HK1070474B - Green switch power supply with standby function and its ic - Google Patents

Description

Green switch power supply with standby function and IC thereof

The technical field is as follows:

the invention belongs to the technical field of switching power supply design, in particular to a green switching power supply (hereinafter referred to as green switching power supply) which can meet the requirement of green environmental protection and has a standby function, which consists of a standby power supply, a (remote control on/off) main power supply, a PFC (power factor correction, hereinafter referred to as active power factor correction) device and an auxiliary circuit, wherein the design of remotely controlling the main power supply by adopting a single green switching power supply IC or a thick film circuit or a module circuit and a remote control signal along with a main error signal is adopted; the invention also discloses a single-end hybrid switching power supply conversion circuit, a method for preventing the current overload and saturation of a switching power supply, the switching power supply and an IC thereof, a digital processing high-quality PFC method and a device thereof, and an IC, and a PC standard (such as ATX, ATX12, SSI and the like) computer switching power supply.

Background art:

as for the switching power supply, there are classifications or definitions such as DC-DC (which means that one direct current power supply is converted into another direct current power supply or more than one direct current power supply) or AC-DC (which means that an alternating current power supply is converted into one direct current power supply or more than one direct current power supply), isolated or non-isolated conversion circuits, Boost (Boost type) or Buck (Buck type) conversion circuits, CCM (continuous current mode) or DCM (discontinuous current mode), and the like; the isolated conversion circuit has a single-end type (flyback type, forward type) and double-end type (push-pull type, half-bridge type and full-bridge type) structure; the transformation techniques include hard switching transformation, soft switching (or resonant switching, or zero switching) transformation; the control technology comprises a PFM (pulse frequency modulation) mode, a PWM (pulse width modulation) mode, a voltage mode and a current mode; and so on. Regardless of the classification and definition of the above known technologies, various switching power supply circuits can be simplified to: the conversion circuit comprises a power tube, a transformer or an inductor and one or more than one rectifying and filtering output circuit, wherein the power tube has one single-end power tube and a plurality of double-end power tubes, the soft switch conversion is adopted and one or more than one auxiliary power tube and the inductor are used for simple non-isolated DC-DC conversion, and the determination of the conversion circuit means that the switching power supply adopts the inductor or the single-end or double-end, hard switch or soft switch and the like; the feedback circuit (voltage or current, etc.) comprises a sampling circuit, an error amplifier and sometimes a feedback isolation circuit, wherein the sampling circuit samples signals of the voltage or current, etc. of the output circuit and sends the signals to the error amplifier for comparison and amplification, and the error amplifier outputs error signals; the control circuit comprises a pulse modulation circuit and a driving circuit, wherein the pulse modulation circuit has a PFM mode (comprising a PFM circuit and a pulse width shaping circuit which are not commonly used), a PWM mode (comprising a PWM circuit and an oscillator which are commonly used) and other modes, generates basic pulses according to error signals, adopts a double-end mode and a frequency division complementary double-pulse generation circuit and adopts soft switching conversion and a soft switching multi-pulse generation circuit, the basic pulses or the double pulses or the multi-pulse are transmitted to the driving circuit to drive a power tube, generally, the larger the error signals are, the larger the pulse duty ratio is, the higher the peak current of the power tube is, and the easier the transformer is saturated; and the auxiliary circuit is selected from auxiliary circuits such as a starting circuit, a protection circuit, a voltage reference circuit, an EMC circuit, an alternating current rectification filter circuit and the like according to needs, wherein the protection circuit comprises protection circuits such as low voltage, high voltage, upper limit current and the like. When the switching power supply is started or overloaded, the transformer or the inductor is easily saturated, and the power tube is easily subjected to overcurrent; therefore, in the prior art, the switching power supply IC (e.g., UCx842, TOP210, etc.) adopts an upper-limit current protection circuit, i.e., the power tube is immediately turned off when the upper-limit current is reached, and the control circuit and the power tube are required to have a fast response capability, otherwise, the potential safety hazards such as damage to the transformer or the power tube still exist. As the start-up circuit, a resistance start-up circuit and a turn-off constant current source start-up circuit are known.

Regarding the single-ended converter circuit, there are a single-ended flyback converter circuit and a single-ended forward converter circuit, wherein the single-ended forward converter circuit needs a magnetic reset circuit and is suitable for a switching power supply with a large power.

Regarding PFC (active power factor correction), there are single-phase PFC and three-phase PFC, CCM (continuous current mode) or DCM (discontinuous current mode), boost + buck and flyback conversion, techniques such as constant frequency control, constant on-time control and equal area control that are matched with DCM, techniques such as peak current control, average current control and hysteresis current control that are matched with CCM, hard switching and soft switching techniques, and the like. Regardless of the classification and definition of the above known technologies, various PFC devices can be simplified to: the conversion circuit comprises a power tube, a transformer or an inductor and an output circuit, wherein one or more auxiliary power tubes and a soft switch conversion circuit thereof are also used for soft switch conversion, and the transformer is used for flyback conversion; the feedback circuit comprises a sampling circuit and an error amplifier, wherein the sampling circuit samples a voltage signal of the output circuit and sends the voltage signal to the error amplifier (the frequency bandwidth of the voltage signal is generally 10-20Hz) to output an error signal; the control circuit comprises a pulse modulation circuit and a drive circuit, wherein an error signal is sent to the pulse modulation circuit, the drive circuit drives a power tube, different pulse modulation circuits are arranged by adopting different conversion circuits and control technologies, but a frequently used constant conduction time control circuit (such as UC3852, the specific control method is that when the power tube is conducted, inductive current rises, and the conduction time is determined by an error signal output by an error amplifier; and the auxiliary circuit is selected from auxiliary circuits such as a starting circuit, a protection circuit, a voltage reference circuit, an EMC circuit, an alternating current rectification circuit and the like according to the requirements of the PFC device. In order to prevent potential safety hazard caused by the fact that the output voltage of a PFC device exceeds the upper limit, in the prior art, when the characteristics of a feedback loop are designed, the capacity of an output capacitor, a power factor and total harmonic distortion are balanced or sacrificed, so that the power factor is reduced and the total harmonic distortion is increased when heavy load is carried out; nevertheless, when the input voltage exceeds the designed value or the output suddenly changes from the heavy load to the light load, the control circuit may not know that the output voltage exceeds the upper limit (for example, the reference design such as UCx852, UCx854, ML 4803) due to the voltage error feedback characteristic or the input voltage filtering, and there is a safety hazard.

