A pg protection circuit and a control method thereof

Abstract

The application provides a PG protection circuit and a control method thereof. The PG protection circuit comprises a protection switch protection unit for detecting the size of a first main power supply AC1 and providing protection for a transistor switch in a later stage, a light coupling gate unit for connecting a second main power supply VDD to a light emitting diode of a light coupling when the transistor switch is turned on after the first main power supply AC1 is detected, an isolation amplification unit for isolating and amplifying the current generated by a voltage dividing resistor and then outputting a to-be-detected voltage signal of the second main power supply VDD when the light coupling gate unit is in a turn-on state, and a PG signal sending unit for outputting a high-level signal according to the size of a delay capacitor after the to-be-detected voltage signal is detected. The reliability of the PG signal control can be effectively improved, and the safety of the system is ensured.

Description

Technical Field

[0001] This invention relates to the field of electronic technology, and in particular to a PG protection circuit and its control method. Background Technology

[0002] The PG (Power Good) signal protection circuit is used to detect whether the power output is normal and sends a valid signal after the power supply voltage stabilizes, indicating that the system can safely start or continue to operate. It is widely used in servers, computer motherboards, communication equipment, and other applications requiring a reliable power supply. It informs the main control logic of these devices (such as CPUs, FPGAs, DSPs, etc.) whether the current power supply has reached and is maintained within the safe operating threshold, thus determining whether the system can safely start or continue subsequent operations. This prevents the system from starting with an incorrect voltage / current, which could lead to hardware damage, data loss, or even more serious safety incidents.

[0003] Traditional PG signal protection circuits typically consist of a resistor divider network, a comparator, and a transistor. The power supply is stepped down to the comparator's input range through the resistor divider network. The comparator compares the power supply output voltage with a preset threshold. Once the output voltage reaches a stable value, the comparator's output voltage drives the transistor to turn on or off, generating a PG signal that is sent to the device's main control logic. However, traditional PG signal protection circuits suffer from low accuracy and poor stability, making them ill-suited for complex power supply ripple and dynamic changes. Furthermore, their protection function is limited, typically only providing simple overvoltage / undervoltage detection. Precise matching of the resistor divider is required, and different power supply architectures (such as 12V, 5V, 3.3V, etc.) need to be configured separately, resulting in relatively low reliability. Summary of the Invention

[0004] Based on the above-mentioned problems, this invention proposes a PG protection circuit and its control method, which can effectively improve the reliability of PG signal control and ensure the safety of the system.

[0005] In view of this, a first aspect of the present invention provides a PG protection circuit, comprising:

[0006] The switch protection unit is used to detect the magnitude of the first main power supply AC1 and provide protection for the transistor switches in the subsequent stage.

[0007] An optocoupler gate unit is used to turn on the transistor switch after detecting the first main power supply AC1, so as to connect the second main power supply VDD to the light-emitting diode of the optocoupler.

[0008] An isolation amplification unit is used to isolate and amplify the current generated by the second main power supply VDD through the voltage divider resistor and output the voltage to be detected when the optocoupler gate unit is in the on state.

[0009] The PG signal transmitting unit is used to output a high-level signal after a delay based on the size of the configured delay capacitor after detecting the voltage signal to be detected.

[0010] Optionally, the switch protection unit includes a voltage divider resistor and a first diode ZDF1 connected in series between the first main power supply AC1 and the power ground PGND. The first end of the voltage divider resistor is connected to the first main power supply AC1, the second end of the voltage divider resistor is connected to the cathode of the first diode ZDF1, and the anode of the first diode ZDF1 is connected to the power ground PGND.

[0011] Optionally, the optocoupler gating unit includes a fourth resistor RF4 connected in series between the second main power supply VDD and power ground PGND, the input terminal of optocoupler OP1, and a field-effect transistor Q4. The second main power supply VDD is connected to the anode of the light-emitting diode (LED) of optocoupler OP1 via the fourth resistor RF4. The cathode of the LED of optocoupler OP1 is connected to the drain of field-effect transistor Q4. The source of field-effect transistor Q4 is connected to power ground PGND, and the gate of field-effect transistor Q4 is connected to the cathode of the first diode ZDF1. The optocoupler gating unit also... The system includes a first capacitor C1, a ninth capacitor C9, and a tenth resistor RF10. The first terminal of the first capacitor C1 is connected to the second main power supply VDD, and the second terminal of the first capacitor C1 is connected to the power ground PGND. The ninth capacitor C9 and the tenth resistor RF10 are connected in parallel with the first diode ZDF1. That is, the first terminals of the ninth capacitor C9 and the tenth resistor RF10 are both connected between the gate of the field-effect transistor Q4 and the cathode of the first diode ZDF1, and the second terminal of the tenth resistor RF10 of the ninth capacitor C9 is connected to the power ground PGND.

