Short-circuit protection circuit for Boost circuit

Abstract

The invention relates to a short-circuit protection circuit for a Boost circuit. The short-circuit protection circuit comprises a short-circuit detection circuit, an intelligent high-side switch and a single-chip microcomputer, the input end of the short circuit detection circuit is connected with the output end of the Boost circuit; the output end of the short circuit detection circuit is connected with a signal pin of the single-chip microcomputer. The intelligent high-side switch is connected in series with the power supply and the input end of the Boost circuit, and the control end of the intelligent high-side switch is connected with a GPIO pin of the single-chip microcomputer; the short-circuit detection circuit detects whether the output of the Boost circuit is short-circuited or not and inputs a detection signal to the single-chip microcomputer, and the single-chip microcomputer controls the on and off of the intelligent high-side switch according to the detection signal to realize short-circuit protection of the Boost circuit. According to the invention, power supply can be quickly cut off when the load is short-circuited, the Boost circuit and the power supply are effectively prevented from being damaged due to overcurrent, and the safety and reliability of the system are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a short-circuit protection circuit for a Boost circuit. Background Art

[0002] In the field of driver amplifier circuits, high-power loads often require a DC voltage in the hundreds of volts range to operate properly. Boost circuits, as classic DC-DC step-up converters, are widely used in this scenario. They boost the voltage of a low-voltage battery or DC power supply to the hundreds of volt range, providing the required high-voltage input for the driver amplifier circuit, ensuring normal operation and sufficient power output.

[0003] However, in practical applications, boost circuits face a serious problem: the risk of sudden load short circuits. Once a load short circuit occurs, the current in the circuit rises sharply, causing overcurrent. Because boost circuits typically operate at high voltage and high current, this overcurrent condition places significant stress on components within the circuit, such as inductors, diodes, and MOSFETs. This can quickly burn out these critical components, even damaging the power supply and circuit boards, resulting in serious safety risks and financial losses.

[0004] Currently, fuses are widely used in the industry as a short-circuit protection measure. Fuses melt in the event of an overcurrent, shutting off the circuit and protecting the equipment. However, this traditional protection solution has significant drawbacks. First, the fuse's melting process takes time, and it cannot quickly cut off the short-circuit current in milliseconds or even less. This can cause irreversible damage to circuit components before the fuse blows. Second, once a fuse blows, it must be manually replaced, which not only increases maintenance costs and system downtime, but also affects the reliability of continuous system operation. These issues are particularly prominent in scenarios where unmanned or maintenance is difficult, such as industrial automation and telecommunications base stations.

[0005] Therefore, there is an urgent need for a Boost circuit short-circuit protection circuit that can detect short-circuit faults in real time and cut off power supply in a very short time to address the shortcomings of the existing technology. Summary of the Invention

[0006] To this end, the technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a short-circuit protection circuit for a Boost circuit. Through the coordinated work of an intelligent high-side switch, a single-chip microcomputer and a short-circuit detection circuit, the power supply can be quickly cut off when a load is short-circuited, effectively preventing the Boost circuit and the power supply from being damaged due to overcurrent, thereby ensuring the safety and reliability of the system.

[0007] To solve the above technical problems, the present invention provides a short-circuit protection circuit for a Boost circuit, comprising: a short-circuit detection circuit, an intelligent high-side switch, and a single-chip microcomputer; the input end of the short-circuit detection circuit is connected to the output end of the Boost circuit for real-time monitoring of the output voltage of the Boost circuit; the output end of the short-circuit detection circuit is connected to a signal pin of the single-chip microcomputer; the intelligent high-side switch is connected in series with a power supply and the input end of the Boost circuit, and the control end of the intelligent high-side switch is connected to a GPIO pin of the single-chip microcomputer; The short-circuit detection circuit is used to detect whether the Boost circuit output is short-circuited, and input the detection signal to the single-chip microcomputer. The single-chip microcomputer controls the conduction and shutdown of the intelligent high-side switch according to the detection signal to achieve short-circuit protection of the Boost circuit.

