Boost circuit capable of being forcibly started under under-voltage protection

Abstract

The utility model relates to a Boost circuit capable of being forcibly started under under-voltage protection. The Boost circuit comprises a power supply chip, a first inductor, a first diode, a first capacitor, a switch module, a boost amplitude control module and a forcible starting module, wherein a voltage detection pin of the power supply chip is connected with the boost amplitude module, and a driving pin is connected with the switch module; the power supply chip outputs low level to the switch module when detecting that the voltage is larger than a second voltage threshold value, and outputs high level to the switch module when detecting that the voltage is smaller than the second voltage threshold value. And one end of the forced starting module is grounded, and the other end of the forced starting module is connected with the boost amplitude control module, and is used for raising the detection voltage at the voltage detection pin position of the power supply chip to be higher than a first voltage threshold. The input voltage of the circuit is not changed, the circuit can be forcibly started at low voltage only by adding the diodes, and redesign is avoided.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of electronic circuit, specifically point to a kind of Boost boost circuit of forced starting under under-voltage protection. BACKGROUND

[0002] Boost boost circuit is a direct current-direct current (DC-DC) converter, it can convert a lower input voltage into a higher output voltage, in electronic circuit setting, widely used in the application required from low voltage power supply to obtain high voltage output, for example, switching power supply, direct current motor transmission, photovoltaic power generation system portable electronic equipment, solar panel charging system, LED lighting and electric vehicle drive control etc. Boost boost circuit is usually composed of switching circuit, inductance, diode, capacitor and control circuit, control circuit connects switching circuit, adjusts the switching frequency and duty cycle of switching element. When switching element (such as MOSFET) is turned on, current flows through switching element and inductor from input voltage source, inductor stores energy;With the increase of current, the magnetic field of inductor enhances, and the voltage across inductor increases. At this time, when the switching element is disconnected again, the energy stored in the inductor is rapidly released, and the current flows to the output capacitor through the diode. Due to the effect of inductor and diode, the output voltage is higher than the input voltage. The output voltage is equal to the input voltage plus the energy stored in the inductor during switching on.

[0003] In Boost boost circuit, how to select the power chip in control circuit determines the boost performance of the whole Boost boost circuit. In order to protect the chip from being damaged under the condition of under-voltage or over-voltage, the protection module logic circuit in part of the power chip limits the voltage value received by the voltage detection pin, and realizes the under-voltage or over-voltage protection of the power chip in actual use. When Boost boost circuit is still not completed, the input voltage in the circuit is divided by resistance and is lower than the under-voltage protection threshold of the power chip, then the voltage detection pin of the power chip detects the voltage signal and enters the under-voltage protection state, the power chip stops working, resulting in that Boost boost circuit cannot be started normally. In order to make Boost boost circuit start normally, the selection of power chip is limited by the under-voltage protection function in the design process, and only other models of chips without under-voltage protection or with under-voltage protection meeting the requirements can be replaced, so that the steps of re-debugging and circuit, packaging design are carried out, resulting in the increase of development cost and loss in the process of circuit design. UTILITY MODEL CONTENTS

[0004] In view of the above prior art still has the deficiency, the utility model discloses a kind of defects and deficiencies in prior art to solve, propose a kind of forcibly started circuit under input low voltage in under-voltage protection, by forcibly raising detection voltage signal, reach the normal start of Boost boost circuit.The Boost boost circuit of forced start under under-voltage protection is solved by adding voltage lifting device, in Boost boost circuit, the voltage detection foot of power supply chip, if there is under-voltage protection function, and input voltage is at low voltage when the detected detection voltage is lower than the set value of chip and cannot start the problem.

