Integrated chip power supply and temperature control protection circuit

Abstract

The invention relates to the technical field of power electronics, and provides an integrated chip power supply and temperature control protection circuit, which comprises a first transformer and a second transformer, the main windings of which respectively form a PFC circuit and an LLC circuit; an auxiliary winding of the first transformer generates a first power supply voltage and a second power supply voltage and supplies power to the PFC control chip and the LLC control chip, and an auxiliary winding of the second transformer outputs a third voltage; the temperature control protection module comprises at least two temperature control switches, an optocoupler isolation unit and a voltage regulation unit; the temperature control switch is used for detecting the temperature of a heating device associated with the second transformer and generating a trigger signal when the temperature exceeds a threshold value; the optocoupler isolation unit is used for transmitting the trigger signal to the voltage regulation unit; and the voltage regulation unit is controlled by a trigger signal to be conducted, the third voltage and the PFC driving voltage are superposed and pulled down to a chip closing threshold, and the PFC and the LLC control chip are switched off synchronously, so that the integration of double-chip combined power supply and rapid temperature control protection is realized.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of power electronics, and particularly relates to an integrated chip power supply and temperature control protection circuit. BACKGROUND

[0002] In a traditional power supply system, the PFC control chip and the LLC control chip adopt independent power supply and protection circuits, and need to be equipped with their own transformers and rectification filtering components, thus resulting in a large circuit size and high cost. In addition, in terms of temperature control protection, the signals are directly coupled and transmitted, and due to the potential difference between the high-voltage and low-voltage areas, electrical interference between the front and rear stages is easily caused, resulting in protection misoperation or response lag, and additional isolation devices are needed to increase complexity. At the same time, the heat dissipation of the discrete modules is dispersed and the synergy is poor, and it is difficult to adapt to the requirements of compactness and high reliability in high-power density scenarios. SUMMARY

[0003] The present disclosure aims to solve the problems of high complexity, high cost and insufficient reliability caused by the discrete design of the PFC and LLC chip power supply and temperature control protection circuit in the existing power supply system, and provides an integrated chip power supply and temperature control protection circuit. Through the reuse design of the auxiliary winding of the transformer, the isolation transmission of the optocoupler temperature control signal and the triode linkage control technology, the integration of the dual-chip joint power supply and rapid temperature control protection is realized.

[0004] According to a first aspect of the present disclosure, an integrated chip power supply and temperature control protection circuit is provided, comprising: a first transformer T1, a second transformer T2 and a temperature control protection module; The main windings of the first transformer T1 and the second transformer T2 respectively constitute a PFC circuit and an LLC resonant conversion circuit; The auxiliary winding of the first transformer T1 generates a first power supply voltage and a second power supply voltage after rectification and filtering, which are isolated from each other, and supplies power to the PFC control chip and the LLC control chip respectively, and the auxiliary winding of the second transformer T2 outputs a third voltage to the temperature control protection module; The temperature control protection module comprises at least two temperature control switches, an optocoupler isolation unit and a voltage regulation unit; The temperature control switch is used to detect the temperature of the heating device associated with the second transformer T2, and generate a trigger signal when the temperature exceeds a threshold value; The optocoupler isolation unit is used to transmit the trigger signal to the voltage regulation unit; The voltage regulation unit is controlled by the trigger signal to turn on, superimposes the third voltage and the PFC drive voltage and pulls down to the chip shutdown threshold value, and synchronously turns off the PFC and LLC control chips.

[0005] As a preferred embodiment, the auxiliary winding of the first transformer T1 is equipped with a power supply module, which comprises a first rectifier diode D1, a second rectifier diode D2 and a π-type filter network, wherein, The cathode of the first rectifier diode D1 and the anode of the second rectifier diode D2 are connected to the first output end of the auxiliary winding of the first transformer T1; The anode of the first rectifier diode D1 and the cathode of the second rectifier diode D2 are connected to the second output end of the auxiliary winding of the first transformer T1; The π-type filter network is composed of a first capacitor C1, a second capacitor C2, a third capacitor C3 and a first current-limiting resistor R1 connected in series, for filtering out high-frequency ripples and generating stable first and second power supply voltages.