[0008] In one embodiment of the present invention, the short circuit detection circuit includes: A voltage dividing branch, one end of which is connected to the output end of the Boost circuit, and the other end of which is grounded, for dividing the output voltage of the Boost circuit; a limiting branch, one end of which is connected to the middle node of the voltage dividing branch, and the other end of which is grounded, for performing limiting processing on the detection signal; a filter element connected between the output end of the limiting branch and the ground, and configured to filter out high-frequency noise in the detection signal; The output end of the limiting branch is a detection signal output end, which is used to connect to a signal pin of a single chip microcomputer.

[0009] In one embodiment of the present invention, the voltage divider branch includes a resistor R1, a resistor R2 and a resistor R3 connected in series in sequence, one end of the resistor R1 is connected to the output end of the Boost circuit, the other end of the resistor R3 is grounded, and the common node of the resistor R2 and the resistor R3 is connected to the limiting branch.

[0010] In one embodiment of the present invention, the amplitude limiting branch includes a Zener diode D3 , a cathode of the Zener diode D3 is connected to the middle node of the voltage dividing branch, and an anode of the Zener diode D3 is grounded.

[0011] In one embodiment of the present invention, the filtering element includes a capacitor C1 , one end of the capacitor C1 is connected to the output end of the amplitude limiting branch, and the other end is grounded.

[0012] In one embodiment of the present invention, a signal regulating branch is further included, and the signal regulating branch is connected to the middle node of the voltage dividing branch for regulating the voltage output by the voltage dividing branch.

[0013] In one embodiment of the present invention, the signal conditioning branch includes a diode D1, a diode D2 and a resistor R4, the anode of the diode D1 is connected to a 3.3V power supply, the cathode is connected to one end of the resistor R4, the other end of the resistor R4 is connected to the output end of the limiting branch, the anode of the diode D2 is grounded, the cathode is connected to the other end of the resistor R4, and the other end of the resistor R4 is also connected to the middle node of the voltage divider branch.

[0014] In one embodiment of the present invention, when the detection signal is at a high level, the intelligent high-side switch is controlled by the single-chip microcomputer to remain on, allowing current to flow from the power supply to the Boost circuit, enabling the Boost circuit to operate normally. When the detection signal is at a low level, the intelligent high-side switch is controlled by the single-chip microcomputer to turn off, cutting off the input voltage to the Boost circuit, causing the Boost circuit to stop operating and achieving short-circuit protection for the Boost circuit.

[0015] In one embodiment of the present invention, the signal pin of the microcontroller is an ADC pin or a digital IO pin. When the detection signal output by the short-circuit detection circuit is an analog signal, the ADC pin receives the analog signal and converts it into a digital signal for processing by the microcontroller; when the detection signal output by the short-circuit detection circuit is a digital signal, the digital IO pin receives the digital signal for processing by the microcontroller.

[0016] In one embodiment of the present invention, the intelligent high-side switch is a voltage-controlled switch or a current-controlled switch.

[0017] The above technical solution of the present invention has the following beneficial effects compared with the prior art: The short-circuit protection circuit for a Boost circuit described in the present invention can monitor the output status of the Boost circuit in real time through a short-circuit detection circuit and input a detection signal into a single-chip microcomputer. The single-chip microcomputer can quickly determine whether a short circuit occurs in the circuit. Once a short circuit is detected, the intelligent high-side switch is immediately controlled to turn off, thereby promptly cutting off the input voltage of the Boost circuit, effectively preventing damage to the Boost circuit and the power supply caused by overcurrent due to the short circuit, and protecting the safety and reliability of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0019] Figure 1 Schematic diagram of the structure of a short-circuit protection circuit for a Boost circuit in a preferred embodiment of the present invention; Figure 2 Schematic diagram of the short circuit detection circuit in the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0021] Reference Figure 1 As shown, the present invention provides a short-circuit protection circuit for a Boost circuit, comprising: a short-circuit detection circuit, an intelligent high-side switch, and a single-chip microcomputer; the input end of the short-circuit detection circuit is connected to the output end of the Boost circuit for real-time monitoring of the output voltage of the Boost circuit; the output end of the short-circuit detection circuit is connected to a signal pin of the single-chip microcomputer; the intelligent high-side switch is connected in series to a power supply and the input end of the Boost circuit, and the control end of the intelligent high-side switch is connected to a GPIO pin of the single-chip microcomputer; The short-circuit detection circuit is used to detect whether the Boost circuit output is short-circuited, and input the detection signal to the single-chip microcomputer. The single-chip microcomputer controls the conduction and shutdown of the intelligent high-side switch according to the detection signal to achieve short-circuit protection of the Boost circuit.

