JP2006262671A - Signal processing circuit used for switching regulator, switching regulator, radio terminal apparatus using the same, and switching regulator control method - Google Patents

Abstract

In a multi-output switching regulator, the number of inductors and the number of PWM signal generators are reduced to reduce the size of the device.
An excitation switch that is turned on to store electric power as magnetic energy in an inductor, first and second synchronous rectification switches that are turned on to release the magnetic energy, and first and second The first and second error amplifiers for detecting the error signal, the PWM signal generator for generating the PWM signal corresponding to the first or second error signal, and the first or second error signal in time division A time-division controller that selects and generates a PWM signal and controls the first or second synchronous rectification switch in a time-division manner is provided.
[Selection] Figure 1

Description

  The present invention relates to a signal processing circuit used for a switching regulator, a switching regulator, a radio terminal apparatus using the same, and a switching regulator control method, and more particularly to a signal processing circuit used for a multi-output switching regulator, a switching regulator, and the same. The present invention relates to a wireless terminal device and a switching regulator control method.

  In recent years, many electronic devices that operate with a plurality of different power supply voltages have been used. In such electronic devices, multi-output switching regulators are frequently used. FIG. 7 shows a conventional basic multi-output switching regulator (a switching regulator having a plurality of different output systems is hereinafter referred to as this). The multi-output switching regulator shown in FIG. 7 is a step-up and two-output switching regulator 100, which is a circuit example of a type of switching regulator having two different output systems.

  The switching regulator 100 shown in FIG. 7 includes a switching regulator circuit 101 and a switching regulator circuit 201 that perform PWM control independently for each output.

  The switching regulator circuit 101 includes a power conversion unit 103 and a PWM control unit 105. The power conversion unit 103 includes an inductor 107, an excitation switch 109, a synchronous rectification switch 111, and a smoothing capacitor 113. The PWM control unit 105 includes a voltage divider 115, an error amplifier 117, a reference voltage generator 119, a triangular waveform generator 121, The comparator 123 is configured. The input terminal 127 is connected to a power source (not shown), and the output terminal 125 is connected to a load (not shown).

  The switching regulator circuit 201 includes a power conversion unit 203 and a PWM control unit 205. The power conversion unit 203 includes an inductor 207, an excitation switch 209, a synchronous rectification switch 211, and a smoothing capacitor 213. The PWM control unit 205 includes a voltage divider 215, an error amplifier 217, a reference voltage generator 219, a triangular waveform generator 221, The comparator 223 is configured. A load (not shown) is connected to the output terminal 225. The input terminal 127 is shared with the switching regulator circuit 101.

  In the switching regulator 100 shown in FIG. 7, the reference voltage generator 119 and the reference voltage generator 219 are provided as separate components, but a common one is used.

  The operation of the switching regulator 100 shown in FIG. 7 will be described. Hereinafter, the operation of the switching regulator circuit 101 will be described. However, since the switching regulator circuit 201 operates in the same manner, the description of the switching regulator circuit 201 is omitted.

  When the voltage that can be handled by the PWM control unit 105 is higher than the voltage Vout1 supplied to the output terminal 125, the voltage Vout1 is divided by the voltage divider 115. Then, an error between the divided voltage Vdiv1 and the reference voltage Vref1 from the reference voltage generator 119 is amplified and an error signal Verr1 is output. Then, the error signal Verr1 and the triangular wave Vsaw1 from the triangular waveform generator 121 are compared by the comparator 123 to output the PWM signal Vsw1 and the PWM signal Vsw2 obtained by inverting the polarity of the PWM signal Vsw1. Here, the triangular waveform generator 121 and the comparator 123 function as a PWM signal generator.

  The excitation switch 109 is turned on (conductive state) or turned off (disconnected state) by the PWM signal Vsw1, and the PWM control operation is performed by turning the synchronous rectification switch 111 on or off by the PWM signal Vsw2.

  That is, when the excitation switch 109 is on and the synchronous rectification switch 111 is off, a current flows from the input terminal 127 to the inductor 107, and the inductor 107 is excited to store magnetic energy. When the excitation switch 109 is turned off and the synchronous rectification switch 111 is turned on, the magnetic energy stored in the inductor 107 is passed as a current to a load connected to the smoothing capacitor 113 and the output terminal 125.

  By repeating the on / off operation of the excitation switch 109 and the synchronous rectification switch 111 in this way, control is performed so that the error signal Verr1 becomes zero, and the voltage Vout1 is a ratio of ON / OFF of the PWM signal Vsw1 (duty ratio). Accordingly, the input voltage Vin is controlled so as to have an arbitrarily boosted voltage value.

  The switching regulator circuit 201 operates in the same manner, and the voltage Vout2 is controlled so as to have a voltage value arbitrarily boosted with respect to the input voltage Vin.

  As another conventional technique, one inductor, an excitation switch for supplying a pulse current to the inductor, a plurality of capacitors each holding an individual output voltage, and a current flowing through the inductor correspond to each capacitor. There is known a switching regulator including a plurality of synchronous rectification switches and a control unit in which one of the plurality of synchronous rectification switches is sequentially controlled (see, for example, Patent Document 1).

JP 2002-354822 A

  However, the conventional multi-output switching regulator using a plurality of inductors requires the same number of inductors, triangular wave generators and comparators (PWM signal generators) as the number of output systems, which reduces the mounting area and circuit scale. The power consumption is large due to the large size and the use of many power elements in the large current path. As a result, this has been a major obstacle to the downsizing and low power consumption of devices equipped with switching regulators. Also, the conventional multi-output switching regulator disclosed in the patent document with one inductor cannot determine the magnitude of magnetic energy stored in the inductor for each output of each system, and from a plurality of output terminals. When there is a large difference in the amount of electric power to be extracted, it may be difficult to obtain a highly stable voltage.

  The present invention is a signal processing circuit for a switching regulator that can stably extract output even when there is a large difference in the amount of power extracted from a plurality of output terminals, which is small in size and solves such problems. The present invention provides a switching regulator, a wireless terminal device using the switching regulator, and a control method therefor.

