Figure 10 1000, produces slope compensation signal VSLOPE.

Comparing unit 1202 comprises comparator C OM1.Comparator C OM1 has in-phase input end, inverting input and output, wherein in-phase input end receives the poor of voltage reference signal VREF and slope compensation signal VSLOPE, inverting input is coupled to the output of switching circuit 1204 to receive output voltage VO UT, and output provides comparison signal SET.In one embodiment, slope compensation signal VSLOPE also can be applied to output voltage VO UT, rather than is deducted from voltage reference signal VREF.

ON time control unit 1201 produces ON time signal COT, with the conducting duration of control switch pipe S1.In one embodiment, the conducting duration of switching tube S1 is set to steady state value, or the variable value relevant with input voltage VIN and/or output voltage VO UT.Logical block 1203 is coupled to ON time control unit 1201 and comparing unit 1202, produces control signal CTRL according to ON time signal COT and comparison signal SET.

In one embodiment, switch converters 1200 also comprises drive circuit 1208.Drive circuit 1208 is coupled to logical block 1203 with reception control signal CTRL, and produces the driving signal to the control end of switching tube S1, S2, with conducting and the shutoff of driving switch pipe S1 and S2.

In one embodiment, for fear of noise jamming etc. unit 1202 is relatively impacted, cause switching tube S1 just to be turned off, be switched on again at once, slope compensation circuit also comprises minimum turn-off time quantum 1210.This minimum turn-off time quantum 1210 is at minimum turn-off duration TOFF _MINInterior comparison signal SET shielding with comparing unit 1202 outputs.For specification for simplicity, at this minimum turn-off time quantum 1210 is repeated no more.

Figure 13 is switch converters shown in Figure 12 1200 oscillogram in normal operation according to the utility model one embodiment.When control signal CTRL was high level, switching tube S1 conducting and switching tube S2 turn-offed, and the electric current I L that flows through inductance L increases gradually.When the conducting duration of switching tube S1 reached the set time threshold TTH of ON time control unit 301, control signal CTRL became low level, and switching tube S1 is turned off, and switching tube S2 is switched on, and the electric current I L that flows through inductance L reduces gradually.As shown in figure 14, as output voltage VO UT during less than the difference of voltage reference signal VREF and slope compensation signal VSLOPE, control signal CTRL becomes high level, and switching tube S1 is switched on and switching tube S2 is turned off.Above process constantly repeats.Among Figure 14, when input voltage VIN or load current IOUT did not change, output voltage VO UT was reduced to when setting the identical magnitude of voltage of output voltage VO UTSET essence, and control signal CTRL becomes high level.For ease of showing, represented output voltage VO UT with triangular wave among Figure 14.

In the embodiment shown in fig. 13, slope compensation signal VSLOPE is in switching tube S1 conducting and switching tube S2 equals amplitude VRAMP when turn-offing, switching tube S1 turn-off and during switching tube S2 conducting the slope descend.Slope compensation signal VSLOPE also can have other the form of expression, and for example slope compensation signal VSLOPE keeps the duration of amplitude VRAMP can be longer than time threshold TTH, for example equals time threshold TTH and minimum turn-off duration TOFF _MINSum.Slope compensation signal VSLOPE also with the triangular signal of inductive current IL homophase, in switching tube S1 conducting and switching tube S2 rises on the slope when turn-offing, turn-off and switching tube S2 conducting descends on the slope constantly at switching tube S1.

In the embodiment of following described Figure 15 to Figure 16, slope compensation signal VSLOPE is sawtooth signal, rapidly increases to amplitude when switching tube S1 becomes conducting by shutoff, switching tube S1 turn-off and during switching tube S2 conducting the slope descend.But it will be understood by those skilled in the art that the slope compensation signal VSLOPE with other forms of expression is applicable to the utility model too.