[0022] like Figure 2 As shown, the short circuit detection circuit includes: A voltage dividing branch, one end of which is connected to the output end of the Boost circuit, and the other end of which is grounded, for dividing the output voltage of the Boost circuit; a limiting branch, one end of which is connected to the middle node of the voltage dividing branch, and the other end of which is grounded, for performing limiting processing on the detection signal; a filter element connected between the output end of the limiting branch and the ground, and configured to filter out high-frequency noise in the detection signal; The output end of the limiting branch is a detection signal output end, which is used to connect to a signal pin of a single chip microcomputer.

[0023] This embodiment divides the output voltage of the Boost circuit through a voltage divider branch, converting the high-voltage signal into a low-voltage signal suitable for processing by the microcontroller, thereby enabling accurate monitoring of the output voltage. The limiter branch limits the detection signal to prevent excessively high voltage signals from damaging the microcontroller or other subsequent processing circuits, thereby improving the stability and reliability of the circuit. The filter element effectively filters out high-frequency noise in the detection signal, improving the quality of the detection signal and enabling the microcontroller to more accurately determine the short-circuit state, reducing the possibility of misjudgment.

[0024] The voltage divider branch includes resistors R1, R2, and R3 connected in series. One end of resistor R1 is connected to the output of the boost circuit, the other end of resistor R3 is grounded, and the common node between resistors R2 and R3 is connected to the limiter branch. The voltage divider branch composed of multiple resistors can flexibly adjust the resistance value and number of resistors according to different boost circuit output voltage levels and monitoring requirements. By properly selecting the resistance values ​​of the resistors, high-voltage signals can be converted into low-voltage signals suitable for processing by the microcontroller, achieving accurate monitoring of the output voltage.

[0025] According to Kirchhoff's voltage law and Ohm's law, the current flowing through resistors R1, R2, and R3 is the same, and the voltage drop across each resistor in the circuit is proportional to its resistance value. Assuming the resistance values ​​of resistors R1, R2, and R3 are R1, R2, and R3, respectively, and the output voltage of the boost circuit is Vout, the voltage across resistor R1 is V1 = Vout × [R1 / (R1+R2+R3)], the voltage across resistor R2 is V2 = Vout × [R2 / (R1+R2+R3)], and the voltage across resistor R3 is V3 = Vout × [R3 / (R1+R2+R3)].

[0026] The voltage Vmid at the middle node of the voltage divider (the common node between resistors R2 and R3) is Vout × [(R2 + R3) / (R1 + R2 + R3)]. This voltage Vmid is the voltage after voltage division and is proportional to and lower than the boost circuit's output voltage Vout. By properly selecting the resistance values ​​of R1, R2, and R3, Vmid can be controlled within the low-voltage signal range that the microcontroller can handle, thereby enabling voltage division monitoring of the boost circuit's output voltage.

[0027] In this embodiment, the amplitude limiting branch includes a Zener diode D3 , a cathode of the Zener diode D3 is connected to the middle node of the voltage dividing branch, and an anode of the Zener diode D3 is grounded.