[0006] As a preferred embodiment, the power supply module further comprises a switching triode Q1 and a second current-limiting resistor R2, wherein, The collector of the switching triode Q1 is connected to the cathode of the second rectifier diode D2, the emitter is the output end of the first power supply voltage, and the base is connected to the cathode of the second rectifier diode D2 through the second current-limiting resistor R2; The second current-limiting resistor R2 is used to limit the drive current flowing into the base of the switching triode Q1.

[0007] Power supply module working logic The 18V alternating current output by the auxiliary winding of T1 is half-wave rectified by D1 and D2: D1 rectifies the positive half-cycle voltage and D2 rectifies the negative half-cycle voltage, forming two pulsed direct currents.

[0008] The pulsed direct current is filtered by the π-type filter network (C1-R1-C2, C3) to remove high-frequency ripples (≥100kHz), generating stable first and second power supply voltages V-PFC (12V) and V-LLC (15V).

[0009] Q1 is driven by the V-PFC voltage: the base obtains a bias current through R2, and when it is turned on, it stably outputs V-PFC to the power supply pin of the PFC control chip (such as UCC28056); when it is turned off, it cuts off the V-PFC output, realizing controllable power supply.

[0010] As a preferred embodiment, the auxiliary winding of the second transformer T2 is equipped with a control circuit, which comprises a rectifier diode D7 and a filter capacitor C5, wherein: The anode of the rectifier diode D7 is connected to one end of the auxiliary winding of the second transformer T2, and the cathode is the rectified output end, used for rectifying the alternating voltage output by the auxiliary winding of the second transformer T2; The filter capacitor C5 is connected in parallel to the rectified output end, used for smoothing voltage fluctuations.

[0011] As a preferred embodiment, the temperature control protection module specifically comprises a front-stage temperature control switch 1, a rear-stage temperature control switch 2, an optical coupling isolator and a transistor Q2, wherein, The front-stage temperature control switch 1 and the rear-stage temperature control switch 2 are respectively attached to the heat dissipation surfaces of the front-stage circuit heat generating device and the rear-stage circuit heat generating device of the second transformer T2; The input end of the optical coupling isolator is connected to the rear-stage temperature control switch 2, and the output end is connected to the temperature control protection module; The base of the transistor Q2 receives the optical coupling output signal through the fourth current-limiting resistor R4, and the collector is connected to the rectified output end of the auxiliary winding of the second transformer T2.

[0012] As a preferred embodiment, when the transistor Q2 is turned on, the third voltage output by the auxiliary winding of the second transformer T2 is superimposed with the PFC drive voltage through the aggregation point 1, so that the superimposed voltage is lower than the undervoltage lock threshold of the PFC control chip and the LLC control chip.

[0013] As a preferred embodiment, the transistor Q2 is provided with a drive protection circuit, which includes a base current-limiting resistor R3 and a second voltage stabilizing diode D8, wherein: The base current-limiting resistor R3 is connected in series between the output side of the optical coupling isolator and the base of the transistor Q2, for clamping the drive current flowing into the base of the transistor Q2; The second voltage stabilizing diode D8 is connected in parallel between the base and the emitter of the transistor Q2, for clamping the base voltage of the transistor Q2.

[0014] As a preferred embodiment, the transistor Q2 is further provided with a base protection circuit, which includes a third voltage stabilizing diode D10 and a fourth current-limiting resistor R4, wherein, The cathode of the third voltage stabilizing diode D10 is connected to the base of the transistor Q2 through the ninth unidirectional diode D9, and the anode is grounded, for limiting the base voltage of the transistor Q2 within its reverse breakdown voltage range; The fourth current-limiting resistor R4 is connected in series between the base of the transistor Q2 and the output end of the optical coupling isolation unit, to suppress the overcurrent impact that may occur in the circuit.

[0015] Temperature control protection module triggering mechanism When working normally: the temperature control switches 1 and 2 are disconnected, there is no current at the input end of the optical coupling isolator, the output end is cut off, there is no driving signal at the base of Q2, and it is in the cut-off state.

