A synchronous boost converter with input switch and control chip thereof

Abstract

This invention discloses a synchronous boost converter with an input switch and its control chip in the field of power management technology. The converter includes a main module, a driver module, and an input control switch. The main module increases the DC voltage within the converter. The driver module is connected to the main module and generates a drive signal to the power transistor, rectifier MOSFET, and input switch. The input control switch is connected to the DG pin of the driver module and includes a CS amplifier, a shutdown comparator, a surge comparator, and a DG charge pump circuit. By employing a synchronous boost converter with an input switch, this invention not only limits the current during input power surges but also completely disconnects the current path from the input to the output when an abnormal load necessitates output voltage shutdown, reducing the output voltage to zero. This achieves surge current limiting and circuit breaker protection.

Description

Technical Field

[0001] This invention relates to the field of power management technology, specifically to a synchronous boost converter with an input switch and its control chip. Background Technology

[0002] A boost converter, also known as a DC-DC converter, is a typical DC-DC converter circuit widely used in switching power supplies, DC motor drives, photovoltaic power generation systems, and other fields. Boost converters can be divided into synchronous boost converters and asynchronous boost converters based on their rectification method. Synchronous boost converters, because they use MOSFETs for rectification instead of diodes, reduce forward conduction losses during rectification and thus achieve higher conversion efficiency, making them more widely used in high-power applications.

[0003] A synchronous boost converter consists of an input capacitor CIN, an energy storage inductor LIN, a power transistor QL, a rectifier MOSFET QH, and an output capacitor COUT. In conventional boost topologies, whether synchronous or asynchronous, the rectifier diode or the body diode of the rectifier MOSFET will be forward-biased. The input power can be directly output to the load through the inductor and rectifier devices. This means that the current path between the input and output cannot be completely cut off, so the output voltage cannot drop to zero volts, which will cause continuous shutdown losses and even damage to the load. Summary of the Invention

[0004] The purpose of this invention is to provide a synchronous boost converter with an input switch and its control chip, which can limit the current when the input power supply is surged, and can completely disconnect the current path from the input terminal to the output when the load is abnormal and the output voltage needs to be turned off, so that the output voltage drops to zero.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a synchronous boost converter with an input switch, comprising a synchronous boost converter main module, a drive module, and an input control switch. The synchronous boost converter main module is used to increase the DC voltage within the synchronous boost converter. The drive module is connected to the synchronous boost converter main module and generates a drive signal to provide to the power transistor, the rectifier MOSFET, and the input switch. The input control switch is connected to the DG pin of the drive module and includes a CS amplifier, a shutdown comparator, a surge comparator, and a DG charge pump circuit. The DG charge pump circuit uses a pull-up current source to charge the DG pin. By cooperating with the limiting effect of the Zener diode, the voltage of the DG pin is kept within a threshold range. When the sampling current exceeds the threshold voltage, the surge comparator opens the pull-down current source to discharge the DG pin to the surge current limiting stability point. If the output voltage of the CS amplifier exceeds the upper limit of the threshold, the shutdown comparator outputs a high level to reduce the input current to 0 and discharge the inductor current for circuit breaking protection.

[0007] As a further aspect of the present invention: the driving module includes a VIN pin, a CSP pin, a CSN pin, a DG pin, and a DS pin.

[0008] As a further aspect of the present invention: the non-inverting input terminal and the inverting input terminal of the CS amplifier are connected sequentially to the CSP pin and the CSN pin; the inverting input terminal of the shutdown comparator and the inverting input terminal of the surge comparator are respectively connected to the threshold voltage; the output terminal of the CS amplifier is connected to the non-inverting input terminal of the shutdown comparator and the surge comparator; the output terminal of the surge comparator is connected to the DG charge pump circuit; and the input control switch is used to limit the surge current generated by the synchronous boost converter and shut down the output voltage.