Figure 15 reduces or the oscillogram of load current IOUT when increasing in input voltage VIN for existing switch converters.Input voltage VIN or load current IOUT do not change under the situation, (T3 constantly during less than the difference of voltage reference signal VREF and slope compensation signal VSLOPE as output voltage VO UT, when output voltage VO UT equals to set output voltage VO UTSET), control signal CTRL becomes high level, and switching tube S1 is switched on and switching tube S2 is turned off.Suppose that at T1 constantly input voltage VIN reduces or load current 1OUT increases, the turn-off time begins to reduce.In existing switch converters, slope compensation signal VSLOPE can not change with input voltage VIN or load current IOUT, (T2 constantly when equating being reduced to the difference of voltage reference signal VREF with slope compensation signal VSLOPE for output voltage VO UT, this moment, output voltage VO UT equaled V1501), control signal CTRL becomes high level, and switching tube S1 is switched on and switching tube S2 is turned off.Obviously, V1501 is lower than setting output voltage VO UTSET.At next cycle, switch periods continues to reduce, the intersection point of the difference curve of output voltage VO UT curve and voltage reference signal VREF and slope compensation signal VSLOPE also continues to reduce, and finally is stable to be lower than the first actual output voltage VOUTACT1 that sets output voltage VO UTSET.Be that input voltage VIN reduces or load current IOUT increases, make output voltage VO UT reduce the load regulation variation of switch converters.

Figure 16 is according to the switch converters shown in Figure 12 1200 of the utility model one embodiment oscillogram when the instantaneous decline of load current.Shown in solid line part among Figure 15, suppose that at T1 constantly input voltage VIN reduces or load current IOUT increases, output voltage VO UT reduces, turn-off time begins to reduce, and when output voltage VO UT equaled V1501, switching tube S1 was switched on and switching tube S2 is turned off.Slope compensation circuit 1001 detects that input voltage VIN reduces or load current IOUT increases, and increases the slope (wherein dotted line is the slope compensation signal before not increasing slope) of slope compensation signal at next cycle (T3 to T4 between time period).At T4 constantly, output voltage VO UT is when being reduced to V1601, and control signal CTRL becomes high level, and switching tube S1 is switched on and switching tube S2 is turned off.Obviously, V1601 is higher than V1501, and the slope that increases slope compensation signal has improved load regulation.In ensuing switch periods, slope compensation circuit 1001 continues to adjust the slope of slope compensation signals, the difference curve of output voltage VO UT curve and voltage reference signal VREF and slope compensation signal VSLOPE finally meet at the second actual output voltage VOUTACT2.In certain embodiments, the second actual output voltage VOUTACT2 equals to set output voltage VO UTSET.In some other embodiment, the second actual output voltage VOUTACT2 is lower than setting output voltage VO UTSET.

In another embodiment, the switch periods of slope compensation circuit 1001 detection power switching devices, when switch periods reduces, first electric current 11 increases, thereby has increased the slope of slope compensation signal VSLOPE.In another embodiment, ramp signal produces the turn-off time of circuit 1001 detection power switching devices, reduces when the turn-off time, and first electric current I 1 increases, thereby has increased the slope (for example according to formula 5) of slope compensation signal VSLOPE.In one embodiment, slope compensation circuit 1001 compares the switch periods under current switch periods and the stable state, input voltage VIN reduces or load current IOUT increases if current switch periods than the short certain proportion of switch periods under the stable state or numerical value, then is considered as.It will be understood by those skilled in the art that load detecting circuit also can detect load condition by detecting other parameters relevant with load current, these detection modes all do not break away from protection range of the present utility model.

Though described the utility model with reference to several exemplary embodiments, should be appreciated that used term is explanation and exemplary and nonrestrictive term.The spirit or the essence that do not break away from utility model because the utility model can specifically be implemented in a variety of forms, so be to be understood that, above-described embodiment is not limited to any aforesaid details, and should be in the spirit and scope that the claim of enclosing limits explain widely, therefore fall into whole variations in claim or its equivalent scope and remodeling and all should be the claim of enclosing and contain.

