Energy recovery circuit and method and electronic equipment

Abstract

The invention discloses an energy recovery circuit and method and electronic equipment, and the circuit is used for connecting a power module and a load, and comprises a sampling control module and a voltage conversion circuit. The voltage conversion circuit is a step-down circuit or a step-up circuit and comprises a first switching tube Q1, a second switching tube Q2, an output filter capacitor C and an inductor L; the sampling control module controls on and off of the Q1 and the Q2; when the power supply module supplies power to the load through the voltage conversion circuit, the sampling control module controls the Q1 to be switched on and the Q2 to be switched off so as to control the L to store energy, and controls the Q1 to be switched off and the Q2 to be switched on so as to control the L to supply power to the load; when the power supply module stops supplying power to the load, if the output voltage value Vout of the voltage conversion circuit is larger than or equal to the voltage threshold Vth, the sampling control module controls the Q1 and the Q2 to be conducted and cut off in a staggered mode based on the switching frequency, and the energy of the voltage conversion circuit is reversely provided for the power supply module. In the embodiment of the invention, the electric quantity can be saved.

Description

Technical Field

[0001] The present application relates to the field of electronic circuits, and in particular to an energy recovery circuit, method and electronic equipment. Background Art

[0002] In an electronic device with a power supply and a load, the power supply supplies power to the load. The voltage output by the power supply usually does not match the operating voltage of the load, so a certain degree of voltage change is required between the power supply and the load, such as adding a Buck circuit between the power supply and the load to reduce the voltage or adding a Boost circuit to increase the voltage. However, in the above process, if the power supply is turned off, the power energy in the transformer circuit will dissipate, which will cause a lot of power loss. Summary of the invention

[0003] The embodiments of the present application disclose an energy recovery circuit, method and electronic device, which can save power.

[0004] In a first aspect, the present application provides an energy recovery circuit for connecting a power module and a load, the energy recovery circuit comprising a sampling control module and a voltage conversion circuit; the voltage conversion circuit is a buck circuit or a boost circuit, wherein: the voltage conversion circuit comprises a first switch tube Q1, a second switch tube Q2, an output filter capacitor C and an inductor L; the sampling control module has two control terminals, the two control terminals are respectively connected to the Q1 and the Q2; the two control terminals respectively control the conduction and cutoff of the Q1 and the Q2; when the power module supplies power to the load through the voltage conversion circuit, the sampling control module controls the Q1 to be turned on and the Q2 to be turned off for controlling the L to store energy, and controls the Q1 to be turned off and the Q2 to be turned on for controlling the L to supply power to the load; when the power module stops supplying power to the load through the voltage conversion circuit, if the output voltage value Vout of the voltage conversion circuit is greater than or equal to the voltage threshold Vth, the sampling control module controls the Q1 and the Q2 to be turned on and off alternately based on the switching frequency, and reversely provides the energy of the voltage conversion circuit to the power module.

[0005] Among them, the step-down circuit may refer to the Buck circuit in the embodiment of the present application; the step-up circuit may refer to the Boost circuit in the embodiment of the present application.

[0006] In an embodiment of the present application, after the power is turned off, the energy stored in the capacitor C can be reversely supplied and returned to the power module, so as to achieve the purpose of energy recovery, reduce unnecessary power loss, and save energy.

[0007] In a possible implementation, the sampling control module controls Q1 and Q2 to be turned on and off alternately based on the switching frequency, including: in a corresponding switching cycle of the switching frequency, the sampling control module first controls Q1 to be turned off and Q2 to be turned on; and then controls Q1 to be turned on and Q2 to be turned off. In this way, the state in which the sampling control module controls Q1 and Q2 to be turned on and off is opposite to the state in the power supply process, which can make the circuit switch from the forward power supply to the reverse charging state, forming the effect of energy recovery, and achieving the purpose of saving energy consumption.

[0008] In a possible implementation, when Q1 is turned off and Q2 is turned on, the current direction of L is opposite to the direction of the charging current of L, so as to reversely store energy for L; the charging current is the current when the power module supplies power to the load through the voltage conversion circuit; when Q1 is turned on and Q2 is turned off, the current direction of L is opposite to the direction of the charging current, so as to reversely charge the power module that supplies power to the voltage conversion circuit. In this way, the switching of the on and off states of Q1 and Q2 can enable the inductor to adjust the current direction and perform reverse power supply, thereby recovering energy and saving energy consumption.

[0009] In a possible implementation, the sampling control module further obtains the output voltage value Vout of the voltage conversion circuit based on the acquisition frequency k; when obtaining the Vout, the sampling control module determines whether the Vout is greater than or equal to the Vth. In this way, after the power is turned off, as time goes by, the voltage difference across the capacitor C will decrease, that is, the first output voltage value Vout1 will decrease. When the first output voltage value Vout1 decreases to a certain extent, energy recovery is not cost-effective. After the above judgment, it can be ensured that the recovered energy is greater than the power consumption of the device performing energy recovery, and the benefits and necessity of performing energy recovery are guaranteed.

[0010] In a possible implementation, the sampling control module also has two monitoring terminals E1 and E2; E1 is connected to the voltage output terminal of the voltage conversion circuit, and E2 is connected to the voltage input terminal of the voltage conversion circuit; the sampling control module also obtains the output voltage value Vout of the voltage conversion circuit based on the acquisition frequency, including: the sampling control module obtains the Vout of the voltage conversion circuit based on k through E1; the sampling control module also obtains the input voltage value Vin of the voltage conversion circuit based on k through E2. In this way, the two monitoring terminals can obtain the output voltage value Vout and the input voltage value Vin in real time, thereby providing the sampling control module with timely judgment basis, ensuring the timeliness of the start and end of the energy recovery process, thereby ensuring that energy recovery is profitable.

[0011] In a possible implementation, the sampling control module controls the Q1 and Q2 to be turned on and off alternately based on the switching frequency, including: the sampling control module obtains the duty cycle based on the Vin and the Vout; the sampling control module controls the Q1 and Q2 to be turned on and off alternately based on the switching frequency based on the duty cycle. In this way, after the power is turned off, the energy gradually decreases, and the real-time calculation of the duty cycle can accurately adjust the capacitor voltage to a voltage that can be reversely charged to the power module, ensuring the reliability and timeliness of the charging process.

[0012] In a possible implementation, when the voltage conversion circuit is a buck circuit, the duty cycle is D1=1-Vout / Vin, wherein Vin is the input voltage of the buck circuit, and Vout is the output voltage of the buck circuit; when the voltage conversion circuit is a boost circuit, the duty cycle is D2=Vin / Vout, wherein Vin is the input voltage of the boost circuit, and Vout is the output voltage of the boost circuit. In this way, for a buck circuit, reverse charging requires boosting; for a boost circuit, reverse charging requires bucking. Therefore, by calculating different duty cycles, energy recovery of different circuits can be specifically realized to ensure the reliability of energy recovery.

[0013] In a possible implementation, after the sampling control module obtains the duty cycle based on the Vin and the Vout, the sampling control module also calculates the upper tube on time Ton and the upper tube off time Toff; the sampling control module first controls the Q1 to be off and the Q2 to be on; and then controls the Q1 to be on and the Q2 to be off, including: in the Ton period, the sampling control module first controls the Q1 to be off and the Q2 to be on; in the Toff period, the sampling control module then controls the Q1 to be on and the Q2 to be off. In this way, in the duty cycle stage, the on and off times of Q1 and Q2 can be limited to the Ton and Toff periods, so that the capacitor voltage can be reversely converted into a voltage that meets the reverse charging requirements, ensuring the reliability and stability of charging.

[0014] In a possible implementation, the sampling control module further calculates the upper tube conduction time Ton and the upper tube cut-off time Toff, including: when the voltage conversion circuit is a step-down circuit, if the sampling control module is a pulse width modulation PWM control type, the upper tube conduction time Ton=(1-Vout / Vin)*1 / f; the upper tube cut-off time Toff=(Vout / Vin)*1 / f; if the sampling control module is a pulse frequency modulation PFM control type; the upper tube cut-off time Toff=Ton*Vin / (Vin-Vout)-Ton1; when the voltage conversion circuit is a boost circuit, if the sampling control module is a PWM control type, the upper tube conduction time Ton=Vin / Vout*1 / f; the upper tube cut-off time Toff=1 / f(1-Vin / Vout); if the sampling control module is a PFM control type, the upper tube cut-off time Toff=Ton*(Vout / Vin-1). In this way, for different voltage conversion circuits and control types of different acquisition control modules, it is necessary to calculate Ton and Toff specifically to ensure the reliability of reverse charging during energy recovery.

[0015] In a possible implementation, after the sampling control module determines whether the Vout is greater than or equal to the Vth, if the Vout is less than the Vth, the sampling control module stops executing the control of the Q1 and Q2 to be turned on and off alternately based on the switching frequency. In this way, after the power supply is turned off, as time goes by, the voltage difference across the capacitor C will decrease, that is, the first output voltage value Vout1 will decrease. When the first output voltage value Vout1 decreases to a certain extent, energy recovery is not cost-effective. After the above judgment, it can be ensured that the recovered energy is greater than the power consumption of the device performing energy recovery, and the benefits and necessity of performing energy recovery are guaranteed.

[0016] In a possible implementation, when the voltage conversion circuit is a step-down circuit, the voltage threshold range is 0.1Voutx to 0.5Voutx; Voutx is the output voltage value of the voltage conversion circuit when the power module supplies power to the load through the voltage conversion circuit; when the voltage conversion circuit is a step-up circuit, the voltage threshold range is 1.1Viny to 1.5Viny; Viny is the input voltage value of the voltage conversion circuit when the power module supplies power to the load through the voltage conversion circuit. In this way, the voltage threshold should be designed within a reasonable range to ensure that the increase in energy during the energy recovery process is greater than the energy consumption, thereby ensuring that energy recovery is a positive gain rather than a loss, so as to achieve the purpose of saving energy consumption.

