CN118842279A - Control method and control device for switching power supply - Google Patents

Abstract

The present disclosure relates to a control method and a control device for a switching power supply. A control method for a switching power supply, comprising: generating feedback voltage of each output in multiple paths of outputs based on the output voltage of each output in multiple paths of outputs of the switching power supply; generating logic signals output by each path in the multipath output based on the feedback voltage output by each path in the multipath output, wherein the logic signals output by each path in the multipath output are logic high level signals or logic low level signals and are used for representing the output voltage of the corresponding path of output; and generating a switch control signal for controlling the on or off of the switch of each of the one or more outputs based on the feedback voltage, the logic signal, and the demagnetized pulse width logic signal of the switching power supply of the one or more outputs.

Description

Control method and control device for switching power supply

Technical Field

The present disclosure relates to a switching power supply control technology, and more particularly, to a control method and a control apparatus for a switching power supply.

Background

With the current development of switching power supply technology, many power supply systems require different voltage supplies for application (e.g., different voltage supplies for LED TV, LED backlight and TV control board), and the application cost of such systems can be very high if multiple switching power supply Integrated Circuits (ICs) are utilized to control the output of multiple voltages. Therefore, it is desirable to realize control of multiplexing output by using only one switching power supply IC system, but in the process of controlling multiplexing voltage output, when one output is dimming application or load switching, the other output or outputs need to keep the variation of the output smaller than a certain range regardless of the load. However, in the conventional multi-path output, one path of output is used as main feedback, the other path or paths of output are used as auxiliary feedback, and the multi-path output voltage feedback controls the primary side switch through the optocoupler isolation feedback circuit to realize multi-path load adjustment. The disadvantage of this multiple-path control method is that when the voltage of one path of output changes, the other path or multiple paths of output share a transformer, and the load of one path of output changes greatly due to the existence of the mutual inductance effect, so that the voltage of the other path or multiple paths of output changes greatly, and the control method results in a poor load adjustment rate of the system in multiple-path output application.

Disclosure of Invention

In view of the above, the present disclosure provides a novel control method and control apparatus for a switching power supply.

According to an aspect of embodiments of the present disclosure, there is provided a control method for a switching power supply, including: generating feedback voltage of each output in multiple paths of outputs based on the output voltage of each output in multiple paths of outputs of the switching power supply; generating logic signals of each output in the multipath output based on the feedback voltage of each output in the multipath output, wherein the logic signals of each output in the multipath output are logic high level signals or logic low level signals and are used for representing the output voltage of the corresponding output; and generating a switch control signal for controlling the on or off of a switch of each of the one or more outputs based on the feedback voltage, the logic signal, and the demagnetized pulse width logic signal of the switching power supply of the one or more outputs.

According to another aspect of the embodiments of the present disclosure, there is provided a control apparatus for a switching power supply, including: the output voltage division module is used for: generating feedback voltage of each output in multiple paths of outputs based on the output voltage of each output in multiple paths of outputs of the switching power supply; a comparison module for: generating logic signals of each output in the multipath output based on the feedback voltage of each output in the multipath output, wherein the logic signals of each output in the multipath output are logic high level signals or logic low level signals and are used for representing the output voltage of the corresponding output; and a control module for: and generating a switch control signal for controlling the on or off of a switch of each output of the one or more outputs based on the feedback voltage and logic signal of the one or more outputs and the demagnetizing pulse width logic signal of the switching power supply.

According to still another aspect of the embodiments of the present disclosure, there is provided a switching power supply including the control device as described above.

According to the control method and the control device for the switching power supply, under the condition of multiplexing output application, the method for distributing the secondary side multiplexing output current can be used for adaptively distributing the multiplexed output demagnetizing current, so that the high-precision load cross adjustment rate of multiplexing output is realized, and the high-precision requirement of multiplexing output voltage under the condition that the load is changed dynamically when the multiplexing output is applied is met. By using the control method and the control device for the switching power supply, the energy required by each path of multiplexed output is distributed in a self-adaptive manner through the change of the multiplexed output voltage at the secondary side, so that the accuracy of the load adjustment rate of the multiplexed output can be greatly improved, the working performance of a system is improved, the design cost of the system is saved, and the design difficulty of the system is reduced.