[0028] Zener diode D3, as a limiting element, provides a stable clamping voltage, ensuring the detection signal's voltage range is within the acceptable range of the microcontroller, improving signal stability and reliability. When the Zener diode's reverse voltage reaches its breakdown voltage, it enters the breakdown region. At this point, the Zener diode's reverse current increases dramatically, but the voltage across it remains essentially constant. This constant voltage is called the Zener voltage. The following is the specific process by which Zener diode D3 achieves limiting in this circuit: When the detection signal voltage output by the voltage divider branch (i.e., the voltage Vmid of the middle node) is lower than the Zener voltage of the Zener diode D3, the Zener diode D3 is in a reverse cutoff state and has almost no effect on the circuit. At this time, the detection signal voltage is directly transmitted to the output end of the limiting branch.

[0029] When the detection signal voltage exceeds the Zener voltage of Zener diode D3, it enters its breakdown region and begins conducting. At this point, the voltage across Zener diode D3 is clamped near its Zener voltage and no longer increases significantly with increasing input voltage. Regardless of the output voltage of the voltage divider branch, the output voltage of the limiting branch is limited to the Zener voltage range of Zener diode D3, thus protecting subsequent components such as the microcontroller from damage due to excessive voltage.

[0030] The filter element includes a capacitor C1, one end of which is connected to the output of the limiting branch and the other end is grounded. By utilizing the capacitor's low impedance to high-frequency signals and high impedance to low-frequency signals, high-frequency noise in the detection signal is filtered out, improving signal purity and enabling the microcontroller to more accurately obtain short-circuit information.

[0031] Furthermore, the present invention further includes a signal conditioning branch connected to the intermediate node of the voltage divider branch for regulating the voltage output by the voltage divider branch. The introduction of the signal conditioning branch can further regulate the voltage output by the voltage divider branch, making the detection signal more stable and accurate, and improving the accuracy of short-circuit detection. Through the signal conditioning branch, the voltage level of the detection signal can be flexibly adjusted according to different Boost circuit parameters and microcontroller requirements, thereby enhancing the versatility and adaptability of the protection circuit.

[0032] The signal conditioning branch includes a diode D1, a diode D2, and a resistor R4. The anode of the diode D1 is connected to a 3.3V power supply, the cathode is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the output end of the limiting branch. The anode of the diode D2 is grounded, the cathode is connected to the other end of the resistor R4, and the other end of the resistor R4 is also connected to the middle node of the voltage divider branch. The signal conditioning branch composed of the diode D1, the diode D2, and the resistor R4 can accurately adjust and optimize the detection signal, ensuring that the detection signal has the appropriate voltage amplitude and stability before being transmitted to the single-chip microcomputer. When the detection signal voltage exceeds 3.3V, the diode D1 is turned on to clamp the voltage; when short-circuited, the diode D2 is cut off, and the resistor R4 limits the leakage current to ensure signal stability.

[0033] When the detection signal voltage exceeds 3.3V, diode D1 clamps the detection signal voltage to around 3.3V, preventing excessive voltage from entering the microcontroller and protecting the microcontroller's pins from damage. When the detection signal voltage is below 0V, such as in a short-circuit situation, the detection signal voltage is pulled down to 0V, and diode D2 is cut off, which has no effect on the signal. However, during normal operation, the presence of diode D2 helps stabilize the signal path. Resistor R4 is used to limit the current through diodes D1 and D2, preventing excessive current from damaging diodes D1 and D2 or the microcontroller's pins. At the same time, resistor R4 and capacitor C1 form a low-pass filter, further filtering out high-frequency noise in the detection signal and improving signal stability.

[0034] When a short circuit occurs at the boost circuit's output, the output voltage instantly drops to near 0V. At this point, the voltage at the voltage divider in the short-circuit detection circuit also drops sharply, causing the detection signal voltage to drop to 0V. At this point, diode D1 is cut off because the detection signal voltage is below 3.3V. Diode D2's anode is grounded, and its cathode voltage is also 0V, so D2 is also cut off. Resistor R4 primarily serves to limit potential leakage current, ensuring that the detection signal remains stable at 0V, which is detected by the microcontroller as a low level, triggering the protection mechanism.