[0005] The technical scheme adopted by the utility model to solve the technical problems is as follows:

[0006] A Boost boost circuit of forced start under under-voltage protection, it includes: power supply chip, first inductance, first diode, first capacitor, switch module, boost amplitude control module and forced start module, wherein,

[0007] The voltage detection foot of the power supply chip is connected with the boost amplitude module, the drive foot of the power supply chip is connected with the switch module, and the power supply chip is used to output low level to the switch module when the detection voltage is greater than the second voltage threshold, and output high level to the switch module when the detection voltage is less than the second voltage threshold;

[0008] The switch module is connected with the power supply chip and the inductance boost module respectively, and the switch module is used to receive the level signal output by the drive foot of the power supply chip to control the conduction or turn-off of the Boost boost circuit;

[0009] One end of the first inductance is connected with input voltage, and the other end of the first inductance is connected with the switch module and the anode of the first diode respectively, and the first inductance is used to charge the first capacitor to raise the output voltage;

[0010] The anode of the first diode is connected with the first inductance and the switch module respectively, the cathode of the first diode is connected with the boost amplitude control module and the voltage output end respectively, and the first diode is used to continuously boost the first capacitor to prevent the energy loss of the first capacitor when the switch module is turned on;

[0011] The cathode end of the first capacitor is grounded, and the anode end of the first capacitor is connected with the cathode of the first diode, the first resistor and the voltage output end respectively;

[0012] The boost amplitude control module is connected with the cathode of the first diode and the voltage output end respectively, and the boost amplitude control module is used to divide the boosted output voltage to adjust the boost amplitude of the circuit;

[0013] One end of the forced starting module is grounded, and the other end of the forced starting module is connected with the boost amplitude control module, and the forced starting module is used to lift the detection voltage at the voltage detection pin position of the power supply chip to be higher than the first voltage threshold.

[0014] Further, the inductive boost module comprises a first voltage dividing resistor and a second voltage dividing resistor, wherein one end of the first voltage dividing resistor is connected with the output voltage and the diode respectively, and the other end of the first voltage dividing resistor is connected with the voltage detection pin and the second voltage dividing resistor respectively; the other end of the second voltage dividing resistor is connected with the forced starting module.

[0015] Further, the first capacitor is a polar electrolytic capacitor.

[0016] Further, the switch module comprises a first field effect transistor, the source of the first field effect transistor is grounded, the gate of the first field effect transistor is connected with the driving pin of the power supply chip, and the drain of the first field effect transistor is connected with the first inductor and the anode of the first diode respectively.

[0017] Further, the switch module further comprises a third voltage dividing resistor, one end of the third voltage dividing resistor is connected with the driving pin of the power supply chip and the source of the first field effect transistor respectively, and the other end of the third voltage dividing resistor is connected with the source of the first field effect transistor.

[0018] Further, the forced starting module comprises a second diode, the anode of the second diode is connected with the second voltage dividing resistor, and the cathode of the second diode is grounded.

[0019] Further, the voltage detection pin of the power supply chip is connected with the common connection end of the first voltage dividing resistor and the second voltage dividing resistor.

[0020] Further, the second diode is a silicon diode.

[0021] Further, the power supply chip adopts an ICE2PCS01 chip.

[0022] Further, the first field effect transistor is an N-channel depletion mode MOSFET transistor.

[0023] Compared with the limitation that the power chip with the under-voltage protection function of the Boost voltage increasing circuit cannot start at low voltage in the prior art, the utility model discloses a Boost voltage increasing circuit of under-voltage protection forced start, which comprises: a power chip, one end of the power chip is connected with a forced start module, and the other end is connected with a switch module, when in the working mode, the power chip outputs a pulse signal to the switch module to control the switching frequency and the duty cycle of the switch module, the forced start module is grounded at the other end, the detection voltage of the voltage detection pin of the power chip is improved when the circuit is at low voltage, and the power chip is forced to start, the switch module is connected with the power boost module, and the other end is grounded, responds to the pulse signal from the power chip, and is used for periodically connecting and disconnecting the branch, the inductance boost module is connected with the input end and the output end of the amplification circuit, and is connected with the switch module and the forced start module, and the output voltage after the output voltage is increased is output through charging and discharging. BRIEF DESCRIPTION OF DRAWINGS

[0024] Fig. 1 The system structure block diagram in the Boost voltage increasing circuit provided by the utility model is provided.