The invention of claim 1 is a signal processing circuit used in a switching regulator that outputs power to a plurality of power supply systems,
A plurality of error amplifiers for generating an error signal by comparing signals corresponding to the plurality of power supply systems with reference signals, a PWM signal generator for outputting a PWM signal based on the error signal, and the plurality of error amplifiers Time-division control for sequentially switching the error signal output from each of the output signals to the PWM signal generator and switching the output destination of the PWM signal generated by the PWM signal generator in accordance with the error signal system And a signal processing circuit.

  In a second aspect of the present invention, in the switching regulator that includes a power conversion unit and a PWM control unit and outputs power to a plurality of systems, the power conversion unit is in a conductive state in order to store the power as magnetic energy in the inductor. An excitation switch and a plurality of synchronous rectification switches that are in a conductive state to release the magnetic energy, and the PWM control unit includes a signal and a reference signal corresponding to the output of each of the plurality of systems. A plurality of error amplifiers that detect an error signal that is a difference between the PWM signal generator, a PWM signal generator that generates a PWM signal corresponding to the error signal, and an error signal output from each of the plurality of error amplifiers, and sequentially switching the PWM According to the error signal system, the output destination of the PWM signal generated by the PWM signal generator is input to the signal generator. Time division controller next switch, and a switching regulator having a.

  According to a third aspect of the present invention, the power is applied to both ends of the inductor and the excitation switch connected in series, and the plurality of synchronous rectification switches are connected to a connection point between the inductor and the excitation switch. The switching regulator according to claim 2 is provided.

According to a fourth aspect of the present invention, at least one of the plurality of synchronous rectification switches not connected to the connection point between the inductor and the excitation switch passes the magnetic energy through an inversion voltage holding capacitor. And a charge discharge switch for discharging the charge stored in the inversion voltage holding capacitor is connected,
A connection point between the inverted voltage holding capacitor and the first rectifier diode is connected to a terminal of a second rectifier diode, which has a polarity different from that of the first rectifier diode, and the second rectifier. The switching regulator according to claim 3, wherein a smoothing capacitor is connected via a diode.

  In the invention of claim 5, the power conversion unit includes a power detection sensor that detects a signal according to the magnitude of power of a predetermined system among the plurality of systems, and the time division controller 5. The switching regulator according to claim 2, wherein the modulated signal is generated in accordance with a detection signal from a power detection sensor and the synchronous rectification switch is controlled. 6. did.

  According to a sixth aspect of the present invention, the time division controller controls the error of each system for a period that is an integral multiple of the period of the PWM signal according to the power ratio of each system detected from the power detection sensor. 6. The switching regulator according to claim 5, wherein a signal is the modulated signal, and a synchronous rectification switch of each system corresponding to the modulated signal is controlled based on the PWM signal.

  According to a seventh aspect of the present invention, in the switching regulator according to the fifth or sixth aspect, the power detection sensor is a current sensor.

  According to an eighth aspect of the present invention, in the switching regulator control method for outputting input power to a plurality of systems, a signal corresponding to the output of each of the plurality of systems and a reference signal are compared to detect a plurality of error signals. A switching regulator control method for sequentially selecting the plurality of error signals to obtain a PWM signal, storing magnetic energy in accordance with the PWM signal, and sequentially releasing the magnetic energy to a system corresponding to the error signal; did.

  In a ninth aspect of the present invention, there is provided a wireless terminal device having a switching regulator that outputs power to a plurality of systems, wherein the switching regulator includes a power conversion unit and a PWM control unit, and the power conversion unit outputs the power. An excitation switch that is turned on to store the magnetic energy in the inductor, and a plurality of synchronous rectifier switches that are turned on to release the magnetic energy, and the PWM control unit A plurality of error amplifiers that detect an error signal that is a difference between a signal corresponding to each output and a reference signal, a PWM signal generator that generates a PWM signal corresponding to the error signal, and a plurality of error amplifiers, respectively. The output error signal is sequentially switched and input to the PWM signal generator, and the error signal is generated by the PWM signal generator. The output destination of the serial PWM signal is a radio terminal device comprising a division control unit when switching sequence according to the system of the error signal.

  According to the first aspect of the present invention, a plurality of error amplifiers that generate an error signal by comparing signals corresponding to a plurality of power supply systems with reference signals, respectively, and one PWM signal that outputs a PWM signal based on the error signal The error signal output from each of the generator and the plurality of error amplifiers is sequentially switched and input to the PWM signal generator, and the output destination of the PWM signal generated by the PWM signal generator is set in accordance with the error signal system. And a time-division controller that sequentially switches, so that the circuit can be miniaturized, and signal processing used for a switching regulator that supplies a highly stable voltage even when there is a large difference in the amount of power extracted from a plurality of output terminals A circuit can be provided.

  According to the invention of claim 2, a PWM signal is generated by selecting a plurality of error signals in a time division manner, and a synchronous rectification switch of a system corresponding to the error signal among the plurality of synchronous rectification switches is used as the PWM signal. As a time-division controller is provided for sequential control, the size and power consumption can be reduced, and the magnitude of the magnetic energy stored in the inductor can be determined for each output of each system. It is possible to provide a switching regulator that supplies a highly stable voltage even when there is a large difference in the amount of power extracted from a plurality of output terminals.

  According to the invention of claim 3, the electric power applied to the input terminal is applied to both ends of the inductor and the excitation switch connected in series, and the plurality of synchronous rectification switches are connected to a connection point between the inductor and the excitation switch. Therefore, the output voltage can be made higher than the input voltage.

  According to the fourth aspect of the present invention, the first rectifier diode that allows the magnetic energy to pass through the inversion voltage holding capacitor is connected to the plurality of synchronous rectification switches, and the charge stored in the inversion voltage holding capacitor is discharged. A charge discharge switch is connected, and opposite polarity terminals of the first rectifier diode and the second rectifier diode are connected to each other at a connection point between the inversion voltage holding capacitor and the first rectifier diode, and the second rectifier diode Since a smoothing capacitor is connected via the input voltage, a voltage having a polarity different from the input voltage can be obtained as the output voltage.