[0035] When the detection signal is high, the intelligent high-side switch remains on under the control of the single-chip microcomputer, allowing current to flow from the power supply to the boost circuit, enabling normal operation of the boost circuit. When the detection signal is low, the intelligent high-side switch is turned off under the control of the single-chip microcomputer, cutting off the input voltage to the boost circuit, causing the boost circuit to stop operating and providing short-circuit protection for the boost circuit. The rapid shutdown of the intelligent high-side switch effectively cuts off the input voltage to the boost circuit, effectively protecting the circuit and preventing damage to circuit components caused by overcurrent due to a short circuit.

[0036] The signal pin of the microcontroller is either an ADC pin or a digital IO pin. When the detection signal output by the short-circuit detection circuit is an analog signal, the ADC pin receives the analog signal and converts it into a digital signal for processing by the microcontroller. When the detection signal output by the short-circuit detection circuit is a digital signal, the digital IO pin receives the digital signal for processing by the microcontroller. Depending on the type of signal output by the short-circuit detection circuit, the microcontroller can choose to use either the ADC pin or the digital IO pin for signal reception and processing. This flexibility allows the protection circuit to adapt to different detection signal formats and microcontroller models, enhancing the system's compatibility and versatility.

[0037] Preferably, the intelligent high-side switch is a voltage-type controllable switch or a current-type controllable switch. The current-type controllable switch is turned on and off by controlling the current flowing through itself. When the control current reaches a certain threshold, the switch is closed; when the control current is lower than the threshold, the switch is disconnected; the voltage-type controllable switch is turned on and off by controlling the voltage across it. When the control voltage reaches a certain threshold, the switch is turned on and current can flow; when the control voltage is lower than the threshold, the switch is cut off. The voltage-type switch is preferably a power MOSFET switch and an IGBT switch. Both the power MOSFET switch and the IGBT switch have low on-resistance, fast switching speed and high voltage resistance, which can meet the requirements of the Boost circuit at different power and voltage levels, ensuring the rapid response and reliable operation of the protection circuit. The current-type controllable switch is preferably a transistor. The transistor has a strong current amplification capability and a relatively fast switching speed.

[0038] Based on the above-described short-circuit protection circuit for a boost circuit, when the boost circuit is operating normally, its output voltage is divided by resistors R1, R2, and R3 in the short-circuit detection circuit to generate a detection signal voltage proportional to the output voltage. This voltage is clamped within the 3-3.3V range by an adjustment circuit consisting of resistor R4 and diodes D1 and D2, clamped by Zener diode D3, and filtered by capacitor C1. This voltage is then input to an ADC pin or digital I / O pin of a microcontroller. Upon detecting this high-level signal, the microcontroller determines that the boost circuit is operating normally. Its GPIO pin then outputs a high-level signal, controlling the intelligent high-side switch to remain in the on state, enabling the boost circuit to continuously draw power from the DC power supply and step up the output voltage normally, providing the required 100-volt DC voltage for the load.

[0039] When a short circuit occurs at the output of the boost circuit, the output voltage instantly drops to near 0V. At this point, the voltage at the divider point in the short-circuit detection circuit also drops sharply, causing the detection signal voltage to drop to 0V. The microcontroller monitors the detection signal in real time. Once it detects a low voltage, it immediately determines that a short circuit has occurred in the boost circuit. The microcontroller's GPIO pin outputs a low signal, quickly shutting off the intelligent high-side switch. Once the intelligent high-side switch turns off, it disconnects the boost circuit from the DC power supply, halting operation. This prevents damage to the entire circuit caused by excessive current generated by the short circuit, effectively protecting the boost circuit and its power supply, and preventing further damage to the circuit board.