[0016] When the temperature is over threshold: If the temperature of the pre-stage / post-stage heating device T2 reaches 105℃, the corresponding temperature control switch is closed (such as the post-stage temperature control switch 2 is closed), the optocoupler input is turned on (current 5mA), and the output is saturated and turned on.

[0017] Signal transmission and voltage regulation: the optocoupler output signal drives Q2 to be turned on through R3 and R4, the third voltage of 12V after the T2 auxiliary winding is rectified by D7, and the voltage is superimposed with the PFC driving voltage (12V) through the collection point 1. After superposition, the voltage is pulled down to 4.5V (lower than the chip under-voltage lock threshold 5V), and the PFC and LLC control chips are turned off synchronously.

[0018] Protection circuit cooperation Drive protection: R3 limits the base current of Q2 to be ≤1mA, D8 clamps the base voltage of Q2 to be ≤5.1V, preventing Q2 from being damaged by overdrive; D10 limits the collector voltage of Q2 to be ≤18V, avoiding breakdown.

[0019] Reverse impact protection: D3 prevents the reverse flow of C4 energy into the T1 auxiliary winding; D4 and D5 are connected in series at the V-LLC output end to prevent reverse discharge of the LLC chip.

[0020] Voltage stabilization and discharge: C4 stores energy to maintain the V-PFC / V-LLC voltage stability (ripple ≤50mV); D6 clamps the voltage to 16V to prevent overvoltage damage to the chip; the PE end discharges the leakage current (≤1mA) and the surge energy (such as lightning surge).

[0021] As a preferred embodiment, the circuit further comprises a reverse impact protection device, the reverse impact protection device comprising a first unidirectional diode D4, a second unidirectional diode D5, and a third unidirectional diode D3, wherein, the first unidirectional diode D4 and the second unidirectional diode D5 are connected in series at the output end of the first supply voltage and the second supply voltage, for ensuring unidirectional conduction of current; the third unidirectional diode D3 has an anode connected to the emitter of the switching triode Q1 and a cathode connected to the collection point 1, for preventing reverse current of the auxiliary winding from flowing into the first transformer T1.

[0022] As a preferred embodiment, the circuit further comprises a voltage stabilization and discharge circuit, the voltage stabilization and discharge circuit comprising an electrolytic capacitor C4, a first voltage stabilizing diode D6, and a protective ground terminal PE, wherein, the electrolytic capacitor C4 is connected in parallel at the output end of the first supply voltage and the second supply voltage, for energy storage and filtering; the first voltage stabilizing diode D6 has a cathode connected to the base of the switching triode Q1 and an anode connected to ground, for clamping the first supply voltage and the second supply voltage; A protection ground terminal PE is used for discharging leakage current and surge energy of the filter capacitor C4 and the first voltage stabilizing diode D6.

[0023] Compared with the prior art, the present disclosure realizes the following beneficial effects: (1) The present disclosure integrates the power supply circuit of the PFC and LLC control chips and the temperature control protection circuit through the reuse design of the auxiliary winding of the double transformer, reduces the number of devices required by the independent power supply and protection circuit, reduces the circuit volume, reduces the system cost, and is more suitable for the needs of high power density scenes.

[0024] (2) The present disclosure uses distributed temperature control switches to monitor the temperatures of the T2 pre-stage and post-stage heat generating devices, and combines with the optical coupling isolation transmission temperature control signal to effectively eliminate the electrical interference of the high and low voltage sides, ensuring the safety and reliability of signal transmission. At the same time, the synchronous power-off shutdown of the PFC and LLC chips is realized through the conduction of the triode Q2, which improves the response speed of the temperature control protection and can quickly respond to temperature abnormal conditions.

[0025] (3) The present disclosure adopts a multiple protection design, the base current limiting resistor (R3) and the voltage stabilizing tube (D8) in the Q2 drive protection ensure the safe conduction of the triode; the voltage clamping and anti-rebound devices (such as voltage stabilizing tube D10, unidirectional diodes D4, D5, D3) effectively suppress overvoltage, overcurrent and reverse impact; the energy discharge and filtering components (electrolytic capacitor C4, voltage stabilizing tube D6, protection ground terminal PE) stabilize the power supply voltage, discharge the leakage current and surge energy, and significantly improve the reliability and safety of the system.