[0017] In a possible implementation, when the voltage conversion circuit is a buck circuit, the drain of Q1 is connected to the voltage input terminal of the voltage conversion circuit, the source of Q1 is connected to the first terminal of L and the drain of Q2; the second terminal of L is connected to the first terminal of C and the voltage output terminal of the voltage conversion circuit; the source of Q2 and the second terminal of C are grounded; when the voltage conversion circuit is a boost circuit, the first terminal of L is connected to the voltage input terminal of the voltage conversion circuit, the second terminal of L is connected to the drain of Q1 and the drain of Q2; the source of Q2 is connected to the first terminal of C and the voltage output terminal of the voltage conversion circuit; the source of Q1 and the second terminal of C are grounded. In this way, the buck circuit is a Buck circuit connection mode, and the boost circuit is a Boost circuit connection mode, which cleverly utilizes the mirror symmetry of the Buck circuit and the Boost circuit structure, and the basic logic of forward boost and reverse buck, or forward buck and reverse boost, provides a structural basis for the realization of reverse charging and ensures the reliability of energy recovery.

[0018] In a second aspect, the present application provides an energy recovery method, which is applied to an energy recovery circuit, wherein the energy recovery circuit includes a sampling control module and a voltage conversion circuit; the voltage conversion circuit is a buck circuit or a boost circuit, wherein: the voltage conversion circuit includes a first switch tube Q1, a second switch tube Q2, an output filter capacitor C and an inductor L; the sampling control module has two control terminals, and the two control terminals are respectively connected to the Q1 and the Q2; the two control terminals respectively control the conduction and cutoff of the Q1 and the Q2; when the power module supplies power to the load through the voltage conversion circuit, the sampling control module is used to control the Q1 to be turned on and the Q2 to be turned off for controlling the L to store energy, and to control the Q1 to be turned off and the Q2 to be turned on for controlling the L to supply power to the load; when the power module stops supplying power to the load through the voltage conversion circuit, if the output voltage value Vout of the voltage conversion circuit is greater than or equal to the voltage threshold Vth, the sampling control module is used to control the Q1 and the Q2 to be turned on and off alternately based on the switching frequency, and reversely provide the energy of the voltage conversion circuit to the power module.

[0019] Among them, the step-down circuit may refer to the Buck circuit in the embodiment of the present application; the step-up circuit may refer to the Boost circuit in the embodiment of the present application.

[0020] In an embodiment of the present application, after the power is turned off, the energy stored in the capacitor C can be reversely supplied and returned to the power module, so as to achieve the purpose of energy recovery, reduce unnecessary power loss, and save energy.

[0021] In a possible implementation, the sampling control module is used to control the Q1 and Q2 to be turned on and off alternately based on the switching frequency, including: in a corresponding switching cycle of the switching frequency, the sampling control module is used to first control the Q1 to be turned off and the Q2 to be turned on; and then control the Q1 to be turned on and the Q2 to be turned off. In this way, the state in which the sampling control module controls the Q1 and Q2 to be turned on and off is opposite to the state in the power supply process, which can make the circuit switch from the forward power supply to the reverse charging state, forming the effect of energy recovery, and achieving the purpose of saving energy consumption.

[0022] In a possible implementation, when Q1 is turned off and Q2 is turned on, the current direction of L is opposite to the direction of the charging current of L, so as to reversely store energy for L; the charging current is the current when the power module supplies power to the load through the voltage conversion circuit; when Q1 is turned on and Q2 is turned off, the current direction of L is opposite to the direction of the charging current, so as to reversely charge the power module that supplies power to the voltage conversion circuit. In this way, the switching of the on and off states of Q1 and Q2 can enable the inductor to adjust the current direction and perform reverse power supply, thereby recovering energy and saving energy consumption.

[0023] In a possible implementation, the sampling control module is further used to obtain the output voltage value Vout of the voltage conversion circuit based on the acquisition frequency k; when obtaining the Vout, the sampling control module is further used to determine whether the Vout is greater than or equal to the Vth. In this way, after the power is turned off, as time goes by, the voltage difference across the capacitor C will decrease, that is, the first output voltage value Vout1 will decrease. When the first output voltage value Vout1 decreases to a certain extent, energy recovery is not cost-effective. After the above judgment, it can be ensured that the recovered energy is greater than the power consumption of the device performing energy recovery, ensuring the benefits and necessity of performing energy recovery.

[0024] In a possible implementation, if the output voltage value Vout of the voltage conversion circuit is less than the voltage threshold Vth, the sampling control module is used to stop the control of the Q1 and Q2 to be turned on and off alternately based on the switching frequency. In this way, after the power is turned off, as time goes by, the voltage difference across the capacitor C will decrease, that is, the first output voltage value Vout1 will decrease. When the first output voltage value Vout1 decreases to a certain extent, energy recovery is not cost-effective. After the above judgment, it can be ensured that the recovered energy is greater than the power consumption of the device to perform energy recovery, ensuring the benefits and necessity of performing energy recovery.

[0025] In a possible implementation, the sampling control module also has two monitoring terminals E1 and E2; E1 is connected to the voltage output terminal of the voltage conversion circuit, and E2 is connected to the voltage input terminal of the voltage conversion circuit; the sampling control module is also used to obtain the output voltage value Vout of the voltage conversion circuit based on the acquisition frequency, including: the sampling control module is used to obtain the Vout of the voltage conversion circuit based on k through E1; the sampling control module is also used to obtain the input voltage value Vin of the voltage conversion circuit based on k through E2. In this way, the two monitoring terminals can obtain the output voltage value Vout and the input voltage value Vin in real time, thereby providing the sampling control module with timely judgment basis, ensuring the timeliness of the start and end of the energy recovery process, and thus ensuring that energy recovery is profitable.

[0026] In a possible implementation, the sampling control module is used to control the Q1 and Q2 to be staggered on and off based on the switching frequency, including: the sampling control module is used to obtain the duty cycle based on the Vin and the Vout; the sampling control module is used to control the Q1 and Q2 to be staggered on and off based on the switching frequency based on the duty cycle. In this way, after the power is turned off, the energy gradually decreases, and the real-time calculation of the duty cycle can accurately adjust the capacitor voltage to a voltage that can be reversely charged to the power module, ensuring the reliability and timeliness of the charging process.

[0027] In a possible implementation, when the voltage conversion circuit is a buck circuit, the duty cycle is D1=1-Vout / Vin, wherein Vin is the input voltage of the buck circuit, and Vout is the output voltage of the buck circuit; when the voltage conversion circuit is a boost circuit, the duty cycle is D2=Vin / Vout, wherein Vin is the input voltage of the boost circuit, and Vout is the output voltage of the boost circuit. In this way, for a buck circuit, reverse charging requires boosting; for a boost circuit, reverse charging requires bucking. Therefore, by calculating different duty cycles, energy recovery of different circuits can be specifically realized to ensure the reliability of energy recovery.

[0028] In a possible implementation, the sampling control module is also used to calculate the upper tube on time Ton and the upper tube off time Toff after obtaining the duty cycle based on the Vin and the Vout; the sampling control module first controls the Q1 to be off and the Q2 to be on; and then controls the Q1 to be on and the Q2 to be off, including: in the Ton period, the sampling control module first controls the Q1 to be off and the Q2 to be on; in the Toff period, the sampling control module then controls the Q1 to be on and the Q2 to be off. In this way, in the duty cycle stage, the on and off times of Q1 and Q2 can be limited to the Ton and Toff periods, so that the capacitor voltage can be reversely converted into a voltage that meets the reverse charging requirements, ensuring the reliability and stability of charging.

[0029] In a possible implementation manner, the sampling control module is further used to calculate the upper tube conduction time Ton and the upper tube cut-off time Toff, including: when the voltage conversion circuit is a step-down circuit, if the sampling control module is a pulse width modulation PWM control type, the upper tube conduction time Ton=(1-Vout / Vin)*1 / f; the upper tube cut-off time Toff=(Vout / Vin)*1 / f; if the sampling control module is a pulse frequency modulation PFM control type; the upper tube cut-off time Toff=Ton*Vin / (Vin-Vout)-Ton1; when the voltage conversion circuit is a boost circuit, if the sampling control module is a PWM control type, the upper tube conduction time Ton=Vin / Vout*1 / f; the upper tube cut-off time Toff=1 / f(1-Vin / Vout); if the sampling control module is a PFM control type, the upper tube cut-off time Toff=Ton*(Vout / Vin-1). In this way, for different voltage conversion circuits and control types of different acquisition control modules, it is necessary to calculate Ton and Toff specifically to ensure the reliability of reverse charging during energy recovery.

[0030] In a possible implementation, when the voltage conversion circuit is a step-down circuit, the voltage threshold range is 0.1Voutx to 0.5Voutx; Voutx is the output voltage value of the voltage conversion circuit when the power module supplies power to the load through the voltage conversion circuit; when the voltage conversion circuit is a step-up circuit, the voltage threshold range is 1.1Viny to 1.5Viny; Viny is the input voltage value of the voltage conversion circuit when the power module supplies power to the load through the voltage conversion circuit. In this way, the voltage threshold should be designed within a reasonable range to ensure that the increase in energy during the energy recovery process is greater than the energy consumption, thereby ensuring that energy recovery is a positive gain rather than a loss, so as to achieve the purpose of saving energy consumption.

[0031] In a possible implementation, when the voltage conversion circuit is a buck circuit, the drain of Q1 is connected to the voltage input terminal of the voltage conversion circuit, the source of Q1 is connected to the first terminal of L and the drain of Q2; the second terminal of L is connected to the first terminal of C and the voltage output terminal of the voltage conversion circuit; the source of Q2 and the second terminal of C are grounded; when the voltage conversion circuit is a boost circuit, the first terminal of L is connected to the voltage input terminal of the voltage conversion circuit, the second terminal of L is connected to the drain of Q1 and the drain of Q2; the source of Q2 is connected to the first terminal of C and the voltage output terminal of the voltage conversion circuit; the source of Q1 and the second terminal of C are grounded. In this way, the buck circuit is a Buck circuit connection mode, and the boost circuit is a Boost circuit connection mode, which cleverly utilizes the mirror symmetry of the Buck circuit and the Boost circuit structure, and the basic logic of forward boost and reverse buck, or forward buck and reverse boost, provides a structural basis for the realization of reverse charging and ensures the reliability of energy recovery.