[0012] Optionally, the isolation amplification unit includes a first resistor RF1, a third resistor RF3, the output terminal of optocoupler OP1, a ninth resistor RF9, and a twelfth resistor RF12, sequentially connected in series between the first power supply VCC_S1 and signal ground SGND. The first power supply VCC_S1 is connected to the collector of the output transistor of optocoupler OP1 after passing through the first resistor RF1 and the third resistor RF3. The emitter of the output transistor of optocoupler OP1 is connected to the first terminal of the ninth resistor RF9, and the second terminal of the ninth resistor RF9 is connected to the first terminal of the twelfth resistor RF12. The second terminal of F12 is connected to signal ground SGND; the isolation amplification unit also includes a bipolar transistor Q1 and an output capacitor C10. The emitter of the bipolar transistor Q1 is connected between the first resistor RF1 and the third resistor RF3. The collector of the bipolar transistor Q1 is connected to the emitter of the output transistor of the optocoupler OP1. The base of the bipolar transistor Q1 is connected to the collector of the output transistor of the optocoupler OP1. The first terminal of the output capacitor C10 is connected between the ninth resistor RF9 and the twelfth resistor RF12. The second terminal of the output capacitor C10 is connected to signal ground SGND.

[0013] Optionally, the PG signal transmitting unit includes a voltage detection chip U3 powered by a second power supply VCC_S2, and an eighth resistor RF8, an eleventh resistor RF11, an eleventh capacitor C11, a twelfth capacitor C12, and a second diode ZDF2 connected to the voltage detection chip U3. The voltage detection pin VSEN of the voltage detection chip U3 is connected to the first terminal of the output capacitor C10 of the isolation amplification unit, and the ground pin VSS of the voltage detection chip U3 is connected to the second terminal of the output capacitor C10 of the isolation amplification unit. The second power supply VCC_S2 is connected to the power supply pin V of the voltage detection chip U3 after passing through the eighth resistor RF8. IN supplies power to the voltage detection chip U3. The cathode of the second diode ZDF2 is connected to the power supply pin VIN of the voltage detection chip U3, and the anode of the second diode ZDF2 is connected to the signal ground SGND. The delay capacitor pin CD of the voltage detection chip U3 is connected to the first terminal of the twelfth capacitor, and the second terminal of the twelfth capacitor is connected to the signal ground SGND. The eleventh resistor RF11 is connected between the power supply pin VIN and the output pin VOUT of the voltage detection chip U3. The first terminal of the eleventh capacitor C11 is connected to the output pin VOUT of the voltage detection chip U3, and the second terminal of the eleventh capacitor C11 is connected to the signal ground SGND.

[0014] A second aspect of the present invention provides a control method for any of the above-described PG protection circuits, comprising:

[0015] After the switch protection unit detects the first main power supply AC1, it provides a conduction voltage signal to the transistor switch of the optocoupler gate unit;

[0016] Turn on the optocoupler gate unit to connect the second main power supply VDD to the optocoupler's light-emitting diode;

[0017] The isolation amplifier unit isolates and amplifies the current generated by the second main power supply VDD through the voltage divider resistor to output the voltage signal to be detected.

[0018] After detecting the voltage signal to be detected, the PG signal transmitting unit determines the time delay according to the configured delay duration. Delayed output of high-level signal.

[0019] Optionally, after the switch protection unit detects the first main power supply AC1, it supplies the first main power supply AC1 to the gate of the field-effect transistor Q4 of the optocoupler gate through the voltage divider resistor of the switch protection unit, so as to turn on the optocoupler gate.

[0020] When the voltage of the first main power supply AC1 is greater than the reverse conduction voltage of the first diode ZDF1 When the first diode ZDF1 is broken down, the gate voltage of the field-effect transistor Q4 in the optocoupler gate unit... Below its gate threshold voltage The optocoupler gate unit is disconnected.

[0021] Optionally, the step of turning on the optocoupler gating unit to connect the second main power supply VDD to the light-emitting diode of the optocoupler specifically includes:

[0022] When the gate voltage of the field-effect transistor Q4 in the optocoupler gate unit Greater than its gate threshold voltage When the field-effect transistor Q4 is turned on;

[0023] The second main power supply VDD is applied to the light-emitting diode of the optocoupler through the voltage divider resistor of the optocoupler gate unit to form the input current:

[0024] ,

[0025] in The forward voltage drop of the LED in the optocoupler. The resistance value is the voltage divider resistor of the optocoupler gate unit.

[0026] Optionally, the step of isolating and amplifying the current generated by the second main power supply VDD through the voltage divider resistor to output the voltage signal to be detected specifically includes:

[0027] The input current is converted via an optocoupler Converted to output current:

[0028] ,

[0029] in This refers to the current transfer ratio of the optocoupler;

[0030] when When the isolation amplifier unit is activated, the bipolar transistor Q1 is turned on, and the base current of the bipolar transistor Q1 is:

[0031] ;

[0032] The output current of the isolation amplifier unit at its output resistor RF12 is:

[0033] ,

[0034] in The current gain coefficient of the bipolar transistor Q1 in the isolation amplifier unit;

[0035] The output voltage of the isolation amplifier unit at its output resistor RF12 is:

[0036] .