Regarding the green switching power supply, the green switching power supply includes a standby power supply (or an industrial frequency transformer rectification standby power supply, generally requiring an output within a few watts to tens of watts, and the lower the power consumption is, the better the power consumption is under no load condition, the current advanced level is 220VAC less than 0.2W), a main power supply (generally, the main power supply can output more than tens of watts under a normal state, and the main power supply is closed under a standby state), and a PFC (or passive PFC) device, an EMC circuit and the like are required for the green switching power supply with a large output power; the current design scheme is to separate the standby power supply and the main power supply; meanwhile, people pay more attention to the design of a standby power supply and the design of a single switching power supply, and have no obvious motivation to consider the characteristics of a green switching power supply and adopt a comprehensive design method, so that the cost is more effectively reduced. Regarding the standby power supply, the common design scheme is to adopt a linear voltage-stabilized power supply of a mains transformer, but the linear voltage-stabilized power supply is difficult to adapt to the green environmental protection index with higher and higher requirements; or another preferred solution is to use a stand-alone standby switching power supply, such as a TOP series IC switching power supply design, but at a higher cost than a linear regulated power supply. As for the main power source, there is currently no dedicated main power source IC (and even no dedicated green switching power source IC), but a single switching power source IC design is adopted. According to the current optional devices (such as TOP series, TNY series, TL494, UCx842, ML4803, MC44608, UCx854, UCx852 and other ICs) and design schemes, the designed green switching power supply is not high in cost or can not meet the design index (mainly high in standby power consumption) of the green switching power supply.

The invention content is as follows:

the invention aims to overcome the defects of the prior art and provides a green switching power supply and an IC thereof, wherein the green switching power supply can meet the requirement of green environmental protection, has lower cost or high quality and consists of a standby power supply or unit, a (remote control on/off) main power supply or unit, a PFC device or unit and an auxiliary circuit; a single-ended hybrid switching power supply conversion circuit; a method for preventing current overload and saturation of switching power supply, and its switching power supply and IC; a digital processing high-quality PFC method and its device, IC; a switching power supply for PC standard (such as ATX, ATX12, SSI, etc.) computer.

The green switch power supply provided by the invention comprises a standby power supply, a (remote control on/off) main power supply and an auxiliary circuit, or comprises a PFC (power factor correction) device, a standby power supply, a main power supply and an auxiliary circuit, wherein a remote control signal is sent to the main power supply to control the main power supply to be turned on/off, the standby power supply at least provides a working power supply for the main power supply to be turned on, and the direct-current input end of the standby power supply and the direct-current input end of the main power supply; the standby power supply comprises a standby conversion circuit, a standby feedback circuit, a standby control circuit and a standby auxiliary circuit, wherein the standby control circuit and the DC input end of the standby power supply are grounded; or the standby power supply adopts an RCC switching power supply or a power frequency transformer direct current power supply; the main power supply comprises a main conversion circuit, a main feedback circuit, a main control circuit and a main auxiliary circuit, wherein the main control circuit and the direct-current input end of the main power supply are grounded together; the auxiliary circuit is selected from circuits such as an upper power starting circuit, an alternating current rectification filter circuit, a voltage reference circuit, an EMC circuit and the like according to needs; the PFC device comprises a PFC conversion circuit, a PFC feedback circuit, a PFC control circuit and a PFC auxiliary circuit, or a passive PFC device is adopted, and if the PFC device is adopted, at least one path of output is taken as a direct current input end of a main power supply;

the standby conversion circuit of the standby power supply at least comprises a standby power tube, a standby transformer and one or more than one standby rectifier filter output circuits (standby output and standby output circuits for short), in order to reduce the cost, a single-ended flyback conversion circuit is generally adopted, when larger power is needed, the standby power supply can adopt a single-ended forward or single-ended hybrid conversion circuit, the standby control circuit directly drives the standby power tube, and a soft switch and a double-ended conversion circuit are rarely adopted; the standby feedback circuit adopts a standby isolation feedback circuit or a standby non-isolation feedback circuit; the standby isolation feedback circuit comprises a standby sampling circuit, a standby error amplifier and a standby isolation circuit (generally adopting optical coupler isolation and also adopting other modes for isolation), wherein the standby sampling circuit samples a voltage signal output by standby, sends the voltage signal to the standby error amplifier, generates a standby optical coupler current, outputs a standby error signal through the standby isolation circuit, and the standby error signal is larger when the current of the standby optical coupler is smaller; the standby non-isolation feedback circuit comprises a standby sampling circuit and a standby error amplifier, wherein the standby sampling circuit samples a voltage signal which is proportional to the standby output voltage and can be used as a working power supply of the standby control circuit after being rectified and filtered by a standby transformer winding and sends the voltage signal to the standby error amplifier to output a standby error signal; the standby control circuit at least comprises a standby pulse modulation circuit and a standby driving circuit, the standby pulse modulation circuit generates standby pulses according to standby error signals, the single-end standby conversion circuit is adopted to directly send the standby pulses to the standby driving circuit, the standby driving circuit drives a standby power tube, the standby pulse modulation circuit has a PFM mode, a PWM mode or other modes, the PFM mode has a standby pulse frequency adjusting circuit and a standby pulse width shaping circuit, and the PWM mode has a standby pulse width adjusting circuit and a standby oscillator; the standby auxiliary circuit is selected from circuits such as a standby protection circuit, a standby voltage monitoring circuit and the like according to needs;

the main conversion circuit of the main power supply at least comprises a main power tube, a main transformer and one or more main rectification filter output circuits (main output and main output circuit for short), in order to reduce the cost, a single-end main conversion circuit is generally adopted, the main power tube is directly driven by the main control circuit, and the single-end soft switch main conversion circuit can be adopted when the conversion efficiency is required; the main feedback circuit adopts a main isolation feedback circuit and at least comprises a main sampling circuit, a main error amplifier, a main isolation circuit (generally adopting optical coupling isolation and adopting other isolation modes) and a remote control circuit, wherein the main sampling circuit samples a voltage signal of a main output, sends the voltage signal to the main error amplifier, generates a main optical coupling current and outputs a main error signal through the main isolation circuit, and the remote control circuit adopts the optical coupling isolation (also adopting other isolation modes) to send the remote control signal to the main control circuit; the main control circuit at least comprises a main pulse modulation circuit, a main drive circuit and a main power supply forbidding circuit (if a double-end type and/or soft switch conversion circuit is adopted and other circuits are needed), if a remote control signal is off, the main power supply forbidding circuit forces the main drive circuit to output low level to cut off a main power tube, otherwise, the main pulse modulation circuit generates a main pulse according to a main error signal, the main pulse of the single-end type main pulse conversion circuit is directly transmitted to the main drive circuit, the main drive circuit normally drives the main power tube (normally, the single-end type adopts direct drive), the main pulse modulation circuit has a PFM mode, a PWM mode or other modes, the PFM mode has a main pulse frequency adjusting circuit and a main pulse width shaping circuit, and the PWM mode has a main pulse width adjusting circuit and a main oscillator; the main auxiliary circuit is selected from the main protection circuit, the main voltage monitoring circuit and other circuits as required;

in the PFC device, a PFC conversion circuit at least comprises a PFC power tube, a PFC transformer or a PFC inductor and one or more than one PFC output circuit, wherein the PFC transformer is used for flyback conversion; the PFC feedback circuit comprises a PFC sampling circuit and a PFC error amplifier, wherein the PFC sampling circuit samples a voltage signal of the PFC output circuit and sends the voltage signal to the PFC error amplifier to output a PFC error signal; the PFC control circuit at least comprises a PFC pulse modulation circuit and a PFC driving circuit, the PFC error signal is sent to the PFC pulse modulation circuit, and the PFC driving circuit drives a PFC power tube; and the PFC auxiliary circuit is selected from circuits such as a PFC starting circuit, a PFC protection circuit, an alternating current rectification circuit and the like according to needs.