[0009] The output of the comparator is turned off and connected to the gate of the first MOSFET. The source of the first MOSFET is grounded and the drain of the first MOSFET is connected to the DG pin. The DG pin is connected to the negative terminals of the first Zener diode and the second Zener diode in sequence. The anode of the first Zener diode is connected to the DS pin and the anode of the second Zener diode is connected to the VIN pin. The first Zener diode and the second Zener diode are used to stabilize the voltage at the DG pin.

[0010] A VGS detection circuit is connected between the drain of the first MOSFET and the DS pin.

[0011] As a further aspect of the present invention: the DG charge pump circuit includes a pull-up current source and a pull-down current source. One end of the pull-down current source is connected to the negative terminal of the third Zener diode, the positive terminal of the third Zener diode is connected to the output terminal of the pull-up current source, and the output terminal of the surge comparator is connected to the output terminal of the pull-down current source. The DG charge pump circuit charges the DG pin through the pull-up current source to make the input switch transistor in the on state.

[0012] As a further aspect of the present invention, the amplification gain of the CS amplifier is 10.

[0013] As a further aspect of the present invention: the main module of the synchronous boost converter includes an input capacitor, an energy storage inductor, a power transistor, a rectifier MOSFET, and an output capacitor. One end of the input capacitor is connected to the input terminal of the synchronous boost converter, and the other end of the input capacitor is grounded. One end of the energy storage inductor and the source of the rectifier MOSFET are both connected to the SW pin of the driving module. The drain of the rectifier MOSFET is connected to the output terminal, and the gate of the rectifier MOSFET is connected to the HO pin of the driving module.

[0014] As a further aspect of the present invention: the synchronous boost converter further includes an input control module connected to the driving module pins, the input control module being used to sample the input current of the main module of the synchronous boost converter;

[0015] The input control module includes an input current sampling resistor, an input switching transistor, and a freewheeling diode. One end of the input current sampling resistor is connected to the input terminal, and the other end is connected to the drain of the input switching transistor. The source of the input switching transistor is connected to one end of the energy storage inductor, and the gate of the input switching transistor is connected to the DG pin. The cathode of the freewheeling diode is connected to the source of the input switching transistor, and the anode of the freewheeling diode is grounded. The freewheeling diode is used to discharge the stored energy in the energy storage inductor, thus reducing the output voltage V. OUT It dropped to 0V.

[0016] As a further aspect of the present invention: the synchronous boost converter further includes an undervoltage point setting module, which is used to set the undervoltage point of the input voltage;

[0017] The undervoltage setting module includes a first voltage divider resistor and a second voltage divider resistor. One end of the first voltage divider resistor is grounded, and the other end of the first voltage divider resistor and one end of the second voltage divider resistor are both connected to the UVLO pin of the drive module. The other end of the second voltage divider resistor is connected to the input terminal.

[0018] As a further aspect of the present invention: the synchronous boost converter further includes a compensation signal generation module, which is used to generate a ramp compensation signal for the synchronous boost converter;

[0019] The compensation signal generation module is a third resistor with one end grounded and the other end connected to the constant voltage output pin SLOPE of the drive module. The third resistor, together with the constant voltage output pin SLOPE, generates the internal slope compensation signal.

[0020] As a further aspect of the present invention: the synchronous boost converter further includes a withstand time setting module, which is used to set the withstand time of cycle-by-cycle current limiting;

[0021] The endurance setting module is the first capacitor. One end of the first capacitor is connected to the RES pin of the drive module, and the other end of the first capacitor is grounded.

[0022] As a further aspect of the present invention: the synchronous boost converter further includes a soft-start time setting unit, which is used to set the soft-start time of the drive module;

[0023] The soft-start time setting unit is the second capacitor. One end of the second capacitor is connected to the SS pin of the driver module, and the other end of the second capacitor is grounded.

[0024] As a further aspect of the present invention: the synchronous boost converter further includes an internal clock generation module, which is used to set the internal clock frequency of the drive module;

[0025] The internal clock generation module is a fourth resistor with one end connected to the constant voltage output pin RT of the driver module and the other end grounded. The fourth resistor, together with the constant voltage output pin RT, sets the frequency of the internal clock of the driver module.