[0037] Optionally, the step of the PG signal transmitting unit delaying the output of a high-level signal according to the size of the configured delay capacitor after detecting the voltage signal to be detected specifically includes:

[0038] Determine the comparison threshold voltage of the voltage detection chip U3 of the PG signal transmitting unit. ;

[0039] when At that time, the voltage detection chip U3 is in the delay Then, output a high level. As the PG control signal, where The input voltage is the input voltage at the input pin of the voltage detection chip U3;

[0040] when At that time, the voltage detection chip U3 immediately outputs a low level. As the PG control signal.

[0041] This invention proposes a PG protection circuit and its control method. By setting up a protection unit for detecting the magnitude of the first main power supply AC1 and providing protection for the subsequent transistor switch; an optocoupler gating unit for turning on the transistor switch after detecting the first main power supply AC1 to connect the second main power supply VDD to the LED of the optocoupler; an isolation amplification unit for isolating and amplifying the current generated by the second main power supply VDD through a voltage divider resistor and outputting the voltage to be detected when the optocoupler gating unit is in the conducting state; and a PG signal transmitting unit for delaying and outputting a high-level signal according to the size of the configured delay capacitor after detecting the voltage to be detected, the reliability of PG signal control can be effectively improved, ensuring the safety of the system. Attached Figure Description

[0042] Figure 1 This is a block diagram of a PG protection circuit provided in one embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram of a PG protection circuit provided in one embodiment of the present invention;

[0044] Figure 3 This is a flowchart of a control method for a PG protection circuit provided in one embodiment of the present invention. Detailed Implementation

[0045] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0046] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0047] In the description of this invention, the term "multiple" refers to two or more. Unless otherwise explicitly defined, the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. The terms "connect," "install," "fix," etc., should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "multiple" means two or more.

[0048] In the description of this specification, the terms "one embodiment," "some implementations," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0049] A PG protection circuit and its control method according to some embodiments of the present invention will now be described with reference to the accompanying drawings.

[0050] The switch protection unit is used to detect the magnitude of the first main power supply AC1 and provide protection for the transistor switches in the subsequent stage.

[0051] An optocoupler gate unit is used to turn on the transistor switch after detecting the first main power supply AC1, so as to connect the second main power supply VDD to the light-emitting diode of the optocoupler.

[0052] An isolation amplification unit is used to isolate and amplify the current generated by the second main power supply VDD through the voltage divider resistor and output the voltage to be detected when the optocoupler gate unit is in the on state.

[0053] The PG signal transmitting unit is used to output a high-level signal after a delay based on the size of the configured delay capacitor after detecting the voltage signal to be detected.

[0054] In the above-described embodiment, the PG protection circuit adds protection circuits such as switch protection, optocoupler gating and isolation amplification to the traditional PG signal control scheme. Through adjustable gain and threshold setting, it achieves accurate discrimination of PG signal, thereby avoiding false triggering while maintaining high reliability, significantly improving robustness to fluctuations in the first main power supply AC1 and reducing the risk of power supply interference.

[0055] The first main power supply AC1 is a DC power supply obtained by rectifying the neutral and live wire input power supply. That is, the voltage of the first main power supply AC1 can be a swivel waveform voltage or a straight waveform voltage after the input power supply is rectified by a rectifier bridge or other rectifier devices.

[0056] Specifically, the switch protection unit detects and limits the voltage of the first main power supply AC1, thereby ensuring that subsequent gating and amplification components operate in a safe and predictable voltage environment. The optocoupler gating unit uses the voltage signal generated by the first main power supply AC1 to drive the optocoupler's input circuit, illuminating the optocoupler's LED and transmitting the voltage signal of the second main power supply VDD to the subsequent isolation amplification unit for amplification. This amplification is then detected by the PG signal transmitting unit, triggering the transmission of the PG signal. That is, when the first main power supply AC1 is detected, the optocoupler gating unit is turned on, allowing the second main power supply VDD to provide a detection current to the optocoupler input through a voltage divider network. The isolation amplification unit amplifies this current while maintaining electrical isolation, preventing noise from the first main power supply AC1 and the second main power supply VDD from propagating to subsequent detection circuits. This significantly reduces the false alarm rate while maintaining high sensitivity, improving the overall system safety.

[0057] Optionally, the switch protection unit includes a voltage divider resistor and a first diode ZDF1 connected in series between the first main power supply AC1 and the power ground PGND. The first end of the voltage divider resistor is connected to the first main power supply AC1, the second end of the voltage divider resistor is connected to the cathode of the first diode ZDF1, and the anode of the first diode ZDF1 is connected to the power ground PGND.

[0058] like Figure 2 As shown, in some embodiments of the present invention, the voltage divider resistors include three 1MΩ resistors: a second resistor RF2, a fifth resistor RF5, and a seventh resistor RF7. In other embodiments of the present invention, the voltage divider resistors may also be a single 3MΩ resistor.

[0059] In the technical solution of the above embodiment, the switch protection unit utilizes a series of 1MΩ voltage divider resistors (i.e., the second resistor RF2, the fifth resistor RF5, and the seventh resistor RF7) connected in series between AC1 and power ground PGND, as well as the first diode ZDF1, to protect the downstream transistor from breakdown. Preferably, the first diode ZDF1 is a Zener diode. Utilizing the reverse breakdown characteristic of the Zener diode, wide voltage input compatibility with the first main power supply AC1 can be achieved, limiting the gate voltage of the downstream transistor switch within a safe range and preventing the transistor switch from being damaged by excessive voltage.