[0026] (4) The LLC main circuit adopts soft switching operation, which reduces the loss, and combined with the efficient power supply design, the overall efficiency of the power conversion system is improved.

[0027] It should be understood that the content described in the summary section is not intended to limit the key or important features of the embodiments of the present disclosure, nor to limit the scope of the present disclosure. Other features of the present disclosure will become apparent through the following description. BRIEF DESCRIPTION OF DRAWINGS

[0028] The above and other features, advantages, and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. The accompanying drawings are used to better understand the present disclosure, and do not constitute a limitation on the present disclosure. In the drawings, the same or similar reference signs represent the same or similar elements, wherein: Figure 1 An integrated chip power supply and temperature control protection circuit schematic diagram of an embodiment of the present disclosure is shown; T1: first transformer, T2: second transformer, D1: first rectifier diode, D2: second rectifier diode, C1: first capacitor, C2: second capacitor, C3: third capacitor, C4: electrolytic capacitor, C5: filter capacitor, R1: first current-limiting resistor, R2: second current-limiting resistor, R4: fourth current-limiting resistor, Q1: switching triode, Q2: triode, D3: third unidirectional diode, D4: first unidirectional diode, D5: second unidirectional diode, D6: first voltage stabilizing diode, D7: rectifier diode, D8: second voltage stabilizing diode, D9: ninth unidirectional diode, D10: third voltage stabilizing diode, PE: protective grounding terminal, collection point 1: third voltage and PFC drive voltage collection point. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are some but not all of the embodiments of the present disclosure. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present disclosure.

[0030] In addition, the term "and / or" in this document is only to describe the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this document generally represents an "or" relationship between the front and rear associated objects.

[0031] As Figure 1 Fig. 1 shows an integrated chip power supply and temperature control protection circuit diagram according to an embodiment of the present disclosure. The circuit includes: a first transformer T1, a second transformer T2, and a temperature control protection module; The main windings of the first transformer T1 and the second transformer T2 respectively constitute a PFC circuit and an LLC resonant conversion circuit; The auxiliary winding of the first transformer T1 generates a first power supply voltage and a second power supply voltage after rectification and filtering, which are mutually isolated, and supplies power to a PFC control chip and an LLC control chip respectively. The auxiliary winding of the second transformer T2 outputs a third voltage to the temperature control protection module; The temperature control protection module includes at least two temperature control switches, an optical coupling isolation unit, and a voltage regulation unit; The temperature control switch is used to detect the temperature of a heating device associated with the second transformer T2, and generate a trigger signal when the temperature exceeds a threshold value; The optical coupling isolation unit is used to transmit the trigger signal to the voltage regulation unit; The voltage regulating unit is controlled by the trigger signal to turn on, superimpose the third voltage and the PFC driving voltage, and pull down to the chip closing threshold, thereby synchronously turning off the PFC and LLC control chips.

[0032] As a preferred embodiment, the auxiliary winding of the first transformer T1 is equipped with a power supply module, which includes a first rectifier diode D1, a second rectifier diode D2, and a π-type filter network, wherein, Two rectifier diodes (for example, the first rectifier diode and the second rectifier diode) are connected in a specific polarity across the two output terminals of the auxiliary winding of the first transformer (T1), to achieve rectification, specifically, the cathode of the first rectifier diode D1 and the anode of the second rectifier diode D2 are connected to the first output terminal of the auxiliary winding of the first transformer T1; The anode of the first rectifier diode D1 and the cathode of the second rectifier diode D2 are connected to the second output terminal of the auxiliary winding of the first transformer T1; The π-type filter network is composed of a first capacitor C1, a second capacitor C2, a third capacitor C3, and a first current-limiting resistor R1 connected in series, for filtering out high-frequency ripples and generating stable first and second power supply voltages V-PFC and V-LLC.