Drawings

The disclosure may be better understood from the following description of specific embodiments of the disclosure in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a conventional flyback switching power supply multiplexing application control;

FIG. 2 illustrates a schematic diagram of switching power supply multiplexing adaptive current distribution control according to one embodiment of the present disclosure;

FIG. 3 illustrates a schematic diagram of the configuration of the multiple output demagnetizing current distribution control circuit illustrated in FIG. 2, according to one embodiment of the present disclosure;

FIG. 4 illustrates a schematic diagram of the multi-output switch control circuit shown in FIG. 3, according to one embodiment of the present disclosure;

FIG. 5 illustrates a schematic diagram of the multiplexing switch control circuit shown in FIG. 3, according to another embodiment of the disclosure;

FIG. 6 illustrates a logic timing diagram for using the demagnetizing current distribution switch control circuit illustrated in FIG. 4, according to one embodiment of the present disclosure;

FIG. 7 illustrates a logic timing diagram for using the demagnetizing current distribution switch control circuit illustrated in FIG. 5, according to one embodiment of the present disclosure;

FIG. 8 illustrates a flow diagram of a control method for a switching power supply according to one embodiment of the present disclosure; and

Fig. 9 illustrates a schematic configuration of a control device for a switching power supply according to an embodiment of the present disclosure.

Detailed Description

Features and exemplary embodiments of various aspects of the disclosure will be described in detail below with reference to the accompanying drawings. The example implementations can be implemented in a variety of forms and should not be construed as limited to the implementations set forth herein; rather, these implementations are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example implementations to those skilled in the art. In the drawings, the size of regions and components may be exaggerated for clarity. In addition, in the drawings, the same reference numerals denote the same or similar structures, and thus detailed descriptions thereof will be omitted.

Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the aspects of the disclosure can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring the main technical ideas of the present disclosure.

Fig. 1 shows a schematic diagram of a conventional flyback switching power supply multiplexing application. As shown in fig. 1, the ac voltage vin_ac forms a rectified voltage vin_rec after passing through the ac rectifying circuit 101, when the primary side switch S1 is turned on, the voltage vin_rec magnetizes the transformer T1 through the transformer T1, and when the primary side switch S1 is turned off, the transformer T1 transmits energy to CV1 (resistive load or LED lamp load) and CV2 to CVn (n is equal to or greater than 2) through demagnetization of the secondary side coil of the transformer T1 to achieve multiplexing output. In such conventional multi-output control, generally, any one output CVm (1.ltoreq.m.ltoreq.n) is used as a main feedback, and other outputs are used as sub-feedback, and each output is connected to the upper end of the secondary side ground resistor Rdw through resistors Rup1, rup2, … and Rupn, respectively, so as to form feedback voltage division with the secondary side ground resistor Rdw. As shown in fig. 1, as an example, CV2 is taken as the main feedback, and the other path outputs are taken as the sub-feedback. The feedback voltage V1 of the multiplexing output node is fed back to the primary side in proportion through the optocoupler isolation 104, the primary side feedback voltage FB is generated through the VDD pull-up resistor RFB, and the feedback voltage FB generates the threshold voltage CS_pk through the diode D3 and the proportionality factor K1. The feedback voltage FB generates a clk clock signal through the oscillator OSC 102 circuit via the voltage fb_d of the diode D3, and the clk clock signal generates the on signal of the S1 switch through the switch control logic 103. During the on period of the switch S1, the voltage vin_rec is turned on by the transformer T1 and the switch S1 to generate the induced current Ipk, and the voltage CS generated by the induced current Ipk on the resistor Rs is compared with the threshold voltage cs_pk generated by the feedback voltage FB before, so as to generate a pwm_off signal, and the pwm_off signal generates the off signal of the switch S1 by the switch control logic 103 to turn off the primary side switch S1.