[0026] As a further aspect of the present invention: the synchronous boost converter further includes a working mode setting module, which is used to set the working mode of the drive module;

[0027] The operating modes include diode simulation mode and forced PWM mode. When the drive module operates in diode simulation mode, the MODE pin of the drive module is grounded to prevent the output voltage from flowing back to the input. When the drive module operates in forced PWM mode, the MODE pin of the drive module is connected to VCC to speed up the load response speed of the drive module.

[0028] As a further aspect of the present invention: the synchronous boost converter further includes a constant voltage control loop module and a loop compensation module. The constant voltage control loop module is used to set the output voltage, and the loop compensation module is used to compensate for the stability of the loop in the constant voltage control loop module.

[0029] The constant voltage control loop module includes a third voltage divider resistor and a fourth voltage divider resistor. One end of the third voltage divider resistor is connected to the FB pin of the driver module, and the other end of the third voltage divider resistor is grounded. The third and fourth voltage divider resistors are used to sample the output voltage to form a constant voltage control loop in order to set the output voltage.

[0030] The loop compensation module includes a third capacitor and a fifth resistor. One end of the third capacitor is connected to the COMP pin of the driver module, and the other end of the third capacitor is connected to one end of the fifth resistor. The other end of the fifth resistor is connected to the FB pin of the driver module.

[0031] As a further aspect of the present invention: the synchronous boost converter further includes a filtering module, which is a fourth capacitor with one end grounded and the other end connected to the VCC pin of the driving module. The fourth capacitor is used to filter the low-voltage power supply pin VCC pin. A bootstrap diode is connected between the VCC pin and the BST pin of the driving module. A bootstrap capacitor is connected between the BST pin and the SW pin. The bootstrap diode is used to charge the bootstrap capacitor to complete the power supply for the high-side output.

[0032] Secondly, the present invention also provides a control chip, including a synchronous boost converter with an input switch as described above.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] 1. In this invention, by using a synchronous boost converter with an input switch, it is possible not only to limit the current magnitude when the input power supply experiences a surge, but also to completely disconnect the current path from the input terminal to the output terminal when the load is abnormal and the output voltage needs to be shut off, thereby reducing the output voltage to zero and realizing the functions of surge current limiting and circuit breaking protection.

[0035] 2. In this invention, by using an input switch to completely shut down and reduce the output of the synchronous boost converter to 0V, the power consumption of the synchronous boost converter during shutdown is reduced, and the safety and reliability of the synchronous boost converter are improved. Attached Figure Description

[0036] Figure 1 This is a module connection diagram of the present invention;

[0037] Figure 2 This is a circuit diagram of the synchronous boost converter of the present invention;

[0038] Figure 3 This is a block diagram of the input switch control function of the present invention;

[0039] Figure 4 This is a schematic diagram of the startup waveform of the synchronous boost converter of the present invention;

[0040] Figure 5 This is a block diagram of the control chip of the present invention.

[0041] In the diagram: 1. Synchronous boost converter main module; 2. Input control module; 3. Drive module; 301. Input control switch; 4. Undervoltage point setting module; 5. Compensation signal generation module; 6. Withstand time setting module; 7. Soft start time setting unit; 8. Internal clock generation module; 9. Working mode setting module; 10. Constant voltage control loop module; 11. Loop compensation module; 12. Filtering module. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Example:

[0044] like Figure 1 As shown in the embodiment of the present invention, a synchronous boost converter with an input switch is provided, including a synchronous boost converter main module 1, a drive module 3, and an input control switch 301. The synchronous boost converter main module 1 is used to increase the DC voltage within the synchronous boost converter; the drive module 3 is connected to the synchronous boost converter main module 1 and generates a drive signal to provide to the power transistor Q. L rectifier MOSFET Q H and input switch Q D。

[0045] like Figure 3 As shown, the input control switch 301 is connected to the DG pin of the drive module 3. The input control switch 301 includes a CS amplifier, a shutdown comparator, a surge comparator, and a DG charge pump circuit. The DG charge pump circuit uses a pull-up current source to charge the DG pin. By cooperating with the limiting effect of the Zener diode, the voltage of the DG pin is kept within the threshold range. When the sampling current exceeds the threshold voltage, the surge comparator turns on the pull-down current source to discharge the DG pin to the surge current limiting stability point. If the output voltage of the CS amplifier exceeds the upper limit of the threshold, the shutdown comparator will output a high level to reduce the input current to 0 and discharge the inductor current for circuit breaking protection.