[0032] In a third aspect, the present application provides an electronic device, comprising an energy recovery circuit in any possible implementation of the first aspect and a device connected to the energy recovery circuit.

[0033] In a fourth aspect, an embodiment of the present application provides a chip, comprising an energy recovery circuit in any possible implementation of the first aspect and a device connected to the energy recovery circuit.

[0034] In a fifth aspect, an embodiment of the present application provides a PCB board, comprising computer instructions. When the computer instructions are executed on an electronic device, the electronic device executes an energy recovery circuit and a device connected to the energy recovery circuit in any possible implementation method of the first aspect mentioned above.

[0035] In a sixth aspect, an embodiment of the present application provides a power supply device, the power supply device comprising an energy recovery circuit in any possible implementation of the first aspect and a device connected to the energy recovery circuit. The power supply device may also include a power module and / or a load. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1A and Figure 1B This is a schematic diagram of a set of Buck circuit structures provided in an embodiment of the present application;

[0037] Figure 2A and Figure 2B It is a schematic diagram of a group of Boost circuit structures provided in an embodiment of the present application;

[0038] Figure 3 This is a schematic diagram of a circuit structure of energy recovery provided in an embodiment of the present application;

[0039] Figure 4 This is a schematic diagram of a method for energy recovery provided in an embodiment of the present application;

[0040] Figure 5A and Figure 5B is a circuit diagram of a set of energy recovery processes provided by an embodiment of the present application;

[0041] Fig. 6A and Figure 6B This is a timing diagram of a switch tube being alternately turned on provided by an embodiment of the present application;

[0042] Figure 7 is a schematic diagram of another circuit structure of energy recovery provided in an embodiment of the present application;

[0043] Figure 8 This is a schematic diagram of a method for energy recovery provided in an embodiment of the present application;

[0044] Fig.9A and Fig. 9B This is a circuit diagram of another set of energy recovery processes provided in an embodiment of the present application. DETAILED DESCRIPTION

[0045] In the embodiments of the present application, words such as "first" and "second" are used to distinguish the same or similar items with substantially the same functions and effects. For example, the first chip and the second chip are only used to distinguish different chips, and their order is not limited. Those skilled in the art can understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit them to be different.

[0046] It should be noted that, in the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0047] 1. Buck circuit:

[0048] Buck circuit, also known as "Buck converter", is a step-down converter. It is a DC-to-DC step-down circuit with an output voltage lower than the input voltage.

[0049] Figure 1A and Figure 1B : is a schematic diagram of a group of Buck circuit structures disclosed in an exemplary embodiment of the present application. Among them, Figure 1A and Figure 1B This is a schematic diagram of the same circuit structure at different stages of forward power supply. Figure 1A and Figure 1B As shown, the Buck circuit may include a first switch tube Q1, a second switch tube Q2, an inductor L1, an output filter capacitor C, a control module and a resistor R1.

[0050] In the Buck circuit, the drain of the first switch tube Q1 can be connected to the voltage input terminal Vin, and the source of the first switch tube Q1 can be connected to the first end of the inductor L1 and the drain of the second switch tube Q2. The second end of the inductor L1 can be connected to the first end of the output filter capacitor C, the first end of the resistor R1 and the voltage output terminal Vout. The control module may include two control terminals S1 and S2, wherein the control terminal S1 is connected to the gate of Q1, and the control terminal S2 is connected to the gate of Q2. The control module can control the conduction and cutoff of Q1 and Q2 respectively through S1 and S2. The source of the second switch tube Q2, the second end of the output filter capacitor C and the second end of the resistor R1 can be connected to the GND terminal (grounding).

[0051] Furthermore, the Buck circuit is used in the step-down process of forward power supply, and its two ends can be connected to the power module and the load. The input end of the Buck circuit can be connected to the power module (BAT): the voltage input terminal Vin of the Buck circuit is connected to the positive pole of the power module, and the negative pole of the power module is grounded. The output end of the Buck circuit can be connected to the load: the voltage output terminal Vout of the Buck circuit is connected to one end of the load, and the other end of the load is grounded, that is, the two ends of R1 or C can be connected to the load module. With the above connection structure, the power module can supply power to the load through the voltage conversion of the Buck circuit.

[0052] Of course, the Buck circuit may also include other devices, which is not limited in this application.

[0053] In the process of forward power supply, the voltage conversion process of the Buck circuit can be achieved by alternately switching Q1 and Q2 on and off according to a specific cycle. The following takes one cycle as an example to explain the voltage conversion process in detail:

[0054] Specifically, the forward power supply operation process of a Buck circuit during one cycle can be divided into two stages:

[0055] Phase 1: Q1 is turned on and Q2 is turned off.

[0056] Figure 1A It shows the current direction in the Buck circuit when Q1 is turned on and Q2 is turned off. The left end of the inductor L1 is connected to the voltage input terminal Vin, and the right end of the inductor L1 is connected to the voltage output terminal Vout. In the case of the Buck circuit, Vin>Vout, and the voltage difference across the inductor L1 is Vin-Vout, which is a constant value at this time. If the current to the right of the inductor L1 is defined as positive, then the current of the inductor L1 increases linearly with time t. Specifically, the voltage across the inductor L1 is L*di / dt=Vin-Vout, where Vin-Vout and L are constant, that is, di / dt=(Vin-Vout) / L is a constant, that is, the inductor current i increases linearly with time t. As shown Figure 1A As shown, in stage 1, the current i flows in the direction of Q1->L1->R1 (load)->power module->Q1, and the inductor current increases linearly.

[0057] Phase 2: Q2 is turned on and Q1 is turned off.

[0058] Figure 1BThe figure shows the current direction in the Buck circuit when Q2 is turned on and Q1 is turned off. In this scenario, the inductor L1 needs to continue current and will generate a reverse electromotive force. The control terminal S1 controls Q1 to be turned off and Q2 to be turned on. The voltage difference between the drain and source of Q2 is Vd. Because the drain of Q2 is grounded, the source voltage of Q2 is -Vd, that is, the voltage on the left side of the inductor is -Vd. Since the time when Q2 is turned off is extremely short, the voltage on the right side of the inductor remains unchanged at Vout (at this time, Vd can be regarded as the voltage at the lower end of capacitor C, and Vout can be regarded as the voltage at the upper end of capacitor C). Therefore, the voltage difference between the two ends of inductor L1 is -Vd-Vout. At this time, the current of inductor L1 decreases linearly with time t. Specifically, the voltage across the inductor L1 is L*di / dt=-Vd-Vout, where L (the inductance of the inductor L1) and -Vd-Vout are also constants, i.e., di / dt=-(Vout+Vd) / L is a constant and a negative value, i.e., the inductor current i decreases linearly with time t. Figure 1B As shown, in stage 2, the current i flows in the direction of L1->C->Q2->L1, and the inductor current decreases linearly.

[0059] Repeat the above two stages periodically, that is, Q1 and Q2 can be controlled to be turned on and off periodically according to a certain frequency frame, and the inductor can suppress the impact current. After the entire circuit is stable, within a cycle time, due to the constant load current, the amount of increase in the inductor current when Q1 is turned on is equal to the amount of decrease in the inductor current when Q1 is turned off, that is, the inductor L1 discharges as much as it is charged, and the load current or load voltage changes accordingly. In addition, the voltage across the capacitor C cannot change suddenly. The capacitor C has the function of storing energy, so that the voltage of each cycle can be applied to the load to form a stable output.

[0060] It should be noted that the switching of the above-mentioned phases 1 and 2 is the control logic executed when the voltage input terminal (power module) of the Buck circuit supplies power to the voltage output terminal (load) during the process of turning on the power switch. After the power supply is finished, when the power switch is turned off, Q1 and Q2 are usually cut off. Of course, there may be other situations. For example, Q1 is an NMOS type transistor. After the power switch is turned off, Q2 is periodically turned on once to charge the bootstrap capacitor of Q1 to ensure that Buck is enabled and can quickly respond to the start signal when the power is turned on next time. Among them, the bootstrap capacitor is a common circuit design element, and the bootstrap capacitor and a transistor can constitute a bootstrap circuit. The constituted bootstrap circuit can raise part of the voltage to a higher level, thereby increasing the power supply or signal level of the circuit to ensure the enabled state of Q1. This application is not limited to this. In short, when the power switch is turned off, controlling Q1 and Q2 stops the switching process of the above-mentioned phases 1 and 2.

[0061] 2.Boost circuit:

[0062] Boost circuit, also known as "Boost converter", is a single-tube non-isolated DC converter with an output voltage higher than the input voltage.

[0063] Figure 2A and Figure 2B is a schematic diagram of a group of Boost circuit structures disclosed by way of example in the embodiments of the present application. Figure 2A and Figure 2B This is a schematic diagram of the same circuit structure at different stages of forward power supply. Figure 2A and Figure 2B As shown, the Boost circuit may include a first switch tube Q1, a second switch tube Q2, an inductor L1, an output filter capacitor C, a control module and a resistor R1.

[0064] In the Boost circuit, the first end of the inductor L1 can be connected to the voltage input terminal Vin, and the second end of the inductor L1 can be connected to the drain of the first switch tube Q1 and the drain of the second switch tube Q2. The source of the second switch tube Q2 can be connected to the first end of the output filter capacitor C, the first end of the resistor R1 and the voltage output terminal Vout. The control module may include two control terminals S1 and S2, wherein the control terminal S1 is connected to the gate of Q1, and the control terminal S2 is connected to the gate of Q2. The control module can control the conduction and cutoff of Q1 and Q2 respectively through S1 and S2. The source of the first switch tube Q1, the second end of the output filter capacitor C and the second end of R1 can be connected to the GND terminal (grounding).