[0033] The power supply module further includes a switching triode Q1 and a second current-limiting resistor R2, wherein, The collector of the switching triode Q1 is connected to the cathode of the second rectifier diode D2, the emitter serves as the output terminal of the first power supply voltage, and the base is connected to the cathode of the second rectifier diode D2 through the second current-limiting resistor R2; The second current-limiting resistor R2 is used to limit the driving current flowing into the base of the switching triode Q1.

[0034] As a preferred embodiment, the auxiliary winding of the second transformer T2 is equipped with a control circuit, which includes a rectifier diode D7 and a filter capacitor C5, wherein: The anode of the rectifier diode D7 is connected to one end of the auxiliary winding of the second transformer T2, and the cathode serves as a rectified output terminal for rectifying the alternating voltage output by the auxiliary winding of the second transformer T2; The filter capacitor C5 is connected in parallel to the rectified output terminal, for smoothing voltage fluctuations and providing a relatively stable third voltage.

[0035] As a preferred embodiment, the temperature control protection module specifically includes a front-stage temperature control switch 1, a rear-stage temperature control switch 2, an optocoupler isolator, and a triode Q2 as a voltage regulating unit, wherein, The front-stage temperature control switch 1 and the rear-stage temperature control switch 2 are respectively attached to the heat dissipation surfaces of the front-stage circuit heat generating device and the rear-stage circuit heat generating device of the second transformer T2. The input end of the opto-isolator is connected to the rear-stage temperature control switch 2, and the output end is connected to the temperature control protection module. The base of the triode Q2 receives the signal from the output end of the opto-isolator through the fourth current limiting resistor R4, and the collector is connected to the rectified output end (i.e. the third voltage) of the auxiliary winding of the second transformer T2.

[0036] As a preferred embodiment, when the triode Q2 is triggered to be turned on, it will superimpose the third voltage output by the auxiliary winding of the second transformer T2 on the PFC drive voltage through the collection point 1, which will force the voltage at this node to be pulled down below the under-voltage lock threshold of the PFC and LLC control chips, causing both chips to stop working at the same time.

[0037] As a preferred embodiment, in order to protect the triode Q2, a base drive circuit is provided, which includes a base current limiting resistor R3 and a second voltage stabilizing diode D8, wherein: The base current limiting resistor R3 is connected in series between the output side of the opto-isolator and the base of the triode Q2, for clamping the drive current flowing into the base of the triode Q2; The second voltage stabilizing diode D8 is connected in parallel between the base and the emitter of the triode Q2, for clamping the base voltage of the triode Q2.

[0038] As a preferred embodiment, in order to protect the triode Q2, a base protection circuit is further added, which includes a third voltage stabilizing diode D10 and a fourth current limiting resistor R4, wherein, The cathode of the third voltage stabilizing diode D10 is connected to the base of the triode Q2 through the ninth unidirectional diode D9, and the anode is grounded, for limiting the base voltage of the triode Q2 within its reverse breakdown voltage range; The fourth current limiting resistor R4 is connected in series between the base of the triode Q2 and the output end of the opto-isolator, to suppress the overcurrent impact that may occur in the circuit.

[0039] As a preferred embodiment, the circuit further includes a reverse impact protection device for preventing current reverse impact, which includes a first unidirectional diode D4, a second unidirectional diode D5 and a third unidirectional diode D3, wherein, The first unidirectional diode D4 and the second unidirectional diode D5 are connected in series between the output ends of the first power supply voltage and the second power supply voltage, for ensuring unidirectional conduction of current; The third unidirectional diode D3 has an anode connected to the emitter of the switching triode Q1 and a cathode connected to the collection point 1, and is used to prevent the auxiliary winding current from flowing in the reverse direction into the first transformer T1.

[0040] As a preferred embodiment, the circuit further comprises a voltage stabilizing and energy discharge circuit, which comprises an electrolytic capacitor C4, a first voltage stabilizing diode D6 and a protective ground terminal PE, wherein, The electrolytic capacitor C4 is connected in parallel to the output terminals of the first and second power supply voltages, and is used for energy storage and filtering; The cathodes of the first voltage stabilizing diodes D6 are respectively connected to the bases of the switching triodes Q1, and the anodes are grounded, and are used to clamp the first and second power supply voltages; The protective ground terminal PE is used to discharge the leakage current and surge energy of the filter capacitor C4 and the first voltage stabilizing diode D6.