Or the main power supply adopts a remote control signal to send the main control circuit along with the main error signal to remotely control the on or off of the main power supply; when the main control circuit has a working power supply and the main feedback circuit has no working power supply, the main error signal is smaller than a threshold value (generally the minimum value); when the remote control signal is off, the main error signal is forced to be smaller than a threshold value (or a minimum value), when the remote control signal is on, the main error signal is not acted, if the main error signal is smaller than the threshold value, the remote control signal is off, and the main control circuit turns off the main power supply; the threshold value is an arbitrary value between the minimum value (usually 0) and the maximum value (usually 100%) of the main error signal, and is generally a fraction of the maximum value, when the threshold value is a proper value, the main power supply is easy to judge to turn on or off, and the conversion efficiency of the main power supply during light load is favorably improved, if the threshold value is set to be 25% and the load of the main power supply is less than 25%, the main power supply is circularly operated on/off; the above main power supply part circuit thus becomes: the remote control circuit does not need an independent isolation circuit, when the remote control signal is off, the main error signal is forced to be smaller than a threshold value (such as methods of forcibly adjusting a voltage signal of the main output, or forcibly adjusting the current of the main optical coupler, or directly cutting off a working power supply of the main feedback circuit, and the like), when the remote control signal is on, the remote control circuit does not work, and the main sampling circuit samples the voltage signal of the main output, sends the voltage signal to the main error amplifier, generates the main optical coupler current, and outputs the main error signal through the main isolation circuit; preferably, when the voltage signal of the main output is greater than a set value, the main light coupler has no current and the main error signal is minimum, otherwise, the larger the voltage signal error of the main output is, the larger the current of the main light coupler is, and the larger the main error signal is; a main power supply forbidding circuit, which monitors a main error signal from the main feedback circuit, if the main error signal is less than a threshold value, the remote control signal is off, the main pulse modulation circuit is forced not to output pulse and the main driving circuit outputs low level, or other methods for forcibly closing the main power supply, otherwise, the main pulse modulation circuit generates main pulse according to the main error signal, and the main driving circuit normally drives the main power tube (usually, the single-end type adopts direct driving); in order to ensure that the main error signal is smaller than the threshold value when the main feedback circuit has no working power supply, the main error signal can be input into the main control circuit by adopting a resistor or a constant current source in a pull-down mode.

The green switching power supply is characterized in that a green switching power supply IC is adopted, and the IC at least integrates a standby control circuit, a main control circuit and an auxiliary circuit; the auxiliary circuit comprises a reference voltage source, a starting circuit, a biasing circuit and the like, wherein the reference voltage source provides reference voltage for the internal circuit, the starting circuit establishes an initial working condition for the internal circuit, and the biasing circuit establishes bias for the internal circuit; when the standby pulse modulation circuit and the main pulse modulation circuit both adopt a PWM mode and the same working frequency, the standby pulse modulation circuit and the main pulse modulation circuit share a PWM oscillator, so that the cost is lower; the IC also integrates a PFC error amplifier and a PFC control circuit; the IC also integrates a standby sampling circuit and a standby error amplifier for sampling the working voltage of the IC, a green switching power supply of the IC is usually adopted, the working power supply is provided by the standby power supply, the highest working voltage of the IC is limited by an internal standby feedback circuit, the standby isolation feedback circuit and the internal standby feedback circuit can be still used in a combined mode, but the internal standby feedback circuit has the function of limiting the standby output voltage, and the IC is particularly suitable for the green switching power supply which has low requirement on the precision of the standby output voltage, does not need the standby isolation circuit and has lower cost.

The green switch power supply is characterized in that a remote control signal is sent to a main control circuit along with a main error signal, a main power supply IC is adopted, and the IC is at least integrated with the main control circuit.

The green switching power supply is characterized in that a green switching power supply thick film circuit is adopted, and the thick film circuit at least comprises a standby control circuit and a main control circuit; the thick film circuit preferably further comprises a standby feedback circuit, a main feedback circuit; the thick film circuit also includes a PFC feedback circuit and a PFC control circuit.

The green switching power supply is characterized in that a green switching power supply module circuit is adopted, and the module circuit at least comprises a standby control circuit, a standby feedback circuit, a main control circuit and a main feedback circuit; the module circuit preferably further comprises a standby converter circuit; the module circuit also comprises a PFC feedback circuit and a PFC control circuit.

The invention relates to a PC standard (such as ATX, ATX12, SSI) green computer switch power supply, which at least comprises a standby power supply and a main power supply; the standby conversion circuit of the standby power supply adopts a single-end conversion circuit; the main conversion circuit of the main power supply adopts a single-ended hybrid or single-ended forward conversion circuit; the green computer switching power supply also comprises a PFC device.

The invention provides a single-ended hybrid switch power supply conversion circuit, wherein at least one path of single-ended forward output and at least one path of single-ended flyback output are provided, and any path of single-ended forward output can be the same as one path of single-ended flyback output; the above can be understood that, in the single-ended forward pulse current output, the exciting current does not return to the direct-current input end (winding magnetic reset), but is discharged to the output end of the switching power supply through the secondary winding (the discharging process is equivalent to the single-ended flyback type); the secondary winding is an independent secondary winding or is shared with other forward output windings, and because the energy of the exciting current can be designed to be much smaller than the energy of forward conversion, one path of output end with larger power output can be selected to discharge the exciting current when multi-path output is needed; when a single-ended hybrid converter circuit is generally designed, the equivalent magnetic reset voltage of the input end of the single-ended hybrid converter circuit is smaller than the highest allowable direct-current input voltage, and the number of turns of the winding of the output end is less, so that the voltage resistance of a switching power tube is favorably reduced, the single-ended hybrid converter circuit is suitable for wider input voltage, and the manufacturing of a switching transformer is simplified.

