DC-DC switching power supply circuit and implementation method

Abstract

The embodiment of the invention provides a DC-DC switching power supply circuit and an implementation method, and the DC-DC switching power supply circuit comprises a self-compensation sampling and holding band-gap reference source which is used for generating reference voltage and compensating the periodically closed reference voltage through DC-DC feedback voltage; and the output charge quick response module is used for accelerating rising or falling of the output voltage when the output voltage needs to be changed based on the reference voltage. According to the technical scheme of the embodiment of the invention, the static power consumption of DC-DC can be reduced, and the response speed of the output voltage can be accelerated.

Description

Technical Field

[0001] This document relates to the technical field of integrated circuit design, and in particular to a DC-DC switching power supply circuit and an implementation method. Background Art

[0002] As the core module of the power management system, DC-DC switching power supplies are widely used in portable devices, IoT terminals, industrial control and other fields. With the miniaturization and intelligent development of electronic equipment, DC-DC switching power supplies need to meet the dual requirements of low power consumption and fast dynamic response: In terms of low power consumption, in battery-powered scenarios (such as wearable devices and wireless sensor nodes), the quiescent current of the converter directly affects the system's endurance. It is necessary to minimize the quiescent power consumption of the power supply and turn off unnecessary modules to reduce the quiescent current. In terms of fast response, when the load requires the output voltage to change, the presence of inductors and capacitors at the output end limits the response speed of the DC-DC. Summary of the invention

[0003] The object of the present invention is to provide a DC-DC switching power supply circuit and an implementation method, aiming to solve the above-mentioned problems in the prior art.

[0004] The present invention provides a DC-DC switching power supply circuit, comprising:

[0005] A self-compensating sample-and-hold bandgap reference source is used to generate a reference voltage and use a DC-DC feedback voltage to compensate for the periodically shut-down reference voltage;

[0006] The output charge fast response module is used to accelerate the rise or fall of the output voltage when the output voltage needs to change based on the reference voltage.

[0007] The present invention provides a method for implementing a DC-DC switching power supply circuit, which is used for the above-mentioned DC-DC switching power supply circuit. The method specifically comprises:

[0008] A reference voltage is generated by a self-compensated sample-and-hold bandgap reference source, and a DC-DC feedback voltage is used to compensate for the reference voltage that is periodically turned off;

[0009] The output charge fast response module accelerates the rise or fall of the output voltage based on the reference voltage when the output voltage needs to change.

[0010] The low-power fast-response DC-DC switching power supply circuit of the embodiment of the present invention includes a self-compensating sampling and holding bandgap reference source and an output charge fast response module. The self-compensating sampling and holding bandgap reference source uses the DC-DC feedback voltage for compensation to reduce the voltage leakage caused by periodic shutdown, and the output charge fast response module timely turns on and off the current compensation to accelerate the output voltage regulation. The technical solution of the embodiment of the present invention can reduce the static power consumption of the DC-DC and speed up the output voltage response speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate one or more embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0012] Figure 1 is a schematic diagram of a DC-DC switching power supply circuit according to an embodiment of the present invention;

[0013] Figure 2 is a circuit diagram of a self-compensating sample-and-hold bandgap reference source according to an embodiment of the present invention;

[0014] Figure 3 is a switching timing diagram of a sample-and-hold voltage reference source according to an embodiment of the present invention;

[0015] Figure 4 is a circuit diagram of a charge output fast response module according to an embodiment of the present invention;

[0016] Figure 5 It is a flow chart of a method for implementing a DC-DC switching power supply circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the following will be combined with the drawings in one or more embodiments of this specification to clearly and completely describe the technical solutions in one or more embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this document.

[0018] Device Embodiment

[0019] According to an embodiment of the present invention, a DC-DC switching power supply circuit is provided. Figure 1Schematic diagram of a DC-DC switching power supply circuit according to an embodiment of the present invention. Figure 1 As shown, the DC-DC switching power supply circuit according to the embodiment of the present invention specifically includes:

[0020] The self-compensating sampling and holding bandgap reference source 10 is used to generate a reference voltage and use a DC-DC feedback voltage to compensate for the periodically closed reference voltage; specifically, it is used to:

[0021] Based on the transistor V BE and ΔV BE The temperature characteristics of the two are used to offset each other's temperature coefficients and finally generate a relatively temperature-stable reference voltage. The sample-and-hold function is adopted. It works normally in the sampling stage and uses the capacitor to store charge to prepare for providing the reference voltage in the subsequent holding stage. The holding stage is closed and the reference voltage on the capacitor is used to power the subsequent modules. The feedback voltage of the DC-DC is used as the reference benchmark for compensation to reduce the large changes in the reference voltage caused by the capacitor leakage in the holding stage.