[0060] See also Figure 2 The optocoupler gate unit includes a fourth resistor RF4 connected in series between the second main power supply VDD and power ground PGND, the input terminal of optocoupler OP1, and a field-effect transistor Q4. The second main power supply VDD is connected to the anode of the light-emitting diode (LED) of optocoupler OP1 via the fourth resistor RF4. The cathode of the LED of optocoupler OP1 is connected to the drain of the field-effect transistor Q4. The source of the field-effect transistor Q4 is connected to power ground PGND, and the gate of the field-effect transistor Q4 is connected to the cathode of the first diode ZDF1. The optocoupler gate unit also includes... The circuit includes a first capacitor C1, a ninth capacitor C9, and a tenth resistor RF10. The first terminal of the first capacitor C1 is connected to the second main power supply VDD, and the second terminal of the first capacitor C1 is connected to the power ground PGND. The ninth capacitor C9 and the tenth resistor RF10 are connected in parallel with the first diode ZDF1. That is, the first terminals of the ninth capacitor C9 and the tenth resistor RF10 are both connected between the gate of the field-effect transistor Q4 and the cathode of the first diode ZDF1, and the second terminal of the tenth resistor RF10 of the ninth capacitor C9 is connected to the power ground PGND.

[0061] In the above-described embodiment, the field-effect transistor Q4 is the transistor switch of the optocoupler gating unit mentioned earlier. The optocoupler gating unit uses the field-effect transistor Q4 to control the on / off state of the optocoupler input. More specifically, the switch protection unit provides a stable gate voltage to the field-effect transistor Q4, enabling the field-effect transistor Q4 to conduct the power supply path from VDD to the optocoupler input, thereby achieving optical isolation of the VDD voltage state by the optocoupler before transmitting it to the backend for fast, low-power detection.

[0062] Since the source of the field-effect transistor Q4 is directly connected to the power ground PGND, a completely isolated switching path is formed. By connecting the gate of the field-effect transistor Q4 to the cathode of the first diode ZDF1, when the first main power supply AC1 is stable, the first diode ZDF1 provides a regulated reference level to the gate of the field-effect transistor Q4, ensuring that the field-effect transistor Q4 only conducts when there is sufficient drive at the optocoupler emitter. To suppress transient interference and improve the gating response rate, an RC network consisting of the ninth capacitor C9 and the tenth resistor RF10 is added to the optocoupler gating unit to provide a fast charging and discharging path for the gate of the field-effect transistor Q4, enabling rapid switching when the state of the first main power supply AC1 changes. Simultaneously, by adding a bypass filter capacitor (the first capacitor C1) to stabilize and smooth VDD, power supply noise entering the optocoupler is reduced, achieving precise gating, isolation, and low-power operation under main power supply fluctuations. This improves the reliability of PG signal control and reduces the probability of false triggering.

[0063] Optionally, the isolation amplification unit includes a first resistor RF1, a third resistor RF3, the output terminal of optocoupler OP1, a ninth resistor RF9, and a twelfth resistor RF12, sequentially connected in series between the first power supply VCC_S1 and signal ground SGND. The first power supply VCC_S1 is connected to the collector of the output transistor of optocoupler OP1 after passing through the first resistor RF1 and the third resistor RF3. The emitter of the output transistor of optocoupler OP1 is connected to the first terminal of the ninth resistor RF9, and the second terminal of the ninth resistor RF9 is connected to the first terminal of the twelfth resistor RF12. The second terminal of F12 is connected to signal ground SGND; the isolation amplification unit also includes a bipolar transistor Q1 and an output capacitor C10. The emitter of the bipolar transistor Q1 is connected between the first resistor RF1 and the third resistor RF3. The collector of the bipolar transistor Q1 is connected to the emitter of the output transistor of the optocoupler OP1. The base of the bipolar transistor Q1 is connected to the collector of the output transistor of the optocoupler OP1. The first terminal of the output capacitor C10 is connected between the ninth resistor RF9 and the twelfth resistor RF12. The second terminal of the output capacitor C10 is connected to signal ground SGND.

[0064] In the above embodiment, the bipolar transistor Q1 is a PNP transistor. The isolation amplification unit connects the first power supply VCC_S1 to the output transistor of the optocoupler OP1 via a first resistor RF1 and a third resistor RF3 connected in series. The optocoupler drives the bipolar transistor Q1, amplifying the optocoupler signal while maintaining high input impedance. The emitter of the bipolar transistor Q1 is placed between RF1 and RF3, and its collector is connected to the emitter of the optocoupler OP1 output transistor. Its base receives the drive from the collector of the optocoupler OP1, allowing the bipolar transistor Q1 to differentially amplify the signal amplitude when the signal arrives via the optocoupler. The isolation amplification unit forms a voltage divider network using the ninth resistor RF9 and the twelfth resistor RF12, further converting the amplified current into a regulated voltage level. A C10 is added at the output for bypass filtering to suppress high-frequency noise and provide a smoother voltage output.