The invention provides a method for preventing current overload and saturation of a switching power supply, which is characterized by comprising the following steps of:

1) detecting whether the current of a primary or an inductor or a power tube of the transformer exceeds an upper limit current or not;

2) if the current exceeds the upper limit current, an adjusting signal adjusting or an error signal is generated to adjust, so that the duty ratio is reduced and the peak current of the primary side of the transformer or the inductor or the power tube is reduced in the next pulse modulation period or a plurality of pulse modulation periods. The error signal is an output signal of the error amplifier or an input signal of the pulse modulation circuit; the adjustment error signal is a direct adjustment error signal; the indirect adjustment of the error signal is achieved by adjusting an input signal of the error amplifier or adjusting an output signal of the sampling circuit.

The specific method of the step 2) can be; when the over-limit current is detected, the error signal is adjusted once, and the adjustment amount is a fixed value.

The specific method of the step 2) can also be used; when the current exceeding the upper limit is detected, continuously adjusting the error signal in the current and the following pulse modulation periods, wherein the adjustment amount is from large to zero; in the continuous adjustment process, if the over-limit current is detected again, the adjustment process is restarted, and the adjustment amount is increased to zero again.

The specific method of step 2) is preferably to adjust the error signal, and the output of the error amplifier is preferably an open-circuit pull-up output and has a load capacitor, and is forcibly adjusted to discharge capacitor charges.

The invention provides a switching power supply adopting the method, which is an overload-proof and saturation-proof switching power supply and comprises the following steps: a conversion circuit (including a power tube, a transformer or an inductor, one or more than one rectifying and filtering output circuits, and sometimes a soft switch circuit, etc., which are known various conversion circuits), a feedback circuit (including a sampling circuit, an error amplifier, and sometimes a feedback isolation circuit), the control circuit (including pulse modulation circuit and drive circuit, the pulse modulation circuit has PFM way and PWM way or other ways, adopt PFM way have pulse frequency regulating circuit and pulse width shaping circuit, adopt PWM way have pulse width regulating circuit and oscillator, adopt the double-ended type and also frequency division complementary double pulse generating circuit, adopt the soft switch technology and also soft switch multipulse generating circuit) and auxiliary circuit (choose according to the needs of the switching power supply in starting circuit, protective circuit, voltage reference circuit, EMC circuit, AC rectification filter circuit, etc.; the protection circuit of the auxiliary circuit at least comprises a current sampling circuit of a primary transformer or an inductor or a power tube, an upper limit current detection circuit of the primary transformer or the inductor or the power tube and an adjusting circuit for adjusting or indirectly adjusting an error signal according to an output signal of the detection circuit, wherein the current sampling circuit, the upper limit current detection circuit and the adjusting circuit are sequentially connected. The adjusting circuit can adopt a D trigger with high level presetting triggered by a falling edge, a clock signal of the D trigger is a basic pulse generated by a pulse modulation circuit of the control circuit according to an error signal from a feedback circuit (when the basic pulse is high level, the only power tube or one power tube of the converting circuit is opened), a data port of the D trigger inputs low level, a preset input port of the D trigger inputs an output signal of the detecting circuit (when the detecting circuit detects that the upper limit current is exceeded, the high level is output), and when the D trigger is high level, an open circuit output executes adjustment or indirectly adjusts the error signal; therefore, when the over-limit current is detected, the adjusting circuit adjusts the error signal once, and the adjusting amount is a fixed value.

The switching power supply adopts a single-end type conversion circuit as a conversion circuit, a triode is adopted as a power tube, and the driving circuit has at least two paths of output signals, wherein one path of output signals is connected with the base electrode of the triode, and the other path of output signals is connected with the emitting electrode of the triode; the base of the triode is connected with a high-voltage power supply through a resistor with high resistance. The conversion circuit is matched with a corresponding circuit, a resistor with a high resistance value and a triode can be used as a part of a power-on starting circuit of the auxiliary circuit, and the withstand voltage of the triode is improved.

The switching power supply adopts a switching power supply IC, and the IC at least integrates part of a control circuit and part of a protection circuit.

The invention provides a digital processing high-quality active power factor correction method, which is characterized in that: a reference circuit and a PFC reference signal are adopted to replace a feedback circuit and an error signal of the prior art, wherein the reference circuit at least comprises a voltage signal sampling circuit, a voltage signal detection or analog-to-digital conversion (A/D) circuit, a reference logic circuit and a reference output circuit of an output circuit which are connected in sequence; the reference logic circuit carries out digital logic processing on the digitized voltage signal to generate a digitized reference signal, and adjusts the reference signal at the end point of each set period, and keeps the reference signal unchanged as much as possible in each set period; the period is integral multiple of the mains supply half period, and the end point of each period is synchronous with the edge of the mains supply half period (the mains supply is required to be synchronously input); or said period is much larger than the half period of the mains (an internal clocking period may be used); or the period is neither synchronous with the edge of the mains supply half period nor much larger than the mains supply half period, but the one-time adjustment amount of the reference signal is required to be small (an internal timing period can be adopted) so as to meet all indexes of IEC1000-3-2 and IEC1000-3-4 standards.

The invention provides a power factor correction device adopting the power factor correction method, which comprises the following steps: the conversion circuit comprises a power tube, a transformer or an inductor and an output circuit; a reference circuit; the control circuit comprises a pulse modulation circuit and a driving circuit, and a reference signal is sent to the pulse modulation circuit to control the generation of pulses; the auxiliary circuit comprises an alternating current rectifying circuit and is selected from auxiliary circuits such as a starting circuit, a protection circuit, a voltage reference circuit, an EMC circuit and the like according to the requirements of the PFC device.

The power factor corrector of the present invention is characterized in that the pulse modulation circuit comprises a proportional current circuit, a timing circuit, a pulse width modulation logic circuit, a current amplifier and an oscillator, and the connection relationship is as follows: the input of the proportional current circuit is a PFC reference signal, the output of the proportional current circuit is two paths of proportional current which is sent to the timing circuit, a pair of digital signals of the timing circuit is sent to the pulse width modulation logic circuit, the pulse width modulation logic circuit returns a pair of digital signals to the timing circuit, the output signal of the current amplifier is sent to the timing circuit, the oscillator outputs a signal to the pulse width modulation logic circuit, and finally the pulse width modulation logic circuit outputs a pulse signal. The parts of the pulse modulation circuit will be further described in the following description with reference to the accompanying drawings.

The power factor correction device adopts a power factor correction IC, and the IC is at least integrated with a part of reference circuits; the IC also integrates part of the control circuitry.