[0022] A constant time generator is used to charge a capacitor to a constant voltage based on a constant current source to generate a fixed time, and the fixed time is used as the on-time of the upper tube of the power tube. After that, the upper tube is turned off. When the feedback voltage corresponding to the output voltage drops below the reference voltage, the upper tube is turned on again for a fixed time, and the above process is repeated to ensure the stability of the output voltage. The clock signal generated by the constant time generator is assisted by a non-overlapping clock to control the on and off of the power tube. The non-overlapping clock prevents a pair of power tubes from being turned on at the same time, thereby preventing a short circuit in the circuit and increasing power consumption. In this process, a zero current detector is used to detect the current flowing through the lower tube of the power tube when it is turned on, and the lower tube is turned off after the current drops to 0, thereby preventing energy waste caused by current reverse.

[0023] The output charge fast response module 12 is used to accelerate the rise or fall of the output voltage based on the reference voltage when the output voltage needs to change. Specifically, when the output voltage needs to change, while the DC-DC changes the current on the output inductor, the constant current source is turned on to increase the total output current, change the output voltage on the output capacitor, and turn off the constant current source after the feedback voltage of the DC-DC and the reference voltage comparator are flipped. The constant current source is in the form of a current mirror and a MOS switch.

[0024] The embodiment of the present invention provides a low-power and fast-response DC-DC switching power supply. By adopting a self-compensated sample-and-hold bandgap reference source, the bandgap reference source is intermittently turned on and off, thereby reducing the static power consumption of the DC-DC switching power supply. An output charge fast-response module is adopted to increase the speed of change of the output voltage.

[0025] The above technical solution of the embodiment of the present invention is described below with reference to the accompanying drawings.

[0026] The low-power fast-response DC-DC switching power supply of the embodiment of the present invention comprises: a self-compensating sampling and holding bandgap reference source, and an output charge fast-response module. Specifically:

[0027] Among them, the self-compensated sampling and holding bandgap reference source is based on the temperature characteristics of the VBE and ΔVBE of the transistor, and the temperature coefficients of the two are offset to finally generate a relatively temperature-stable reference voltage. In order to reduce the static power consumption of the system, the bandgap reference source adopts the sampling and holding function. In the sampling stage, the bandgap reference source works normally, and the capacitor is used to store charge to prepare for the reference voltage in the subsequent holding stage; in the holding stage, the bandgap reference source is turned off, and the reference voltage on the capacitor is used to power the subsequent modules. The self-compensation mechanism is to compensate the reference voltage by the feedback voltage of the DC-DC, reducing the large changes in the reference voltage caused by the leakage of the capacitor in the holding stage.

[0028] The constant time generator charges the capacitor to a constant voltage through a constant current source to generate a fixed time. This fixed time is used as the conduction time of the upper tube of the power tube. After that, the upper tube is turned off. When the feedback voltage corresponding to the output voltage drops below the reference voltage, the upper tube is turned on again for a fixed time, and this cycle is repeated to ensure the stability of the output voltage. The clock signal generated by the non-overlapping clock assists the constant time generator to control the conduction and disconnection of the power tube. The non-overlapping clock prevents a pair of power tubes from being turned on at the same time to prevent short circuits and greatly increase power consumption. At the same time, the zero current detector detects the current flowing through the lower tube of the middle power tube when it is turned on in this process, and turns off the lower tube after the current drops to 0 to prevent energy waste caused by current reversal.

[0029] The output charge fast response module is used to quickly change the output voltage when the output voltage needs to change, and improve the DC-DC response speed. In a traditional DC-DC converter, when the output voltage needs to be increased, it is usually necessary to first increase the current in the output inductor until the current exceeds the load current, and then the output capacitor can be charged, so that the output voltage gradually increases. Since the inductor current cannot change instantly, the speed of this process is limited. The present invention enables the current source from Vin to the Vout end (which can be in the form of a current mirror and a MOS switch) when the output voltage needs to be increased, thereby eliminating the process of gradually increasing the output inductor current and directly charging the output capacitor quickly, thereby accelerating the output voltage rise speed. Similarly, when the output voltage needs to be reduced, the current source from Vout to the ground end is enabled, eliminating the process of reducing the output inductor current, and directly discharging the output capacitor quickly, thereby accelerating the output voltage drop speed.