[0046] Preferred, such as Figure 2 As shown, driver module 3 is a BST7970 driver chip, and driver module 3 includes VIN pin, CSP pin, CSN pin, DG pin and DS pin.

[0047] Preferred, such as Figure 2 As shown, the non-inverting and inverting input terminals of the CS amplifier are connected to the CSP and CSN pins in sequence. The inverting input terminals of the shutdown comparator and the surge comparator are connected to the threshold voltages respectively. The output terminal of the CS amplifier is connected to the non-inverting input terminal of the shutdown comparator and the surge comparator. The output terminal of the surge comparator is connected to the DG charge pump circuit. The input control switch 301 is used to limit the surge current generated by the synchronous boost converter and shut down the output voltage.

[0048] The output of the comparator is turned off and connected to the gate of the first MOSFET NM1. The source of the first MOSFET NM1 is grounded and the drain of the first MOSFET NM1 is connected to the DG pin. The DG pin is connected to the negative terminals of the first Zener diode DZ1 and the second Zener diode DZ2 in sequence. The positive terminal of the first Zener diode DZ1 is connected to the DS pin and the positive terminal of the second Zener diode DZ2 is connected to the VIN pin. The first Zener diode DZ1 and the second Zener diode DZ2 are used to stabilize the voltage at the DG pin.

[0049] A VGS detection circuit is connected between the drain of the first MOSFET NM1 and the DS pin.

[0050] Preferred, such as Figure 3 As shown, the DG charge pump circuit includes a pull-up current source and a pull-down current source. One end of the pull-down current source is connected to the cathode of the third Zener diode, and the anode of the third Zener diode is connected to the output of the pull-up current source. The output of the surge comparator is connected to the output of the pull-down current source. The DG charge pump circuit charges the DG pin through the pull-up current source to power the input switch Q. D It is in the conductive state.

[0051] Preferred, such as Figure 3 As shown, the amplification gain of the CS amplifier is 10.

[0052] During normal operation, the DG charge pump circuit charges the DG with a 25μA pull-up current source, and the input switch Q... D The circuit is in a fully conductive state, and the voltage at the DG pin is limited by the first Zener diode DZ1 and the second Zener diode DZ2, and will not exceed (VIN pin voltage +11V) or the DS pin voltage +16V; then the input current is sampled by the resistor R. CS The CSP and CSN pins sample the input current and convert the sampled signal I... IN *R CS After amplification by a CS amplifier with a gain of 10, V is obtained. SENSE1 signal, i.e. 10*I IN *R CS If signal V SENSE1 If the voltage exceeds 1.1V, the surge current limiting function will be triggered. The surge comparator will output a high level and activate a 95μA pull-down current source. The voltage at pin DG will discharge with a pull-down current of 95μA - 25μA = 70μA, which will then be input to the switching transistor Q. D The current-carrying capacity decreases, and consequently the input current I... IN Input switch Q D The surge current is reduced due to the current limiting factor and eventually stabilizes at the surge current limiting point [1.1V / 10*R]. CS If an abnormal load causes an increase in input current I... INThe surge increases rapidly, and before the surge current limiting stabilizes, V SENSE1 If the voltage exceeds 1.6V, that is, I IN >[1.6V / 10*R CS This will trigger the circuit breaker protection, turning off the comparator output to a high level, causing the first MOSFET NM1 to conduct and pull down, rapidly turning off the input switch Q with a peak current of 0.3A. D , so that the input current I IN It quickly drops to 0, while the inductor current I... L The freewheeling diode D will be used. F Leakage, slowly from input I IN The current value decreased to 0.

