Bidirectional DC-DC circuit based on MCU control

Abstract

The utility model discloses a bidirectional DC-DC circuit based on MCU control, relates to the field of DC-DC power supply modules, and is used for solving the problems of complex feedback loop, low reliability of a soft start circuit and existence of switching power-down time in the current bidirectional working DC-DC control circuit. Comprising a central controller, a BUCK / BOOST chopper circuit, a PWM drive circuit and a current sampling feedback circuit. A first signal receiving end and a second signal receiving end of the central controller are electrically connected with input and output voltage signals of the BUCK / BOOST chopper circuit, and a third signal receiving end of the central controller is electrically connected with a current feedback signal output end of the current sampling feedback circuit; a switching signal output end of the central controller outputs a switching signal to a switching signal input end of a gate driver in the PWM driving circuit; and the output end of the gate driver controls a switching tube of the BUCK / BOOST chopper circuit to perform switching chopping work. Therefore, simpler feedback circuit control is realized, the reliability of the soft start circuit is improved, and no switching power-down time exists.

Description

Technical Field

[0001] The utility model relates to the field of DC-DC power supply modules, in particular to a bidirectional DC-DC circuit based on MCU control. Background Art

[0002] DC-DC is a device that converts electrical energy of one voltage value into electrical energy of another voltage value in a DC circuit. Its basic working principle is to use transformers, inductors, filter capacitors, switch tubes, controllers and other circuit components to convert the input DC power into DC power of another voltage. This DC power module can usually provide different voltage and current outputs to meet different application requirements. The DC-DC power module has the advantages of easy maintenance, flexible design, cost and time saving, high power, high efficiency and high reliability.

[0003] However, the circuit of a conventional DC-DC power module can generally only work in one direction. This is because the conventional DC-DC control circuit is often composed of analog circuits. When working in one direction, the output voltage or current can be simply fed back to the controller to form a closed loop. However, when working in the reverse direction, the control loop will be very complicated. This is mainly reflected in two aspects. First, an additional reverse feedback loop is required. In order to ensure that the forward and reverse feedback loops are not effective at the same time, a certain dead zone must be added to the switching time of the two loops. The power converter needs to be shut down during the dead zone, otherwise an open loop state will occur, damaging the converter, which will add a switching power-off time to the power converter. Second, the control of the soft start circuit is complex when working in reverse. Since the duty cycle of a conventional controller increases slowly from 0 when working in forward direction, its complementary signal starts to decrease from 100% duty cycle when working in reverse direction, which causes the switch tube to be in a short-circuit state when the chip is started. Therefore, an additional soft start circuit must be added to the complementary signal to ensure that the switch tube can also be slowly turned on when starting the reverse work and will not enter a short-circuit state. However, this obviously increases the design complexity of the DC-DC control circuit. How to make the DC-DC power supply module have high reliability of the soft start circuit and no switching power-off time when implementing a simpler feedback circuit control has become a key issue to be solved in this field.

[0004] Therefore, there is a need to provide a bidirectional DC-DC circuit that enables a DC-DC power supply module to achieve simpler feedback circuit control, with high reliability of the soft start circuit and no switching power-off time. Utility Model Content

[0005] In order to solve the problems raised in the above background technology, the utility model provides a bidirectional DC-DC circuit based on MCU control, which solves the problems of complex feedback loop, low reliability of soft start circuit and switching power-off time in the current bidirectional DC-DC control circuit.

[0006] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a bidirectional DC-DC circuit based on MCU control, which includes a central controller, a BUCK / BOOST chopper circuit, a PWM drive circuit and a current sampling feedback circuit, wherein the BUCK / BOOST chopper circuit includes two circuit working structures of a BUCK chopper circuit or a BOOST chopper circuit; the BUCK / BOOST chopper circuit includes a first switch tube Q1 and a second switch tube Q2, the PWM drive circuit includes a gate driver, and the current sampling feedback circuit includes a sampling resistor R6 and an operational amplifier; the switch signal output end of the central controller outputs two switch signals to the switch signal input end of the gate driver, wherein the two switch signals include a main switch signal and a complementary switch signal complementary thereto; the first output end and the second output end of the gate driver are electrically connected to the gates of the first switch tube Q1 and the second switch tube Q2 in the BUCK / BOOST chopper circuit, respectively; the sampling One end of the resistor R6 is electrically connected to the non-inverting input port of the operational amplifier, and the other end is electrically connected to the inverting input port of the operational amplifier. The current signal collected by the sampling resistor R6 is amplified by the operational amplifier and output to the central controller, wherein the output port of the operational amplifier is used as the current feedback signal output end and connected to the third signal receiving end of the central controller; the source of the first switch tube Q1 is connected to the drain of the second switch tube Q2, and is electrically connected to one end of an inductor, and the other end of the inductor is used as the output end of the BUCK chopper circuit or the input end of the BOOST chopper circuit in the BUCK / BOOST chopper circuit, and is connected to the first signal receiving end of the central controller; the first signal receiving end of the central processor is electrically connected to the input voltage of the BOOST chopper circuit, or the output voltage of the BUCK chopper circuit, the second signal receiving end is electrically connected to the output voltage of the BOOST chopper circuit, or the input voltage of the BUCK chopper circuit, and the third signal receiving end is electrically connected to the current feedback signal output end of the current sampling feedback circuit.