[0025] Fig. 2 The circuit principle diagram in the Boost voltage increasing circuit provided by the utility model is provided.

[0026] Fig. 3 The internal circuit principle diagram of the ICE2PCS01 chip voltage detection pin is provided. DETAILED DESCRIPTION

[0027] The utility model provides a Boost voltage increasing circuit of under-voltage protection forced start, in order to make the purpose, technical scheme and effect of the utility model more clear, explicit, the following refers to the drawing and raises the example to the utility model and is further detailedly explained.The specific embodiments described here are only used to explain the utility model, and are not used to limit the utility model.

[0028] In the embodiments and claims, unless otherwise limited, the articles "a," "an," and "the" also include plural referents, i.e. "a" or "an" can also mean "one or more" and "the" can also mean "one or more." If there is any conflict between a definition provided herein and any definition found in a document incorporated herein by reference, the definition provided herein prevails. The terms "first," "second," and the like, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another, and the "first" "second" and / or the like can be used interchangeably with respect to the description of the technology. Thus, the features labeled as "first" and "second" can include at least one of the features.

[0029] It should further be understood that the word "comprise", "comprising", "comprises" and the like in this specification, means "including, but not limited to", and should not be interpreted as meaning "consisting only of". It is further understood that the use of relational terms such as first, second, and the like, do not denote any order or importance, but rather the terms are used to distinguish one feature from another. It is further understood that the features with "first" and "second" can include at least one of the features.

[0030] It should be understood that the terms used herein are not intended to limit the present technology to the precise forms discussed, and as such, the foregoing is not intended to limit the scope of the technology, but rather these terms should be understood to cover any general equivalents unless otherwise defined. It is also to be understood that the terminology used herein is for the purpose of describing only the present technology and is not intended to be limiting.

[0031] In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the realization of ordinary technical personnel in the art, when the combination of technical solutions appears contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist, nor is it within the protection scope required by the present technology.

[0032] The inventor found that in the process of building a Boost circuit, the person skilled in the art often needs to consider whether the power supply chip has an undervoltage protection function, or whether the undervoltage protection function matches the detection voltage in the circuit environment of the power supply chip. In the prior art Boost circuit, the power supply chip sends a control pulse signal to the switch tube to control the switching state of the switch tube to change constantly, and the above process is repeated, so that the output voltage Uout of the circuit is finally higher than the input voltage Uin. When the circuit is working normally and the Boost circuit has not completed the voltage boost, the detection voltage value detected at the voltage detection pin of the power supply chip may be lower than the undervoltage protection value set by the chip. At this time, the undervoltage protection of the power supply chip is turned on, causing the switch tube in the Boost circuit to be forced to stop, and the Boost circuit cannot work normally. The diode in the Boost circuit is continuously turned on, and if the input voltage Uin of the circuit and the voltage detection pin are continuously in a low voltage state, the switch tube is continuously pulled high, and the Boost circuit cannot return to the normal working state. Therefore, in the prior art Boost circuit, the use of a power supply chip containing an undervoltage protection function will cause the Boost circuit to be difficult to start. In this case, the person skilled in the art can only choose to replace the power supply chip with another chip model without an undervoltage protection function. However, there are differences between different chip models in terms of packaging, driving voltage and other settings, which results in a large amount of time spent on redesigning the circuit and debugging when temporarily replacing the power supply chip, and increases unnecessary losses and costs in the production process.

[0033] Please also refer to Figs. 1 to 3 The present application provides a preferred embodiment of a Boost circuit that can be forced to start under undervoltage protection.