  According to the invention of claim 5, the power conversion unit includes a power detection sensor that detects a signal corresponding to the magnitude of power of a predetermined system among the plurality of systems, and the time-division controller includes the power detection Since the modulated signal is generated according to the detection signal from the sensor for use and the synchronous rectification switch is controlled, the magnetic energy accumulated in the inductor is distributed to each system according to the power level of the predetermined system. Can do.

  According to the invention of claim 6, the error signal of each system is used as a modulated signal for a period that is an integral multiple of the period of the PWM signal in accordance with the power ratio of each system, and each system is controlled based on the PWM signal. Since the synchronous rectification switch is controlled, the magnetic energy stored in the inductor can be used effectively.

  According to the seventh aspect of the present invention, since the power detection sensor is a current sensor, it is possible to easily detect the magnitude of power supplied to the load without losing power, and based on this result, the time division controller Can be operated.

  According to the eighth aspect of the present invention, a PWM signal is obtained from a modulated signal obtained by selecting a plurality of error signals in time division, and magnetic energy can be released in time division to a system corresponding to the modulated signal. Even when there is a large difference in the amount of power extracted from the terminals, the switching regulator that supplies a highly stable voltage can be controlled.

  According to the invention of claim 9, by mounting a switching regulator capable of supplying a high stability voltage even when there is a large difference in the amount of power extracted from a plurality of output terminals, and that can be reduced in size, to the wireless terminal device, It is possible to reduce the size of the wireless terminal device.

  The signal processing circuit according to the present embodiment is a signal processing circuit used in a switching regulator that outputs power to a plurality of power supply systems, and compares the signals corresponding to the plurality of power supply systems with reference signals, respectively, to generate an error signal. And a plurality of error amplifiers that generate PWM signals, a PWM signal generator that outputs a PWM signal based on the error signal, and an error signal output from each of the plurality of error amplifiers are sequentially switched and input to the PWM signal generator. The signal processing circuit includes a time division controller that sequentially switches the output destination of the PWM signal generated by the PWM signal generator according to the error signal system.

  Since this signal processing circuit has a plurality of error amplifiers that generate error signals by comparing signals corresponding to a plurality of power supply systems with reference signals, it is possible to generate error signals for each system. In addition, one PWM signal generator that outputs a PWM signal based on the error signal is provided, and error signals output from a plurality of error amplifiers are sequentially switched and input to the PWM signal generator. Can be output. Furthermore, since the output destination of the PWM signal generated by this PWM signal generator is sequentially switched according to the system of the error signal, by connecting a switch to this output destination, each of the electric energy extracted from a plurality of output terminals A signal processing circuit used for a switching regulator that supplies a highly stable voltage even when the difference is large can be provided.

  The switching regulator according to the present embodiment is a switching regulator that outputs input power to a plurality of systems. This switching regulator includes a power converter and a PWM controller.

  The power conversion unit includes an excitation switch that is in a conductive state in order to store electric power as magnetic energy in the inductor, and a synchronous rectification switch that releases magnetic energy.

  The PWM control unit also includes a plurality of error amplifiers that detect an error signal that is a difference between a signal corresponding to the output of each of a plurality of systems and a reference signal, and a PWM signal generation that generates a PWM signal corresponding to the error signal. A container. By the power conversion unit and the PWM control unit having such a configuration, operations of boosting (making the output voltage larger than the input voltage) and inverting (making the polarity of the input voltage and the output voltage different) can be performed. Here, the signal corresponding to the output of each of the plurality of systems may be the output voltage itself, may be the output voltage divided, may be the output current itself, It may be a shunt, may be output power, or may be a signal proportional to the output power. The reference signal is a signal corresponding to the output. For example, when selecting a voltage as a signal according to the output, both a reference voltage, when selecting a current as a signal according to the output, a reference current, and when selecting power as a signal according to the output, both the reference power Called.

  The switching regulator according to the present embodiment further generates a modulated signal by sequentially selecting a plurality of error signals in a time division manner in the PWM control unit, and corresponds to the error signal among the plurality of synchronous rectification switches. A time-division controller that sequentially controls the synchronous rectification switch of the system to be controlled according to the PWM signal. In this way, the time division controller sequentially selects error signals from different error amplifiers and converts them to PWM signals, and selects the synchronous rectifier switch of the system corresponding to the selected error signal (modulated signal). By controlling with a PWM signal, the output of a plurality of systems can be controlled.

  The input power is stored as magnetic energy in the inductor by the action of the excitation switch, and is output to each system by the synchronous rectification switch. Depending on the mode of connection between the synchronous rectification switch and other elements, not only boosting but also polarity change is possible.

  For example, as an example of a connection mode between a synchronous rectification switch and another element, input power is applied to both ends of an inductor and an excitation switch connected in series, and a plurality of synchronous rectification switches are connected to the inductor and the excitation switch. It may be connected to a point.

  When the elements are connected in this way, each time the excitation switch is turned on, magnetic energy is stored in the inductor, and at the same time as the excitation switch is turned off, the stored magnetic energy can be distributed to each system by a plurality of synchronous rectification switches. it can.

  In addition, as an aspect of connection between another synchronous rectification switch and another element, at least one of a plurality of synchronous rectification switches that are not connected to the connection point between the inductor and the excitation switch is connected to an inversion voltage holding capacitor. A first rectifier diode that passes magnetic energy is connected, and a charge discharge switch that discharges the charge stored in the inverted voltage holding capacitor is connected, and a connection point between the inverted voltage holding capacitor and the first rectifier diode. And a smoothing capacitor is connected via the second rectifier diode such that the first rectifier diode and the second rectifier diode are connected to different polarity terminals. You may make it do.