[0007] According to the above-mentioned bidirectional DC-DC circuit based on MCU control, further, a first diode D1 is connected between the gate of the first switch tube Q1 and the gate driver, the positive terminal of the first diode D1 is electrically connected to the gate of the first switch tube Q1, and the negative terminal of the first diode D1 is electrically connected to the gate driver; a second diode D2 is connected between the gate of the second switch tube Q2 and the gate driver, the positive terminal of the first diode D2 is electrically connected to the gate of the first switch tube Q1, and the negative terminal of the second diode D2 is electrically connected to the gate driver.

[0008] According to the above-mentioned bidirectional DC-DC circuit based on MCU control, further, a resistor R3 is connected in parallel between the two ends of the first diode D1; and a resistor R4 is connected in parallel between the two ends of the second diode D2.

[0009] According to the above-mentioned bidirectional DC-DC circuit based on MCU control, further, one end of the sampling resistor R6 is connected to the input ground and is connected to the non-inverting input port of the operational amplifier through the resistor R5, and the other end of the sampling resistor R6 is connected to the output ground and is electrically connected to the inverting input port of the operational amplifier through the resistor R8.

[0010] According to the above-mentioned bidirectional DC-DC circuit based on MCU control, further, a rectifier diode D3 is connected in parallel between the source and the drain of the first switch tube Q1, the positive end of the rectifier diode D3 is connected to the source of the first switch tube Q1, and the negative end of the rectifier diode D3 is connected to the drain of the first switch tube Q1; a freewheeling diode D4 is connected in parallel between the source and the drain of the second switch tube Q2, the positive end of the freewheeling diode D4 is connected to the source of the second switch tube Q2, and the negative end of the freewheeling diode D4 is connected to the source of the first switch tube Q1.

[0011] According to the above-mentioned bidirectional DC-DC circuit based on MCU control, further, the drain of the first switch tube Q1 serves as the input end of the BUCK chopper circuit or the output end of the BOOST chopper circuit in the BUCK / BOOST chopper circuit, and is respectively electrically connected to the positive electrode of a filter capacitor and the second signal receiving end of the central controller, and the other end of the filter capacitor is electrically connected to the input ground.

[0012] According to the above-mentioned bidirectional DC-DC circuit based on MCU control, further, a feedback resistor R9 is connected in parallel between the inverting input port and the output port of the operational amplifier; the non-inverting input port of the operational amplifier is connected to the input ground through a resistor R7, the output end is connected to the filter capacitor, and the non-inverting input port of the operational amplifier is connected to an external power supply through a resistor R11.

[0013] According to the above-mentioned bidirectional DC-DC circuit based on MCU control, further, the switch signal output end of the central controller includes two switch signal output ends, wherein any one switch signal output end outputs the main switch signal, and the other switch signal output end outputs the complementary switch signal; the main switch signal and the complementary switch signal are output to the gate driver.

[0014] Beneficial effects:

[0015] (1) The bidirectional DC-DC circuit disclosed in the utility model uses a central controller for soft start control. The switch signal output end of the central controller can simultaneously output a main switch signal and a complementary switch signal, and input the main switch signal and the complementary switch signal to the BUCK / BOOST chopper circuit for control through a PWM drive circuit. The central controller, that is, the MCU, is used for signal control. When the converter is turned on, the main switch signal and the complementary switch signal can be soft started at the same time. This circuit structure in which the central controller performs soft start control avoids the large current caused by a large duty cycle when the converter is turned on. Naturally, there is no need to design an additional soft start circuit for the complementary switch signal, which obviously reduces the control complexity of the bidirectional DC-DC circuit.