[0034] In some preferred embodiments, as Fig. 1 , Fig. 2The utility model provides a Boost boost circuit under the forced start of the under voltage protection, the Boost boost circuit under the forced start of the under voltage protection includes: power supply chip 100, first inductance L1, first diode D1, first capacitor EC1, switch module 200, boost amplitude control module 300 and forced start module 400. One end of power supply chip 100 and forced start module 400 are connected, and the other end is connected with switch module 200, when being in working mode, power supply chip 100 outputs the level signal to switch module 200 to adjust the switching frequency and duty cycle of switch module 200. Switch module 200 is connected with boost amplitude control module 300, and the other end is grounded, and periodically connects and disconnects branch in response to the signal from power supply chip 100. One end of first inductance L1 is connected with input voltage Uin, and the other end is connected with switch module 200 and first diode D1 anode respectively, which is used to store energy when switch module 200 is turned on and release energy when switch module 200 is turned off. First inductance L1 charges first capacitor EC1 and raises circuit voltage. The anode of first diode D1 is connected with first inductance L1 and switch module 200 respectively, and the cathode is connected with boost amplitude control module 300 and output voltage Uout respectively, first diode D1 unidirectionally conducts, which is used to make first capacitor EC1 continuously boost and prevent first capacitor EC1 energy loss when switch module 200 is turned on. The cathode of first capacitor EC1 is grounded, and the anode is connected with the cathode of first diode D1, boost amplitude control module 300 and output voltage Uout respectively. Further, first capacitor EC1 can adopt polarity electrolytic capacitor. The other end of forced start module 400 is grounded, and provides potential difference when the circuit is in low voltage, thereby improving the detection voltage Usense at the voltage detection foot of power supply chip 100 to be greater than the first voltage threshold, thereby forcibly starting power supply chip 100 when input low voltage.

[0035] Specifically, the Boost boost circuit under the forced start of the under voltage protection is connected with DC source input end, the input voltage Uin of DC source input end is DC 21V to DC 31V DC voltage, and DC source input end is used to input Boost circuit and carry out boost conversion. Power supply chip 100 is provided with first voltage threshold, second voltage threshold and third voltage threshold, for example, can be set as: the first voltage threshold is 0.6V, the second voltage threshold is 3V, and the third voltage threshold is 3.25V.

[0036] The working principle of the Boost voltage boosting circuit is as follows: the seventh pin of the power supply chip 100 provides a 15V power supply for the ICE2PCS01 chip; the eighth pin is a driving pin, and the driving signal is provided for the switch module 200, when the driving pin outputs a high level, the switch module 200 is turned on. At this time, the input voltage is grounded through the first inductor L1 and the switch module 200. Since the inductor has the characteristic of hindering the current from changing abruptly, the inductor current increases linearly at a certain ratio, and the linear increase ratio is related to the inductance of the inductor. With the increase of the inductor current, the inductor stores some energy, and the polarity direction of the first inductor L1 is left positive and right negative. When the driving pin of the power supply chip outputs a low level, the switch module 200 is turned off. Since the inductor current cannot change abruptly, the current flowing through the first inductor L1 does not immediately become zero, but slowly decreases at a certain ratio. Since the switch module 200 is turned off, the inductor current can only be discharged through the first diode D1, that is, the inductor charges the first capacitor EC1 through the first diode D1, and the polarity direction of the first inductor L1 is left negative and right positive. The left end of the first inductor is negative, and the left end is the input voltage Uin, so the output voltage Uout of the right end is greater than the input voltage Uin. The circuit completes the voltage boosting function, and the voltage boosting amplitude of the output voltage is determined by the voltage boosting amplitude control module 300 and the second voltage threshold of the power supply chip 100.

[0037] The preferred embodiment of the utility model discloses a kind of Boost voltage boosting circuit of forced start under under-voltage protection, by increasing forced start module between the voltage detection pin of power supply chip and GND pole, the voltage drop between two points is improved, to force the signal voltage of voltage detection pin, realize the forced start of under-voltage protection chip at low voltage. Relative to prior art, the utility model does not need to consider the influence of under-voltage protection of power supply chip represented by second voltage threshold on Boost voltage boosting circuit working condition, can realize the same function with the chip without under-voltage protection function, improve the emergency handling capability of Boost voltage boosting circuit under special condition.