[0065] Optionally, the PG signal transmitting unit includes a voltage detection chip U3 powered by a second power supply VCC_S2, and an eighth resistor RF8, an eleventh resistor RF11, an eleventh capacitor C11, a twelfth capacitor C12, and a second diode ZDF2 connected to the voltage detection chip U3. The voltage detection pin VSEN of the voltage detection chip U3 is connected to the first terminal of the output capacitor C10 of the isolation amplification unit, and the ground pin VSS of the voltage detection chip U3 is connected to the second terminal of the output capacitor C10 of the isolation amplification unit. The second power supply VCC_S2 is connected to the power supply pin V of the voltage detection chip U3 after passing through the eighth resistor RF8. IN supplies power to the voltage detection chip U3. The cathode of the second diode ZDF2 is connected to the power supply pin VIN of the voltage detection chip U3, and the anode of the second diode ZDF2 is connected to the signal ground SGND. The delay capacitor pin CD of the voltage detection chip U3 is connected to the first terminal of the twelfth capacitor, and the second terminal of the twelfth capacitor is connected to the signal ground SGND. The eleventh resistor RF11 is connected between the power supply pin VIN and the output pin VOUT of the voltage detection chip U3. The first terminal of the eleventh capacitor C11 is connected to the output pin VOUT of the voltage detection chip U3, and the second terminal of the eleventh capacitor C11 is connected to the signal ground SGND.

[0066] In the above-described embodiment, the PG signal transmitting unit uses a second power supply VCC_S2 to power the voltage detection chip U3. Specifically, it provides a stable, low-noise power supply and delay filtering for the voltage detection chip U3 through the eighth resistor RF8, the eleventh capacitor C11, the twelfth capacitor C12, and the second diode ZDF2, ensuring that the voltage measurement of the voltage at the output capacitor C10 of the isolation amplifier unit by the voltage detection chip U3 is not affected by transient interference. The eighth resistor RF8 is connected between the second power supply VCC_S2 and the power supply pin VIN of the voltage detection chip U3 to form an input resistance. The second diode ZDF2 provides a voltage regulation reference based on this, ensuring that the power supply voltage of the voltage detection chip U3 is always kept within the safe operating range of the chip, thereby avoiding misjudgment caused by power supply fluctuations. The twelfth capacitor C12 is connected as a delay capacitor between the delay capacitor pin CD of the voltage detection chip U3 and the signal ground SGND, providing the necessary time constant for the internal timer or sampling process of the voltage detection chip U3, thus improving detection accuracy. The eleventh resistor RF11 and the eleventh capacitor C11 form an output bypass network, which is used to reduce the output noise of the output voltage VOUT of the voltage detection chip U3 and smooth the output of the PG control signal.

[0067] In the above-described embodiment, the voltage detection chip U3 generates a corresponding PG control signal based on the voltage measured by its voltage detection pin VSEN through its internal comparison logic, and outputs it to the subsequent protection or control module through the output pin VOUT, thereby achieving accurate and reliable judgment of the main power supply status and improving the safety and response speed of the entire PG system.

[0068] like Figure 3 As shown, a second aspect of the present invention provides a control method for any of the above-described PG protection circuits, comprising:

[0069] After the switch protection unit detects the first main power supply AC1, it provides a conduction voltage signal to the transistor switch of the optocoupler gate unit;

[0070] Turn on the optocoupler gate unit to connect the second main power supply VDD to the optocoupler's light-emitting diode;

[0071] The isolation amplifier unit isolates and amplifies the current generated by the second main power supply VDD through the voltage divider resistor to output the voltage signal to be detected.

[0072] After detecting the voltage signal to be detected, the PG signal transmitting unit determines the time delay according to the configured delay duration. Delayed output of high-level signal.

[0073] The PG protection circuit control method described above combines switch protection, optocoupler gating, isolation amplification, and threshold comparison to achieve dynamic, accurate monitoring and rapid response of the main power supply status. The switch protection unit protects the downstream transistor switches, ensuring that the downstream optocoupler gating unit remains on within a safe voltage range. When the first main power supply AC1 is detected, the optocoupler gating unit turns on, safely connecting the second main power supply VDD to the optocoupler's LED, converting the main power supply status into an optical signal for electrical isolation. Simultaneously, VDD is converted into a measurable current through a voltage divider network, and the voltage to be detected is output through the isolation amplification unit, thus increasing the signal amplitude while maintaining electrical isolation and preventing noise backpropagation. Upon detecting a change in the voltage signal to be detected, the PG signal transmitting unit generates a PG control signal, enabling the system to detect the first main power supply AC1 and, within a preset delay... Then a high-level signal is emitted.

[0074] Furthermore, when the first main power supply AC1 is interrupted, the transistor switch of the optocoupler gating unit is turned off, the output voltage of the isolation amplifier unit disappears, and the PG signal transmitting unit immediately outputs a low-level signal. When the voltage detection chip U3 of the PG signal transmitting unit detects the disappearance of the voltage to be detected on its voltage detection pin VSEN, it directly outputs a low-level signal through its output pin VOUT without delay. This ensures that the protection measures are triggered promptly when the first main power supply AC1 is interrupted, significantly reducing the probability of false alarms and improving response speed, system safety, and reliability.