The best technical scheme of the green switching power supply comprises the following steps: the design of a single-chip green switching power supply IC, wherein a standby power supply adopts a single-ended flyback or single-ended hybrid mode, a PWM mode, a standby driving circuit directly drives a standby power tube and an overload prevention and saturation prevention design (the standby power consumption can be less than 0.2W or lower when the output capacity of the peak value is ensured to reach 5V @2.5A and the standby power consumption can be less than 0.5W or lower when no standby output exists, and a more rigorous green power supply standard can be supported); the main power supply adopts a single-ended flyback mode or a single-ended hybrid mode, a PWM mode is adopted, the main power supply shares a PWM oscillator with a standby power supply, a main driving circuit directly drives a main power tube, a remote control signal controls the on/off of the main power supply along with a main error signal, and the overload and saturation prevention design PFC device adopts a digital processing high-quality PFC design.

Has the advantages that:

the green switching power supply is designed by adopting the single-chip green switching power supply IC, so that the circuit can be simplified, the cost can be effectively reduced, and the quality can be improved; the monolithic green switching power supply thick film circuit or module circuit is adopted, and the circuit has the characteristics of reliable performance and easy maintenance; the remote control signal is sent to the main control circuit along with the main error signal to control the on/off of the main power supply, so that the cost is lower, and the effect of preventing misoperation is achieved; the single-end hybrid mode is adopted to replace the single-end forward mode, so that the withstand voltage of the power tube is reduced, and the power tube is safer; the overload and saturation prevention is adopted, and the high-quality PFC is digitally processed, so that the method has outstanding technical advantages and high quality; the technology is used for PC standard (such as ATX, ATX12, SSI and the like) computer switching power supplies, and can effectively reduce cost and improve quality.

Drawings

The following detailed description is to be read with reference to the drawings and non-limiting examples of the invention.

Fig. 1 is a schematic diagram of an overload protection and saturation protection unlimited PWM switching power supply with a starting circuit.

Fig. 2 is a schematic diagram of another overload protection and saturation prevention non-limiting PWM switching power supply with a starting circuit.

Fig. 3 is a schematic diagram of an embodiment of a preferred overload and saturation prevention non-limiting PWM main power supply.

Fig. 4 is a schematic diagram of a preferred, high quality, non-limiting PFC principle for digital processing.

Fig. 5 is a schematic diagram of another non-limiting PFC concept with high quality for preferred, digital processing.

Fig. 6 is a schematic diagram of a preferred, simplified digital processing high quality non-limiting PFC principle.

Fig. 7 is a schematic diagram of an embodiment of a preferred non-limiting green switching power supply.

Fig. 8 is a schematic diagram of an embodiment of a preferred non-limiting green switching power supply.

Fig. 9 is a schematic diagram of an embodiment of a preferred non-limiting green switching power supply.

FIG. 10 is a schematic diagram of an exemplary non-limiting PC ATX standard green switching power supply application.

FIG. 11 is a schematic diagram of another non-limiting PC ATX standard green switching power supply application.

Fig. 12 is a schematic diagram illustrating a preferred PFC-free non-limiting PC ATX standard green switching power supply application.

Fig. 13 is a schematic diagram of a single-ended hybrid switching power supply.

Fig. 14 is a schematic diagram of a single-ended hybrid switching power supply.

The voltage values and the resistance values marked in all the figures are unlimited values, and can be set to other values according to design targets and requirements, and the MOS tube or the triode can be generally changed in driving and exchanged with the triode or the MOS tube.

Detailed Description

Fig. 1 and 2, the Q1 is a preferred economical power transistor (e.g. 13003, BUX87, etc.) as an independent switch power supply (e.g. a charger, a green switch power supply IC standby power supply unit, or a universal switch power supply); qd is a preferable internal power tube or an external power tube; the dotted line frame is an IC part, however, Rb and Qa can be integrated in the IC or externally arranged according to the semiconductor process, Rb can be integrated in the IC according to the optimized resistance value of the general smaller output power, and the external parallel resistor can meet the requirement when the output power is larger than the internal output power. Fig. 3 can be used as the main power source of a green switching power supply IC, the dashed box is the IC circuit part, and the high-power tube Q2 can be externally arranged or integrated in the IC. Ia and Ib current sources.

S0, schmitt comparator, IC power supply voltage monitoring circuit (or part of the start-up circuit), which is activated if SO low, and is activated if SO high. Fig. 1 shows a startup state, where Qa is turned off, pcl.qc is high-resistance (or output is controlled), and a high-voltage high-resistance value R1 provides a base micro-current to turn on a power tube Q1 with a small collector current, and charges an IC power supply capacitor CO through a diode Da to form a startup circuit, so that for the startup safety of Q1, the startup circuit can detect a charging current, control pcl.qc output, and change the base current of Q1, so that the Q1 current is a safe value (e.g., 3 mA); in a normal state, PCL, QC and Qa are normal outputs, and R1 is out of action; therefore, considering the amplification of Q1, the loss sustained by the start-up circuit in the normal state is at least an order of magnitude smaller than that of the start-up circuit limited by resistance. FIG. 2, in the start-up state, the high voltage current source is turned on to charge the capacitor C0, forming a PWMs start-up circuit; and in the normal state, the PWMs restore to the normal state, and the high-voltage current source is closed. In fig. 3, since the main power supply and the standby power supply can share the IC power supply voltage monitoring circuit, SO can be made to act also on the PWM2 (not shown), and in the on state, the PWM2 is turned off.

FIG. 1, in normal state, PCL.QC and PCL.Q outputs are the same, e.g. output high, Q1 and Qa are turned on, Rb detects Q1 instantaneous current; if the output is changed from high level to low level, Qa is cut off, but due to the storage effect, Q1 is not cut off immediately, diode Da freewheels, or a delay circuit is designed to delay Qa to cut off Q1 and then turn off, or Qa clamps the emitter of Q1 to about 1.5V (the value can improve the withstand voltage of Q1 and lower the power consumption of IC), and the base voltage of Q1 is 0V, so that the collector withstand voltage of Q1 is improved. FIG. 2, in normal state, when PCLS. Q outputs high level, Qd is turned on, and Rb detects Qd instantaneous current; if the output is low, Qd is turned off. FIG. 3 shows that in normal state, if PCL2.Q outputs high level, Q2 is turned on, and R2 detects Q2 transient current; if the output is low, Q2 is off.

S2, the PWM comparator (or PWM circuit, shown in current mode or voltage mode) starts to conduct on the power tube at the rising edge of the oscillator Q, the primary current of the transformer increases, the voltage drop of Rb or R2 also increases, when the voltage drop is equal to or greater than the error signal (the voltage UC1 or UC2 reflected on C1 or C2), S2 outputs low level, and the power tube is turned off; but the oscillator determines the maximum duty ratio, and the principle is that S2 still outputs high level, and the oscillator Q becomes low level, then the power tube is closed; s1, the schmitt comparator (or as a main power supply inhibiting circuit) is based on the principle that when the error signal is lower than the set value (threshold), the PWM period of the power tube is forced to be turned off, and when the error signal is higher than the set value, the PWM period of the power tube is turned on, thereby improving the conversion efficiency of the switching power supply under light load.