When the output of the CV1 is dimmed or dynamically switched, the feedback of each output is proportional feedback according to the sizes of the resistors Rup2, … and Rupn, so that when the voltage variation range of the output of the CV1 is large, the output voltages of the other outputs CV2, … and CVn can have large voltage variation due to the mutual inductance effect of the secondary side of the transformer. For example, when the CV1 circuit is performing dynamic load switching or dimming, the voltage variation range of one circuit output in the CVs 2, …, CVn may be up to 20% or more, so the poor load adjustment rate of the conventional multiplexing architecture brings great trouble to the multiplexing application design. To accommodate such output with relatively large output voltage variations, the latter applications also add additional system costs. For example, when the path of CV2 is in the path of LED for Pulse Width Modulation (PWM) dimming or load dynamic switching under the condition of audio power amplifier load, the fluctuation of output voltage is larger, the output of the path of CV2 leads to the fact that the power supply voltage of the path of CV2 for the audio power amplifier load is reduced more due to mutual inductance effect and proportion feedback, the output of the path of CV2 leads to insufficient power supply, and the phenomenon of underpower exists when the system is applied in power amplifier, so that the application of the system is influenced.

Fig. 2 illustrates a schematic diagram of switching power supply multiplexing adaptive current distribution control according to one embodiment of the present disclosure. As shown in fig. 2, the input ac signal vin_ac generates a rectified voltage vin_rec after passing through the ac rectifying circuit, when the switch S1 is turned on, the voltage vin_rec magnetizes the transformer T1, T1 stores energy, and when the switch S1 is turned off, the energy stored in the transformer T1 is induced to release energy through the secondary side coil, so as to multiplex the released energy to the secondary side. The multiplexed output voltages CV1, CV2, … and CVn are respectively passed through an output voltage dividing network to obtain feedback voltage dividing values VFB1, VFB2, … and VFBn for representing the output voltages. The feedback divided voltages VFB1, VFB2, …, VFBn are compared with the reference voltage Vref1 by the comparator network 210 to generate logic high-low level signals fb1_req, fb2_req, …, fbn_req of the feedback voltages. The demagnetizing current distribution control circuit 208 receives the feedback divided voltages VFB2, …, VFBn of the second to nth paths, and generates the multiplexed output switch control signals s2_ctrl to sn_ctrl by taking as input the logic signals fb2_req, …, fbn_req, and the demagnetizing pulse width logic signal Demag representing the output voltages. When the switch control signal Sm_ctrl (2 m n) of a certain path is high, the switch Sm (2 m n) of the path is conducted.

Because of the turn ratio of the secondary winding NS1 and the turns NS2 to Nsn, the voltage obtained by subtracting the conducting voltage drop of the diode D1 from the reflected voltage Vau1 of one path of the CV1 is smaller than the voltage of one path of the CV1, at this time, when the switch Sm (m is not smaller than 2 and not larger than n) of one path is conducted, the energy sensed by the secondary winding is completely transmitted to the path of output CVm through the switch Sm, no energy is transmitted to one path of the CV1 during the conduction period of the switch Sm, and all the energy is transmitted to the corresponding path of output CVm in the cv2, … and CVn. When the output switch control signal Sm_ctrl (m is more than or equal to 2 and less than or equal to n) is at a low level, the switch Sm is turned off, and after the switch Sm is turned off, the energy induced by the secondary side coil of the transformer T1 is completely transmitted to one path of CV 1. The multi-output switch is alternately conducted by controlling the conduction time of the switch Sm and the conduction selection of the switches S2, … and Sn at different moments in the secondary side demagnetizing period, so that the energy distribution of multi-output in each period is controlled and finally the high-precision cross adjustment rate of the multi-output switch power supply system is realized. The primary side switch S1 of the circuit shown in FIG. 2 is turned on by transmitting a multiplexed output feedback signal FBm _req (1.ltoreq.m.ltoreq.n) signal to the primary side via an isolation (e.g. capacitive isolation, coil mutual inductance isolation, or optocoupler isolation) or non-isolation feedback signal transmission circuit 206, so as to obtain a corresponding feedback voltage pulse trigger signal Tri_on, where the feedback voltage pulse trigger signal Tri_on generates a turn-on signal of the switch S1 through the switch control logic circuit 205 to control the turn-on of the switch S1. The cs_pk threshold voltage/current generation module 204 receives as input the feedback voltage pulse trigger signal tri_on to generate a threshold voltage/current signal cs_pk that varies with the feedback voltage signal period. The comparator 202 compares the threshold voltage/current signal cs_pk with a signal CS (which may be a voltage signal or a current signal) obtained by the current detection module 203 based on the induced current Ipk through the switch S1 when the switch S1 is on, generates an off signal tri_off of the switch S1, which turns off the primary side switch S1 by the primary side switch control logic circuit 205.