[0075] Optionally, the step of the switch protection unit providing a conduction voltage signal to the transistor switch of the optocoupler gating unit after detecting the first main power supply AC1 specifically includes:

[0076] The first main power supply AC1 is supplied to the gate of the field-effect transistor Q4 of the optocoupler gate unit through the voltage divider resistor of the switch protection unit, so as to turn on the optocoupler gate unit.

[0077] When the voltage of the first main power supply AC1 is greater than the reverse conduction voltage of the first diode ZDF1 When the first diode ZDF1 is broken down, the gate voltage of the field-effect transistor Q4 in the optocoupler gate unit... Below its gate threshold voltage The optocoupler gate unit is disconnected.

[0078] In the PG protection circuit control method of the above embodiment, in order to ensure that the optocoupler gate unit can be turned on when the first main power supply AC1 is in the normal operating range, the switch protection unit needs to provide the transistor switch of the optocoupler gate unit with a voltage greater than its gate threshold voltage when the first main power supply AC1 is in the normal operating range. gate voltage This ensures that when the voltage of the first main power supply AC1 exceeds the safe range, the first diode ZDF1 begins to conduct in reverse, and the gate voltage of the transistor switch in the optocoupler gate unit is lower than its gate threshold voltage. The circuit is disconnected. When the voltage of the first main power supply AC1 does not exceed the safe range, the optocoupler gating unit is activated and turned on, allowing the second main power supply VDD to enter the isolation link through the optocoupler's light-emitting diode, ensuring that the PG control signal is only generated when the voltage of the first main power supply AC1 is within the safe range.

[0079] The technical solution of this implementation method immediately switches the state of the optocoupler gating unit when the first main power supply AC1 disappears or exceeds the safe range, thereby realizing real-time suppression and precise control of main power supply fluctuations and greatly improving the stability and safety of the PG protection system under different working conditions.

[0080] Optionally, the step of turning on the optocoupler gating unit to connect the second main power supply VDD to the light-emitting diode of the optocoupler specifically includes:

[0081] When the gate voltage of the field-effect transistor Q4 in the optocoupler gate unit Greater than its gate threshold voltage When the field-effect transistor Q4 is turned on;

[0082] The second main power supply VDD is applied to the light-emitting diode of the optocoupler through the voltage divider resistor of the optocoupler gate unit to form the input current:

[0083] ,

[0084] in The forward voltage drop of the LED in the optocoupler. The resistance value is the voltage divider resistor of the optocoupler gate unit.

[0085] In the PG protection circuit control method of the above embodiment, when the gate voltage of the field-effect transistor Q4... Greater than its gate threshold voltage When the second main power supply is activated, the field-effect transistor Q4 immediately turns on, forming a path from the fourth resistor RF4 to the light-emitting diode of the optocoupler to ground, generating an input current at the input terminal of the optocoupler. .

[0086] The technical solution of this embodiment utilizes the reverse breakdown characteristic of the first diode ZDF1 to achieve wide voltage input compatibility with the first main power supply AC1, limiting the gate voltage of the subsequent transistor switch within a safe range and avoiding false triggering due to low or excessive voltage fluctuations. At the same time, the field-effect transistor Q4 provides a completely isolated switching path, so that the second main power supply VDD only drives the optocoupler when the conditions are met, thereby achieving precise and reliable control over the generation of the PG signal.

[0087] Optionally, the step of isolating and amplifying the current generated by the second main power supply VDD through the voltage divider resistor to output the voltage signal to be detected specifically includes:

[0088] The input current is converted via an optocoupler Converted to output current:

[0089] ,

[0090] in This refers to the current transfer ratio of the optocoupler;

[0091] when When the isolation amplifier unit is activated, the bipolar transistor Q1 is turned on, and the base current of the bipolar transistor Q1 is:

[0092] ;

[0093] The output current of the isolation amplifier unit at its output resistor RF12 is:

[0094] ,

[0095] in The current gain coefficient of the bipolar transistor Q1 in the isolation amplifier unit;

[0096] The output voltage of the isolation amplifier unit at its output resistor RF12 is:

[0097] .

[0098] Furthermore, when When the isolation amplifier unit's bipolar transistor Q1 is turned off, the base current of the bipolar transistor Q1... ;

[0099] The output current of the isolation amplifier unit at its output resistor RF12 is:

[0100] ;

[0101] The output voltage of the isolation amplifier unit at its output resistor RF12 is:

[0102] .

[0103] In the PG protection circuit control method of the above embodiment, the optocoupler input current generated by driving the second main power supply VDD is transmitted via an optocoupler. The current transfer ratio (CTR) of the optocoupler is converted to the output current. The bipolar transistor Q1 and the voltage divider network are used to isolate and amplify the voltage signal to be detected, ensuring that the PG control maintains accuracy at different current levels. When the output current... Exceeding the threshold When the bipolar transistor Q1 is turned on, the base current of the bipolar transistor Q1 is equal to... Thus through The gain amplifies the base current into the collector current. And generate a corresponding output voltage on the twelfth resistor RF12. If the output current Below the threshold When the bipolar transistor Q1 is turned off, the current flowing through the twelfth resistor RF12 is equal to the output current. Maintain a linear relationship.