[0053] Preferred, such as Figure 2 As shown, the main module 1 of the synchronous boost converter includes an input capacitor. Energy storage inductor Power transistors rectifier MOSFET and output capacitor Input capacitor One end is connected to the input terminal of the synchronous boost converter, and the input capacitor... The other end is grounded, energy storage inductor One end is connected to the rectifier MOSFET The sources of all are connected to the SW pin of driver module 3, and the rectifier MOSFETs The drain is connected to the output terminal, and the rectifier MOSFET is used. The gate is connected to the HO pin of the driver module 3.

[0054] Preferred, such as Figure 1 As shown, the synchronous boost converter also includes an input control module 2 connected to the pin of the drive module 3. The input control module 2 is used to sample the input current of the main module 1 of the synchronous boost converter.

[0055] like Figure 2 As shown, the input control module 2 includes an input current sampling resistor R. CS Input switch Q D and freewheeling diode D F Input current sampling resistor R CS One end is connected to the input terminal, and the current sampling resistor R CS The other end is connected to the input switch transistor Q. D The drain of the input switch Q D The source is connected to the energy storage inductor. One end is the input switch Q. D The gate is connected to the DG pin, and the freewheeling diode D... F The negative terminal is connected to the input switch transistor Q. DThe source of the freewheeling diode D F The positive terminal is grounded, and the freewheeling diode D F Used for discharging energy storage inductors The stored electrical energy makes the output voltage V OUT It dropped to 0V.

[0056] Preferred, such as Figure 1 As shown, the synchronous boost converter also includes an undervoltage setting module 4, which is used to set the undervoltage point of the input voltage.

[0057] like Figure 2 As shown, the undervoltage point setting module 4 includes a first voltage divider resistor R. UV1 Second voltage divider resistor R UV2 The first voltage divider resistor R UV1 One end is grounded, and the first voltage divider resistor R UV1 The other end and the second voltage divider resistor R UV2 One end of each is connected to the UVLO pin of the driver module 3, and the second voltage divider resistor R UV2 The other end is connected to the input terminal.

[0058] Preferred, such as Figure 1 As shown, the synchronous boost converter also includes a compensation signal generation module 5, which is used to generate a ramp compensation signal for the synchronous boost converter.

[0059] like Figure 2 As shown, the compensation signal generation module 5 is a third resistor R with one end grounded and the other end connected to the constant voltage output pin SLOPE of the drive module 3. SLOPE The third resistor R SLOPE The slope compensation signal is produced in conjunction with the constant voltage output pin SLOPE.

[0060] Preferred, such as Figure 1 As shown, the synchronous boost converter also includes a withstand time setting module 6, which is used to set the withstand time of cycle-by-cycle current limiting.

[0061] like Figure 2 As shown, the endurance setting module 6 is the first capacitor C. RES The first capacitor C RES One end is connected to the RES pin of driver module 3, and the first capacitor C RES The other end is grounded.

[0062] Preferred, such as Figure 1 As shown, the synchronous boost converter also includes a soft-start time setting unit 7, which is used to set the soft-start time of the drive module 3.

[0063] like Figure 2As shown, the soft-start time setting unit 7 is the second capacitor C. SS The second capacitor C SS One end is connected to the SS pin of driver module 3, and the second capacitor C SS The other end is grounded.

[0064] Preferred, such as Figure 1 As shown, the synchronous boost converter also includes an internal clock generation module 8, which is used to set the internal clock frequency of the drive module 3.

[0065] like Figure 2 As shown, the internal clock generation module 8 is a fourth resistor R connected at one end to the constant voltage output pin RT of the driver module 3 and at the other end to ground. T The fourth resistor R T The frequency of the internal clock of the drive module 3 is set in conjunction with the constant voltage output pin RT.

[0066] Preferred, such as Figure 1 As shown, the synchronous boost converter also includes a working mode setting module 9, which is used to set the working mode of the drive module 3.