[0038] Please refer to Fig. 3 In the further implementation of the preferred embodiment, the power supply chip 100 uses ICE2PCS01 chip, has high efficiency, stability and reliability, can be widely used in various scenes of power grid power supply, can further improve the efficiency and safety of Boost voltage boosting circuit. The voltage detection pin of ICE2PCS01 chip is connected with the voltage boosting amplitude control module 300, detects the detection voltage in the voltage boosting amplitude control module 300, and the detection voltage is converted into high and low level output from the driving pin in the power supply chip 100. Fig. 3The logic circuit at the voltage detection pin of the ICE2PCS01 chip is shown, and the voltage detection pin of the ICE2PCS01 chip is connected with the non-inverting input terminal of the operational amplifier C4, the inverting input terminal of the operational amplifier C3 and the inverting input terminal of the operational amplifier OTA1 respectively. The third voltage threshold of the ICE2PCS01 chip is at the non-inverting input terminal of the operational amplifier C3, and when the detection voltage value at the voltage detection pin is less than 0.6V, the open-loop undervoltage protection module of the ICE2PCS01 power supply chip 100 starts; the second voltage threshold of the ICE2PCS01 chip is at the non-inverting input terminal of the operational amplifier OTA1, and when the voltage in the voltage detection pin is greater than 3V, the driving pin outputs low level to control the first field effect tube Q1 in the Boost circuit to be turned off; when the voltage in the voltage detection pin is less than 3V, the driving pin outputs high level to control the first field effect tube Q1 in the Boost circuit to be turned on. The third voltage threshold of the ICE2PCS01 chip is connected to the inverting input terminal of the operational amplifier C4, and when the detection voltage value at the voltage detection pin is greater than 3.25V, the overvoltage protection module starts, and the power supply chip protection logic module commands the power supply chip 100 to stop working to prevent the external circuit from damaging the power supply chip 100. The driving pin is connected with the switch module 200 to control the switch module 200 to be turned on and off at a certain frequency to realize the voltage boosting function at the output voltage Uout of the Boost circuit.

[0039] In some preferred embodiments, as shown in the figure, the voltage detection pin of the power supply chip 100 is connected with the non-inverting input terminal of the operational amplifier C4, the inverting input terminal of the operational amplifier C3 and the inverting input terminal of the operational amplifier OTA1 respectively. Fig. 2 As shown in the figure, the voltage boosting amplitude control module 300 includes a first voltage dividing resistor R1 and a second voltage dividing resistor R2; one end of the first voltage dividing resistor R1 is connected with the output voltage Uout, the anode terminal of the first diode D1 and the first capacitor EC1, and the other end is connected with the voltage detection pin of the power supply chip 100 and the second voltage dividing resistor R2 respectively; the other end of the second voltage dividing resistor R2 is connected with the forced starting module 400. The voltage boosting amplitude control module 300 divides the output voltage Uout at the output terminal and inputs through the voltage detection pin of the power supply chip 100, so that the amplitude of the output voltage boosting is determined by the second voltage threshold of the voltage boosting amplitude control module 300 and the power supply chip 100.

[0040] Further, as shown in the figure, Fig. 2As shown, the switch module 200 includes a first field effect tube Q1 and a third voltage dividing resistor R3, the first field effect tube Q1 is grounded at the source, the gate is connected to the driving pin of the power supply chip 100, and the drain is connected to the first inductor L1 and the anode of the first diode D1 respectively; one end of the third voltage dividing resistor R3 is connected to the driving pin of the power supply chip 100 and the source of the first field effect tube Q1 respectively, and the other end is connected to the source of the first field effect tube Q1. The gate of the first field effect tube Q1 receives the output level of the driving pin of the power supply chip 100. When the gate of the first field effect tube Q1 receives a high level, the source and the drain of the first field effect tube Q1 are turned on. At this time, the input voltage Uin is grounded through the first inductor L1 and the first field effect tube Q1. Since the inductor has the characteristic of hindering the sudden change of current, the inductor current increases linearly at a certain rate. At this time, the first inductor L1 stores energy. When the gate of the first field effect tube Q1 receives a low level, the source and the drain of the first field effect tube Q1 are cut off. At this time, since the inductor current cannot suddenly change, that is, the current flowing through the first inductor L1 will not immediately become zero, but will slowly decrease at a certain rate. The input voltage Uin and the inductor current can only be discharged through the first diode D1, that is, the first inductor L1 is discharged through the first diode D1, the first capacitor EC1 is charged, and the Boost circuit realizes the function of voltage boosting. The two ends of the third voltage dividing resistor R3 are connected to the gate and the source of the first field effect tube Q1 respectively, and provide a bias voltage for the first field effect tube Q1. At the same time, the third voltage dividing resistor R3 functions as a discharge resistor, discharges static electricity through the gate and the source of the first field effect tube Q1, prevents the first field effect tube Q1 from being misoperated due to being in a high resistance state, and protects the first field effect tube Q1 from being broken down.