[0041] According to the above embodiments of the present disclosure, the following technical effects are achieved: (1) The present disclosure integrates the power supply circuit of the PFC and LLC control chip and the temperature control protection circuit through the multiplexing design of the auxiliary winding of the double transformer, reduces the number of devices required for the independent power supply and protection circuit, reduces the circuit size, reduces the system cost, and is more suitable for the needs of high power density scenarios.

[0042] (2) The present disclosure uses distributed temperature control switches to monitor the temperatures of the pre-stage and post-stage heat generating devices of T2, and combines with the optical coupling isolation transmission of the temperature control signal to effectively eliminate the electrical interference of the high and low voltage sides, and ensure the safety and reliability of the signal transmission. At the same time, the synchronous power-off shutdown of the PFC and LLC chips is realized through the conduction of the triode Q2, which improves the response speed of the temperature control protection and can quickly respond to temperature abnormal conditions.

[0043] (3) The present disclosure adopts a multiple protection design, the base current limiting resistor (R3) and the voltage stabilizing tube (D8) in the Q2 drive protection ensure the safe conduction of the triode; the voltage clamping and anti-rebound devices (such as voltage stabilizing tube D10, unidirectional diodes D4, D5, D3) effectively suppress overvoltage, overcurrent and reverse impact; the energy discharge and filtering components (electrolytic capacitor C4, voltage stabilizing tube D6, protective ground terminal PE) stabilize the power supply voltage, discharge the leakage current and surge energy, and significantly improve the reliability and safety of the system.

[0044] (4) The LLC main circuit adopts soft switching operation, which reduces the loss, and combined with the efficient power supply design, the overall efficiency of the power conversion system is improved.

[0045] It should be noted that for the foregoing method embodiments, for the sake of simple description, they are all expressed as a combination of a series of actions, but those skilled in the art should know that the disclosure is not limited by the order of the described actions, because according to the disclosure, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily required by the disclosure.

[0046] The integrated chip power supply and temperature control protection circuit according to the disclosure is further described below.

[0047] The control method of the integrated chip power supply and temperature control protection circuit provided by the disclosure realizes the synchronous start-stop and rapid fault isolation of the PFC and LLC chips through the double-winding cooperative power supply and cross-level temperature control linkage mechanism. The temperature control protection adopts a multi-node cooperative triggering strategy to ensure the action reliability, and the system has automatic recovery capability, specifically including the following stages: I. System startup phase The input alternating current is coupled through the main winding of the first transformer T1, and D1 and D2 rectify the voltage of the auxiliary winding of T1, and a π-type filter network generates two isolated DC voltages V-PFC and V-LLC.

[0048] The base of the switching triode Q1 obtains a bias current through R2 to turn on, V-PFC is output to the PFC control chip, and V-LLC is directly output to the LLC control chip. The two chips complete initialization (undervoltage lockout release), the PFC circuit starts power factor correction (Boost topology, 65 kHz), the LLC circuit enters the resonance working mode (soft switching, 100-300 kHz), and the system output stable voltage.

[0049] II. Steady state running phase Power supply stability control: C4 stores energy to filter and dynamically suppress power supply fluctuations, maintaining the chip operating voltage within the tolerance range (for example: voltage fluctuation ≤±0.5V), and D6 clamps the voltage to prevent overvoltage caused by sudden changes in input voltage.

[0050] Distributed temperature monitoring: The temperature control switches 1 and 2 detect the temperature of the pre-stage / post-stage heat generating devices in real time (for example, normal working temperature ≤85℃), maintain the off state, the optocoupler isolator has no output, and Q2 is cut off.

[0051] Reverse impact protection: D3, D4, and D5 ensure unidirectional current flow and block reverse current paths to prevent reverse discharging of the auxiliary winding or the chip; the PE terminal continuously discharges leakage current to ensure safety.