[0067] Preferably, the operating modes include diode simulation mode and forced PWM mode. When the drive module 3 operates in diode simulation mode, the MODE pin of the drive module 3 is grounded to prevent the output voltage from flowing back to the input. When the drive module 3 operates in forced PWM mode, the MODE pin of the drive module 3 is connected to VCC to speed up the load response speed of the drive module 3.

[0068] Preferred, such as Figure 1 As shown, the synchronous boost converter also includes a constant voltage control loop module 10 and a loop compensation module 11. The constant voltage control loop module 10 is used to set the output voltage, and the loop compensation module 11 is used to compensate for the stability of the loop in the constant voltage control loop module 10.

[0069] like Figure 2 As shown, the constant voltage control loop module 10 includes a third voltage divider resistor R. FB1 and the fourth voltage divider resistor R FB2 The third voltage divider resistor R FB1 One end is connected to the FB pin of driver module 3, and the third voltage divider resistor R FB1 The other end is grounded, and the third voltage divider resistor R FB1 and the fourth voltage divider resistor R FB2 Used to sample the output voltage to form a constant voltage control loop, in order to set the output voltage;

[0070] Loop compensation module 11 includes a third capacitor C COMP and the fifth resistor R COMPThe third capacitor C COMP One end is connected to the COMP pin of driver module 3, and the third capacitor C COMP The other end is connected to the fifth resistor R COMP One end, the fifth resistor R COMP The other end is connected to the FB pin of driver module 3.

[0071] Preferred, such as Figure 1 As shown, the synchronous boost converter also includes a filter module 12, such as... Figure 2 As shown, the filter module 12 is a fourth capacitor C with one end grounded and the other end connected to the VCC pin of the driver module 3. VCC The fourth capacitor C VCC Used for filtering the low-voltage power supply pin VCC, a bootstrap diode D is connected between the VCC pin and the BST pin of driver module 3. BST A bootstrap capacitor C is connected between the BST pin and the SW pin. BST Bootstrap diode D BST Used for bootstrap capacitor C BST Charge to complete power supply to the high-side output.

[0072] The working principle of the converter is as follows: When powered on, the drive module 3 is in the off state. The voltage of the UVLO pin of the drive module 3 gradually increases as the voltage of the VIN pin increases. When the increased pin voltage exceeds the 0.4V off threshold, the drive module 3 enters the standby state, and the VCC power supply voltage is gradually formed inside it.

[0073] Driver module 3 starts working through the modules connected via pins. At this time, the RT pin of driver module 3 outputs a constant 1.2V voltage. On the other hand, the internal clock signal of driver module 3 begins to be generated. Until the voltage value of the UVLO pin exceeds the 1.2V standby threshold, driver module 3 enters normal operation and begins the soft-start process. The waveform generated during this process is as follows: Figure 4 As shown;

[0074] Once driver module 3 is working properly, it will first turn on the input switch Q. D With the DG pin outputting a 25μA pull-up current, the input switch Q... D The gate-source voltage VGS gradually rises until it is fully turned on, and the input power supply will directly apply a large current to the output capacitor C. OUT Charging is initiated, thereby triggering surge current limiting protection, which is achieved by controlling the input switch Q. D The control limits the charging current to the surge current limit point.

[0075] When the output voltage rises to near the input voltage, the drive module 3 disengages from the surge current limiting protection, and the input switch Q... DThe VGS voltage continues to rise, eventually reaching the VGS detection point. The internal VGS_Detect signal flips, opening the soft-start charging current of the SS pin, and the voltage of the SS pin begins to rise.

[0076] When the voltage at the SS pin exceeds the voltage at the FB pin, the output LO starts emitting a PWM waveform to drive the power transistor Q. L When the circuit is turned on, the converter operates according to the working principle of a synchronous boost circuit, affecting the output capacitor C. OUT Continue charging until the voltage at the SS pin reaches 1.2V. At this point, the duty cycle is fully extended, the constant voltage loop is fully established, and the converter begins to supply power normally.