[0016] (2) The bidirectional DC-DC circuit disclosed by the utility model, the traditional bidirectional DC-DC circuit uses two analog circuits for loop feedback. In order to ensure that the two loops do not conflict when switching directions, a certain dead zone must be added to the switching time of the two loops. The power converter needs to be shut down during the dead zone, otherwise it will be in an open loop state, damaging the converter, which will increase a switching power-off time for the power converter; while the bidirectional DC-DC circuit disclosed by the utility model, the central controller simultaneously samples the input and output voltages of the BUCK / BOOST chopper circuit through two built-in analog-to-digital conversion channels. When the working direction needs to be switched, only the central controller program needs to switch the feedback voltage, and then control the change of the PWM duty cycle of the switch signal according to the collected voltage. There is no time for switching the feedback loop, and the working direction of the converter can be switched smoothly in the working state without shutting down, and there is no power-off time for switching the direction.

[0017] (3) The bidirectional DC-DC circuit disclosed in the utility model is provided with a BUCK / BOOST chopper circuit and a current sampling feedback circuit. The first signal receiving end and the second signal receiving end of the central controller receive the input and output voltage signals of the BUCK / BOOST chopper circuit. The central controller receives the input and output voltages and then compares them with the program setting values ​​to achieve perfect overvoltage and undervoltage protection; and the second signal receiving end of the central controller receives the current feedback signal of the current sampling feedback circuit. The central controller compares it with the program setting value. Once the received current signal voltage is higher than the setting value, overcurrent protection is immediately performed. At the same time, the amplified current signal sends the received signal to the comparator inside the central controller and compares it with another voltage reference. When the current signal voltage is higher than the reference voltage, the comparator outputs a high level. When the comparator outputs high, the interrupt of the central controller is triggered, and the central controller can immediately perform protection. Abnormal voltage and current protection in this circuit is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a circuit diagram in an embodiment of the utility model. DETAILED DESCRIPTION

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the utility model or the prior art, the utility model will be briefly introduced below in combination with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the structure of the drawings is only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. It should be noted that the description of these embodiments is used to help understand the utility model, but does not constitute a limitation of the utility model.

[0020] Embodiment 1:

[0021] like Figure 1 As shown, the present embodiment provides a bidirectional DC-DC circuit based on MCU control, wherein the bidirectional DC-DC circuit based on MCU control includes a central controller, a BUCK / BOOST chopping circuit, a PWM drive circuit and a current sampling feedback circuit; the BUCK / BOOST chopping circuit includes a first switch tube Q1 and a second switch tube Q2, the PWM drive circuit includes a gate driver, and the current sampling feedback circuit includes a sampling resistor R6 and an operational amplifier; the central controller mentioned here is the MCU, and in this embodiment, a chip model CH32F103C8T6 is preferably used. This is because CH32F103C8T6 has a wealth of ADC peripherals, timer peripherals and comparator peripherals, which can well achieve the technical effect of the bidirectional DC-DC circuit based on MCU control in this embodiment.

[0022] The present embodiment provides a bidirectional DC-DC circuit based on MCU control, wherein the switch signal output end of the central controller (CH32F103C8T6) outputs the switch signal to the switch signal input end of the gate driver; wherein the two switch signals include a main switch signal and a complementary switch signal complementary thereto, the switch signal is a pulse width modulation signal PWM output by the central controller (CH32F103C8T6), the main switch signal is PWMA, and the complementary switch signal complementary thereto is PWMB, when the power is turned on, the central controller (CH32F103C8T6) soft-starts the main switch signal PWMA and the complementary switch signal PWMB at the same time, PWMA and PWMB will not have a 100% duty cycle when the power is turned on, but both start to increase slowly from 0 until the closed loop or the two-way duty cycle reaches 45%, and then the two-way switch signal is switched, and at this time the main switch signal PWMA is controlled by feedback; this avoids the large current caused by the large duty cycle when the power is turned on, and improves the reliability of the bidirectional DC-DC circuit.