  With this connection, when the excitation switch is turned off, the current based on the magnetic energy stored in the inductor when the excitation switch is turned on passes through the synchronous rectification switch and the inversion voltage holding capacitor to the first rectification. It flows to the diode. In this case, the polarity of the first rectifier diode is selected so that the stored magnetic energy can be transferred to the inversion voltage holding capacitor. When the excitation switch is turned on again, the charge discharge switch is also turned on at the same time, so that the reference point of the voltage of the inverting voltage holding capacitor is inverted, and a voltage having a reverse polarity is obtained from the inverting voltage holding capacitor. Then, the different polarity voltage is peak-held and smoothed by the second rectifier diode and the smoothing capacitor connected to the second rectifier diode, and a DC voltage having a polarity different from the input voltage can be obtained.

  In addition, the power conversion unit includes a power detection sensor that detects a signal corresponding to the power level of a predetermined system among a plurality of systems, and the time division controller detects a detection signal from the power detection sensor. Accordingly, the modulated signal may be generated and the synchronous rectification switch may be controlled.

  In this way, it is possible to control the magnitude of the power supplied to each of the systems provided with the power detection sensor in accordance with the magnitude of the power of the system.

  For example, the time division controller uses the error signal of each system as a modulated signal for a period that is an integral multiple of the period of the PWM signal in accordance with the power ratio of each system detected from the power detection sensor, and PWM It is also possible to control the synchronous rectification switch of each system based on the signal, and in this way, the error signal corresponding to this system is modulated for a longer period in a system where more power is supplied. The excitation switch and the synchronous rectification switch corresponding to the system are controlled by the PWM signal corresponding to this signal. In other words, the more power is supplied to the system, the more magnetic energy is supplied from the inductor.

  At this time, the power detection sensor may be a current sensor. For example, when a current sensor using a Hall element is used, it is possible to detect power with almost no loss in the current sensor.

  The switching regulator control method according to the present embodiment is a switching regulator control method for outputting input power to a plurality of systems, and compares a signal corresponding to the output of each of the plurality of systems with a reference signal. Switching regulator control method for detecting error signal, sequentially selecting a plurality of error signals, obtaining a PWM signal, storing magnetic energy according to the PWM signal, and sequentially releasing the magnetic energy to a system corresponding to the error signal It is.

  That is, a plurality of error signals are sequentially selected to obtain a PWM signal, and magnetic energy is sequentially released in a time division manner to the system corresponding to the error signal, so that there is a difference in the power level in each output system. Even in the case, the stored magnetic energy can be distributed to each system according to the magnitude of electric power, so that a single control system is operated in a time-sharing manner, that is, the magnitude of the load of a plurality of systems, Even when there is a difference in load power consumption, stable power supply is possible.

  Since the wireless terminal device according to the present embodiment has the switching regulator, it is possible to reduce the size of the wireless terminal device.

  Hereinafter, the present embodiment will be specifically described with reference to the drawings.

  FIG. 1 is a circuit diagram of a switching regulator 10 having a booster 2 output.

The step-up / two-output switching regulator 10 according to the first embodiment (including two output systems and a switching regulator in which the output voltage at the output terminal is larger than the input voltage at the input terminal) includes the power conversion unit 14a and the PWM conversion unit. The PWM converter includes a PWM controller 16a and a time division controller 40a.

  The large difference between the multi-output switching regulator 100 shown in the background art and the switching regulator 10 of this embodiment is that an inductor for storing magnetic energy is composed of one inductor 15, a triangular waveform generator 39 and a comparator 38. It is composed of one PWM signal generator, and further has a time-division controller 40a.

  The power converter 14a includes an inductor 15, an excitation switch 20, a first synchronous rectification switch 21 and a second synchronous rectification switch 22, a first smoothing capacitor 23 and a second smoothing capacitor 24, a first current detection sensor 17, and A second current detection sensor 18 is provided. Input power is supplied to the input terminal 27 from the outside, and the first output terminal 46 that is the output terminal of the first system and the second output terminal 47 that is the output terminal of the second system have loads ( (Not shown) are connected.

  The power applied to the input terminal 27 is applied to both ends of the inductor 15 and the excitation switch 20 connected in series, and the first synchronous rectification switch 21 and the second synchronous rectification switch 22 are excited with the inductor 15. It is connected to a connection point with the switch 20.

  The PWM controller 16a includes a first voltage divider 31 and a second voltage divider 32, a first error amplifier 33 and a second error amplifier 34, a reference voltage generator 35, a triangular waveform generator 39, and a comparator 38. It is configured. Here, the triangular waveform generator 39 and the comparator 38 function as a PWM signal generator.

In the comparator 38, the triangular wave Vsaw from the triangular waveform generator 39 and the modulated signal Vmods are compared, and the PWM signal Vsw1 from the comparator 38 and a PWM signal that is a negative polarity signal obtained by inverting the polarity of the PWM signal Vsw1. Vsw2 is output.

  The time division controller 40a includes an error signal selector (not shown), and the error signal selector selects either the error signal Verr1 from the first error amplifier 33 or the error signal Verr2 from the second error amplifier 34. The error signal is switched and sequentially selected to select one error signal, which is output to the comparator 38 as the modulated signal Vmods.

  The excitation switch 20 is controlled by the PWM signal Vsw1. On the other hand, the time division controller 40a controls in time division whether the first synchronous rectification switch 21 is controlled by the control signal Vdsw1 or the second synchronous rectification switch 22 is controlled by the control signal Vdsw2. Here, when the error signal Verr1 is selected as the modulated signal Vmods, only the first synchronous rectification switch 21 is controlled, the second synchronous rectification switch 22 is turned off, and the error signal Verr2 is converted to the modulated signal. When selected as Vmods, only the second synchronous rectification switch 22 is controlled, and the first synchronous rectification switch 22 is turned off. That is, as either the error signal Verr1 or the error signal Verr2 from the second error amplifier 34 is sequentially selected, the first synchronous rectification switch 21 is controlled by the control signal Vdsw1, or the second signal is output by the control signal Vdsw2. Whether to control the synchronous rectification switch 22 is sequentially selected. At this time, an error signal and a control signal belonging to the same system are selected as a pair.