[0040] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A short-circuit protection circuit for a Boost circuit, characterized in that: The invention comprises: a short-circuit detection circuit, an intelligent high-side switch and a single-chip microcomputer; the input end of the short-circuit detection circuit is connected to the output end of the Boost circuit; the output end of the short-circuit detection circuit is connected to the signal pin of the single-chip microcomputer; the intelligent high-side switch is connected in series with the power supply and the input end of the Boost circuit, and the control end of the intelligent high-side switch is connected to the GPIO pin of the single-chip microcomputer; The short-circuit detection circuit detects whether the Boost circuit output is short-circuited and inputs a detection signal to the single-chip microcomputer. The single-chip microcomputer controls the on and off of the intelligent high-side switch according to the detection signal to achieve short-circuit protection of the Boost circuit.

2. The short-circuit protection circuit for a Boost circuit according to claim 1, wherein: The short circuit detection circuit comprises: A voltage dividing branch, one end of which is connected to the output end of the Boost circuit, and the other end of which is grounded, for dividing the output voltage of the Boost circuit; a limiting branch, one end of which is connected to the middle node of the voltage dividing branch, and the other end of which is grounded, for performing limiting processing on the detection signal; a filter element connected between the output end of the limiting branch and the ground, and configured to filter out high-frequency noise in the detection signal; The output end of the limiting branch is a detection signal output end, which is used to connect to a signal pin of a single chip microcomputer.

3. The short-circuit protection circuit for a Boost circuit according to claim 2, wherein: The voltage divider branch includes resistors R1, R2 and R3 connected in series, one end of the resistor R1 is connected to the output end of the Boost circuit, the other end of the resistor R3 is grounded, and a common node between the resistors R2 and R3 is connected to the limiting branch.

4. The short-circuit protection circuit for a Boost circuit according to claim 2, wherein: The amplitude limiting branch includes a Zener diode D3 , a cathode of the Zener diode D3 is connected to the middle node of the voltage dividing branch, and an anode of the Zener diode D3 is grounded.

5. The short-circuit protection circuit for a Boost circuit according to claim 2, wherein: The filtering element includes a capacitor C1 , one end of the capacitor C1 is connected to the output end of the amplitude limiting branch, and the other end is grounded.

6. The short-circuit protection circuit for a Boost circuit according to claim 2, wherein: It also includes a signal adjustment branch, which is connected to the middle node of the voltage dividing branch and is used to adjust the voltage output by the voltage dividing branch.

7. The short-circuit protection circuit for a Boost circuit according to claim 6, characterized in that: The signal conditioning branch includes a diode D1, a diode D2, and a resistor R4. The anode of the diode D1 is connected to a 3.3V power supply, the cathode is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the output end of the limiting branch. The anode of the diode D2 is grounded, the cathode is connected to the other end of the resistor R4, and the other end of the resistor R4 is also connected to the middle node of the voltage divider branch.

8. The short-circuit protection circuit for a Boost circuit according to claim 1, wherein: When the detection signal is at a high level, the intelligent high-side switch is controlled by the single-chip microcomputer to remain on, and current flows from the power supply to the Boost circuit, so that the Boost circuit works normally; when the detection signal is at a low level, the intelligent high-side switch is controlled by the single-chip microcomputer to be turned off, cutting off the input voltage of the Boost circuit, causing the Boost circuit to stop working, thereby achieving short-circuit protection for the Boost circuit.

9. The short-circuit protection circuit for a Boost circuit according to claim 1, wherein: The signal pin of the single-chip microcomputer is an ADC pin or a digital IO pin. When the detection signal output by the short-circuit detection circuit is an analog signal, the ADC pin receives the analog signal and converts it into a digital signal for processing by the single-chip microcomputer; when the detection signal output by the short-circuit detection circuit is a digital signal, the digital IO pin receives the digital signal for processing by the single-chip microcomputer.

10. The short-circuit protection circuit for a Boost circuit according to claim 1, characterized in that: The intelligent high-side switch is a voltage-type controllable switch or a current-type controllable switch.

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