[0030] like Figure 2 As shown, switch φ 2 Disconnect, switch φ 1The closed period is the sampling state, and the bandgap reference source works normally. Due to the clamping of the amplifier on the voltage, the resistor R 2 The upper voltage is V r2 =V BE1 -V BE2 , flows through transistor M 1 、M 2 、M 3 The current is Current flows through resistor R 4 Generate reference voltage Where V BE1 It is C TAT Voltage, V BE1 -V BE2 YesP TAT Voltage, by properly selecting the resistance value, the temperature coefficients of the two can be offset to obtain a relatively temperature-stable voltage V ref During normal operation of the bandgap reference source, the output capacitor C out Charge to V ref , providing a reference voltage to store charge for subsequent hold states.

[0031] Switch φ 2 Closed, switch φ 1 The disconnection period is the hold state, at which time the bandgap reference source is turned off and the large output capacitor C out Provides reference voltage for subsequent modules. However, due to the switch φ 1 It is implemented in the form of MOS tube. When it is turned off, the gate-source voltage V GS Close to 0, there is still a subthreshold current:

[0032]

[0033] The larger subthreshold current will cause the capacitance C out The charge on the switch φ 1 Leakage, voltage V ref It gradually decreases and cannot be maintained constant. Therefore, the DC-DC feedback voltage V fb Received as Figure 2 Position A shown, due to the steady state V fb With V ref The difference is only the ripple voltage of DC-DC, so the switch tube φ 1 The gate-drain voltage is reduced to a ripple voltage, which greatly reduces the subthreshold current and can keep Vref basically unchanged in the holding state. The unstable time is very short, and the unstable state has a great influence on V ref The impact is small.

[0034] Figure 3The switching timing diagram of the proposed sample-and-hold voltage reference source is shown, and intermittent sampling is performed under the control of the clock signal to update the reference voltage. 1 In φ 2 The purpose of turning it on again after a certain period of time is to wait for the voltage generated by the bandgap reference source to stabilize. 2 Prior to φ 1 Turning off can also prevent the output C from being damaged when the bandgap reference source stops working. out Upper voltage V ref The bandgap reference operates once every N clock cycles, theoretically reducing power consumption by a factor of N compared to a continuously operating reference voltage source. This reduction in power consumption is reflected in the lower quiescent current of the buck converter.

[0035] Figure 4 The figure is a schematic diagram of the output charge fast response module. When the output voltage needs to rise, the traditional DC-DC needs to increase the current on the output inductor first, and then the part of the current on the output inductor that is greater than the load current can charge the output capacitor to gradually increase the output voltage. Since the current on the inductor cannot change suddenly, the speed of this voltage increase process is limited. The present invention opens V in To V out The current source at the end can be realized by using a current mirror and a MOS switch, eliminating the process of gradually increasing the current on the output inductor and directly charging the output capacitor quickly, thus accelerating the output voltage rise speed; similarly, when the output voltage needs to be reduced, turning on V out The current source to the ground terminal eliminates the process of reducing the current on the output inductor and can directly discharge the output capacitor quickly, accelerating the output voltage drop. After the DC-DC feedback voltage and the reference voltage comparator are flipped, the constant current source is turned off, indicating that the output voltage regulation has been completed at this time.

[0036] Combined with the embodiments, it can be seen that the low-power fast-response DC-DC switching power supply of the present invention adopts a self-compensating sampling and holding bandgap reference source based on the traditional COT control mode, and alternately works and shuts down, thereby reducing the static power consumption of the system. The self-compensation mechanism ensures that V ref The output charge fast response module is used to open the current source to the input or ground when the output voltage rises or falls, quickly changing the voltage on the output capacitor, and realizing a fast response of the DC-DC output voltage.