[0052] III. Temperature control protection phase Trigger signal generation: temperature control switch (such as the rear switch 2) is closed, the optocoupler input is turned on, and the output is saturated and turned on.

[0053] Drive Q2 on: the optocoupler output signal is input to the Q2 base after current limiting by R3 and R4, D8 clamps the base voltage, and Q2 is saturated and turned on.

[0054] Synchronous chip off: the 12V third voltage of the T2 auxiliary winding is superimposed with the PFC drive voltage at the summary point 1, and is pulled down to 4.5V (<5V under-voltage lock threshold), the PFC and LLC control chips are turned off at the same time, and the main circuit stops working.

[0055] Four, recovery phase (temperature ≤90℃) Temperature control switch reset: the temperature of the heat generating device drops to 90℃, the temperature control switch is automatically turned off, the optocoupler input is powered off, and the output is cut off.

[0056] Q2 cut-off: the Q2 base has no driving signal, and the recovery cut-off state is restored, the summary point 1 voltage rises to 12V, and the chip under-voltage lock is released.

[0057] System restart: the PFC and LLC control chips are reinitialized, the main circuit resumes normal operation, and the "normal operation phase" process is repeated.

[0058] The control method realizes the cooperative work and rapid protection of the PFC and LLC chips through integrated power supply design, optocoupler isolated temperature control signal transmission, and linkage shutdown mechanism, and takes into account the requirements of high integration, high reliability, and high power density.

[0059] In the technical solution of the present disclosure, the acquisition, storage, and application of user personal information comply with relevant laws and regulations and do not violate public order and good customs.

[0060] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present disclosure can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present disclosure can be achieved, and the present disclosure is not limited herein.

[0061] The above specific embodiments do not constitute a limitation on the protection scope of the present disclosure. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. An integrated chip power supply and temperature control protection circuit, characterized in that: include: A first transformer (T1), a second transformer (T2) and a temperature control protection module; The main windings of the first transformer (T1) and the second transformer (T2) constitute a PFC circuit and an LLC resonant conversion circuit respectively; The auxiliary winding of the first transformer (T1) generates a mutually isolated first power supply voltage and a second power supply voltage after rectification and filtering, and supplies power to the PFC control chip and the LLC control chip respectively, and the auxiliary winding of the second transformer (T2) outputs a third voltage to the temperature control protection module; The temperature control protection module includes at least two temperature control switches, an optical coupling isolation unit and a voltage regulation unit; The temperature-controlled switch is used to detect the temperature of a heating device associated with the second transformer (T2) and generate a trigger signal when the temperature exceeds a threshold; The optical coupling isolation unit is used to transmit the trigger signal to the voltage regulation unit; The voltage regulating unit is controlled to be turned on by the trigger signal, superimposes the third voltage and the PFC driving voltage and pulls them down to the chip shutdown threshold, and synchronously shuts down the PFC and LLC control chips.

2. The circuit according to claim 1, characterized in that The auxiliary winding of the first transformer (T1) is equipped with a power supply module, which includes a first rectifier diode (D1), a second rectifier diode (D2) and a π-type filter network, wherein: The cathode of the first rectifier diode (D1) and the anode of the second rectifier diode (D2) are connected to the first output end of the auxiliary winding of the first transformer (T1); The anode of the first rectifier diode (D1) and the cathode of the second rectifier diode (D2) are connected to the second output end of the auxiliary winding of the first transformer (T1); The π-type filter network is composed of a first capacitor (C1), a second capacitor (C2), a third capacitor (C3) and a first current-limiting resistor (R1) connected in series, and is used to filter out high-frequency ripples and generate stable first and second power supply voltages.

3. The circuit according to claim 2, characterized in that The power supply module further includes a switching transistor (Q1) and a second current limiting resistor (R2), wherein: The collector of the switching transistor (Q1) is connected to the cathode of the second rectifier diode (D2), the emitter serves as the output end of the first power supply voltage, and the base is connected to the cathode of the second rectifier diode (D2) through a second current limiting resistor (R2); The second current limiting resistor (R2) is used to limit the driving current flowing into the base of the switching transistor (Q1).