[0104] The technical solution of this embodiment dynamically determines the output current. Relative to threshold The size of the sensor is adjusted to improve sensitivity in high-current scenarios and avoid unnecessary saturation and distortion in low-current scenarios, thereby achieving accurate and reliable detection of the PG state while maintaining electrical isolation and low noise characteristics.

[0105] Optionally, after detecting the voltage signal to be detected, the PG signal transmitting unit determines the time delay according to the configured delay duration. The specific steps for delaying the output of a high-level signal include:

[0106] Determine the comparison threshold voltage of the voltage detection chip U3 of the PG signal transmitting unit. ;

[0107] when At that time, the voltage detection chip U3 is in the delay Then, output a high level. As the PG control signal, wherein The input voltage is the input voltage at the input pin of the voltage detection chip U3;

[0108] when At that time, the voltage detection chip U3 immediately outputs a low level. As the PG control signal.

[0109] Specifically, the twelfth capacitor C12 is a delay capacitor, and the delay duration is... The delay duration can be configured by setting different sizes of delay capacitors, depending on the size of the twelfth capacitor C12. This is to meet the PG control system's response requirements for power-on delay.

[0110] It responds immediately after a power outage, without any delay.

[0111] In the PG protection circuit control method of the above embodiment, by introducing a comparison threshold into the PG protection circuit... The voltage detection chip U3 is capable of detecting the voltage to be detected generated by the isolation amplification unit. The signal is compared in real time with a preset safety boundary to achieve precise PG control signal generation. Specifically, when the voltage to be detected... Exceeding the comparison threshold voltage When the voltage detection chip U3 outputs a high level, the output voltage of the voltage detection chip U3 is... It is equal to its supply voltage VIN. When the voltage to be detected... Below the comparison threshold voltage When the voltage detection chip U3 returns to a low level, the output voltage of the voltage detection chip U3 is... It equals 0.

[0112] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0113] As described above, these embodiments of the present invention do not exhaustively cover all details, nor do they limit the invention to the specific embodiments described. Clearly, many modifications and variations can be made based on the above description. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to effectively utilize the invention and its modifications. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A PG protection circuit, characterized in that, include: The switch protection unit is used to detect the magnitude of the first main power supply AC1 and provide protection for the transistor switches in the subsequent stage. An optocoupler gate unit is used to turn on the transistor switch after detecting the first main power supply AC1, so as to connect the second main power supply VDD to the light-emitting diode of the optocoupler. An isolation amplification unit is used to isolate and amplify the current generated by the second main power supply VDD through the voltage divider resistor and output the voltage to be detected when the optocoupler gate unit is in the on state. The PG signal transmitting unit is used to output a high-level signal after a delay based on the size of the configured delay capacitor after detecting the voltage signal to be detected. The switch protection unit includes a voltage divider resistor and a first diode ZDF1 connected in series between the first main power supply AC1 and the power ground PGND. The first end of the voltage divider resistor is connected to the first main power supply AC1, the second end of the voltage divider resistor is connected to the cathode of the first diode ZDF1, and the anode of the first diode ZDF1 is connected to the power ground PGND. The optocoupler gating unit includes a fourth resistor RF4 connected in series between the second main power supply VDD and power ground PGND, the input terminal of optocoupler OP1, and a field-effect transistor Q4. The second main power supply VDD is connected to the anode of the light-emitting diode (LED) of optocoupler OP1 via the fourth resistor RF4. The cathode of the LED of optocoupler OP1 is connected to the drain of the field-effect transistor Q4. The source of the field-effect transistor Q4 is connected to power ground PGND, and the gate of the field-effect transistor Q4 is connected to the cathode of the first diode ZDF1. The optocoupler gating unit also includes a first capacitor C1, a ninth capacitor C9, and a tenth resistor RF10. The first terminal of the first capacitor C1 is connected to the second main power supply VDD, and the second terminal of the first capacitor C1 is connected to power ground PGND. The ninth capacitor C9 and the tenth resistor RF10 are connected in parallel with the first diode ZDF1, meaning that the first terminals of both the ninth capacitor C9 and the tenth resistor RF10 are connected between the gate of the field-effect transistor Q4 and the cathode of the first diode ZDF1, and the second terminals of the ninth capacitor C9 and the tenth resistor RF10 are connected to power ground PGND. The isolation amplification unit includes a first resistor RF1, a third resistor RF3, the output terminal of optocoupler OP1, a ninth resistor RF9, and a twelfth resistor RF12, sequentially connected in series between the first power supply VCC_S1 and signal ground SGND. The first power supply VCC_S1 is connected to the collector of the output transistor of optocoupler OP1 after passing through the first resistor RF1 and the third resistor RF3. The emitter of the output transistor of optocoupler OP1 is connected to the first terminal of the ninth resistor RF9. The second terminal of the ninth resistor RF9 is connected to the first terminal of the twelfth resistor RF12. The second terminal of 12 is connected to signal ground SGND; the isolation amplification unit also includes a bipolar transistor Q1 and an output capacitor C10. The emitter of the bipolar transistor Q1 is connected between the first resistor RF1 and the third resistor RF3. The collector of the bipolar transistor Q1 is connected to the emitter of the output transistor of the optocoupler OP1. The base of the bipolar transistor Q1 is connected to the collector of the output transistor of the optocoupler OP1. The first terminal of the output capacitor C10 is connected between the ninth resistor RF9 and the twelfth resistor RF12. The second terminal of the output capacitor C10 is connected to signal ground SGND.