Fig. 3 illustrates a schematic diagram of the configuration of the multiplexed demagnetization current distribution control circuit 208 illustrated in fig. 2 according to one embodiment of the present disclosure. As shown in fig. 3, VFB2, …, VFBn are feedback divided voltages of the multiplexed outputs CV2, …, CVn, respectively, and the switch X2 to the switch Xn is selected to be turned on by the multiplexed output feedback divided voltage selection circuit 301 based on the high and low levels of the signals fb2_req to fbn_req in different periods, and only one switch is allowed to be turned on in each switching period. For example, when switch X2 is on, the other switches X3 to Xn are off, at which time only the feedback divided voltage VFB2 is transmitted to the positive terminal of the transconductance amplifier EA2, at which time only the EA2 integrating circuit is active. In the present period, the feedback voltage VFB21 generates the integrated voltage Vcomp2 on the integrating capacitor Ccomp2 by comparison with the reference voltage Vref of the negative terminal of EA2, and the integrated voltage Vcomp2 increases when VFB21 is higher than the reference voltage Vref2 and decreases when VFB21 is lower than the reference voltage Vref 2. The S2 control module 302 receives the integrated voltage Vcomp2 and the detected demagnetized pulse width signal Demag as inputs, and generates a control signal s2_ctrl of the switch S2. And so on, the conduction of the switch Xm (m is more than or equal to 2 and less than or equal to n) is controlled in different periods, so that the conduction of the switches S2, … and Sn of the multiplexing outputs CV2 to CVn is controlled, and finally, the voltage adjustment of the multiplexing outputs is realized.

For ease of description, two different implementations of the demagnetization current distribution for controlling the two outputs CV1 and CV2 by switching on or off the switch S2 in the present period are described below with one switching period when only the switch X2 is on and the EA2 integration circuit is active, while the other third-to-n switches X3, …, xn are off and the EA3 to EAn integration circuits are not operated as examples.

When the secondary side starts demagnetizing, one path of CV1 is demagnetized first, and the other path of CV2 is demagnetized later. Fig. 4 illustrates a schematic diagram of the multiplexing switch control circuit 302 shown in fig. 3, according to an embodiment of the disclosure. As shown in fig. 4, when the demagnetizing signal Demag changes from low level to high level, the constant current source I1 charges the capacitor Cr to generate the voltage Vramp, and when the demagnetizing signal Demag changes from high level to low level, the voltage Vramp of the capacitor Cr is reset by S3. The voltage Vramp is connected to the positive terminal of the comparator and the voltage Vcomp2 is connected to the negative terminal of the comparator. When the secondary side starts demagnetizing, the demagnetizing signal Demag changes from low level to high level, the voltage Vramp on the initial state capacitor Cr is 0V, which is lower than the integrated voltage Vcomp2, and the signal s2_ctrl outputs low level through comparison of the comparator, so that the switch S2 is in an off state when the demagnetization starts, and at this time, the energy sensed by the secondary side is completely transmitted to the CV1 path. With the constant current source I1 continuously charging the capacitor Cr, the voltage Vramp on the capacitor Cr continuously rises, and when the voltage Vramp is greater than the integrated voltage Vcomp2, the signal s2_ctrl changes from low level to high level, and the switch S2 starts to be turned on. Because of the specific turn ratio design of the transformer multipath output, during the on period of the switch S2, the energy sensed by the secondary side can be completely distributed to one path of CV2, and no energy is distributed to the path of CV1 at the moment. As shown in fig. 6, a waveform diagram is shown in which the output of CV1 is demagnetized first and the output of CV2 is demagnetized later. Since the voltage of the CV2 output changes when the CV1 output performs load dimming or changes, when the CV2 output is lower than a preset voltage, the feedback voltage VFB2 of the CV2 output is continuously lower than the reference voltage Vref2, and the integrated voltage Vcomp2 on the integrating capacitor Ccomp2 is continuously reduced, so that the pulse width of the switch control signal s2_ctrl of the switch S2 is gradually increased, and as the pulse width of the s2_ctrl is gradually increased, the demagnetizing current is2 distributed by the secondary side CV2 is gradually increased, so that the CV2 output is increased and finally stabilized at the preset value.