[0065] Furthermore, the Boost circuit is used in the forward power supply boosting process, and its two ends can be connected to the power module and the load. The input end of the Boost circuit can be connected to the power module (BAT): the voltage input terminal Vin of the Boost circuit is connected to the positive pole of the power module, and the negative pole of the power module is grounded. The output end of the Boost circuit can be connected to the load: the voltage output terminal Vout of the Boost circuit is connected to one end of the load, and the other end of the load is grounded, that is, the two ends of R1 or C can be connected to the load module. With the above connection structure, the power module can supply power to the load through the voltage conversion of the Boost circuit.

[0066] Of course, the Boost circuit may also include other devices, which is not limited in this application.

[0067] In the process of forward power supply, the voltage conversion process of the Boost circuit can be achieved by switching Q1 and Q2 on and off alternately according to a specific cycle. The following takes one cycle as an example to explain the voltage conversion process in detail: Specifically, the forward power supply working process of the Boost circuit in one cycle can be divided into two stages:

[0068] Phase 1: Q1 is turned on, Q2 is turned off:

[0069] Figure 2A It shows the current direction in the Boost circuit when Q1 is turned on and Q2 is turned off. Q1 is turned on, the right end of the inductor L1 is grounded, Q1 is turned off, the input voltage Vin charges the inductor L1, and the voltage at the first end of the inductor L1 is Vin. Since Q1 is turned on, the voltage at the right end of the inductor L1 is close to 0. That is, in the above process, the input voltage charges the inductor L1, and the voltage across the inductor L1 is Vin. V=L*di / dt. Among them, the inductance L is a constant value, and the voltage across the inductor is V=Vin, which is also a constant value. Therefore, the inductor current i increases linearly with time t. As shown Figure 2A As shown, the direction of current I is L1->Q1->power module->L1, and the inductor current increases linearly. The output voltage can be provided by capacitor C, which has been charged in stage 2 of the previous power cycle.

[0070] Phase 2: Q2 is turned on, Q1 is turned off:

[0071] Figure 2A It shows the current direction in the Boost circuit when Q2 is turned on and Q1 is turned off. Since the inductor L1 has been charged in stage one, current flows through it, the direction of the current is to the right, the current across the inductor L1, the voltage drop of Q2 is Vd, and the voltage on the right side of the inductor L1 is Vout + Vd. The voltage on the left side of the inductor L1 is the power supply output Vin. This is Vout + Vd> Vin in the boost circuit. The voltage difference across the inductor L1 is Vin-(Vout + Vd) = V = L*di / dt, the inductance value L is a constant value, and V is a negative constant value. At this time, the inductor current i decreases linearly with time t. The inductor L1 is discharged at this time, which can supply power to the resistor R1 and the load, and charge the output filter capacitor C. As shown Figure 2B As shown, in stage 2, the current i flows in the direction of L1->Q2->C (R1 and load)->power module->L1, and the inductor current decreases linearly.

[0072] In the above two stages, Q2 is turned on, the inductor L1 is charged by the power module, and the capacitor C releases energy to the load. After Q2 is turned off, the inductor and the power supply jointly supply power to the load. In the same cycle, the output voltage is the sum of the voltage of the power module and the inductor voltage for a part of the time, and the output voltage is maintained by the capacitor voltage for another part of the time. The average output voltage is higher than the voltage of the power module to achieve the purpose of boosting.

[0073] It should also be noted that the switching of the above-mentioned phase one and phase two is the control logic executed when the voltage input terminal of the Boost circuit supplies power to the voltage output terminal during the process of turning on the power switch. After the power supply is finished, when the power switch is turned off, Q1 and Q2 are usually cut off. Of course, there may be other situations, which are not limited in this application. In short, when the power switch is turned off, Q1 and Q2 are controlled to stop the switching process of the above-mentioned phase one and phase two.

[0074] 3. Control module of the switching power supply corresponding to the control signal:

[0075] in, Figure 1A to Figure 2B The gates Gate of Q1 and Q2 in the circuit can receive control signals from the control end of the control module, and the control signals can adjust the on and off states of the switch tubes Q1 and Q2.

[0076] There are many control modes for general control modules, such as PWM control, PFM control and pulse width modulation PSM control and so on.

[0077] Among them, the more common one is fixed switching frequency control, which is the so-called PWM control. Exemplarily, the gates of Q1 and Q2 can be connected to the two control terminals of the PWM control module respectively. The driving voltage of the gate (the voltage at the gate terminal) can be a pulse width modulation (PWM) signal. The signal period of the PWM signal is Ts, then the signal frequency is f=1 / Ts, the (upper tube, high-side mosfet) on time is Ton, and the off time is Toff, then the period Ts=Ton+Toff, and the duty cycle D=Ton / Ts. Since the PWM control module controls the switch tube at an extremely high frequency, it can control the on and off time of the switch tube, the charging and discharging time of the inductor, and cooperate with the output filter capacitor, so that a stable Vout can be obtained.

[0078] Among them, the control mode of the switching power supply can also be pulse frequency modulation (PFM) control, or COT control. In this control mode, Ton is fixed, and the control module can adjust the duration of Toff in time according to the calculation results, and then change T, thereby realizing real-time adjustment of the duty cycle.

[0079] In addition, the switching frequency f is a key parameter of the switching power supply (Buck, Boost and other power supply types), which is usually set to several hundred kHz to tens of MHz. The switching frequency of the switching power supply chip IC of the manufacturer on the market is usually between 500kHz and 1.5MHz. Some power supply chip ICs also provide users with several switching frequency gears for users to choose. This application does not limit the size of the switching frequency f.

[0080] In the above implementation, in order to improve the transient response performance of the power supply in the power supply application, a large-capacity capacitor is usually added to the power supply output or power conversion network. Figure 1A or Figure 2A The capacitance value of C in the figure. The larger the capacitance value of C, the greater the energy that the power supply can charge to the capacitor. If the power supply is turned off, the energy stored in capacitor C will slowly dissipate. Especially in power supply applications that are frequently started and stopped, the energy dissipation of the capacitor caused by the power supply being turned off is considerable, resulting in a waste of electricity.

[0081] For example, in the power supply of the radio frequency integrated circuit RFIC of the terminal device, the normal cycle for the control module to start power supply and shut down power supply is about 2s, and the control end of the control module controls the on and off switching cycles of Q1 and Q2 in milliseconds. Therefore, in the power supply that starts and stops very frequently, the energy dissipation is also considerable, resulting in waste of electric energy.

[0082] In view of the above-mentioned problem of energy waste, this embodiment proposes an energy recovery circuit and method. The energy recovery circuit may include a sampling control module and a voltage conversion circuit. Among them, the voltage conversion circuit may be a Boost circuit or a Buck circuit. The voltage conversion circuit includes a first switch tube and a second switch tube. When the power module stops supplying power to the load through the voltage conversion circuit, the sampling control module may control the first switch tube and the second switch tube to be alternately turned on; the conduction of the first switch tube is used to control the charging of the inductor, and the conduction of the second switch tube is used to control the capacitor to supply power to the load.

[0083] The sampling control module may include four ports, two monitoring terminals and two control terminals. The two monitoring terminals may be connected to the voltage output terminal and the voltage input terminal of the voltage conversion circuit respectively, for monitoring the magnitude of the voltage value of the output voltage and the input voltage of the voltage conversion circuit, and the two control terminals may be connected to the gates (control terminals) of the first switch tube and the second switch tube respectively, for controlling the conduction and cutoff of the two switch tubes. When the power supply of the voltage conversion circuit is turned off, the sampling control module starts the energy recovery process. In the energy recovery process, the sampling control module may obtain the voltage values ​​of the output voltage and the input voltage, and determine whether the output voltage Vout is greater than or equal to the voltage threshold. When the output voltage Vout is greater than or equal to the voltage threshold, the first switch tube and the second switch tube are alternately turned on according to the first duty cycle, and reverse charging is performed. In this way, after the power supply is turned off, the energy stored in the capacitor C is reversely supplied and returned to the power supply input voltage network, so as to achieve the purpose of energy recovery and reduce unnecessary power loss.

[0084] In the embodiment of the present application, the working process of the voltage conversion circuit may include two types: a forward power supply process and a reverse charging process. In the forward power supply process, the power module supplies power to the load through the voltage conversion circuit. In the reverse charging process, the power module stops supplying power to the load, and the voltage conversion circuit performs an energy recovery process to reversely provide the stored energy (energy storage) in the capacitor to the power module for energy recovery.

[0085] Figure 3 Schematic diagram of a circuit structure of energy recovery disclosed in an exemplary embodiment of the present application. Figure 3 As shown, the energy recovery circuit may include a sampling control module and a Buck circuit (voltage conversion circuit). Among them, the sampling control module may include four ports, two monitoring terminals E1 and E2 and two control terminals S1 and S2. The monitoring terminal can monitor the magnitude of the voltage value, and the control terminal can control the conduction and cutoff of the switch tube. Among them, the monitoring terminal E1 can be connected to the input voltage terminal, and can be used to obtain the voltage value Vin of the input voltage; the monitoring terminal E2 can be connected to the output voltage terminal, and can be used to obtain the voltage value Vout of the output voltage. The control terminal S1 can be connected to the gate Gate of the first switch tube Q1, and can be used to control the conduction and cutoff of Q1, and the control terminal S2 can be connected to the gate Gate of the second switch tube Q2, and can be used to control the conduction and cutoff of Q2.

[0086] also, Figure 3 The connection structure of the first switch tube Q1, the second switch tube Q2, the inductor L, the output filter capacitor C and the resistor R1 can be referred to Figure 1A and Figure 1B Related description.

[0087] like Figure 3As shown, the drain Drain of the first switch tube Q1 and the monitoring terminal E1 of the sampling control module can be connected to the voltage input terminal Vin, and the source Source of the first switch tube Q1 can be connected to the first end of the inductor L1 and the drain Drain of the second switch tube Q2. The voltage output terminal Vout can be connected to the monitoring terminal E2 of the sampling control module, the first end of the capacitor C, the first end of the resistor R1 and the second end of the inductor L1. The source Source of the second switch tube Q2, the second end of the capacitor C and the second end of the resistor R1 can be connected to the GND terminal (ground), the control terminal S1 of the sampling control module can be connected to the gate Gate of Q1, and the control terminal S2 of the sampling control module can be connected to the gate Gate of Q2.