  In the present embodiment, the PWM controller 16a and the time division controller 40a are configured by an IC (semiconductor device), and the size is reduced. The PWM controller 16a and the time division controller 40a constitute a signal processing circuit according to the present invention.

  Next, the operation of the switching regulator 10 will be described with reference to FIG.

  In FIG. 2, a first cycle T1 that is a predetermined cycle and a second cycle T2 that is a predetermined cycle are alternately repeated. Here, both the first period T1 and the second period T2 are set to be an integral multiple of the period of the triangular wave Vsaw. In FIG. However, it is not necessarily limited to 1. For example, the first period T1 may be twice the period of the triangular wave Vsaw, and the second period T2 may be three times the period of the triangular wave Vsaw. The first period T1 and the second period T2 are set in the time division controller 40a.

  Each signal and related operations will be described in order from the top of FIG. The error signal Verr1 is obtained by dividing the voltage VouT1, which is the voltage of the first output terminal 46, by the first voltage divider 31, and dividing the voltage Vdiv1 by the first voltage divider 31, and the reference voltage Vref. Is amplified by the first error amplifier 33.

  The error signal Verr2 is obtained by dividing the voltage Vout2 that is the voltage of the second output terminal 47 by the second voltage divider 32, and dividing the voltage Vdiv2 by the second voltage divider 32 and the reference voltage Vref. Is amplified by the second error amplifier 34.

  The modulated signal Vmods is either the error signal Verr1 or the error signal Verr2 selected by the time division controller 40a, the error signal Verr1 in the first period T1, and the error signal Verr2 in the second period T2. Are used as modulated signals Vmods. The triangular wave Vsaw is a sawtooth wave that is a kind of triangular wave, and the same waveform is repeated through the first period T1 and the second period T2. The triangular wave Vsaw and the modulated signal Vmods are input signals input to the input terminal of the comparator 38, respectively.

  The PWM signal Vsw1 is a signal obtained from the positive output terminal of the comparator 38. When the PWM signal Vsw1 is at a high level (upper position in FIG. 2), the excitation switch 20 is turned on, and when the PWM signal Vsw1 is at a low level (lower position in FIG. 2), the excitation switch 20 is turned off. The Since the value of the modulated signal Vmods is different between the first period T1 and the second period T2, the time during which they are turned on is also different. The longer the time during which the PWM signal Vsw1 is at the high level, the larger the magnitude of the magnetic energy stored in the inductor 15, but there is no time to release the stored magnetic energy when the entire period is on. Therefore, in order to ensure the time for releasing this magnetic energy, for example, the time for turning on is limited to 95% of the total period.

  When the control signal Vdsw1 is at a high level, the first synchronous rectification switch 21 is turned on. The first synchronous rectification switch 21 is turned on only in the period of the first cycle T1, and is not turned on in the second cycle T2. This control is performed by the time division controller 40a. Specifically, when the error signal Verr1 is the modulated signal Vmods, the PWM signal Vsw2 is output as the control signal Vdsw1 in the first period T1. Become.

  In addition, when the control signal Vdsw2 is at a high level, the second synchronous rectification switch 22 is turned on. The second synchronous rectification switch 22 is turned on only in the period of the second period T2, and is not turned on in the first period T1. This control is performed by the time division controller 40a. Specifically, when the error signal Verr2 is the modulated signal Vmods, the PWM signal Vsw2 is output as the control signal Vdsw2 in the second period T2. Become.

  The switching regulator 10 that operates as described above can be considered to be composed of two switching regulator circuits that operate in a time-sharing manner. The switching regulator 10 increases or decreases until the error signal Verr1 becomes zero, and in the first period T1. The on-time of the PWM signal Vsw1 is controlled and the on-time of the control signal Vdsw1 is also controlled. As a result, the value of the voltage Vout1 of the first output terminal 46 is maintained at a constant value. At the same time, the on-time of the PWM signal Vsw1 is controlled and the on-time of the control signal Vdsw2 is also controlled in the second period T2 so as to increase or decrease until the error signal Verr2 becomes zero. The value of the voltage Vout2 at the output terminal 47 is kept constant.

When the error signal Verr1 or the error signal Verr2 has a negative value, the comparator 38 operates so that the PWM signal Vsw1 becomes a low level. Therefore, the value of the voltage Vdiv1 or the voltage Vdiv2 is higher than the value of the reference voltage Vref. In a large range, the PWM signal Vsw <b> 1 is at a low level, and magnetic energy is not sent to the first smoothing capacitor 23 or the second smoothing capacitor 24.

  Here, the relationship between the open loop gain G1 of the PWM control system of the first system, the error signal Verr1, and the power P1 transmitted to the output of the first system will be described.

  Since the open loop gain G1 can take only a finite value, the value of the error signal Verr1 increases as the magnitude of the power P1 transmitted to the output of the first system increases. That is, the steady deviation of the voltage Vout1 is large. The same applies to the relationship between the open loop gain G2 of the PWM control system of the second system, the error signal Verr2, and the power P2 transmitted to the output of the second system. The open loop gain G1 and the open loop gain G2 include PWM modulation gain (conversion gain generated by PWM modulation).

  In particular, when the inductor 15 is shared, the same input voltage Vin is obtained from the input terminal 27, and a plurality of systems are operated, the first cycle T1 and the second cycle T2, which are time division cycles, are equal. In this case, as a result, the values of the open loop gain G1 and the open loop gain G2 become substantially the same value.

  On the other hand, the magnitude of the electric power sent to the load is proportional to the magnitude of the magnetic energy stored in the inductor 15. Therefore, the greater the amount of power consumed by the load, the more magnetic energy must be transmitted to the load. Here, the magnitude of the electric power supplied from the first output terminal 46 of the first system to the load and the magnitude of the electric power supplied from the second output terminal 47 of the second system to the load are greatly different. 2, if the first cycle T1 and the second cycle T2 are always equal, the on-time of the control signal Vdsw1 and the on-time of the control signal Vdsw2 in FIG. The value of the steady deviation in the system on the side where the supplied power is large becomes large, and it becomes difficult to maintain the constant voltage characteristic.