Another secondary side multiplexing current distribution scheme is described below with reference to fig. 5. That is, when the secondary side starts to demagnetize, the path of CV2 is demagnetized first, and the path of CV1 is demagnetized later. Fig. 5 shows a schematic diagram of a multiplexing switch control circuit according to another embodiment of the disclosure. The voltage Vramp is connected to the negative terminal of the comparator and the integrated voltage Vcomp2 is connected to the positive terminal of the comparator. When the demagnetization is just started on the secondary side, the signal Demag changes from low level to high level, the voltage on the capacitor Cr is 0V, and the integrated voltage Vcomp2 is greater than 0V, so that the integrated voltage Vcomp2 and the voltage Vramp are compared, and the signal s2_ctrl is initially high level, so that the switch S2 is in a conducting state at the beginning of the demagnetization, and the CV2 is demagnetized first. Based on a specific turn ratio design, at this time, the secondary side demagnetizing energy is completely transmitted to the CV2 path through the switch S2, along with the continuous charging of the capacitor Cr by the constant current source I2, the voltage Vramp continuously climbs, when the voltage Vramp is greater than the integral voltage Vcomp2, the signal S2_ctrl is changed from a high level to a low level, and the switch S2 is turned off, so that the energy stored in the secondary side coil cannot be transmitted to the CV2 path, and the secondary side energy is completely transmitted to the CV1 path. As shown in fig. 7, since the voltage of the output of the CV2 is changed when the output of the CV1 is subjected to load dimming or load change, when the voltage of the output of the CV2 is lower than a preset value, the feedback voltage VFB2 of the output of the CV2 is lower than a preset Vref2 voltage, and more energy is required to make the output voltage of the CV2 reach the preset value. In order to gradually increase the pulse width of the switch control signal s2_ctrl of the switch S2 so that one path of the CV2 gets more energy, the voltage Vcomp2 is continuously increased so that the pulse width of the switch control signal s2_ctrl of the switch S2 is gradually increased, and the demagnetizing current is2 distributed to one path of the CV2 is gradually increased during secondary side demagnetization, so that the output of the CV2 is increased and finally stabilized at a preset value.

It should be noted that, the secondary side multiplexing current distribution method according to the embodiment of the present disclosure is not limited to primary side control, secondary side control, and isolated or non-isolated circuits, which is not limited by the present disclosure.

Fig. 8 shows a flow diagram of a control method for a switching power supply according to one embodiment of the present disclosure. As shown in fig. 8, in step 810, a feedback voltage for each of the multiple outputs of the switching power supply may be generated based on the output voltage for each of the multiple outputs. In step 820, a logic signal of each output of the multiple outputs may be generated based on the feedback voltage of each output of the multiple outputs, where the logic signal of each output of the multiple outputs is a logic high level signal or a logic low level signal, and is used to represent that the output voltage of the corresponding output is lower or higher than a preset voltage. In step 830, a switch control signal may be generated for controlling the on or off of the switch of each of the one or more outputs based on the feedback voltage of the one or more outputs, the logic signal, and the demagnetizing pulse width logic signal of the switching power supply.

In an example embodiment, generating the feedback voltage for each of the multiple outputs based on the output voltage for each of the multiple outputs of the switching power supply in step 810 may include: for each path of output in the multipath output of the switching power supply, based on the output voltage of the path of output, generating the feedback voltage of the path of output through an output voltage dividing circuit.

In one example embodiment, generating the logic signal for each of the multiple outputs based on the feedback voltage for each of the multiple outputs in step 820 may include: based on the feedback voltage and the reference voltage of each output in the multiple outputs, logic signals of each output in the multiple outputs are generated through a comparator circuit.

In an example embodiment, generating the switch control signal for controlling the on or off of the switch of one or more of the outputs based on the feedback voltage, the logic signal, and the demagnetizing pulse width logic signal of the switching power supply in step 830 may include: based on the logic signals of the one or more paths of output, the feedback voltage of the one or more paths of output which is controlled by the feedback voltage selection circuit to be the logic high level signal is input to the positive input end of the transconductance amplifier so as to generate an integral voltage on an integral capacitor connected with the output end of the transconductance amplifier; and generating a switch control signal for controlling on or off of the switch of the output based on the integrated voltage and the demagnetized pulse width logic signal.