[0088] The power module can supply power to the load through the Buck circuit. Therefore, the voltage input terminal Vin and GND can be connected to the positive and negative poles of the power module (BAT) respectively, and the voltage output terminal Vout and GND can be connected to the load. Exemplarily, the power module is the battery module in the mobile phone, and the load is the upper RF chip, various processors, screen module, etc. in the mobile phone. Of course, the above energy recovery scenario is only an example, and this application is not limited to this.

[0089] Figure 4 This is a schematic diagram of a method for energy recovery disclosed in an exemplary embodiment of the present application. Figure 4 The energy recovery method can be Figure 3 The sampling control module in is executed. Figure 4 As shown, the energy recovery method may include but is not limited to the following steps:

[0090] S401: The sampling control module obtains a power-off signal.

[0091] The sampling control module may also include a trigger terminal ( Figure 3 (not shown in the figure), the trigger end can be used to receive a power-off signal from the outside. For example, the CPU can be connected to the trigger end of the sampling control module. When the CPU determines to turn off the power, it can stop supplying power to the voltage input end and send a power-off signal to the sampling control module. Correspondingly, the sampling control module can receive the power-off signal. If the CPU is in the process of supplying power to the RFIC chip, the CPU may frequently send a power-off signal and a power-on signal, instructing the sampling control module to frequently switch the power supply state, that is, repeatedly switch between the two states of starting power supply and stopping power supply.

[0092] S402: The sampling control module obtains a first input voltage value Vin1 and a first output voltage value Vout1.

[0093] The monitoring terminal 1 of the sampling control module is connected to the voltage input terminal, and the sampling control module can collect the first input voltage value Vin1 through the monitoring terminal 1; the monitoring terminal 2 of the sampling control module is connected to the voltage output terminal, and the first input voltage Vout1 can be collected through the monitoring terminal 2.

[0094] The above acquisition process can be performed according to a specific cycle. The sampling control module can collect Vin1 and Vout1 according to the first acquisition frequency k1 (the corresponding acquisition cycle is 1 / k1). For sampling control modules of different chips, k1 varies greatly. Usually, the acquisition is carried out in a polling manner, that is, the sampling control module collects continuously, and after each acquisition is completed, the next cycle of acquisition is immediately started. In order to ensure the transient response speed of the power supply, the higher the acquisition frequency, the better.

[0095] S403: The sampling control module determines whether the first output voltage value Vout1 is greater than or equal to the first voltage threshold Vth1. If Vout1 is greater than or equal to (greater than) the first voltage threshold Vth1, execute S405 to execute the energy recovery process; otherwise, execute S404 to end the energy recovery process.

[0096] Specifically, the sampling control module can determine whether the first output voltage value Vout1 is greater than the first voltage threshold Vth1. When the first output voltage value Vout1 is greater than or equal to (greater than) the first voltage threshold Vth1, S405 can be executed, that is, the energy recovery process is executed; when the first output voltage value Vout1 is less than (less than or equal to) the first voltage threshold Vth1, S404 is executed to end the energy recovery process.

[0097] Among them, the sampling control module obtains Vout1 according to the first acquisition frequency k1. Each time Vout1 is obtained, the sampling control module executes a process of judging whether the first output voltage value Vout1 is greater than or equal to the first voltage threshold Vth1. Therefore, the judgment operation can be performed at the first acquisition frequency k1. After the power is turned off, as time goes by, the voltage difference across the capacitor C will decrease, that is, the first output voltage value Vout1 will decrease. When the first output voltage value Vout1 decreases to a certain extent, energy recovery is not cost-effective, and the energy recovery execution process is stopped. In this way, it can be ensured that the recovered energy is greater than the power consumption of the device when executing energy recovery, and the benefits and necessity of executing energy recovery can be guaranteed.

[0098] Among them, the first voltage threshold Vth1 is the voltage value of the preset value of the sampling control module. The first voltage threshold Vth1 can be 0.1Voutx~0.5Voutx, Voutx is the voltage value of the stable output during the charging process (the voltage value of the voltage output end), that is, the voltage value across the output capacitor C during the normal operation of the Buck circuit, which can also be understood as the working voltage of the load module. Exemplarily, the first voltage threshold is 0.2Voutx. That is, it can be understood that when the voltage of the output capacitor of the Buck circuit is greater than 0.2 times the normal working voltage of Buck, the output capacitor voltage has enough energy on the capacitor, and the reverse charging needs to continue to work. In this way, it can be ensured that when the capacitor energy is sufficient, the energy is continuously recovered; when the capacitor energy is less than a threshold value, it is determined that the capacitor energy is insufficient and not worth recycling, that is, the energy recovery process is terminated. In the embodiment of the present application, in the process of designing the circuit structure of energy recovery, the size of a first voltage threshold Vth1 can be determined in advance, and it can be directly used during the execution of S403.

[0099] S404: The sampling control module ends the energy recovery process.

[0100] The sampling control module can stop the energy recovery process of S401 to S406, stop obtaining the first input voltage value Vin1 and the first output voltage value Vout1, stop calculating the first duty cycle D1, and stop controlling the staggered conduction of the first switch tube and the second switch tube based on the first duty cycle D1, and execute the reverse charging process.

[0101] S405: The sampling control module calculates the first duty cycle D1.

[0102] When the sampling control module obtains the first input voltage value Vin1 and the first output voltage value Vout1 through two monitoring terminals, the sampling control module can calculate the first duty cycle D1 according to the first switching frequency f1, the first input voltage value Vin1 and the first output voltage value Vout1. Among them, the first time period T1 is the reciprocal of the first switching frequency 1 / f1, T1=1 / f1=Ton1+Toff1. The first time period is the time period for switching the first switch tube and the second switch tube, and the first switching frequency is the frequency of switching the first switch tube and the second switch tube on and off. The first upper tube conduction time Ton1 is the conduction time of Q2 in the reverse charging circuit process of the Buck circuit (i.e. Figure 3 The first upper tube cut-off time Toff1 is the cut-off time of Q2 in the reverse charging circuit of the Buck circuit (i.e. Figure 3 The conduction time of Q1 in the circuit).

[0103] The reverse charging process of the Buck circuit can be understood as the forward power supply process of the Boost circuit. The duty cycle calculation process of the Boost circuit can be: the upper tube conduction time Ton = (1-Vin / Vout) * 1 / f; the upper tube cut-off time: Toff = Vin / Vout * 1 / f. The upper tube is in the boost circuit. Figure 2A The in refers to the first switch tube Q1. So far, the duty cycle can be calculated as D1=Ton / T=1-Vin / Vout.

[0104] Figure 3 Buck circuit in Figure 2A The Boost circuit topology in is mirror-symmetrical, that is, the output voltage Vout of the reverse charge is Figure 3 The first input voltage value Vin1 in the reverse charging is Figure 3 The first output voltage value Vout1 in Figure 3 In the process of reverse charging, the first duty cycle is calculated as D1=1-Vout1 / Vin1.

[0105] Furthermore, the sampling control module also needs to determine the first upper tube conduction time Ton1 and the first upper tube off time Toff1 during the reverse charging process. At this time, the first upper tube conduction time Ton1 refers to Figure 3 The conduction time of the second switch tube Q2 in the first upper tube is Toff1. Figure 3 The on-time of the first switch tube Q1 (the off-time of the second switch tube Q2).

[0106] In a possible implementation, if the sampling control module is of PWM control type, the first switching frequency f1 is known to be fixed. After collecting Vin1 and Vout1, the sampling control module also needs to calculate Ton1 and Toff1:

[0107] Ton1=(1-Vout1 / Vin1)*1 / f1

[0108] Toff1=T1-Ton1=1 / f1-(1-Vout1 / Vin1)*1 / f1=(Vout1 / Vin1)*1 / f1

[0109] In another possible implementation, if the sampling control module is a pulse frequency modulation PFM control type, in this case, Ton1 is fixed and known (in this case, f1, T1 and D1 are uncertain), after sampling Vin1 and Vout1, D1, T1 and Toff1 can be calculated:

[0110]

[0111]

[0112]

[0113] It should be noted that in the embodiment of the present application, the first acquisition frequency k1 and the first switching frequency f1 are different, k1 refers to the frequency of collecting the output voltage and the output voltage, corresponding to the two monitoring ends of the sampling control module, and f1 refers to the frequency of controlling the switch switching, corresponding to the two control ends of the sampling control module.

[0114] It should be noted that the first duty cycle D1 is calculated once each time Vout1 and Vin1 are obtained, and the calculation frequency of the first duty cycle D1 is the same as that of Vout1 and Vin1, which is k1. The first duty cycle obtained by each calculation may not be the same.

[0115] S406: The sampling control module controls the first switch tube and the second switch tube to be turned on and off alternately based on the first duty cycle D1 to execute the reverse charging process.

[0116] The sampling control module can control the second switch tube to turn on and the first switch tube to turn off based on the first duty cycle; then control the first switch tube to turn on and the second switch tube to turn off in order to control the two switch tubes to turn on alternately for reverse charging. As time changes, the first duty cycle calculated each time in S405 may not be the same. In S406, the sampling control module needs to control the first switch tube and the second switch tube to turn on alternately based on the latest calculated first duty cycle. If the first duty cycle changes, the sampling control module switches the duty cycle to the first duty cycle after the change.

[0117] Figure 5A and Figure 5B It is a circuit diagram of a set of reverse charging processes exemplarily shown in an embodiment of the present application.

[0118] The reverse charging process of one cycle may include the following phase three and phase four, where phase three is performed first and then phase four.

[0119] like Figure 5A As shown in the figure, the control result of the third stage of the reverse charging process is exactly the same as Figure 2A The first stage of the forward power supply process is the same (mirror symmetrically): the sampling control module controls the first switch tube Q1 to be turned off and the second switch tube Q2 to be turned on.