[0077] During normal operation of the converter, if a load failure occurs, the circuit breaker protection mechanism of drive module 3 will be triggered. The DG pin will quickly discharge to the DS pin, allowing the input switch Q to discharge. D Off, energy storage inductor L IN The stored energy will pass through the freewheeling diode D F Discharge occurs, at which point the output voltage V OUT It will drop to 0V.

[0078] Secondly, the present invention also provides a control chip, including a synchronous boost converter with an input switch as described above.

[0079] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A synchronous boost converter with an input switch, characterized in that, include: The synchronous boost converter main module is used to increase the DC voltage within the synchronous boost converter. The main module includes an input capacitor, an energy storage inductor, a power transistor, a rectifier MOSFET, and an output capacitor. One end of the input capacitor is connected to the input terminal of the synchronous boost converter, and the other end is grounded. One end of the energy storage inductor and the source of the rectifier MOSFET are both connected to the SW pin of the drive module. The drain of the rectifier MOSFET is connected to the output terminal, and the gate of the rectifier MOSFET is connected to the HO pin of the drive module. The synchronous boost converter also includes an input control module connected to the drive module pins, which samples the input current of the synchronous boost converter main module. The input control module includes an input current sampling resistor, an input switch transistor, and a freewheeling diode. One end of the input current sampling resistor is connected to the input terminal, and the other end of the current sampling resistor is connected to the drain of the input switch transistor. The source of the input switch transistor is connected to one end of the energy storage inductor, and the gate of the input switch transistor is connected to the DG pin. The cathode of the freewheeling diode is connected to the source of the input switch transistor, and the anode of the freewheeling diode is grounded. The freewheeling diode is used to discharge the stored energy in the energy storage inductor to reduce the output voltage VOUT to 0V. The synchronous boost converter also includes a compensation signal generation module, which is used to generate a ramp compensation signal for the synchronous boost converter. The compensation signal generation module is a third resistor with one end grounded and the other end connected to the constant voltage output pin SLOPE of the drive module. The third resistor, together with the constant voltage output pin SLOPE, generates an internal ramp compensation signal. The synchronous boost converter also includes a withstand time setting module, which is used to set the withstand time of cycle-by-cycle current limiting. The withstand time setting module is a first capacitor. One end of the first capacitor is connected to the RES pin of the drive module, and the other end of the first capacitor is grounded. The synchronous boost converter also includes a working mode setting module, which is used to set the working mode of the drive module. The operating modes include diode simulation mode and forced PWM mode. When the drive module operates in diode simulation mode, the MODE pin of the drive module is grounded to prevent the output voltage from flowing back to the input. When the drive module operates in forced PWM mode, the MODE pin of the drive module is connected to VCC to accelerate the load response speed of the drive module. The synchronous boost converter also includes a constant voltage control loop module and a loop compensation module. The constant voltage control loop module is used to set the output voltage, and the loop compensation module is used to compensate for the stability of the loop in the constant voltage control loop module. The constant voltage control loop module includes a third voltage divider resistor and a fourth voltage divider resistor. One end of the third voltage divider resistor is connected to the FB pin of the driver module, and the other end of the third voltage divider resistor is grounded. The third and fourth voltage divider resistors are used to sample the output voltage to form a constant voltage control loop in order to set the output voltage. The loop compensation module includes a third capacitor and a fifth resistor. One end of the third capacitor is connected to the COMP pin of the driver module, and the other end of the third capacitor is connected to one end of the fifth resistor. The other end of the fifth resistor is connected to the FB pin of the driver module. A drive module, which is connected to the main module of the synchronous boost converter and generates drive signals; An input control switch is connected to the DG pin of the drive module. The input control switch includes a CS amplifier, a shutdown comparator, a surge comparator, and a DG charge pump circuit. The DG charge pump circuit uses a pull-up current source to charge the DG pin. By cooperating with the limiting effect of the Zener diode, the voltage of the DG pin is kept within the threshold range. When the sampling current exceeds the threshold voltage, the surge comparator turns on the pull-down current source to discharge the DG pin to the surge current limiting stability point. If the output voltage of the CS amplifier exceeds the upper limit of the threshold, the comparator is turned off and outputs a high level to reduce the input current to 0 and discharge the inductor current for circuit breaking protection.