[0037] Method Embodiment

[0038] According to an embodiment of the present invention, a method for implementing a DC-DC switching power supply circuit is provided, which is used in the above-mentioned DC-DC switching power supply circuit. Figure 5 FIG. 1 is a flow chart of a method for implementing a DC-DC switching power supply circuit according to an embodiment of the present invention. Figure 5 As shown, the implementation method of the DC-DC switching power supply circuit according to the embodiment of the present invention specifically includes:

[0039] Step S501, generating a reference voltage by a self-compensating sample-and-hold bandgap reference source, and using a DC-DC feedback voltage to compensate for the periodically closed reference voltage; specifically comprising:

[0040] Based on the transistor V BE and ΔV BE The temperature characteristics of the two are used to offset each other's temperature coefficients and finally generate a relatively temperature-stable reference voltage. The sample-and-hold function is adopted. It works normally in the sampling stage and uses the capacitor to store charge to prepare for providing the reference voltage in the subsequent holding stage. The holding stage is closed and the reference voltage on the capacitor is used to power the subsequent modules. The feedback voltage of the DC-DC is used as the reference benchmark for compensation to reduce the large changes in the reference voltage caused by the capacitor leakage in the holding stage.

[0041] The constant time generator charges the capacitor to a constant voltage based on a constant current source to generate a fixed time, and the fixed time is used as the conduction time of the upper tube of the power tube. After that, the upper tube is turned off. When the feedback voltage corresponding to the output voltage drops below the reference voltage, the upper tube is turned on again for a fixed time, and the above process is repeated to ensure the stability of the output voltage;

[0042] The clock signal generated by the non-overlapping clock auxiliary constant time generator controls the conduction and disconnection of the power tube. The non-overlapping clock prevents a pair of power tubes from being turned on at the same time, thereby preventing the circuit from short-circuiting and increasing power consumption. In this process, the zero current detector detects the current flowing through the power tube when the lower tube of the power tube is turned on, and turns off the lower tube after the current drops to 0, preventing energy waste caused by current reverse.

[0043] Step S501, accelerating the rise or fall of the output voltage based on the reference voltage by means of the output charge fast response module when the output voltage needs to change. Specifically comprising:

[0044] When the output voltage needs to change, while the DC-DC changes the current on the output inductor, the constant current source is turned on to increase the total output current, change the output voltage on the output capacitor, and turn off the constant current source after the DC-DC feedback voltage and the reference voltage comparator are flipped. The constant current source is in the form of a current mirror and a MOS switch.

[0045] The self-compensated sample-and-hold bandgap reference source is based on the temperature characteristics of the transistor's VBE and ΔVBE, which offset the temperature coefficients of the two and ultimately produce a relatively temperature-stable reference voltage. In order to reduce the static power consumption of the system, the bandgap reference source adopts a sample-and-hold function. During the sampling phase, the bandgap reference source works normally, and the capacitor stores charge to prepare for the reference voltage in the subsequent holding phase; during the holding phase, the bandgap reference source is turned off, and the reference voltage on the capacitor is used to power subsequent modules. The self-compensation mechanism uses the feedback voltage of the DC-DC to compensate for the reference voltage, reducing the large changes in the reference voltage caused by the leakage of the capacitor during the holding phase.

[0046] The constant time generator charges the capacitor to a constant voltage through a constant current source to generate a fixed time. This fixed time is used as the conduction time of the upper tube of the power tube. After that, the upper tube is turned off. When the feedback voltage corresponding to the output voltage drops below the reference voltage, the upper tube is turned on again for a fixed time, and this cycle is repeated to ensure the stability of the output voltage. The clock signal generated by the non-overlapping clock assists the constant time generator to control the conduction and disconnection of the power tube. The non-overlapping clock prevents a pair of power tubes from being turned on at the same time to prevent short circuits and greatly increase power consumption. At the same time, the zero current detector detects the current flowing through the lower tube of the middle power tube when it is turned on in this process, and turns off the lower tube after the current drops to 0 to prevent energy waste caused by current reversal.

[0047] The output charge fast response module is used to quickly change the output voltage when the output voltage needs to change, and improve the DC-DC response speed. In a traditional DC-DC converter, when the output voltage needs to be increased, it is usually necessary to first increase the current in the output inductor until the current exceeds the load current, and then the output capacitor can be charged, so that the output voltage gradually increases. Since the inductor current cannot change instantly, the speed of this process is limited. The present invention enables the current source from Vin to the Vout end (which can be in the form of a current mirror and a MOS switch) when the output voltage needs to be increased, thereby eliminating the process of gradually increasing the output inductor current and directly charging the output capacitor quickly, thereby accelerating the output voltage rise speed. Similarly, when the output voltage needs to be reduced, the current source from Vout to the ground end is enabled, eliminating the process of reducing the output inductor current, and directly discharging the output capacitor quickly, thereby accelerating the output voltage drop speed.