  FIG. 3 shows the waveforms of the respective parts when more suitable control is performed by making the lengths of the first period T1 and the second period T2 different. The name of each waveform is the same as that shown in FIG.

  In FIG. 3, the first period T1 is set to twice the period of the triangular wave Vsaw, and the second period T2 is set to be the same as the period of the triangular wave Vsaw.

In such a cycle setting, the maximum amount of power that can be supplied to each load is approximately proportional to the cycle in which the control in each system is operating, so the first output The maximum amount of power supplied to the load connected to the terminal 46 can be made larger than the maximum amount of power supplied to the load connected to the second output terminal 47.

Here, there are various ways of defining the maximum amount. For example, the maximum amount is determined from the target value of the value of the voltage Vout1 of the first output terminal 46 and the value of the voltage Vout2 of the second output terminal 47. In the case where the value is defined by the value of the steady deviation, the maximum power can be extracted from either the first system or the second system by appropriately setting the first period T1 and the second period T2. .

Here, how to determine the first period T1 and the second period T2 will be described.

  The time division controller 40a controls the lengths of the first period T1 and the second period T2. First, the time-division controller 40a uses the first current detection sensor 17 and the second current detection sensor 18 to determine the value of the current Iout1 flowing through the load connected to the first output terminal 46 and the second output terminal 47. The value of the current Iout2 connected to is detected.

  Here, since the voltage values of the voltage Vout1 and the voltage Vout2 at the first output terminal 46 and the second output terminal 47 are controlled to be substantially constant values, they are detected by the first current detection sensor 17. The product of the current Iout1 and the voltage Vout1 is the value of the electric power P1 supplied from the first output terminal 46 to the load, and the product of the current Iout2 and the voltage Vout2 detected by the second current detection sensor 18 is the second output. This is the value of the electric power P2 supplied from the terminal 47 to the load. In this case, since the value of the voltage Vout1 and the value of the voltage Vout2 are substantially constant, the first current detection sensor 17 and the second current detection sensor 18 can function as a power detection sensor.

  The time division controller 40a operates as follows. First, the time division controller 40a detects the ratio between the value of the power P1 and the value of the power P2. If the power ratio is, for example, 2: 1 (power P1 value / power P2 value = 2), the ratio between the first period T1 and the second period T2 is 2: 1. In addition, the time division controller 40a controls.

In principle, any ratio can be set as long as the ratio between the first period T1 and the second period T2 is an integral multiple of the period of the triangular wave Vsaw, but the first period T1 or the second period When the length of T2 becomes too long, the ripple voltage of the voltage Vout1 or the voltage Vout2 increases. Therefore, it is desirable to impose restrictions on the lengths of the first period T1 and the second period T2. A wattmeter (power sensor) is provided (not shown) without detecting the current, and the value of the power P1 supplied directly from the first output terminal 46 to the load and the load from the second output terminal 47 The value of the electric power P2 supplied to the power supply may be detected and used for the control in the time division controller 40a.

Specifically, an example of how the first period T1 and the second period T2 are determined in the time division controller 40a will be described below. That is, when the value of the power P1 of the first system is P1, the value of the power P2 of the second system is P2, the time of the first period T1 is T1, and the time of the second period T2 is T2, T1 and T2 are determined so that the relationship represented by [Equation 1] and [Equation 2] is established.

In [Expression 1] and [Expression 2], when each of the first period T1 and the second period T2 is an integral multiple of the period of the triangular wave Vsaw, [Expression 1] and [Expression 2] When [Expression 1] and [Expression 2] are strictly applied, it is difficult to set one of the first period T1 and the second period T2 to an integral multiple of the period of the triangular wave Vsaw. Or when the lengths of the first period T1 and the second period T2 that allow each of the first period T1 and the second period T2 to be an integral multiple of the period of the triangular wave Vsaw exceed a predetermined value. Is appropriately rounded up, rounded down, rounded off, etc., and is a length that is an integral multiple of the period of the triangular wave Vsaw, and the length of each of the first period T1 and the second period T2 within a predetermined length range. Shall be rounded.

  Since such control constitutes a feedback control system, finally, the on-time of the excitation switch 20 in the first period T1 and the second period T2, that is, the duty ratio of the on-time of the control signal Vdsw1 and the control signal Control is performed such that the duty ratio of the on-time of Vdsw2 becomes a substantially constant value throughout the first period and the second period, the magnetic energy storage capability of the inductor 15 is used on average, and the size of the inductor 15 is small. Therefore, the increase in the steady deviation of the output voltage caused by the power difference between the systems can be reduced, and the copper loss in the inductor 15 can be reduced, so that the efficiency of the switching regulator can be improved. In addition, even when there is a large difference in the amount of power extracted from the output terminal, a highly stable voltage can be obtained.

  As another control method in the time-division controller 40a, the ratio between the on-time of the excitation switch 20 and the period of the triangular wave Vsaw in the first period T1 and the second period T2, or the excitation in the first period T1. A ratio between the ON time of the switch 20 and the ON time of the excitation switch 20 in the second period T2 may be used. For example, the ratio between the ON time of the excitation switch 20 in the first period T1 and the ON time of the excitation switch 20 in the second period T2 is used as a control signal instead of the power value, and this ratio is The first period T1 and the second period T2 can be determined so as to approach 1. In this case, the on-time detection means of the excitation switch 20 in each cycle associated with the power in each system can function as a power detection sensor.