Claims (21)

1. a slope compensation circuit that is used for switch converters is characterized in that, comprising:

First voltage cell has first end and second end, and first voltage signal is provided;

First arithmetic element provides current controling signal based on the operation result of described first voltage signal and second voltage signal at its output;

First switch has first end and second end, and its first end is coupled to first end of described first voltage cell;

First electric capacity has first end and second end, and its first end is coupled to second end of described first switch, and its second end is coupled to second end of described first voltage cell;

Second switch has first end and second end, and its first end is coupled to first end of described first electric capacity; And

First current unit, have first end, second end and control end, its first end is coupled to second end of described second switch, its second end is coupled to second end of described first electric capacity, its control end is coupled to the output of described first arithmetic element, provides first current signal based on described current controling signal.

2. slope compensation circuit as claimed in claim 1, it is characterized in that, described switch converters comprises the input that receives input voltage, output and at least one device for power switching of output voltage are provided, control the turn-on and turn-off of described device for power switching by a control signal, described switch converters is transformed to described output voltage with described input voltage, and described second voltage signal reflects the variation of the turn-off time of the ON time of the load current of the output voltage of the input voltage of described switch converters or described switch converters or described switch converters or described device for power switching or described device for power switching.

3. slope compensation circuit as claimed in claim 2, it is characterized in that, when the input voltage of described switch converters reduces or the load current of described switch converters increases or turn-off time of described device for power switching when reducing, described first current signal increases.

4. slope compensation circuit as claimed in claim 1 is characterized in that, described computing is addition or subtraction or multiplication or division.

5. slope compensation circuit as claimed in claim 1 is characterized in that, described first voltage cell comprises:

First resistance has first end and second end, and its first end is configured to first end of described first voltage cell, and its second end is configured to second end of described first voltage cell; And

First current source has first end and second end, and its first end or second end are coupled to first end or second end of described first resistance.

6. slope compensation circuit as claimed in claim 1, it is characterized in that, described first arithmetic element has first input end, described slope compensation circuit also comprises first testing circuit, have first input end, second input and output, its first input end and second input are coupled to the two ends of first voltage cell, and its output is coupled to the first input end of described first arithmetic element so that first detection signal that is ratio with first voltage signal to be provided.

7. slope compensation circuit as claimed in claim 1, it is characterized in that, described first arithmetic element has second input, described slope compensation circuit also comprises second detecting unit, have input and output, its input receives reflection switching tube conducting or first status signal of turn-off time, and its output is coupled to second input of described first arithmetic element so that described second voltage signal to be provided, described second detecting unit comprises

Second current unit has first end and second end, and second current signal is provided;

The 3rd switch has first end and second end, and its first end is coupled to first end of described second current unit, conducting or shutoff under the control of described first status signal;

Second electric capacity has first end and second end, and its first end is coupled to second end of described the 3rd switch, and its second end is coupled to second end of described second current unit;

The 4th switch has first end and second end, and its first end is coupled to first end of described second electric capacity, and its second end is coupled to second end of described second electric capacity; And

Sampling hold circuit has input and output, and its input is coupled to first end of described second electric capacity, and its output provides the sampling inhibit signal as described second voltage signal.

8. slope compensation circuit as claimed in claim 7 is characterized in that, described sampling hold circuit is exported the voltage peak in previous cycle.

9. slope compensation circuit as claimed in claim 7 is characterized in that, second detecting unit also comprises,

Described second current unit has first end, second end and control end, provides second electric current based on the tertiary voltage signal;

Described sampling hold circuit has input and output, and its input is coupled to first end of described second electric capacity, and its output provides adopts guarantor's signal; And

Division circuit has first input end, second input and output, and its first input end receives described tertiary voltage signal, and its second input receives the described guarantor's signal of adopting, and its output provides the division signal as described second voltage signal.

10. slope compensation circuit as claimed in claim 9 is characterized in that, described division circuit provides described division signal based on described tertiary voltage signal and the described merchant who adopts guarantor's signal; Described first arithmetic element provides described current controling signal based on amassing at its output of described first voltage signal and described second voltage signal.

11. slope compensation circuit as claimed in claim 9 is characterized in that, described division circuit provides described division signal based on the described merchant who adopts guarantor's signal and described tertiary voltage signal; Described first arithmetic element based on described first voltage signal and second voltage signal the merchant provide described current controling signal at its output.