[0048] like Figure 2 As shown, switch φ 2 Disconnect, switch φ 1 The closed period is the sampling state, and the bandgap reference source works normally. Due to the clamping of the amplifier on the voltage, the resistor R 2 The upper voltage is V r2 =V BE1 -V BE2 , flows through transistor M 1 、M2 、M 3 The current is Current flows through resistor R 4 Generate reference voltage Where V BE1 It is C TAT Voltage, V BE1 -V BE2 YesP TAT Voltage, by properly selecting the resistance value, the temperature coefficients of the two can be offset to obtain a relatively temperature-stable voltage V ref During normal operation of the bandgap reference source, the output capacitor C out Charge to V ref , providing a reference voltage to store charge for subsequent hold states.

[0049] Switch φ 2 Closed, switch φ 1 The disconnection period is the hold state, at which time the bandgap reference source is turned off and the large output capacitor C out Provides reference voltage for subsequent modules. However, due to the switch φ 1 It is implemented in the form of MOS tube. When it is turned off, the gate-source voltage V GS Close to 0, there is still a subthreshold current:

[0050]

[0051] The larger subthreshold current will cause the capacitance C out The charge on the switch φ 1 Leakage, voltage V ref It gradually decreases and cannot be maintained constant. Therefore, the DC-DC feedback voltage V fb Received as Figure 2 Position A shown, due to the steady state V fb With V ref The difference is only the ripple voltage of DC-DC, so the switch tube φ 1 The gate-drain voltage is reduced to a ripple voltage, which greatly reduces the subthreshold current and can keep Vref basically unchanged in the holding state. The unstable time is very short, and the unstable state has a great influence on V ref The impact is small.

[0052] Figure 3 The switching timing diagram of the proposed sample-and-hold voltage reference source is shown, and intermittent sampling is performed under the control of the clock signal to update the reference voltage. 1 In φ 2 The purpose of turning it on again after a certain period of time is to wait for the voltage generated by the bandgap reference source to stabilize. 2 Prior to φ 1 Turning off can also prevent the output C from being damaged when the bandgap reference source stops working.out Upper voltage V ref The bandgap reference operates once every N clock cycles, theoretically reducing power consumption by a factor of N compared to a continuously operating reference voltage source. This reduction in power consumption is reflected in the lower quiescent current of the buck converter.

[0053] Figure 4 The figure is a schematic diagram of the output charge fast response module. When the output voltage needs to rise, the traditional DC-DC needs to increase the current on the output inductor first, and then the part of the current on the output inductor that is greater than the load current can charge the output capacitor to gradually increase the output voltage. Since the current on the inductor cannot change suddenly, the speed of this voltage increase process is limited. The present invention opens V in To V out The current source at the end can be realized by using a current mirror and a MOS switch, eliminating the process of gradually increasing the current on the output inductor and directly charging the output capacitor quickly, thus accelerating the output voltage rise speed; similarly, when the output voltage needs to be reduced, turning on V out The current source to the ground terminal eliminates the process of reducing the current on the output inductor and can directly discharge the output capacitor quickly, accelerating the output voltage drop. After the DC-DC feedback voltage and the reference voltage comparator are flipped, the constant current source is turned off, indicating that the output voltage regulation has been completed at this time.

[0054] In the above technical solution, the low-power fast-response DC-DC switching power supply of the embodiment of the present invention uses a self-compensating sampling and holding bandgap reference source to periodically work and shut down, and the sampling capacitor stores the reference voltage, effectively reducing the equivalent power consumption of the reference power supply. The power consumption saved after adopting this module is proportional to the ratio of the working time to the sampling and holding cycle time. The output charge fast response module directly charges and discharges the output capacitor without waiting for the current on the output inductor to change, thereby improving the response speed of the DC-DC to the output voltage.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A DC-DC switching power supply circuit, characterized in that: include: A self-compensated sample-and-hold bandgap reference source is used to generate a reference voltage and use a DC-DC feedback voltage to compensate for the periodically shut-down reference voltage; The output charge fast response module is used to accelerate the rise or fall of the output voltage when the output voltage needs to change based on the reference voltage.

2. The DC-DC switching power supply circuit according to claim 1, characterized in that: The self-compensating sample-and-hold bandgap reference source is specifically used for: Based on the transistor V BE and ΔV BE The temperature characteristics of the two are used to offset each other's temperature coefficients and finally generate a relatively temperature-stable reference voltage. The sample-and-hold function is adopted. It works normally in the sampling stage and uses the capacitor to store charge to prepare for providing the reference voltage in the subsequent holding stage. The holding stage is closed and the reference voltage on the capacitor is used to power the subsequent modules. The feedback voltage of the DC-DC is used as the reference benchmark for compensation, reducing the large changes in the reference voltage caused by the capacitor leakage in the holding stage.