  Further, as another control method in the time division controller 40a, the voltage Vout1 of the first output terminal 46 or the voltage Vout2 of the second output terminal 47 may be used. For example, when the voltage Vout1 drops below a specified voltage value, the first period T1 that is the period of the first system that is the system that is lower than the predetermined voltage is used to reduce the steady-state deviation. Is set to be longer than the current cycle. Note that, when the voltage Vout2 falls below a specified voltage value, the first cycle T1 is reset to be longer than the current cycle. In this case, a means for detecting a decrease in voltage from a predetermined value in each system indicating that power to be supplied to the load is insufficient can be functioned as a power detection sensor.

  FIG. 4 shows a circuit of the multi-output switching regulator 11 according to the second embodiment.

  The multi-output switching regulator 11 according to the second embodiment includes a power conversion unit 14b, a PWM controller 16b, and a time division controller 40b. The switching regulator 10 of the first embodiment can further output a voltage Vout3 that is a negative voltage from the third output terminal 48. Parts having the same configuration as in the first embodiment and performing the same functions are denoted by the same reference numerals as in the first embodiment, and description thereof is omitted.

The circuit portion related to the third system that outputs the voltage Vout3 includes a third synchronous rectifier switch 25, an inverted voltage holding capacitor 26, a first rectifier diode 29, a second rectifier diode 28, a third smoothing capacitor 30, The charge discharge switch 49 and the third current detection sensor 19 are included. The inverting amplifier 60 inverts the negative polarity of the VouT 3 to be positive, and is necessary because the reference voltage Vref, which is a common reference voltage, is positive. The time division controller 40b has substantially the same configuration and operation as the time division controller 40a, but outputs a control signal Vdsw3 for controlling the third synchronous rectification switch 25.

Further, a third voltage divider 36 and a third error amplifier 37 are provided. The third voltage divider 36 outputs a voltage Vdiv3, and the third error amplifier 37 outputs an error signal Verr3. It is made like that.

  Here, a first rectifier diode 29 is connected to the third synchronous rectifier switch 25 via an inverted voltage holding capacitor 26, and a charge discharge switch 49 is also connected to the third synchronous rectifier switch 25. ing. A second rectifier diode 28 is connected to a connection point between the inverted voltage holding capacitor 26 and the first rectifier diode 29. The connection between the first rectifier diode 29 and the second rectifier diode 28 is to connect terminals of different polarities of the respective diodes to each other. A third smoothing capacitor 30 is connected to the second rectifier diode 28, and a connection point between the third smoothing capacitor 30 and the second rectifier diode 28 is connected to a third output terminal 48. A load (not shown) is connected to the third output terminal 48, and the current flowing through the load can be detected by the third current detection sensor 19.

  The circuit unit that generates the voltage Vout3 operates as described below at the time of the third period T3. The third period T3 is a continuation of the first period T1 and the second period T2 described above, and passes again from the first period T1 to the second period T2 and further through the third period T3. The cycle returning to the first period T1 is repeated. FIG. 5 shows operation waveforms of each part.

  When the control signal Vdsw3 is at a high level, the third synchronous rectification switch 25 is turned on. The third synchronous rectification switch 25 is turned on only in the period of the third cycle T3, and is not turned on in the first cycle and the second cycle T2. This control is performed by the time division controller 40b. Specifically, when the error signal Verr3 is the modulated signal Vmods, the PWM signal Vsw2 is output as the control signal Vdsw3 in the third period T3. Become.

  When the PWM signal Vsw1 in the third period T3 is at a high level, the excitation switch 20 is turned on, magnetic energy is stored in the inductor 15, the PWM signal Vsw1 is at a low level, and the excitation switch 20 is turned off. Vdsw3 becomes a high level, and the stored magnetic energy is released as a current and flows through the first rectifier diode 29 while charging the inverted voltage holding capacitor 26.

  The excitation switch 20 is turned on again when the PWM signal Vsw1 is at a high level, magnetic energy is stored in the inductor 15, and the charge discharge switch 49 is turned on and stored in the inverted voltage holding capacitor 26 to be charged. Is discharged through the second rectifier diode 28 and the charge discharge switch 49, the negative peak voltage is held in the third smoothing capacitor 30, and the negative voltage Vout3 is generated at the third output terminal 48.

Here, the third cycle T3 is set to a predetermined cycle, but the third cycle is determined based on the output from the third current detection sensor 19 as in the first embodiment. Is also good. That is, the value of the power P1 of the first system is P1, the value of the power P2 of the second system is P2, the value of the power P3 of the third system is P3, the value of the first period T1 is T1, the second T1, T2, and T3 may be determined so that the relationship expressed by the above [Equation 3] to [Equation 5] is satisfied when the value of the period T2 is T2 and the value of the third period T3 is T3. It ’s good.

In [Expression 3] to [Expression 5], when each of the first period T1 to the third period T3 can be an integral multiple of the period of the triangular wave Vsaw, [Expression 3] to [Expression 5] When [Expression 3] to [Expression 5] are strictly applied, it is difficult to set any one of the first period T1 to the third period T3 to an integral multiple of the period of the triangular wave Vsaw. Or when the lengths of the first period T1 to the third period T3 in which each of the first period T1 to the third period T3 can be an integral multiple of the period of the triangular wave Vsaw exceeds a predetermined value. Is appropriately rounded up, rounded down, rounded off, etc., and has a length that is an integral multiple of the period of the triangular wave Vsaw, and the length of each of the first period T1 to the third period T3 within a predetermined length range. Shall be rounded. Here, in order to obtain the power value of each system, the current Iout1 detected by the first current detection sensor 17, the current Iout2 detected by the second current detection sensor 18, and the third current detection sensor 19 are detected. Current Iout3 may be used, or another method similar to that in the first embodiment may be used.

Since such control constitutes a feedback control system, the on-time of the excitation switch 20 in the first period T1 to the third period T3, that is, the duty ratio of the on-time of the control signal Vdsw1, the control signal Control is performed such that the duty ratio of the on-time of Vdsw2 and the duty ratio of the on-time of the control signal Vdsw3 become substantially constant values through the first to third periods, and the magnetic energy storage capability of the inductor 15 is averaged. Since it is used, the size of the inductor 15 can be reduced. In this way, the increase in the steady deviation of the output voltage due to the power difference between the systems can be reduced, and the copper loss in the inductor 15 can be reduced, so that the efficiency of the switching regulator can be improved. In addition, even when there is a large difference in the amount of power extracted from the output terminal, a highly stable voltage can be obtained.