4. The circuit according to claim 1, wherein: The auxiliary winding of the second transformer (T2) is equipped with a control circuit, which includes a rectifier diode (D7) and a filter capacitor (C5), wherein: The anode of the rectifier diode (D7) is connected to one end of the auxiliary winding of the second transformer (T2), and the cathode serves as a rectifier output end, and is used to rectify the AC voltage output by the auxiliary winding of the second transformer (T2); The filter capacitor (C5) is connected in parallel to the rectifier output end and is used to smooth voltage fluctuations.

5. The circuit according to claim 1, wherein: The temperature control protection module specifically includes a front-stage temperature control switch (1), a rear-stage temperature control switch (2), an optical coupler isolator and a transistor (Q2), wherein: The front-stage temperature control switch (1) and the rear-stage temperature control switch (2) are respectively attached to the heat dissipation surfaces of the front-stage circuit heating device and the rear-stage circuit heating device of the second transformer (T2); The input end of the optical coupler isolator is connected to the subsequent temperature control switch (2), and the output end is connected to the temperature control protection module; The base of the transistor (Q2) receives the optocoupler output signal through the fourth current-limiting resistor (R4), and the collector is connected to the rectifier output end of the auxiliary winding of the second transformer (T2).

6. The circuit according to claim 5, characterized in that When the transistor (Q2) is turned on, the third voltage output by the auxiliary winding of the second transformer (T2) is superimposed on the PFC drive voltage through the aggregation point (1), so that the superimposed voltage is lower than the undervoltage lockout threshold of the PFC control chip and the LLC control chip.

7. The circuit according to claim 5, characterized in that The transistor (Q2) is provided with a driving protection circuit, the driving protection circuit comprising a base current limiting resistor (R3) and a second voltage stabilizing diode (D8), wherein: The base current limiting resistor (R3) is connected in series between the output side of the optocoupler isolator and the base of the transistor (Q2) to clamp the driving current flowing into the base of the transistor (Q2); The second voltage-stabilizing diode (D8) is connected in parallel between the base and emitter of the transistor (Q2) and is used to clamp the base voltage of the transistor (Q2).

8. The circuit according to claim 5, characterized in that The transistor (Q2) is further provided with a base protection circuit, comprising a third voltage-stabilizing diode (D10) and a fourth current-limiting resistor (R4), wherein: The cathode of the third voltage-stabilizing diode (D10) is connected to the base of the triode (Q2) via a ninth unidirectional diode (D9), and the anode is grounded, so as to limit the base voltage of the triode (Q2) to within the reverse breakdown voltage range; The fourth current limiting resistor (R4) is connected in series between the base of the transistor (Q2) and the output end of the optical coupling isolation unit to suppress possible overcurrent shock in the loop.

9. The circuit according to claim 3, characterized in that The circuit further comprises a reverse surge protection device, wherein the reverse surge protection device comprises a first unidirectional diode (D4), a second unidirectional diode (D5) and a third unidirectional diode (D3), wherein: The first unidirectional diode (D4) and the second unidirectional diode (D5) are connected in series to the output ends of the first power supply voltage and the second power supply voltage, and are used to ensure unidirectional conduction of current; The third unidirectional diode (D3), with an anode connected to the emitter of the switching transistor (Q1) and a cathode connected to the aggregation point (1), is used to prevent the auxiliary winding current from flowing in reverse into the first transformer (T1).

10. The circuit according to claim 1, wherein: The circuit further includes a voltage stabilization and discharge circuit, which includes an electrolytic capacitor (C4), a first voltage stabilizing diode (D6) and a protective grounding terminal (PE), wherein: The electrolytic capacitor (C4) is connected in parallel to the output ends of the first power supply voltage and the second power supply voltage, and is used for energy storage and filtering; The cathode of the first voltage stabilizing diode (D6) is respectively connected to the base of the switching transistor (Q1), and the anode is grounded, and is used to clamp the first power supply voltage and the second power supply voltage; The protective ground terminal (PE) is used to discharge the leakage current and surge energy of the filter capacitor (C4) and the first voltage regulator diode (D6).

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