2. The PG protection circuit according to claim 1, characterized in that, The PG signal transmitting unit includes a voltage detection chip U3 powered by a second power supply VCC_S2, and an eighth resistor RF8, an eleventh resistor RF11, an eleventh capacitor C11, a twelfth capacitor C12, and a second diode ZDF2 connected to the voltage detection chip U3. The voltage detection pin VSEN of the voltage detection chip U3 is connected to the first terminal of the output capacitor C10 of the isolation amplification unit, and the ground pin VSS of the voltage detection chip U3 is connected to the second terminal of the output capacitor C10 of the isolation amplification unit. The second power supply VCC_S2 is connected to the power supply pin VIN of the voltage detection chip U3 after passing through the eighth resistor RF8 to transmit the signal to the voltage detection chip U3. The voltage detection chip U3 is powered by the following: the cathode of the second diode ZDF2 is connected to the power supply pin VIN of the voltage detection chip U3, and the anode of the second diode ZDF2 is connected to the signal ground SGND; the delay capacitor pin CD of the voltage detection chip U3 is connected to the first terminal of the twelfth capacitor C12, and the second terminal of the twelfth capacitor C12 is connected to the signal ground SGND; the eleventh resistor RF11 is connected between the power supply pin VIN and the output pin VOUT of the voltage detection chip U3; the first terminal of the eleventh capacitor C11 is connected to the output pin VOUT of the voltage detection chip U3, and the second terminal of the eleventh capacitor C11 is connected to the signal ground SGND.

3. The control method for the PG protection circuit according to any one of claims 1-2, characterized in that, include: After the switch protection unit detects the first main power supply AC1, it provides a conduction voltage signal to the transistor switch of the optocoupler gate unit; Turn on the optocoupler gate unit to connect the second main power supply VDD to the optocoupler's light-emitting diode; The isolation amplifier unit isolates and amplifies the current generated by the second main power supply VDD through the voltage divider resistor to output the voltage signal to be detected. After detecting the voltage signal to be detected, the PG signal transmitting unit determines the time delay according to the configured delay duration. Delayed output of high-level signal.

4. The control method for the PG protection circuit according to claim 3, characterized in that, After the switch protection unit detects the first main power supply AC1, the specific steps of providing a conduction voltage signal to the transistor switch of the optocoupler gate unit include: The first main power supply AC1 is supplied to the gate of the field-effect transistor Q4 of the optocoupler gate unit through the voltage divider resistor of the switch protection unit, so as to turn on the optocoupler gate unit. When the voltage of the first main power supply AC1 is greater than the reverse conduction voltage of the first diode ZDF1 When the first diode ZDF1 is broken down, the gate voltage of the field-effect transistor Q4 in the optocoupler gate unit... Below its gate threshold voltage The optocoupler gate unit is disconnected.

5. The control method for the PG protection circuit according to claim 4, characterized in that, The specific steps of turning on the optocoupler gate unit to connect the second main power supply VDD to the light-emitting diode of the optocoupler include: When the gate voltage of the field-effect transistor Q4 of the optocoupler gate unit... Greater than its gate threshold voltage When the field-effect transistor Q4 is turned on; The second main power supply VDD is applied to the light-emitting diode of the optocoupler through the voltage divider resistor of the optocoupler gate unit to form the input current: ， in The forward voltage drop of the LED in the optocoupler. The resistance value is the voltage divider resistor of the optocoupler gate unit.

6. The control method for the PG protection circuit according to claim 5, characterized in that, The specific steps of isolating and amplifying the current generated by the second main power supply VDD through a voltage divider resistor to output the voltage signal to be detected include: The input current is converted via an optocoupler Converted to output current: ， in This refers to the current transfer ratio of the optocoupler; when When the isolation amplifier unit is activated, the bipolar transistor Q1 is turned on, and the base current of the bipolar transistor Q1 is: ； The output current of the isolation amplifier unit at its output resistor RF12 is: ， in The current gain coefficient of the bipolar transistor Q1 in the isolation amplifier unit; The output voltage of the isolation amplifier unit at its output resistor RF12 is: 。 7. The control method for the PG protection circuit according to claim 3, characterized in that, After detecting the voltage signal to be detected, the PG signal transmitting unit determines the time delay according to the configured delay duration. The specific steps for delaying the output of a high-level signal include: Determine the comparison threshold voltage of the voltage detection chip U3 of the PG signal transmitting unit. ; when At that time, the voltage detection chip U3 is in the delay Then, output a high level. As the PG control signal, The input voltage is the input voltage at the input pin of the voltage detection chip U3; when At that time, the voltage detection chip U3 immediately outputs a low level. As a PG control signal.

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