12. slope compensation circuit as claimed in claim 9 is characterized in that, is proportionate relationship or linear relationship between described first current signal and the described current controling signal.

13. slope compensation circuit as claimed in claim 9 is characterized in that, is proportionate relationship or linear relationship between described second current signal and the described tertiary voltage signal.

14. slope compensation circuit as claimed in claim 9 is characterized in that,

Have first electricity between described first current signal and the described current controling signal and lead the factor;

Have second electricity between described second current signal and the described tertiary voltage signal and lead the factor;

The product that described first electricity is led the factor and described second electric capacity equals the product that described second electricity is led the factor and described first electric capacity.

15. a switch converters is characterized in that, comprising:

Switching circuit has the input, the output that output voltage is provided and at least one device for power switching that receive input voltage;

The ON time control unit produces the ON time signal;

Each described slope compensation circuit provides slope compensation signal in the claim 1 to 14;

Comparing unit is coupled to slope compensation unit and switching circuit, based on the output voltage generation comparison signal of slope compensation signal, reference signal and switching circuit; And

Logical block is coupled to ON time control unit and comparing unit, produces control signal according to ON time signal and comparison signal, with conducting and the shutoff of controlling described device for power switching device for power switching.

16. switch converters as claimed in claim 15 is characterized in that, described control signal comprises first control signal and second control signal, and described switching circuit comprises:

First device for power switching has first end, second end and control end, and its first termination is received described input voltage, and its control end is coupled to described logical block to receive described first control signal;

Second device for power switching has first end, second end and control end, and its first end is coupled to second end of first device for power switching, its second end ground connection, and its control end is coupled to logical block to receive described second control signal;

Inductor has first end and second end, and wherein first end is coupled to second end of described first device for power switching and first end of described second device for power switching; And

Output capacitor is coupled between second end and ground of described inductor.

17. switch converters as claimed in claim 15, it is characterized in that, described comparing unit comprises comparator, described comparator has first input end, second input and output, its first input end receives the poor of described reference signal and described slope compensation signal, its second input is coupled to the output of described switch converters to receive the feedback signal of output voltage or sign output voltage, and its output provides comparison signal.

18. control circuit as claimed in claim 15, it is characterized in that, described comparing unit comprises comparator, described comparator has first input end, second input and output, its first input end receives described reference signal, its second input receives feedback signal and the described slope compensation signal sum that characterizes described output voltage, and its output provides comparison signal.

19. one kind is used for switch converters, it is characterized in that, comprising:

Switching circuit has the input, the output that output voltage is provided and at least one device for power switching that receive input voltage;

The ON time control unit produces the ON time signal;

Slope compensation circuit produces slope compensation signal;

Comparing unit is coupled to slope compensation unit and switching circuit, based on the output voltage generation comparison signal of slope compensation signal, reference signal and switching circuit; And

Logical block is coupled to ON time control unit and comparing unit, produces control signal according to ON time signal and comparison signal, with conducting and the shutoff of at least one device for power switching in the control switch circuit; Wherein, when input voltage reduces or load current when increasing, the slope of described slope compensation signal increases to improve line regulation or the load regulation of described switch converters.

20. switch converters as claimed in claim 19 is characterized in that, if the turn-off time of described device for power switching reduces, the input voltage that then is considered as described switch converters reduces or the load current increase.

21. switch converters as claimed in claim 19 is characterized in that, described control signal comprises first control signal and second control signal, and described switching circuit comprises:

First device for power switching has first end, second end and control end, and its first termination is received described input voltage, and its control end is coupled to described logical block to receive described first control signal;

Second device for power switching has first end, second end and control end, and its first end is coupled to second end of first device for power switching, its second end ground connection, and its control end is coupled to logical block to receive described second control signal;

Inductor has first end and second end, and wherein first end is coupled to second end of described first device for power switching and first end of described second device for power switching; And

Output capacitor is coupled between second end and ground of described inductor.

Images