S3, the upper limit current comparator (or the upper limit current detection circuit), if the transformer primary or the power tube reaches the upper limit current, S3 starts the overload protection and saturation protection control logic S5 (the adjusting circuit)) The power tube is turned off at the same time (optionally, the reason is that the turn-off of the power tube is responsible for S2). There are many solutions to S5, and the simplest solution is considered in the present invention to be that S5 is enabled once, and S4 is turned on for one oscillator cycle; however, the condition is satisfied that the average current (referred to as I4) of S4 is greater than the current source Ia (fig. 1 and 2) or the main voltage feedback current reduction source Ib (fig. 3, difference Ic) during a PWM (or oscillator) cycle; i4 and Ia or Ic can jointly contribute to UC1 or UC2 within one PWM cycle, and can be selected at 2.8V^＊Within (-10%), and the maximum output current should be above 95%, such as Ia contributing 2.8V to UC1^＊3.3%, then I4 is preferably 3-4 times Ia; therefore, the error signal is reduced (i.e. the error signal is forcibly adjusted), the duty ratio becomes smaller in the next PWM period or periods, and the peak current of the transformer primary or the power tube is reduced; for a fast power tube, a transformer with sufficient capacity and a control circuit with fast response, when overload occurs, an error signal is near the maximum value; for a slower power tube, or a transformer with insufficient capacity (once the transformer is saturated, the primary current of the transformer rises rapidly and reaches or exceeds the upper limit current) or a control circuit with slow response, when the overload occurs, the error signal is smaller than the maximum value of theoretical calculation, and the control circuit switches off the power tube in advance; although the power tube exceeds the upper limit current or the transformer is saturated, the time is extremely short, the safety of the power tube and the transformer can be ensured, and the reliability is improved.

Alternatively to S5, S5 is activated once, I4 ═ Ia (or Ic)^＊1.2; subsequent PWM cycle S5 if not enabled, I4 ═ Ia (or Ic)^＊0.8, and then stops S5; the above-mentioned multiples 1.2 and 0.8 may be other values greater than 1 and less than 1, but the transient response of the switching power supply should be taken into account; the scheme can further improve the protection of the power tube and the transformer and increase the maximum output current. The S5 may also adopt a digital processing logic scheme to adaptively converge the I4 when overloaded. To facilitate monitoring during use, S5 preferably outputs an overload monitoring signal (the principle is that S5 is activated once to produce an output, which can be directly indicated by an LED, not shown).

In the single-ended continuous current mode shown in fig. 1, 2 and 3, delay circuits should be designed for PCL, PCLs, PCL2 and S5 to prevent the power tube from being turned off by mistake or turned on by mistake by S5 due to turn-on spike.

The PWM control technology of the overload and saturation prevention switching power supply is also suitable for structures such as a push-pull type structure, a half-bridge type structure and a full-bridge type structure, if the overload and saturation prevention protection circuit is added to detect that the primary current of the power tube or the transformer exceeds the upper limit current, the error signal is forcibly adjusted (for example, S3, S5 and S5 are added to TL494 to forcibly adjust the level of 3 pins or 4 pins), so that in the next PWM period or a plurality of PWM periods, the duty ratio is reduced, the primary peak current of the power tube or the transformer is reduced, the power tube and the transformer are protected, and the safety and the reliability of the switching power supply are improved.

The above discussion of FIG. 1 may be partly modified as follows: a single economical switch power triode is adopted, and the PWM control circuit (or IC) is suitable for a single-end type. When the power supply is started, one path of high-resistance state (or controlled output) connected with the base electrode is provided, the high-voltage high-resistance resistor provides base electrode micro current of the power tube, and the power tube emits the micro current to charge (or limit current charging) the filter capacitor of the IC power supply through the diode, so that the starting is finished. In a normal state, the PWM is in a positive period, one path of the PWM makes the base electrode of the power tube biased positively, the other path of the PWM pulls down the emitting electrode of the power tube, and the power tube is conducted; in the PWM negative period, one path of the base electrode of the power tube is pulled down, the power tube cannot be immediately cut off due to the storage effect, the diode can be used for enabling the emitter of the power tube to continue current, or the pull-down emitter is turned off when the power tube is cut off in a time delay mode, or the emitter of the power tube is clamped, but after the power tube is cut off, the base electrode of the power tube is reversely biased, and therefore the collector withstand voltage of the power tube is improved.

Fig. 4, 5, and 6 show an IC circuit within a dotted frame as an independently usable PFC. R3 detects the current of PFC inductor Lp, and PFC current (i.e. Lp current) reference output filter capacitor Cir and high power transistor Qp may be externally disposed or integrated in an IC. UD, commercial power rectification synchronous input, RV and a high-voltage high-resistance current-limiting resistor. Rh, RI, PFC output voltage signal sampling circuit, do not filter or filter out the high-frequency noise greater than about several thousand Hz; and A, detecting a voltage signal, and outputting high-voltage Vhh, high-voltage Vh, low-voltage VI and low-voltage VII signals by adopting a four-voltage comparator or an A/D (analog/digital) converter. IR0, PFC current reference output accumulator (converting to capacitor Cir voltage based on overflow output, providing reference for PFC current, a D/a (digital/analog) conversion; but capacitor Cir voltage is inversely proportional to IR 1); IR1, current PFC current reference output register; IR2, PFC current reference output register IR3, large-period PFC average current reference output register; II, a current PFC current reference output register (IR1) large period accumulator; CT, large cycle counter; IR0, IR1, IR2 and IR3 (according to the precision requirement) are preferably 8 bits or 9 bits, CT (the large period should be larger than the commercial power period and can be selected in a wide range) is preferably 12 bits, and II is preferably 20 bits or 21 bits.

Fig. 4, PFC current reference generation Logic (i.e., digital processing unit, IR Logic): delaying for a plurality of times after power-on reset, allowing a signal by a PFC Logic position, finishing PFC soft start characteristics, setting IR2 and IR3 to be half of the maximum value, and resetting II and CT; completing a large period, loading the current reference output average value of the large period obtained from II into IR3, and starting a new large period; voltage detection 0000 (namely Vhh is 0, Vh is 0, VI is 0, VII is 0, and only 0000, 0001, 0011, 0111 and 1111 states), IR1 is set to be maximum (stf), so that PFC output voltage is prevented from falling too much; voltage detection 1111, IR1 set 0(cIO), PFC Logic set inhibit signal, prevent PFC output voltage from exceeding upper limit, PFC Logic set enable signal after voltage detection resumes to 0011; voltage detection is not 0000 or 1111, PFC Logic is allowed, IR2 is loaded into IR 1; voltage detection 0000 to 0001 or 1111 to 0111, IR3 loading IR2, using a large cycle average current reference; detecting voltages from 0111 to 0011 to 0111, adjusting IR2 downwards, and searching for an actual IR2 value; detecting voltages 0011 to 0001 and then 0011, adjusting IR2 upwards, and searching for an actual IR2 value; for more stable loads, IR2 is adjusted down or up, either by one or by one; for loads with larger variations, an adjustment equivalent register may be used, which is increased if IR2 is continuously adjusted down or continuously adjusted up, and decreased otherwise, so that IR2 is adjusted down or up, and decreased or increased for IR 2; limiting measures may be taken to ensure that IR2 is greater than a specified value for PFC operation in continuous current mode.