[0041] Specifically, the first field effect tube Q1 can be further selected as an N-channel depletion mode MOSFET tube, thereby improving the ability of the first field effect tube Q1 to work at low voltage, reducing loss, and having good response speed when the circuit input is at low voltage.

[0042] Among them, the forced starting module 400 includes a second diode D2, which is a silicon diode IN4148 with a potential difference of 0.7V between its two ends. The anode of the second diode D2 is connected to the second voltage dividing resistor R2, and the cathode is grounded. The voltage Usense detected at the voltage detection pin of the power supply chip 100 is the sum of the voltage dividing of the second voltage dividing resistor R2 and the potential difference of the second diode D2 itself. Therefore, the detection voltage Usense value is obviously higher than the second voltage threshold of the power supply chip 100, thereby pulling up the voltage detection pin of the power supply chip 100 through the potential difference.

[0043] Further, in another preferred embodiment of the utility model, the input voltage is DC power 21V-31V, the first voltage dividing resistor R1 in voltage dividing module is 990KΩ, the second voltage dividing resistor R2 is 24KΩ, the power supply chip 100 selected is taken power supply chip ICE2PCS01 as an example, the second voltage threshold Usense=3V, at this time, the voltage of power supply chip 100 voltage detection foot is the sum of the voltage of second voltage dividing resistor R2 and the voltage of second diode D2. Output voltage Usense is the second voltage threshold at the voltage detection foot of power supply chip 100, Ud is the potential difference of second diode itself, and the output voltage Uout=

(990K+24K) / 24K

[0044] Further, in another preferred embodiment of the utility model, Boost voltage increasing circuit is commonly used in power module, and the target output voltage Uout of Boost voltage increasing circuit under forced starting under under-voltage protection is DC125V. Since the amplitude of output voltage increasing is determined by voltage increasing amplitude control module 300 and the second voltage threshold of power supply chip 100, the output voltage Usense is the voltage value at the voltage detection pin of the power supply chip 100, Ud is the potential difference between the two ends of the second diode. It can be obtained that when the target output voltage Uout is DC 125V, the set value of the second voltage dividing resistor R2 is 19KΩ. Therefore, the Boost voltage increasing circuit with forced start under under-voltage protection in the utility model only needs to slightly lower the resistance value of the second voltage dividing resistor R2, so as to achieve the effect of the output voltage required by the Boost voltage increasing circuit. Meanwhile, after the forced start module is added, the power supply chip that cannot work due to the under-voltage protection function can be forced to start when the circuit input is low voltage, so that the circuit wiring is avoided to be modified and re-debugged, and the cost is saved.

[0045] The utility model discloses a kind of Boost voltage increasing circuits with forced start under under-voltage protection, by increasing diode between the voltage detection pin of power supply chip and ground pole to improve the voltage drop between two points, so as to force to raise the detection voltage at voltage detection pin, the resistance value of second voltage dividing resistor R2 of Boost voltage increasing circuit slightly lower can reach the effect of target output voltage, without worrying about circuit cannot start, avoid redesign, save a lot of time.In addition, the utility model realizes the forced start of under-voltage protection chip at low voltage, and realizes the same function with the chip without under-voltage protection function, improves the emergency handling capability of Boost voltage increasing circuit under special condition.