[0120] Phase 3: Q1 is turned off, Q2 is turned on, and the inductor current flows from right to left. Figure 2A When the Boost circuit in FIG. 1 is working (when the power is turned on), the direction of the inductor current (mirror symmetry, from left to right) is consistent, and the inductor L1 is reversely charged. The duration of the reverse charging state 1 can be equal to the duration of Ton1.

[0121] When Q2 is turned on, the left end of the inductor L1 is grounded through Q2, and the voltage at the left end of the inductor L1 is close to 0V. The voltage at the second end of the inductor L1 is equal to the real-time voltage Vout1 at the upper end of the capacitor C (i.e., the output voltage of the Buck circuit). Among them, since the inductance L1 of the inductor L1 is a fixed constant, the voltage drop Vx across the inductor L1 is Vout1. Since Vout1 will become smaller and smaller with reverse charging, the voltage drop Vx across the inductor L1 will become smaller and smaller. Because L1 does not change, based on Vx=L1*di / dt, di / dt gradually becomes smaller, and the current increment becomes smaller and smaller, but the inductor current will still increase. The current curve is similar to a parabola in the rising stage. Figure 5A As shown, the direction of the current i is C->L1->Q2->C. The voltage of capacitor C can charge the inductor L1.

[0122] like Figure 5B As shown, the control result in stage 4 of the reverse charging process is exactly the same as Figure 2B The second stage of the forward power supply process is the same (mirror symmetrically): the sampling control module controls the second switch tube Q2 to be turned off, and the first switch tube Q1 to be turned on.

[0123] Phase 4: Q2 is turned off, Q1 is turned on, the current of the inductor L1 cannot change suddenly, and the current flows through the inductor L1 and Q1 into the power supply (Battery, BAT) to charge the power module BAT. The duration of the reverse charging state 2 can be equal to the duration of Toff1.

[0124] exist Figure 5A In stage three, the inductor L1 has been energy stored, and current flows through it, with the direction of the current flowing from right to left. Among them, since L1 is fixed, the voltage at the second end of the inductor L1 is the real-time voltage Vout of the first end of the capacitor C, and the voltage at the first end of the inductor L1 is Vin, where Vin is the input voltage of the Buck circuit, and the voltage drop across the inductor L1 is Vx=Vout-Vin. Because, in the Buck circuit, Vout is smaller than Vin, and Vout will become smaller and smaller with reverse charging, so the voltage drop Vx across the inductor is a negative value and will become smaller and smaller. Because L1 is unchanged, based on Vx (negative value)=L1*di / dt, di / dt is a negative value and becomes smaller and smaller. The current i of the inductor L1 decreases more and more with time t, and the inductor current becomes smaller and smaller. The current curve is similar to a parabola in the descending stage. As shown Figure 5B As shown, the direction of the current i is C->L1->Q1->BAT->C. The inductor L1 is discharged at this time and can charge the power supply BAT.

[0125] In the above process, the reverse charging process (reverse process) of the Buck circuit topology can be regarded as the normal working process of the Boost circuit. When the power supply of the Buck circuit stops working, the reverse power supply of the Buck circuit can be realized by controlling the turn-on sequence of the switch tubes Q2 first and then Q1. The sampling control module needs to adjust the turn-on timing of Q2 and Q1 in real time according to the real-time voltage of Vout and Vin, so that the circuit outputs a fixed VIN voltage, thereby reversely recovering the energy stored in the output capacitor C to the power module BAT. In the above process, the mirror symmetry of the Buck circuit topology and the Boost circuit topology is cleverly utilized. The working principle of the Buck circuit is to step down from left to right and step up from right to left to recover energy, so as to reduce the loss of electric energy and save energy.

[0126] Fig. 6A 1 is a timing diagram of the alternating conduction of the switch tubes in a reverse charging process disclosed in an exemplary embodiment of the present application. Fig. 6A As shown, the sampling control module can determine the first duty cycle and control the first switch tube and the second switch tube to be turned on and off. After each execution of S406, the electronic device determines whether to continue the energy recovery process. Assuming that the acquisition control module executes S403 for the first time, the acquisition control module can determine that Vout1 is greater than the voltage threshold Vth. When the energy recovery process is executed, the reverse charging process is executed according to the first switching frequency f1, that is, it includes first controlling stage three and then being in stage four.

[0127] like Fig. 6A As shown, when the power-off signal is obtained, the energy recovery process is executed from the moment Ts. Determine whether to execute the reverse charging process (S403) once. If the judgment result is yes, from the moment t1 to the moment t2, the Q1 state can be first executed as off and the Q2 state can be changed to the Q1 state being on and the Q2 state being off. The acquisition control module can continue to determine whether to execute the reverse charging process according to the first acquisition frequency k1: if yes, the above reverse charging process is executed once from the moment t2 to the moment t3. In the case of continuing to judge that the execution of the reverse charging process is yes, the above reverse charging process is continued from the moment t3 to the moment t4. At the moment Te, it is determined that the reverse charging process is not executed, that is, S404 is executed to end the energy recovery process. The time period and duty cycle of each of the above may be the same or different, and this application is not limited to this.

[0128] It should be noted that in actual applications, in order to prevent Q1 and Q2 from being turned on at the same time at the switching moment (the upper tube Q1 and the lower tube (low-side mosfet) Q2 are turned on at the same time, which will cause Vin to pass directly to GND and cause the MOS tube to burn out), at the moment when Q1 and Q2 switch their states, Q1 and Q2 will be turned off for a very short time. This period of time is the so-called dead time. Fig. 6A As shown, taking the switching cycle from time t1 to time t2 as an example, there is a dead time during the period when the Q1 state switches from off to on, and there is also a dead time during the period when the Q1 state switches from on to off (the next cycle).

[0129] In order to compare the forward power supply process of the Buck circuit before the power is turned off, Figure 6B 1 is a timing diagram of the alternating conduction of the switch tubes in the forward power supply process disclosed in an exemplary embodiment of the present application. Figure 6B As shown, starting from the time Ta, the power switch is turned on (for example, the acquisition control module receives the power on signal from the CPU) and the electronic device starts the forward working process of the Buck circuit: in a switching cycle from the time s1 to the time s2, the state of Q1 is first turned on and then turned off, and the state of Q2 is first turned off and then turned on. In the period from the time s1 to the time sx, Q1 is turned on and Q2 is turned off, corresponding to the reference Figure 1A In the first stage; from time sy to time sz, Q1 is turned off and Q2 is turned on, corresponding to the reference Figure 1B The switching cycle from s2 to s3, and the switching cycle from s3 to s4 are all processed according to the same execution logic as above, which will not be repeated. At Ts, the power is turned off, and the sampling control module can receive the power off signal. The energy recovery process after Ts can be referred to Fig. 6A The relevant description is not repeated here.

[0130] Figure 7 FIG. 1 is a schematic diagram of another circuit structure of energy recovery disclosed in an exemplary embodiment of the present application. Figure 7As shown, the energy recovery circuit may include a sampling control module and a Boost circuit (voltage conversion circuit). Among them, the sampling control module may include four ports, two monitoring terminals E1 and E2 and two control terminals S1 and S2. The monitoring terminal can monitor the magnitude of the voltage value, and the control terminal can control the conduction and cutoff of the switch tube. Among them, the monitoring terminal E1 can be connected to the input voltage terminal, and can be used to obtain the voltage value Vin of the input voltage; the monitoring terminal E2 can be connected to the output voltage terminal, and can be used to obtain the voltage value Vout of the output voltage. The control terminal S1 can be connected to the gate Gate of the first switch tube Q1, and can be used to control the conduction and cutoff of Q1, and the control terminal S2 can be connected to the gate Gate of the second switch tube Q2, and can be used to control the conduction and cutoff of Q2.

[0131] also, Figure 7 The connection structure of the first switch tube Q1, the second switch tube Q2, the inductor L1, the output filter capacitor C and the resistor R1 can refer to Figure 2A and Figure 2B Related description.

[0132] like Figure 7 As shown, the first end of the inductor L1 and the monitoring end E1 of the sampling control module can be connected to the voltage input end Vin, and the second end of the inductor L1 can be connected to the drain Drain of the first switch tube Q1 and the drain Drain of the second switch tube Q2. The voltage output end Vout can be connected to the monitoring end E2 of the sampling control module, the first end of the capacitor C, the first end of the resistor R1, and the source Source of the second switch tube Q2. The source Source of the first switch tube Q1, the second end of the capacitor C, and the second end of the resistor R1 can be connected to the GND end (grounded). The control end S1 of the sampling control module can be connected to the gate Gate of Q1, and the control end S2 of the sampling control module can be connected to the gate Gate of Q2.

[0133] The power module can supply power to the load through the Boost circuit. Therefore, the voltage input terminal Vin and GND can be connected to the positive and negative poles of the power module (BAT) respectively, and the voltage output terminal Vout and GND can be connected to the two ends of the load.

[0134] Figure 8 : is a schematic flow chart of another energy recovery method disclosed in an exemplary embodiment of the present application. Figure 8 The energy recovery method can be Figure 7 The sampling control module in is executed. Figure 8 As shown, the energy recovery method may include but is not limited to the following steps:

[0135] S801: The sampling control module obtains a power-off signal.

[0136] The specific description of S801 can refer to the relevant description of S401, which is not repeated here.

[0137] S802: The sampling control module obtains a second input voltage value Vin2 and a second output voltage value Vout2.

[0138] The above acquisition process may be performed according to a specific period. The sampling control module may acquire Vin2 and Vout2 according to a second acquisition frequency k2 (the corresponding acquisition period is 1 / k2).

[0139] S803: The sampling control module determines whether the second output voltage value Vout2 is greater than or equal to the second voltage threshold Vth2. If Vout2 is greater than or equal to (greater than) the second voltage threshold Vth2, execute S805 to execute the energy recovery process; otherwise, execute S804 to end the energy recovery process.