3. The DC-DC switching power supply circuit according to claim 1, characterized in that: The self-compensating sample-and-hold bandgap reference source is specifically used for: The constant time generator charges the capacitor to a constant voltage based on a constant current source to generate a fixed time, and the fixed time is used as the conduction time of the upper tube of the power tube. After that, the upper tube is turned off. When the feedback voltage corresponding to the output voltage drops below the reference voltage, the upper tube is turned on again for a fixed time, and the above process is repeated to ensure the stability of the output voltage; The clock signal generated by the non-overlapping clock auxiliary constant time generator controls the conduction and disconnection of the power tube. The non-overlapping clock prevents a pair of power tubes from being turned on at the same time, thereby preventing the circuit from short-circuiting and increasing power consumption. In this process, the zero current detector detects the current flowing through the power tube when the lower tube of the power tube is turned on, and turns off the lower tube after the current drops to 0, preventing energy waste caused by current reverse.

4. The DC-DC switching power supply circuit according to claim 1, characterized in that: The output charge fast response module is specifically used for: when the output voltage needs to change, while the DC-DC changes the current on the output inductor, turning on the constant current source to increase the total output current, changing the output voltage on the output capacitor, and turning off the constant current source after the feedback voltage of the DC-DC and the reference voltage comparator are flipped.

5. The DC-DC switching power supply circuit according to claim 4, characterized in that: The constant current source is in the form of a current mirror and a MOS switch.

6. A method for implementing a DC-DC switching power supply circuit, used in the DC-DC switching power supply circuit according to any one of claims 1 to 5, the method specifically comprising: A reference voltage is generated by a self-compensated sample-and-hold bandgap reference source, and a DC-DC feedback voltage is used to compensate for the reference voltage that is periodically turned off; The output charge fast response module accelerates the rise or fall of the output voltage based on the reference voltage when the output voltage needs to change.

7. The method according to claim 6, characterized in that The method of generating a reference voltage by a self-compensating sampling and holding bandgap reference source and compensating the periodically closed reference voltage by using a DC-DC feedback voltage specifically includes: Based on the transistor V BE and ΔV BE The temperature characteristics of the two are used to offset each other's temperature coefficients and finally generate a relatively temperature-stable reference voltage. The sample-and-hold function is adopted. It works normally in the sampling stage and uses the capacitor to store charge to prepare for providing the reference voltage in the subsequent holding stage. The holding stage is closed and the reference voltage on the capacitor is used to power the subsequent modules. The feedback voltage of the DC-DC is used as the reference benchmark for compensation, reducing the large changes in the reference voltage caused by the capacitor leakage in the holding stage.

8. The method according to claim 6, characterized in that The method of generating a reference voltage by a self-compensating sampling and holding bandgap reference source and compensating the periodically closed reference voltage by using a DC-DC feedback voltage specifically includes: The constant time generator charges the capacitor to a constant voltage based on a constant current source to generate a fixed time, and the fixed time is used as the conduction time of the upper tube of the power tube. After that, the upper tube is turned off. When the feedback voltage corresponding to the output voltage drops below the reference voltage, the upper tube is turned on again for a fixed time, and the above process is repeated to ensure the stability of the output voltage; The clock signal generated by the non-overlapping clock auxiliary constant time generator controls the conduction and disconnection of the power tube. The non-overlapping clock prevents a pair of power tubes from being turned on at the same time, thereby preventing the circuit from short-circuiting and increasing power consumption. In this process, the zero current detector detects the current flowing through the power tube when the lower tube of the power tube is turned on, and turns off the lower tube after the current drops to 0, preventing energy waste caused by current reverse.

9. The method according to claim 6, characterized in that The output charge fast response module is used to accelerate the rise or fall of the output voltage when the output voltage needs to change based on the reference voltage, and specifically includes: When the output voltage needs to change, while the DC-DC changes the current on the output inductor, the constant current source is turned on to increase the total output current, changing the output voltage on the output capacitor, and the constant current source is turned off after the DC-DC feedback voltage and the reference voltage comparator are flipped.

10. The method according to claim 9, characterized in that The constant current source is in the form of a current mirror and a MOS switch.

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