In one example embodiment, generating a switch control signal for controlling the on or off of a switch of the output based on the integrated voltage and the demagnetized pulse width logic signal comprises: controlling a capacitance voltage of the charging capacitor based on the demagnetizing pulse width logic signal; and generating a switch control signal for controlling on or off of the switch of the path output by the comparator based on the capacitor voltage and the integrated voltage.

Fig. 9 illustrates a schematic configuration of a control device for a switching power supply according to an embodiment of the present disclosure. As shown in fig. 9, an apparatus 900 for a control apparatus of a switching power supply according to an embodiment of the present disclosure may include an output voltage division module 910, a comparison module 920, and a control module 930.

The output voltage division module 910 may be configured to generate a feedback voltage of each of the multiple outputs based on an output voltage of each of the multiple outputs of the switching power supply. The comparison module 920 may be configured to generate a logic signal of each output of the multiple outputs based on the feedback voltage of each output of the multiple outputs, where the logic signal of each output of the multiple outputs is a logic high level signal or a logic low level signal, and is used to characterize that the output voltage of the corresponding output of the multiple outputs is lower than or higher than a preset voltage. The control module 930 may be configured to generate a switch control signal for controlling on or off of the switch of one or more outputs based on the feedback voltage, the logic signal, and the demagnetizing pulse width logic signal of the switching power supply.

In one example embodiment, the output voltage divider module 910 may be configured to: for each path of output in the multipath output of the switching power supply, based on the output voltage of the path of output, generating the feedback voltage of the path of output through an output voltage dividing circuit.

In one example embodiment, the comparison module 920 may be configured to: and generating logic signals output by each path of the multipath output based on the feedback voltage and the reference voltage of each path of output in the multipath output.

In one example embodiment, the control module 930 may be configured to: based on one or multiple output logic signals, a feedback voltage selecting circuit is used for controlling one output feedback voltage of which the logic signal is a logic high level signal in the one or multiple outputs to be input to a positive input end of a transconductance amplifier so as to generate an integral voltage on an integral capacitor connected with an output end of the transconductance amplifier; and generating a switch control signal for controlling on or off of the switch of the output based on the integrated voltage and the demagnetized pulse width logic signal.

In one example embodiment, the control module 930 may be configured to: controlling a capacitance voltage of the charging capacitor based on the demagnetizing pulse width logic signal; and generating a switch control signal for controlling on or off of the switch of the path output by the comparator based on the capacitor voltage and the integrated voltage.

The control method and the control device for a switching power supply according to the embodiments of the present disclosure described in connection with fig. 8 and 9 may refer to the embodiments of the present disclosure described in detail above in connection with other drawings, and for brevity, certain details will not be repeated. It is to be understood that the functional blocks and method steps shown in the structural and flow diagrams described above may be implemented in hardware, software, firmware, or a combination thereof.

Therefore, according to the control method and the control device for the switching power supply, under the condition of multiplexing output application, the method for distributing the secondary side multiplexing output current can be used for adaptively distributing the multiplexed output demagnetizing current, so that the high-precision load cross adjustment rate of multiplexing output is realized, and the high-precision requirement of multiplexing output voltage under the condition that the load is dynamically changed greatly when the multiplexing output is applied by a system is met. By using the control method and the control device for the switching power supply, the energy required by each path of multiplexed output is distributed in a self-adaptive manner through the change of the multiplexed output voltage at the secondary side, so that the accuracy of the load adjustment rate of the multiplexed output can be greatly improved, the working performance of a system is improved, the design cost of the system is saved, and the design difficulty of the system is reduced.

It should be further noted that the control method and the control device for a switching power supply according to the embodiments of the present disclosure may be used for various circuit topologies such as Buck, boost, buck-Boost, flyback, forward, and asymmetric half-bridge, and the power conversion topology structure of the switch power supply system according to the embodiment of the disclosure may include a quasi-resonant valley conduction control of various circuit topologies such as Buck Boost, boost, buck-Boost, flyback, forward, and asymmetric half-bridge, which is not limited in this disclosure.