[0023] The present embodiment provides a bidirectional DC-DC circuit based on MCU control, wherein the first output terminal and the second output terminal of the gate driver are respectively electrically connected to the gates of the first switch tube Q1 and the second switch tube Q2 in the BUCK / BOOST chopper circuit, and the gate driver receives two switching signals PWMA and PWMB, and after enhancing its driving capability, outputs the switching tube driving signals GATEA and GATEB for the first switch tube Q1 and the second switch tube Q2 accordingly, driving and controlling the first switch tube Q1 and the second switch tube Q2 to perform chopping operation; one end of the sampling resistor R6 is connected to the input ground, and is connected to the non-inverting input port of the operational amplifier through the resistor R5, the other end of the sampling resistor R6 is connected to the output ground, and is electrically connected to the inverting input port of the operational amplifier through the resistor R8, and the current signal collected by the sampling resistor R6 is amplified by the operational amplifier and output to the central controller (CH32F103C8T6), and the sampling resistor R6 preferably adopts a small resistance resistor, which can reduce loss and increase the conversion efficiency of the circuit; the specific resistance value can be selected according to the bidirectional DC-DC circuit provided by the present embodiment in different usage scenarios.

[0024] The present embodiment provides a bidirectional DC-DC circuit based on MCU control, wherein the first signal receiving end and the second signal receiving end of the central controller (CH32F103C8T6) receive the input and output voltage feedback signals of the BUCK / BOOST chopper circuit, the voltage feedback signal is the voltage sampled by the central controller (CH32F103C8T6) from the BUCK / BOOST chopper circuit, which is compared with the program setting value in the central controller (CH32F103C8T6), and the duty cycle of the PWM is adjusted by the timer of the central controller (CH32F103C8T6), and perfect overvoltage and undervoltage protection is achieved at the same time; the third signal receiving end of the central controller (CH32F103C8T6) is electrically connected to the current feedback signal output end of the current sampling feedback circuit, the current feedback signal is the current sampled by the central controller (CH32F103C8T6) from the current sampling feedback circuit, which is compared with the program setting value in the central controller (CH32F103C8T6), and perfect overcurrent and short-circuit protection is achieved. Taking the current feedback signal as an example, the current sampling feedback circuit samples the current signal through the resistor R6, uses the operational amplifier to amplify the sampled current signal, and sends the amplified current signal to the central controller (CH32F103C8T6). The central controller (CH32F103C8T6) compares it with the program setting value. Once the sampled current signal voltage is higher than the setting value, overcurrent protection is immediately performed; at the same time, the amplified current signal is sent to the comparator inside the central controller (CH32F103C8T6) and compared with another voltage reference. When the current signal voltage is higher than the reference voltage, the comparator outputs a high level. When the comparator outputs a high level, the interrupt of the central controller (CH32F103C8T6) is triggered, and the central controller (CH32F103C8T6) can immediately perform short-circuit protection. Here, two sets of protection methods are used for overcurrent and short circuit because overcurrent protection generally requires a certain delay time to avoid false triggering, while short-circuit protection requires a fast response, so a comparator is used to trigger. Such a central controller (CH32F103C8T6) is combined with the BUCK / BOOST chopper circuit and the current sampling feedback circuit to realize PWM signal control and abnormal voltage and current protection.

[0025] Embodiment 2:

[0026] like Figure 1 As shown, the bidirectional DC-DC circuit based on MCU control provided in this embodiment has two working modes, including buck working and boost working:

[0027] Buck operation: At this time, the first switch tube Q1 works as a buck active tube, and the second switch tube Q2 works as a synchronous freewheeling tube. When the first switch tube Q1 is turned on, the current flows from BAT_BUS+ through the drain of the first switch tube Q1 to the source, and then flows to the output U+ through the inductor. When the first switch tube Q1 is turned off, the second switch tube Q2 will be turned on to provide a current flowing from the source to the drain to ensure the freewheeling of the inductor, and a working cycle ends here. The entire circuit works as a BUCK-type buck topology, with BAT_BUS as the input side and U+ as the output side. The central controller (CH32F103C8T6) controls the main switch signal PWMA by sampling the U+ voltage to achieve closed-loop operation, that is, when the sampled U+ voltage is less than the program setting value, the central controller (CH32F103C8T6) will increase the duty cycle of PWMA to increase the current passing through the first switch tube Q1, thereby increasing the voltage of U+, otherwise it will reduce the duty cycle of PWMA and reduce the voltage of U+. At the same time, the complementary switching signal PWMB of PWMA is used as a synchronous freewheeling signal to reduce the freewheeling loss and increase the conversion efficiency of the converter.