[0140] The second voltage threshold Vth2 is a voltage value preset by the sampling control module. For different types of Boost circuits, the range of the second voltage threshold Vth2 may be different.

[0141] The Boost circuit may be a synchronous type. When the Boost upper tube (the second switch tube Q2) is a transistor, the Boost circuit is called a synchronous Boost.

[0142] In one case, when Figure 7 When the Boost circuit is synchronous, the second voltage threshold can be set to 0.1Vouty~0.5Vouty. Vouty is the voltage value of the stable output during the forward power supply process (voltage output end), that is, the voltage value across the output capacitor C during the forward power supply process of the Boost circuit. For example, the second voltage threshold Vth2 is 0.2*Vouty. That is, it can be understood that when the voltage of the output capacitor of the Boost circuit is greater than the output capacitor voltage of 0.2 times the normal working voltage of the Boost, there is enough energy on the capacitor, and reverse charging needs to continue to work.

[0143] In another case, when Figure 7When the Boost circuit in is a synchronous Boost, the range of the second voltage threshold can be 1.1Viny to 1.5Viny, where Viny is the voltage value of the stable input during the forward power supply process, that is, the voltage value of the voltage output terminal during the normal operation of the Boost circuit. For example, the second voltage threshold Vth2 can be set to 1.2*Viny, that is, when the Vout network capacitor voltage is greater than or equal to (greater than) 1.2 times Viny, it is considered that the energy of capacitor C is sufficient and the energy recovery process needs to be continued. When it is less than (less than or equal to) 1.2*Viny, it is determined that the energy of capacitor C is very little and is not worth recovering, that is, S804 is executed.

[0144] S804: The sampling control module ends the energy recovery process.

[0145] The sampling control module may stop the energy recovery process of S801 to S806 .

[0146] S805: The sampling control module calculates the second duty cycle D2.

[0147] When the sampling control module obtains the second input voltage value Vin2 and the second output voltage value Vout2 through two monitoring terminals, the sampling control module can calculate the second duty cycle D2 according to the second switching frequency f2, the second input voltage value Vin2 and the second output voltage value Vout2. Among them, the second time period T2 is the reciprocal of the second switching frequency 1 / f2, T2=1 / f2=Ton2+Toff2. The second time period is the time period for switching the first switch tube and the second switch tube, and the second switching frequency is the frequency for switching the first switch tube and the second switch tube. The second upper tube conduction time Ton2 is the conduction time of Q2 during the reverse charging process of the Boost circuit (i.e. Figure 7 The second upper tube cut-off time Toff2 is the cut-off time of Q2 in the reverse charging circuit process of the Boost circuit (i.e. Figure 7 The conduction time of Q1 in the circuit).

[0148] The reverse charging circuit of the Boost circuit is the Buck circuit. The duty cycle calculation formula of the Buck circuit is as follows: upper tube turn-on time: Ton = Vout / Vin*1 / f; upper tube turn-off time: Toff = (1-Vout / Vin)*1 / f; switching period: T = 1 / f, where f is the switching frequency, duty cycle: D = Ton / T = Vout / Vin.

[0149] In this application Figure 7 The Boost circuit in Figure 1A The Buck circuit topology in is mirror-symmetrical, and the output voltage Vout of the Boost reverse charging is Figure 7Vin2 in the figure; the input voltage Vin for Boost reverse charging is Figure 7 Therefore, Figure 7 In the process of reverse charging, the second duty cycle D2 = Vin2 / Vout2.

[0150] Furthermore, the sampling control module also needs to determine the second upper tube conduction time Ton2 and the second upper tube off time Toff2 during the reverse charging process. At this time, the second upper tube conduction time Ton2 refers to Figure 7 The conduction time of the second switch tube Q2 in the second upper tube, the cut-off time Toff2 refers to Figure 7 The cut-off time of the second switch tube Q2 in.

[0151] In a possible implementation, if the sampling control module is of PWM control type, the second switching frequency f2 is known to be fixed. After collecting Vin2 and Vout2, the sampling control module also needs to calculate Ton2 and Toff2:

[0152]

[0153]

[0154] In another possible implementation, if the sampling control module is a pulse frequency modulation PFM control type, Ton2 is fixed and known (at this time, f2, T2 and D2 are uncertain), after sampling Vin2 and Vout2, D2, T2 and Toff2 can be calculated:

[0155] D2=Vin2 / Vout2=Ton2 / T2

[0156]

[0157]

[0158] S806: The sampling control module controls the first switch tube and the second switch tube to be turned on and off alternately based on the second duty cycle D2 to execute the reverse charging process.

[0159] The sampling control module can first control the second switch tube to be turned on and the first switch tube to be turned off based on the second duty cycle D2; then control the first switch tube to be turned on and the second switch tube to be turned off in sequence to control the two switch tubes to switch on alternately for reverse charging.

[0160] Fig.9A and Fig. 9B It is a circuit diagram of another set of reverse charging processes exemplarily shown in an embodiment of the present application.

[0161] The reverse charging process of one cycle may include the following phase three and phase four, where phase three is performed first and then phase four.

[0162] like Fig.9A As shown in the figure, the control result of the third stage of the reverse charging process is exactly the same as Figure 1A The first stage of the forward power supply process is the same (mirror symmetrically): the sampling control module controls the first switch tube Q1 to be turned off and the second switch tube Q2 to be turned on.

[0163] Phase 3: Q1 is turned off, Q2 is turned on, the inductor current flows from right to left, and the inductor current direction during Boost operation is opposite, charging the inductor L1 in reverse, and supplying power to the power supply BAT through the capacitor and inductor.

[0164] When Q2 is turned on and Q1 is turned off, the voltage at the right end of the inductor L1 is the real-time voltage at the upper end of the capacitor C, which can be the output voltage Vout of the Boost circuit. The voltage at the left end of the inductor L1 is Vin, which is the input voltage of the Boost circuit. If the current direction of the inductor L1 is changed from the right end to the left end, the voltage drop across the inductor L1 is Vx = Vout-Vin. Since the boost circuit is a voltage-boosting circuit, Vout is greater than Vin, Vx is a positive value, and decreases with time. Based on L1*di / dt = Vout-Vin, and the inductor L1 is a constant, the inductor current i increases. Fig.9A As shown, in the reverse charging state 1, the current i flows in the direction of C->Q2->L1->BAT->C.

[0165] like Fig. 9B As shown, the control result in stage 4 of the reverse charging process is exactly the same as Figure 1B The second phase of the forward power supply process is the same (mirror symmetrically). The sampling control module controls the second switch tube Q2 to be turned off and the first switch tube Q1 to be turned on.

[0166] Phase 4: Q2 is turned off, Q1 is turned on, the current in the inductor L1 cannot change suddenly, and the current flows into the power supply (Battery, BAT) through the inductor L1 and Q1 to charge the power supply BAT.

[0167] When Q2 is cut off and Q1 is turned on, the right end of the inductor L1 is grounded through Q1. Therefore, the voltage at the right end of the inductor L1 is close to 0V. If the inductor L1 continues to flow, an electromotive force will be generated. Since the disconnection time is extremely short, the voltage at the first end of the inductor remains unchanged at Vin. Therefore, the voltage difference across the inductor L1 is Vx = -Vin. Based on L*di / dt = Vx, Vx is a negative value, and the inductance value of the inductor L1 is a constant, the inductor current is reduced. If Fig. 9BAs shown, in the reverse charging state 2, the current i flows in the direction of L1->BAT->Q1->L1, and the inductor current decreases.

[0168] In the above process, the Boost circuit topology can be regarded as the reverse process of the Buck circuit topology. When the Boost circuit stops working and starts the reverse charging process, the reverse Boost power supply of the circuit can be realized by controlling the turn-on sequence of the switch tubes Q2 and then Q1. The sampling control module needs to adjust the turn-on timing of Q2 and Q1 in real time according to the real-time voltage of Vout2 and Vin2, so that the Boost circuit reversely outputs a fixed VIN voltage, thereby reversely charging the energy stored in the capacitor C to the power module BAT. In the above process, the mirror symmetry of the Boost circuit topology and the Buck circuit topology is cleverly utilized. The working principle of the Boost circuit is to step up from left to right and step down from right to left to recover energy, so as to reduce the loss of electric energy and save energy.

[0169] It should be noted that the above Figure 8 S801 to S806 may correspond to the relevant description of S401 to S406, and the same parts will not be repeated here.

[0170] In addition, the switching state of Q1 and Q2 during reverse charging can be referred to Fig. 6A The content is not repeated here.

[0171] It should be noted that the methods and circuits of the above embodiments can be used in switching power supplies, integrated circuits, (Organic Light-Emitting Diode, OLED) bias driver chip ICs or organic laser display OLED power management integrated circuits PMIC (Power Management IC, PMIC), backlight driver ICs and other related fields.

[0172] The switch tube Q provided in the embodiment of the present application can be an insulated gate bipolar transistor (IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET), a triode, a thyristor, a thyristor and other power switch tube devices, or other controllable devices, which are not limited in the present application. Among them, the control end of the switch tube can be the gate of the transistor, the base of the triode, or the port for controlling the switch to be closed and opened, which is not limited in the present application.

[0173] In addition, the second switch tube in the Boost circuit may also be a diode or a transistor, which is not limited in the present application.

[0174] This embodiment can be used for switching power supplies, power electronic power modules, semiconductor power chips, power modules for consumer electronic products such as PCs, tablets, mobile phones, wearable devices, etc., but this application does not limit this.

[0175] The present application embodiment discloses a printed circuit board (PCB), which may include the above-mentioned Figure 3 to Figure 9B For example, the PCB board may include a circuit of a power module, and the power supply voltage regulating circuit may be integrated into the power module of the PCB board to supply power to other loads.

[0176] The present application embodiment discloses a chip, which may include the above Figure 3 to Figure 9B For example, the power supply chip can integrate the above power supply voltage regulation circuit in the output circuit of the power module, and the circuit can regulate the voltage in the process of supplying power to other modules.

[0177] The present application embodiment discloses a power supply system, which may include the above-mentioned Figure 3 to Figure 9B Any energy recovery circuit in.