  Note that the switching regulators of Embodiments 1 and 2 described above can be applied to a wireless terminal device such as a mobile phone device. Hereinafter, an example in which the above-described switching regulator is applied to a wireless terminal device will be briefly described with reference to FIG. FIG. 6 is a block diagram of the wireless terminal device in the present embodiment, except for the power supply portion.

  As shown in FIG. 6, the wireless terminal device 70 inputs DC power from an external AC adapter or the like to supply power to the internal circuit, and supplies power from the rechargeable battery to the internal circuit when there is no DC input. The power supply circuit 71 has a switching regulator 72 that generates a power supply of a system different from the voltage output from the power supply circuit 71 and supplies the power to the internal circuit. The switching regulator 72 may have either the configuration shown in the first embodiment or the configuration shown in the second embodiment as long as a necessary power supply system can be generated.

  As described above, in the wireless terminal device 70 in which only one power supply system is input from the outside, when a plurality of power supply systems are necessary for the internal circuit, the switching regulator according to the above-described embodiment can be applied to obtain a highly stable voltage. The circuit can be supplied and the circuit can be miniaturized.

It is a block diagram concerning a 1st embodiment. It is a wave form diagram of each part concerning a 1st embodiment. It is a wave form diagram of each part concerning a 1st embodiment. It is a block diagram concerning a 2nd embodiment. It is a wave form chart of each part concerning a 2nd embodiment. It is a block diagram of the radio | wireless terminal apparatus which concerns on embodiment. It is a block diagram which shows background art.

Explanation of symbols

10, 11 Switching regulators 14a, 14b Power converter 15 Inductors 16a, 16b PWM controller 20 Excitation switches 21, 22, 25 Synchronous rectifier switches 33, 34, 37 Error amplifier 35 Reference voltage generator 38 Comparator 39 Triangular wave generator 40a 40b Time division controller 70 Wireless terminal device

Claims (9)

A signal processing circuit used in a switching regulator that outputs power to a plurality of power supply systems,
A plurality of error amplifiers that generate error signals by comparing signals corresponding to the plurality of power supply systems with reference signals, respectively,
A PWM signal generator that outputs a PWM signal based on the error signal;
The error signals output from the plurality of error amplifiers are sequentially switched and input to the PWM signal generator, and the output destination of the PWM signal generated by the PWM signal generator is set according to the error signal system. A signal processing circuit comprising: a time-division controller that sequentially switches. In a switching regulator that includes a power conversion unit and a PWM control unit and outputs power to a plurality of systems,
The power converter is
An excitation switch that is conductive to store the power as magnetic energy in the inductor;
A plurality of synchronous rectification switches that are conductive to release the magnetic energy; and
The PWM control unit
A plurality of error amplifiers for detecting an error signal that is a difference between a signal corresponding to an output of each of the plurality of systems and a reference signal;
A PWM signal generator for generating a PWM signal according to the error signal;
The error signals output from the plurality of error amplifiers are sequentially switched and input to the PWM signal generator, and the output destination of the PWM signal generated by the PWM signal generator is set according to the error signal system. A switching regulator comprising: a time-division controller that sequentially switches. The power is applied across the inductor and the excitation switch connected in series,
The switching regulator according to claim 2, wherein the plurality of synchronous rectification switches are connected to a connection point between the inductor and the excitation switch. At least one of the plurality of synchronous rectification switches not connected to the connection point between the inductor and the excitation switch is connected to a first rectification diode that allows the magnetic energy to pass through an inverted voltage holding capacitor. And a charge discharge switch for discharging the charge stored in the inversion voltage holding capacitor is connected,
A connection point between the inverted voltage holding capacitor and the first rectifier diode is connected to a terminal of a second rectifier diode, which has a polarity different from that of the first rectifier diode,
The switching regulator according to claim 3, wherein a smoothing capacitor is connected via the second rectifier diode. The power conversion unit includes a power detection sensor that detects a signal corresponding to the magnitude of power of a predetermined system among the plurality of systems.
5. The switching regulator according to claim 2, wherein the time division controller controls the synchronous rectification switch in accordance with a detection signal from the power detection sensor.   The time-division controller determines the error signal of each system as the modulated signal for a period that is an integral multiple of the period of the PWM signal, according to the power ratio of each system detected from the power detection sensor. 6. The switching regulator according to claim 5, wherein the synchronous rectification switch of each system corresponding to the modulated signal is controlled based on the PWM signal.   The switching regulator according to claim 5, wherein the power detection sensor is a current sensor. In the control method of the switching regulator that outputs input power to multiple systems,
Detecting a plurality of error signals by comparing a signal corresponding to the output of each of the plurality of systems and a reference signal;
The PWM signal is obtained by sequentially selecting the plurality of error signals,
Stores magnetic energy according to the PWM signal,
A switching regulator control method for sequentially releasing the magnetic energy to a system corresponding to the error signal. There is a wireless terminal device having a switching regulator that outputs power to a plurality of systems,
The switching regulator includes a power conversion unit and a PWM control unit,
The power converter is
An excitation switch that is conductive to store the power as magnetic energy in the inductor;
A plurality of synchronous rectification switches that are conductive to release the magnetic energy; and
The PWM control unit
A plurality of error amplifiers for detecting an error signal that is a difference between a signal corresponding to an output of each of the plurality of systems and a reference signal;
A PWM signal generator for generating a PWM signal according to the error signal;
The error signals output from the plurality of error amplifiers are sequentially switched and input to the PWM signal generator, and the output destination of the PWM signal generated by the PWM signal generator is set according to the error signal system. A wireless terminal device comprising: a time-division controller that sequentially switches.

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