[0028] Boost operation: At this time, the second switch tube Q2 works as a boost active tube, and the first switch tube Q1 works as a synchronous rectifier tube. When the second switch tube Q2 is turned on, the current flows from U+ through the inductor and then flows through the second switch tube Q2 to U-. When the second switch tube Q2 is turned off, the first switch tube Q1 is turned on. At this time, since the current on the inductor cannot change suddenly, the current still flows from U+ through the inductor, and then through the first switch tube Q1 to BAT_BUS+, and a working cycle ends here. The entire circuit is a BOOST-type boost topology, with U+ as the input side and BAT_BUS as the output side. The central controller (CH32F103C8T6) collects the BAT_BUS+ voltage and compares it with the program setting value, and then controls the duty cycle of the complementary switch signal PWMB to achieve closed-loop operation. That is, when the BAT_BUS+ voltage is less than the set value, the central controller (CH32F103C8T6) will increase the duty cycle of PWMB, so the current flowing through the inductor will increase, the current flowing to BAT_BUS+ will also increase, and the BAT_BUS+ voltage will increase. Conversely, the duty cycle of PWMB will be reduced, and the BAT_BUS+ voltage will decrease. At the same time, the main switch signal PWMA is used as a synchronous rectification signal to reduce rectification losses and increase the efficiency of the converter.

[0029] Using the central controller (CH32F103C8T6) as the controller, the main switch signal PWMA and the complementary switch signal PWMB can be soft-started respectively during the power-on phase of the power converter, that is, the duty cycle of PWMA and PWMB is controlled to increase slowly from 0 until the closed loop or the duty cycle of both channels reaches 45%, and then the two PWM channels are switched to complementary signals, and the duty cycle of the main switch PWM is controlled by feedback. Therefore, whether in the boost state or the buck state, the large current caused by direct startup with a large duty cycle can be avoided.

[0030] Embodiment 3:

[0031] like Figure 1As shown, the present embodiment provides a bidirectional DC-DC circuit based on MCU control. In a preferred implementation, a diode D1 is connected between the gate of the first switch tube Q1 and the gate driver, the positive terminal of the diode D1 is electrically connected to the gate of the first switch tube Q1, and the negative terminal of D1 is electrically connected to the gate driver; a diode D2 is connected between the gate of the second switch tube Q2 and the gate driver, the positive terminal of the diode D2 is electrically connected to the gate of the first switch tube Q1, and the negative terminal of D1 is electrically connected to the gate driver; two ends of the diode D1 and the diode D2 are respectively connected in parallel with an Resistor R3 and resistor R4; a rectifier diode D3 is connected in parallel at both ends of the first switch tube Q1, the positive end of the rectifier diode D3 is connected to the source of the first switch tube Q1, and the negative end of the rectifier diode D3 is connected to the drain of the first switch tube Q1; a freewheeling diode D4 is connected in parallel at both ends of the second switch tube Q2, the positive end of the freewheeling diode D4 is connected to the source of the second switch tube Q2, and the negative end of the freewheeling diode D4 is connected to the source of the first switch tube Q1; the source of the first switch tube Q1 is connected to the drain of the second switch tube Q2, and is electrically connected to one end of the inductor, and the other end of the inductor is used as a voltage feedback signal The output end is connected to the first signal receiving end of the central controller; the drain of the first switch tube Q1 serves as the input end of the BUCK chopper circuit or the output end of the BOOST chopper circuit, and is electrically connected to the positive electrode of the filter capacitor and the second signal receiving end of the central controller, and the other end of the filter capacitor is electrically connected to the input ground; the source of the second switch tube Q2 is connected to the output ground; one end of the sampling resistor R6 is connected to the input ground, and is connected to the non-inverting input port of the operational amplifier through the resistor R5, and the other end of the sampling resistor R6 is connected to the output ground, and is electrically connected to the inverting input port of the operational amplifier through the resistor R8; the operational amplifier The output port of is used as the current feedback signal output terminal and connected to the third signal receiving terminal of the central controller; a feedback resistor R9 is connected in parallel between the inverting input port and the output port of the operational amplifier; the non-inverting input terminal of the operational amplifier is grounded through a resistor R7, the output terminal is connected to a filter capacitor, and the non-inverting input port is connected to an external power supply through a resistor R11; the switch signal output terminal of the central controller includes two signal output terminals, any one of which outputs a main switch signal, and the other outputs a complementary switch signal; the main switch signal and the complementary switch signal are output to the gate driver.