[0178] The present application embodiment discloses a power supply circuit, which may include an energy recovery circuit and a load circuit. The energy recovery circuit may be the above-mentioned Figure 3 to Figure 9B Any one of .

[0179] The present application embodiment discloses a power supply circuit, which may include an energy recovery circuit and a power supply. The power supply voltage regulation circuit may be the above-mentioned Figure 3 to Figure 9B Any one of .

[0180] The present application embodiment discloses an electronic device, which includes an energy recovery circuit. The energy recovery circuit can be the above-mentioned Figure 3 to Figure 9B Any one of the above. The electronic device may be a mobile phone, a tablet, a computer, a computing device, a smart watch, a server, a calculator, and the like, without limitation.

[0181] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more available media integrated. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state hard disk), etc.

Claims

1. An energy recovery circuit, used to connect a power module and a load, characterized in that: It includes a sampling control module and a voltage conversion circuit; the voltage conversion circuit is a step-down circuit or a step-up circuit, wherein: The voltage conversion circuit includes a first switch tube Q1, a second switch tube Q2, an output filter capacitor C and an inductor L; The sampling control module has two control terminals, which are respectively connected to Q1 and Q2; the two control terminals respectively control the conduction and cutoff of Q1 and Q2; In the case where the power supply module supplies power to the load through the voltage conversion circuit, the sampling control module controls Q1 to be turned on and Q2 to be turned off to control L to store energy, and controls Q1 to be turned off and Q2 to be turned on to control L to supply power to the load; When the power module stops supplying power to the load through the voltage conversion circuit, if the Vout of the voltage conversion circuit is greater than or equal to the Vth, the sampling control module controls Q1 and Q2 to be turned on and off alternately based on the switching frequency, and reversely provides the energy of the voltage conversion circuit to the power module.

2. The circuit according to claim 1, characterized in that The sampling control module controls the Q1 and the Q2 to be turned on and off alternately based on the switching frequency, including: In a corresponding switching cycle of the switching frequency, the sampling control module first controls Q1 to be turned off and Q2 to be turned on; and then controls Q1 to be turned on and Q2 to be turned off.

3. The circuit according to claim 2, characterized in that When Q1 is turned off and Q2 is turned on, the current direction of L is opposite to the charging current of L, so as to store energy in the reverse direction of L; The charging current is the current when the power module supplies power to the load through the voltage conversion circuit; When Q1 is turned on and Q2 is turned off, the current direction of L is opposite to the direction of the charging current, so as to reversely charge the power module that supplies power to the voltage conversion circuit.

4. The circuit according to any one of claims 1 to 3, characterized in that: The sampling control module also obtains the output voltage value Vout of the voltage conversion circuit based on the acquisition frequency k; When the Vout is acquired, the sampling control module determines whether the Vout is greater than or equal to the Vth.

5. The circuit according to claim 4, characterized in that The sampling control module also has two monitoring terminals E1 and E2; E1 is connected to the voltage output terminal of the voltage conversion circuit, and E2 is connected to the voltage input terminal of the voltage conversion circuit; the sampling control module also obtains the output voltage value Vout of the voltage conversion circuit based on the acquisition frequency, including: the sampling control module obtains the Vout of the voltage conversion circuit based on the k through the E1; the sampling control module also obtains the input voltage value Vin of the voltage conversion circuit based on the k through the E2.

6. The circuit according to claim 5, characterized in that The sampling control module controls the Q1 and the Q2 to be turned on and off alternately based on the switching frequency, including: The sampling control module obtains a duty cycle based on the Vin and the Vout; The sampling control module controls Q1 and Q2 to be turned on and off alternately based on the switching frequency based on the duty cycle.

7. The circuit according to claim 6, characterized in that In the case where the voltage conversion circuit is a buck circuit, the duty cycle is D1=1-Vout / Vin, wherein Vin is the input voltage of the buck circuit, and Vout is the output voltage of the buck circuit; In the case where the voltage conversion circuit is a boost circuit, the duty cycle is D2 = Vin / Vout, wherein Vin is the input voltage of the boost circuit, and Vout is the output voltage of the boost circuit.

8. The circuit according to claim 6 or 7, characterized in that After the sampling control module obtains the duty cycle based on the Vin and the Vout, the sampling control module further calculates the upper tube on time Ton and the upper tube off time Toff; The sampling control module first controls Q1 to be turned off and Q2 to be turned on; and then controls Q1 to be turned on and Q2 to be turned off, including: In the Ton period, the sampling control module first controls Q1 to be turned off and Q2 to be turned on; In the Toff period, the sampling control module controls Q1 to be turned on and Q2 to be turned off.

9. The circuit according to claim 8, characterized in that The sampling control module also calculates the upper tube on time Ton and the upper tube off time Toff, including: In the case where the voltage conversion circuit is a step-down circuit, if the sampling control module is a pulse width modulation PWM control type, the upper tube conduction time Ton = (1-Vout / Vin)*1 / f; the upper tube cut-off time Toff = (Vout / Vin)*1 / f; if the sampling control module is a pulse frequency modulation PFM control type; the upper tube cut-off time Toff = Ton*Vin / (Vin-Vout)-Ton1; In the case where the voltage conversion circuit is a boost circuit, if the sampling control module is a PWM control type, the upper tube conduction time Ton=Vin / Vout*1 / f; the upper tube cut-off time Toff=1 / f(1-Vin / Vout); if the sampling control module is a PFM control type, the upper tube cut-off time Toff=Ton*(Vout / Vin-1).

10. The circuit according to any one of claims 4 to 9, characterized in that: After the sampling control module determines whether the Vout is greater than or equal to the Vth, if the Vout is less than the Vth, the sampling control module stops executing the control of the Q1 and the Q2 to be turned on and off alternately based on the switching frequency.

11. The circuit according to any one of claims 1 to 10, characterized in that: When the voltage conversion circuit is a step-down circuit, the voltage threshold range is 0.1Voutx to 0.5Voutx; Voutx is the output voltage value of the voltage conversion circuit when the power module supplies power to the load through the voltage conversion circuit; When the voltage conversion circuit is a boost circuit, the voltage threshold range is 1.1Viny to 1.5Viny; Viny is the input voltage value of the voltage conversion circuit when the power module supplies power to the load through the voltage conversion circuit.

12. The circuit according to any one of claims 1 to 11, characterized in that: In the case where the voltage conversion circuit is a step-down circuit, the drain of Q1 is connected to the voltage input terminal of the voltage conversion circuit, the source of Q1 is connected to the first end of L and the drain of Q2; the second end of L is connected to the first end of C and the voltage output terminal of the voltage conversion circuit; the source of Q2 and the second end of C are grounded; When the voltage conversion circuit is a boost circuit, the first end of L is connected to the voltage input end of the voltage conversion circuit, the second end of L is connected to the drain of Q1 and the drain of Q2; the source of Q2 is connected to the first end of C and the voltage output end of the voltage conversion circuit; the source of Q1 and the second end of C are grounded.

13. An energy recovery method, characterized in that: The method is applied to an energy recovery circuit, which includes a sampling control module and a voltage conversion circuit; the voltage conversion circuit is a buck circuit or a boost circuit, wherein: The voltage conversion circuit includes a first switch tube Q1, a second switch tube Q2, an output filter capacitor C and an inductor L; The sampling control module has two control terminals, which are respectively connected to Q1 and Q2; the two control terminals respectively control the conduction and cutoff of Q1 and Q2; In the case where the power supply module supplies power to the load through the voltage conversion circuit, the sampling control module is used to control the Q1 to be turned on and the Q2 to be turned off to control the L to store energy, and to control the Q1 to be turned off and the Q2 to be turned on to control the L to supply power to the load; When the power supply module stops supplying power to the load through the voltage conversion circuit, if the output voltage value Vout of the voltage conversion circuit is greater than or equal to the voltage threshold Vth, the sampling control module is used to control Q1 and Q2 to be turned on and off alternately based on the switching frequency, and to reversely provide the energy of the voltage conversion circuit to the power supply module.

14. The method according to claim 13, characterized in that The sampling control module is used to control the Q1 and the Q2 to be turned on and off alternately based on the switching frequency, including: In a corresponding switching cycle of the switching frequency, the sampling control module is used to first control Q1 to be turned off and Q2 to be turned on; and then control Q1 to be turned on and Q2 to be turned off.

15. The method according to claim 14, characterized in that When Q1 is turned off and Q2 is turned on, the current direction of L is opposite to the charging current of L, so as to store energy in the reverse direction of L; The charging current is the current when the power module supplies power to the load through the voltage conversion circuit; When Q1 is turned on and Q2 is turned off, the current direction of L is opposite to the direction of the charging current, so as to reversely charge the power module that supplies power to the voltage conversion circuit.

16. The method according to any one of claims 13 to 15, characterized in that: If the Vout of the voltage conversion circuit is less than the Vth, the sampling control module is used to stop controlling the Q1 and the Q2 to be turned on and off alternately based on the switching frequency.

17. The method according to any one of claims 13 to 16, characterized in that: The sampling control module is used to control the Q1 and the Q2 to be turned on and off alternately based on the switching frequency, including: The sampling control module is used to obtain a duty cycle based on the input voltage value Vin and the Vout; The sampling control module is used to control Q1 and Q2 to be turned on and off alternately based on the switching frequency based on the duty cycle.

18. The method according to any one of claims 13 to 17, characterized in that: In the case where the voltage conversion circuit is a buck circuit, the duty cycle is D1=1-Vout / Vin, wherein Vin is the input voltage of the buck circuit, and Vout is the output voltage of the buck circuit; In the case where the voltage conversion circuit is a boost circuit, the duty cycle is D2 = Vin / Vout, wherein Vin is the input voltage of the boost circuit, and Vout is the output voltage of the boost circuit.

19. An electronic device, characterized in that: The electronic device comprises the energy recovery circuit as claimed in any one of claims 1-12.

20. A chip, characterized in that: The chip comprises the energy recovery circuit as described in any one of claims 1-12.

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