Fig. 5, PFC current reference generation Logic (IR1 Logic): basically similar to the above IR Logic principle, except that the modification of IR2 (down-regulation or up-regulation or loading) is synchronized with the rising edge or falling edge of UD (hereinafter referred to as UD synchronization, i.e. mains half cycle synchronization); voltage detection 0000 to 0001 or 1111 to 0111, UD synchronization IR3 is loaded into IR 2; voltage detection 0111, UD synchronous IR2 is adjusted downwards; voltage detection 0001, UD synchronous IR2 up-regulation; voltage detection 0011 is not active, so Vh, VI can be combined into one signal, with only four states 0000, 0001, 0111, 1111, but not combining IR2 will reduce the frequency of change; thus, the PFC current reference is constant during a half cycle of the mains.

Fig. 6, PFC current reference generation Logic (IR2 Logic): delaying for a plurality of times after power-on reset, setting a PFC Logic allowing signal, and finishing PFC soft start characteristics; voltage detection 1111, PFC Logic disable signal; UD synchronous voltage detection 0111, PFC current reference position Ri 1; UD synchronous voltage detection 0011, PFC Logic position permission signals and PFC current reference positions Ri 2; UD synchronous voltage detection 0001, PFC current reference position Ri 3; UD synchronous voltage detection 0000 and PFC current reference position Ri 4; ri1, Ri2, Ri3 and Ri4 current references (arranged from small to large, scheme 1: 25%, 50%, 75% and 100%, scheme 2: 40%, 60%, 80% and 100%, and VA needs to be correspondingly adjusted in different schemes) can be regarded as D/A conversion, so that 4-bit D/A conversion can be designed, IR2Logic is designed into more complex Logic, a more accurate PFC current reference is calculated according to voltage detection, and the change of the PFC current reference and UD synchronization are guaranteed.

The PFC current reference generation logic units shown in fig. 4, 5 and 6 can directly replace the error amplifier of UC3854 (or similar ICs) to form a new safer, more reliable and high-quality continuous current mode control IC; or directly replace the error amplifier of UC3852 (or similar IC) to form a new safer, more reliable and high-quality non-continuous current mode constant-conduction-time control IC.

The PFC of fig. 4, 5, 6 may be in average current mode, and operate in CCM or DCM (but for DCM, R3 detection PFC current must be filtered and sent to-4 amplifier); -4 is a PFC current amplifier whose output is fed to a timing circuit; imk is a proportional current circuit composed of three triodes or MOS transistors, one current reference input and two proportional current outputs; the timing circuit consists of two proportional capacitors (30 PF and 15PF in the figure, internal or external IC, Ct2 and Ct1 for short), two triodes or MOS (Ta and Tb) for discharging of the proportional capacitors, and two amplifiers (Aa and Ab) for monitoring the voltage of the proportional capacitors, wherein a pair of digital signal inputs respectively control the on/off of the Ta and the Tb, and the Aa and the Ab output a pair of digital signals; the PFC benchmark output circuit outputs current benchmark through Cir and Ri (or directly), and Imk generates equal steady current to charge two capacitors with the capacity ratio of 2: 1; the PFC Logic (pulse width modulation Logic) principle is: the oscillator works synchronously with the oscillator but is controlled by a PFC Logic allowing signal; the oscillator rises, the PFC enters a turn-off period, namely the PFC power tube Qp is turned off, the current of the PFC inductor Lp is reduced, the discharge tube Ta of Ct2 is turned off and is charged in a steady flow manner, the discharge tube Tb of Ct1 is kept on, and the voltage of Ct1 is kept at 0; when the current represented by the voltage of Ct2 is equal to the PFC inductance current, namely the rising edge of the comparator Aa, the discharge tube Tb of Ct1 is closed and the charging is stabilized; when the Ct1 voltage catches up with the voltage of Ct2, namely the rising edge of the comparator Ab, the PFC starting period is started, the PFC power tube Qp is started, the current of the PFC inductor Lp is increased, the discharge tubes Ta and Tb of the discharge tubes Ta and Ct1 of the Ct2 are started, and the Ct2 and Ct1 are discharged to be 0 voltage until the rising edge of the next oscillator is finished and a new PFC period is started; it can be demonstrated that this control principle allows PFC to be in ideal average current mode with continuous current mode and R3 detection without filtering, and Lp current to be the average current at the time of the Aa rising edge.

The VA voltage signal detection shown in fig. 4, 5, and 6 may also use detection output signals other than four, or output voltage values of a/D converter (e.g. one bit a/D, etc.), so it can be understood that VA is a/D conversion, and the PFC current reference is finally generated as D/a converter (or reference output circuit), but the PFC current reference generation logic (or reference logic circuit) should conform to the following principle: the VA input does not filter or filter high-frequency noise; preferably, Vhh logic is provided, when the PFC is in Vhh-1, the PFC is disabled, and the PFC output voltage is prevented from exceeding the upper limit; logic VII is preferably provided, and when the PFC is at VII ═ 0, the PFC is set to a larger or maximum current reference, so as to prevent the PFC output voltage from dropping too much, and for the convenience of monitoring during use, it is preferable to output a VII monitoring signal (the principle is to output a monitoring signal when VII ═ 0, which is not shown in the figure); although Vhh and VII are optional, Vhh and vipfc are safer and more reasonable; when the non-Vhh is 1 or the non-VII is 0, the PFC keeps the PFC current reference constant during a large period, i.e. adjusts the primary current reference at the beginning or end of the large period, and the large period is preferably synchronized with the edge of the half-cycle integral multiple of the mains supply, or is much larger than the half-cycle of the mains supply, or the PFC current reference adjustment is small; depending on the complexity of the VA input 2 a/D and PFC current reference generation D/a conversion, more accurate PFC current reference generation logic may be employed. Therefore, the current reference generation logic of the PFC technique can be implemented by an IC having a digital processing capability, such as a single chip microcomputer.

Therefore, the digital processing PFC control circuit has ideal power factor (equal to 1) and ideal total harmonic distortion (equal to 0), and is a high-quality PFC control circuit.