The present disclosure may be embodied in other specific forms without departing from its spirit or essential characteristics. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the disclosure being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (11)

1. A control method for a switching power supply, comprising:

generating feedback voltage of each output in multiple paths of outputs based on the output voltage of each output in multiple paths of outputs of the switching power supply;

Generating logic signals of each output in the multipath output based on the feedback voltage of each output in the multipath output, wherein the logic signals of each output in the multipath output are logic high level signals or logic low level signals and are used for representing the output voltage of the corresponding output; and

And generating a switch control signal for controlling the on or off of a switch of each output of the one or more outputs based on the feedback voltage and logic signal of the one or more outputs and the demagnetizing pulse width logic signal of the switching power supply.

2. The method of claim 1, wherein generating a feedback voltage for each of the multiple outputs based on the output voltage for each of the multiple outputs of the switching power supply comprises:

and generating feedback voltage of one path of output through an output voltage dividing circuit based on the output voltage of the one path of output aiming at each path of output in the multipath output of the switching power supply.

3. The method of claim 1, wherein generating the logic signal for each of the multiple outputs based on the feedback voltage for each of the multiple outputs comprises:

Based on the feedback voltage and the reference voltage of each output in the multiple outputs, logic signals of each output in the multiple outputs are generated through a comparator circuit.

4. The method of claim 1, wherein generating a switch control signal for controlling the on or off of a switch of each of the one or more outputs based on the feedback voltage of the one or more outputs, a logic signal, and a demagnetizing pulse width logic signal of the switching power supply comprises:

Based on the logic signals of the one or more paths of output, the feedback voltage of the one or more paths of output, in which the logic signals are logic high level signals, is controlled by a feedback voltage selection circuit to be input to the positive input end of a transconductance amplifier so as to generate an integral voltage on an integral capacitor connected with the output end of the transconductance amplifier; and

And generating a switch control signal for controlling the on or off of the switch of the one output based on the integrated voltage and the demagnetizing pulse width logic signal.

5. The method of claim 4, wherein generating a switch control signal for controlling the on or off of the switch of the one output based on the integrated voltage and the demagnetizing pulse width logic signal comprises:

based on the demagnetizing pulse width logic signal, controlling the capacitance voltage of the charging capacitor; and

Based on the capacitor voltage and the integrated voltage, a switch control signal is generated by a comparator for controlling the on or off of the switch of the one output.

6. A control device for a switching power supply, comprising:

The output voltage division module is used for: generating feedback voltage of each output in multiple paths of outputs based on the output voltage of each output in multiple paths of outputs of the switching power supply;

A comparison module for: generating logic signals of each output in the multipath output based on the feedback voltage of each output in the multipath output, wherein the logic signals of each output in the multipath output are logic high level signals or logic low level signals and are used for representing the output voltage of the corresponding output; and

A control module for: and generating a switch control signal for controlling the on or off of a switch of each output of the one or more outputs based on the feedback voltage and logic signal of the one or more outputs and the demagnetizing pulse width logic signal of the switching power supply.

7. The apparatus of claim 6, wherein the output voltage divider module is to:

and generating feedback voltage of one path of output through an output voltage dividing circuit based on the output voltage of the one path of output aiming at each path of output in the multipath output of the switching power supply.

8. The apparatus of claim 6, wherein the comparison module is to:

And generating logic signals of each output in the multipath output based on the feedback voltage and the reference voltage of each output in the multipath output.

9. The apparatus of claim 6, wherein the control module is to:

Based on the logic signals of the one or more paths of output, the feedback voltage of the one or more paths of output, in which the logic signals are logic high level signals, is controlled by a feedback voltage selection circuit to be input to the positive input end of a transconductance amplifier so as to generate an integral voltage on an integral capacitor connected with the output end of the transconductance amplifier; and

And generating a switch control signal for controlling the on or off of the switch of the one output based on the integrated voltage and the demagnetizing pulse width logic signal.

10. The apparatus of claim 9, wherein the control module is to:

based on the demagnetizing pulse width logic signal, controlling the capacitance voltage of the charging capacitor; and

Based on the capacitor voltage and the integrated voltage, a switch control signal is generated by a comparator for controlling the on or off of the switch of the one output.

11. A switching power supply comprising a control device as claimed in any one of claims 6-10.