[0032] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A bidirectional DC-DC circuit based on MCU control, characterized in that: It includes a central controller, a BUCK / BOOST chopper circuit, a PWM drive circuit and a current sampling feedback circuit, wherein the BUCK / BOOST chopper circuit includes two circuit working structures of a BUCK chopper circuit or a BOOST chopper circuit; the BUCK / BOOST chopper circuit includes a first switch tube Q1 and a second switch tube Q2, the PWM drive circuit includes a gate driver, and the current sampling feedback circuit includes a sampling resistor R6 and an operational amplifier; The switch signal output terminal of the central controller outputs two switch signals to the switch signal input terminal of the gate driver, wherein the two switch signals include a main switch signal and a complementary switch signal complementary to the main switch signal; The first output terminal and the second output terminal of the gate driver are electrically connected to the gates of the first switch tube Q1 and the second switch tube Q2 in the BUCK / BOOST chopper circuit, respectively; one end of the sampling resistor R6 is electrically connected to the non-inverting input port of the operational amplifier, and the other end is electrically connected to the inverting input port of the operational amplifier, and the current signal collected by the sampling resistor R6 is amplified by the operational amplifier and output to the central controller, wherein the output port of the operational amplifier is used as the current feedback signal output terminal and connected to the third signal receiving terminal of the central controller; The source of the first switch tube Q1 is connected to the drain of the second switch tube Q2, and is electrically connected to one end of an inductor. The other end of the inductor is used as the output end of the BUCK chopper circuit or the input end of the BOOST chopper circuit in the BUCK / BOOST chopper circuit, and is connected to the first signal receiving end of the central controller; the first signal receiving end of the central controller is electrically connected to the input voltage of the BOOST chopper circuit, or the output voltage of the BUCK chopper circuit, and the second signal receiving end is electrically connected to the output voltage of the BOOST chopper circuit, or the input voltage of the BUCK chopper circuit.

2. The bidirectional DC-DC circuit based on MCU control according to claim 1, characterized in that: A first diode D1 is connected between the gate of the first switch tube Q1 and the gate driver, the positive terminal of the first diode D1 is electrically connected to the gate of the first switch tube Q1, and the negative terminal of the first diode D1 is electrically connected to the gate driver; a second diode D2 is connected between the gate of the second switch tube Q2 and the gate driver, the positive terminal of the first diode D2 is electrically connected to the gate of the first switch tube Q1, and the negative terminal of the second diode D2 is electrically connected to the gate driver.

3. The bidirectional DC-DC circuit based on MCU control according to claim 2 is characterized in that: A resistor R3 is connected in parallel to both ends of the first diode D1 ; a resistor R4 is connected in parallel to both ends of the second diode D2 .

4. The bidirectional DC-DC circuit based on MCU control according to claim 1, characterized in that: One end of the sampling resistor R6 is connected to the input ground and is connected to the non-inverting input port of the operational amplifier through the resistor R5. The other end of the sampling resistor R6 is connected to the output ground and is electrically connected to the inverting input port of the operational amplifier through the resistor R8.

5. The bidirectional DC-DC circuit based on MCU control according to claim 1, characterized in that: A rectifier diode D3 is connected in parallel between the source and drain of the first switch tube Q1, the positive terminal of the rectifier diode D3 is connected to the source of the first switch tube Q1, and the negative terminal of the rectifier diode D3 is connected to the drain of the first switch tube Q1; a freewheeling diode D4 is connected in parallel between the source and drain of the second switch tube Q2, the positive terminal of the freewheeling diode D4 is connected to the source of the second switch tube Q2, and the negative terminal of the freewheeling diode D4 is connected to the source of the first switch tube Q1.

6. The bidirectional DC-DC circuit based on MCU control according to claim 1, characterized in that: The drain of the first switch tube Q1 serves as the input end of the BUCK chopper circuit or the output end of the BOOST chopper circuit in the BUCK / BOOST chopper circuit, and is electrically connected to the positive electrode of a filter capacitor and the second signal receiving end of the central controller, respectively, and the other end of the filter capacitor is electrically connected to the input ground.

7. The bidirectional DC-DC circuit based on MCU control according to claim 6, characterized in that: A feedback resistor R9 is connected in parallel between the inverting input port and the output port of the operational amplifier; the non-inverting input port of the operational amplifier is connected to the input ground through a resistor R7, the output end is connected to the filter capacitor, and the non-inverting input port of the operational amplifier is connected to an external power supply through a resistor R11.

8. The bidirectional DC-DC circuit based on MCU control according to claim 1, characterized in that: The switch signal output end of the central controller includes two switch signal output ends, wherein any one switch signal output end outputs the main switch signal, and the other switch signal output end outputs the complementary switch signal; the main switch signal and the complementary switch signal are output to the gate driver.

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