2. The synchronous boost converter with input switch according to claim 1, characterized in that: The driving module includes a VIN pin, a CSP pin, a CSN pin, a DG pin, and a DS pin.

3. The synchronous boost converter with input switch according to claim 2, characterized in that: The non-inverting and inverting inputs of the CS amplifier are connected sequentially to the CSP and CSN pins. The inverting inputs of the shutdown comparator and the surge comparator are connected to the threshold voltages, respectively. The output of the CS amplifier is connected to the non-inverting inputs of the shutdown comparator and the surge comparator. The output of the surge comparator is connected to the DG charge pump circuit. The input control switch is used to limit the surge current generated by the synchronous boost converter and shut down the output voltage. The output of the comparator is turned off and connected to the gate of the first MOSFET. The source of the first MOSFET is grounded and the drain of the first MOSFET is connected to the DG pin. The DG pin is connected to the negative terminals of the first Zener diode and the second Zener diode in sequence. The anode of the first Zener diode is connected to the DS pin and the anode of the second Zener diode is connected to the VIN pin. The first Zener diode and the second Zener diode are used to stabilize the voltage at the DG pin. A VGS detection circuit is connected between the drain of the first MOSFET and the DS pin.

4. The synchronous boost converter with input switch according to claim 1, characterized in that: The DG charge pump circuit includes a pull-up current source and a pull-down current source. One end of the pull-down current source is connected to the negative terminal of the third Zener diode, and the positive terminal of the third Zener diode is connected to the output terminal of the pull-up current source. The output terminal of the surge comparator is connected to the output terminal of the pull-down current source. The DG charge pump circuit charges the DG pin through the pull-up current source to make the input switch transistor in the conducting state.

5. The synchronous boost converter with input switch according to claim 4, characterized in that: The amplification gain of the CS amplifier is 10.

6. The synchronous boost converter with input switch according to claim 1, characterized in that: The synchronous boost converter also includes an undervoltage point setting module, which is used to set the undervoltage point of the input voltage; The undervoltage setting module includes a first voltage divider resistor and a second voltage divider resistor. One end of the first voltage divider resistor is grounded, and the other end of the first voltage divider resistor and one end of the second voltage divider resistor are both connected to the UVLO pin of the drive module. The other end of the second voltage divider resistor is connected to the input terminal.

7. The synchronous boost converter with input switch according to claim 1, characterized in that: The synchronous boost converter also includes a soft-start time setting unit, which is used to set the soft-start time of the drive module. The soft-start time setting unit is the second capacitor. One end of the second capacitor is connected to the SS pin of the driver module, and the other end of the second capacitor is grounded.

8. The synchronous boost converter with input switch according to claim 1, characterized in that: The synchronous boost converter also includes an internal clock generation module, which is used to set the internal clock frequency of the drive module. The internal clock generation module is a fourth resistor with one end connected to the constant voltage output pin RT of the driver module and the other end grounded. The fourth resistor, together with the constant voltage output pin RT, sets the frequency of the internal clock of the driver module.

9. The synchronous boost converter with input switch according to claim 1, characterized in that: The synchronous boost converter also includes a filtering module, which is a fourth capacitor with one end grounded and the other end connected to the VCC pin of the driver module. The fourth capacitor is used to filter the low-voltage power supply pin VCC pin. A bootstrap diode is connected between the VCC pin and the BST pin of the driver module. A bootstrap capacitor is connected between the BST pin and the SW pin. The bootstrap diode is used to charge the bootstrap capacitor to complete the power supply for the high-side output.

10. A control chip, characterized in that, Including a synchronous boost converter with an input switch as described in any one of claims 1-9.

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