Fig. 7, 8, 9 adopt the green switching power supply designed by overload prevention, saturation prevention, digital processing high quality PFC, the monolithic green switching power supply IC is designed, the standby error amplifier and the main error amplifier adopt TL431, the standby isolation circuit and the main isolation circuit, the Pm remote control signal is sent to the main control circuit along with the main error signal, the remote control circuit adopts the triode as the switch to directly control the working power supply of the main feedback circuit, the three preferable green switching power supply ICs (the circuits in the dashed line frames of fig. 1 to 6 need to be cited) are arranged in the dashed line frame, for the convenience of monitoring in the using process, the standby power supply overload monitoring signal, the main power supply overload monitoring signal, the PFC VII monitoring signal are preferably respectively output or combined into one monitoring signal (none of them is shown); if the PFC is not needed, two other green switching power supply ICs without PFC functions are formed. The IC, the main power supply, the standby power supply and the PFC device can share the same oscillator of a fully integrated or external timing element, and all required frequencies can be converted and retrieved.

Fig. 10, fig. 11, fig. 12 adopt a PC standard (such as ATX, ATX12, SSI, etc.) green computer switching power supply designed for overload prevention, saturation prevention, digital processing high quality PFC, monolithic green switching power supply IC design, a standby error amplifier, a main error amplifier adopt TL431, a standby isolation circuit and a main isolation circuit, a-PS-on remote control signal is sent to the main control circuit along with the main error signal, and the remote control circuit adopts a triode as a switch to directly control the working power supply of the main feedback circuit; the standby power supply adopts a single-end type; the main power supply adopts a single-end hybrid type, and excitation current is discharged to the main output by 5V (or 12V or 3.3V or a combination of the V and the V) through a diode Dfb.

Fig. 13 and 14 show single-ended hybrids where the Uo2 output power should be greater than Uo 1.

Claims (8)

1. A green switch power supply with standby function at least comprises a standby power supply and a main power supply; the standby power supply at least comprises a standby conversion circuit, a standby feedback circuit and a standby control circuit; the main power supply at least comprises a main conversion circuit, a main feedback circuit and a main control circuit; the standby power supply direct current input end, the standby control circuit, the main power supply direct current input end and the main control circuit are grounded together; the method is characterized in that: 1) adopting a single green switch power supply IC with a standby function, at least integrating a standby control circuit, a main control circuit and an auxiliary circuit, finishing the starting of the IC by a unique power-on starting circuit, and providing a working power supply for the IC by a standby power supply; 2) the main feedback circuit consists of a main sampling circuit, a main error amplifier, a main isolation circuit and a remote control circuit; the main control circuit consists of a main pulse modulation circuit, a main drive circuit and a main power supply inhibition circuit; in the main feedback circuit, a main sampling circuit samples a voltage signal output by a main, a main error amplifier outputs a main error signal through a main isolation circuit, the remote control circuit isolates the remote control signal and transmits the remote control signal to the main control circuit, if the remote control signal is off, the main power supply forbidding circuit forces the main driving circuit to output a low level to cut off a main power tube, otherwise, the main pulse modulation circuit generates a main pulse according to the main error signal, and the main driving circuit outputs the main pulse normally.

2. A green switching power supply with standby function according to claim 1, wherein said green switching power supply integrates at least a standby control circuit, a main control circuit and an auxiliary circuit; 1) the standby control circuit consists of a standby pulse modulation circuit and a standby driving circuit, and the standby pulse modulation circuit generates standby pulses according to the standby error signals; 2) the main control circuit consists of a main pulse modulation circuit, a main drive circuit and a main power supply inhibition circuit; a remote control signal is sent to the main power supply inhibiting circuit, if the remote control signal is off, the main power supply inhibiting circuit forces the main driving circuit to output low level, otherwise, the main pulse modulating circuit generates main pulse according to the main error signal, and the main driving circuit outputs normally; 3) the auxiliary circuit at least comprises a reference voltage source, a starting circuit and a biasing circuit.

3. The green switching power supply with standby function as claimed in claim 2, wherein said standby pulse modulation circuit and said main pulse modulation circuit use PWM circuit, same operating frequency and shared oscillator.

4. The green switching power supply with standby function as claimed in claim 2, wherein the green switching power supply further integrates a PFC error amplifier and a PFC control circuit; the PFC control circuit at least comprises a PFC pulse modulation circuit and a PFC driving circuit.

5. A main power supply IC is characterized in that the IC integrates at least a main pulse modulation circuit, a main drive circuit and a main power supply forbidding circuit; the remote control signal is sent to the IC along with the main error signal; the main power supply inhibition circuit monitors the main error signal, if the main error signal is smaller than a threshold value, the remote control signal is considered to be off, the main power supply inhibition circuit forces the main driving circuit to output low level, otherwise, the main pulse modulation circuit generates main pulse according to the main error signal, and the main driving circuit outputs normally.

6. A green switch power supply with a standby function at least comprises a standby power supply, a main power supply and an auxiliary circuit, wherein the main power supply at least comprises a main conversion circuit, a main feedback circuit and a main control circuit, and the main control circuit and a direct current input end of the main power supply are grounded together; it is characterized in that a remote control signal is sent to the main control circuit along with the main error signal to remotely control the on/off of the main power supply; the standby power supply at least provides a working power supply for the main power supply when the main power supply is started; the main feedback circuit comprises a main sampling circuit, a main error amplifier, a main isolation circuit and a remote control circuit, wherein if the remote control signal is off, the remote control circuit forces the main error signal to be smaller than a threshold value, and if the remote control signal is on, the remote control circuit loses the function, the main sampling circuit samples a voltage signal output by a main, sends the voltage signal to the main error amplifier, generates a main light coupling current, and outputs the main error signal through the main isolation circuit; the main control circuit at least comprises a main pulse modulation circuit, a main drive circuit and a main power supply forbidding circuit, wherein the main power supply forbidding circuit monitors a main error signal, if the main error signal is smaller than a threshold value, the remote control signal is considered to be off, the main power supply forbidding circuit forces the main drive circuit to output low level, otherwise, the main pulse modulation circuit generates a main pulse according to the main error signal, and the main drive circuit outputs the main pulse normally.

7. A green switching power supply with standby function as claimed in claim 6, wherein in the main feedback circuit, when the voltage signal of the main output is greater than the set value, the main optical coupler has no current and the main error signal is minimum, otherwise, the larger the voltage signal error of the main output, the larger the main optical coupler current and the larger the main error signal are; the main control circuit adopts a resistor or a constant current source to pull down and input a main error signal.

8. A PCATX standard green computer switching power supply, characterized in that the green switching power supply with standby function of claim 1 is used; the standby conversion circuit adopts a single-end conversion circuit; the main conversion circuit adopts a single-ended hybrid or single-ended forward conversion circuit.