[0046] The above embodiments are only preferred embodiments for fully illustrating the utility model, and the protection scope of the utility model is not limited to this. Equivalent replacement or transformation made by the person skilled in the art on the basis of the utility model is within the protection scope of the utility model.

Claims

1. A Boost converter circuit capable of forced startup under undervoltage protection, characterized in that, include: The power supply chip, first inductor, first diode, first capacitor, switching module, boost amplitude control module, and forced start module; among them, The voltage detection pin of the power chip is connected to the boost amplitude control module, and the drive pin of the power chip is connected to the switching module. The power chip is used to output a low level to the switching module when the detected voltage is greater than the second voltage threshold, and to output a high level to the switching module when the detected voltage is less than the second voltage threshold. The switching module is connected to the power chip and the boost amplitude control module respectively. The switching module is used to receive the level signal output by the power chip drive pin and control the Boost circuit to be turned on or off. One end of the first inductor is used to connect to the input voltage, and the other end of the first inductor is connected to the switching module and the anode of the first diode, respectively. The first inductor is used to charge the first capacitor to increase the output voltage. The anode of the first diode is connected to the first inductor and the switching module, respectively, and the cathode of the first diode is connected to the boost amplitude control module and the voltage output terminal, respectively. The first diode is used to continuously boost the voltage of the first capacitor to prevent energy loss of the first capacitor when the switching module is turned on. The cathode of the first capacitor is grounded, and the anode of the first capacitor is connected to the cathode of the first diode, the first resistor, and the voltage output terminal, respectively. The boost amplitude control module is connected to the cathode of the first diode and the voltage output terminal respectively. The boost amplitude control module is used to divide the boosted output voltage to adjust the boost amplitude of the circuit. One end of the forced start module is grounded, and the other end of the forced start module is connected to the boost amplitude control module. The forced start module is used to raise the detection voltage at the voltage detection pin of the power chip so that the detection voltage is higher than the first voltage threshold.

2. The Boost converter circuit with forced start under under-voltage protection according to claim 1, characterized in that, The boost amplitude control module includes: a first voltage divider resistor and a second voltage divider resistor; wherein, one end of the first voltage divider resistor is connected to the output voltage and the diode respectively, and the other end is connected to the voltage detection pin and the second voltage divider resistor respectively; the other end of the second voltage divider resistor is connected to the forced start module.

3. The Boost converter circuit with forced start under under-voltage protection according to claim 1, characterized in that, The first capacitor is a polarized electrolytic capacitor.

4. The Boost converter circuit with forced start under under-voltage protection according to claim 2, characterized in that, The switching module includes: a first field-effect transistor, the source of the first field-effect transistor being grounded, the gate of the first field-effect transistor being connected to the driving pin of the power supply chip, and the drain of the first field-effect transistor being connected to the anode of the first inductor and the first diode, respectively.

5. The Boost converter circuit with forced start under under-voltage protection according to claim 4, characterized in that, The switching module further includes a third voltage divider resistor, one end of which is connected to the power chip drive pin and the source of the first field-effect transistor, and the other end of which is connected to the source of the first field-effect transistor.

6. The Boost converter circuit with forced start under under-voltage protection according to claim 2, characterized in that, The forced start module includes a second diode, the anode of which is connected to the second voltage divider resistor, and the cathode of which is grounded.

7. The Boost converter circuit with forced start under under-voltage protection according to claim 2, characterized in that, The voltage detection pin of the power chip is connected to the common terminal of the first voltage divider resistor and the second voltage divider resistor.

8. The Boost converter circuit with forced start under under-voltage protection according to claim 6, characterized in that, The second diode is a silicon diode.

9. The Boost converter circuit with forced start under under-voltage protection according to claim 7, characterized in that, The power supply chip used is the ICE2PCS01 chip.

10. The Boost converter circuit with forced start under under-voltage protection according to claim 4, characterized in that, The first field-effect transistor is an N-channel depletion-type MOSFET.

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