A switching power supply circuit with higher reliability

Abstract

The application provides a switching power supply circuit with higher reliability, comprising a primary side master control circuit, a secondary side master control circuit and an isolation communication module, the primary side master control circuit comprises a first control module, a PFC voltage regulation output circuit, a second conversion module and a PFC controller; the secondary side master control circuit comprises a second control module, and an indoor and outdoor power supply judgment module and an output voltage and current detection module connected with the second control module respectively, wherein the PFC controller controls the PFC voltage regulation output circuit to output stable conversion voltage, the second control module controls the output of the second conversion module according to the detection value of the output voltage and current detection module to realize voltage and current loop closed loop control, the second control module obtains the detection result of the indoor and outdoor power supply judgment module, and the second control module controls current derating output when supplying power for an indoor power supply line. The application can improve the safety of power utilization.

Description

Technical Field

[0001] This invention relates to the field of switching power supply technology, and specifically to a switching power supply circuit with higher reliability. Background Technology

[0002] A switching power supply is an electrical device that converts AC voltage into the required DC voltage. Its input AC voltage is rectified and filtered to obtain a high-voltage DC voltage. Since switching power supplies are powered by external three-phase AC power, and different cables support different power levels, household wiring, considering factors such as electrical safety and cost-effectiveness, can support relatively low power compared to outdoor power cables, generally used for low-power applications such as lighting. However, the load on a switching power supply may require very high power. Prolonged use will cause the indoor power lines to operate at high power continuously, leading to overheating and even fires, seriously endangering the lives and property of users. Currently, the power supply of switching power supplies is generally determined by the load, without considering the adaptability of the power supply lines and potential safety hazards. Therefore, it is necessary to optimize the existing switching power supply method. Summary of the Invention

[0003] To address the problem of existing technologies lacking indoor / outdoor differentiation circuits, which poses indoor safety hazards, this invention provides a more reliable switching power supply circuit.

[0004] This invention provides a more reliable switching power supply circuit, comprising a primary-side main control circuit, a secondary-side main control circuit, and an isolation communication module disposed between the primary-side and secondary-side main control circuits. The primary-side main control circuit includes a first control module, a relay timing control module connected to the first control module, a PFC voltage regulation output circuit, a second conversion module disposed at the output end of the PFC voltage regulation circuit, and a PFC controller. The secondary-side main control circuit includes a second control module, an indoor / outdoor power supply judgment module, and an output voltage and current detection module respectively connected to the second control module. The PFC controller controls the PFC voltage regulation output circuit to output a stable conversion voltage. Simultaneously, the second control module controls the output of the second conversion module based on the detection value of the output voltage and current detection module, realizing closed-loop control of the voltage and current loop. The second control module obtains the detection result of the indoor / outdoor power supply judgment module. When the power input terminal supplies power to the indoor power supply line, the second control module controls the current to be dated, thereby reducing the load on the indoor power supply line.

[0005] Furthermore, the primary-side main control circuit also includes a first temperature detection module connected to the first control module, and the secondary-side main control circuit also includes a second temperature detection module connected to the second control module.

[0006] Furthermore, the primary-side main control circuit also includes an AC power interface, a first conversion module connected to the output terminal of the AC power interface to convert external AC power into DC high voltage power, a PFC voltage regulation output circuit for converting the DC high voltage power into a stable conversion voltage and outputting it, and a third conversion module for converting the conversion voltage into a 24V DC voltage. The switching power supply circuit also has several operation buttons and auxiliary power supply branches connected to the 24V DC voltage, and a second conversion module for converting the conversion voltage into a 96V DC working voltage.

[0007] Furthermore, it also includes a delay control module, the input of which is connected to the output of the third conversion module, and the output of which is connected to the enable terminal of the power management chip of the auxiliary power supply branch.

[0008] Furthermore, the delay control module includes an optocoupler U8 and a transistor Q19. The primary side of the optocoupler U8 is connected to the control terminal of the second control module. The secondary side pin 1 of the optocoupler U8 is connected to the base of the transistor Q19 through a resistor R306. The collector is connected to the enable terminal of the power management chip through a resistor R303. The emitter is connected to the power ground. The timing control process of the switching power supply circuit is as follows: when the switching power supply circuit is powered on, the first control module supplies power. When the first delay time is reached, the relay timing control module is turned on, and AC power is directly output to the subsequent stage through the relay branch. When the second delay time is reached, power is supplied to the PFC controller, and the PFC controller starts working. When the third delay time is reached, communication is established with the second control module. The second control module outputs a control signal to the optocoupler U8, controls the level of the transistor Q19 to flip, and sends a trigger signal to the enable terminal of the power management chip. The power management chip outputs the operating voltage.

[0009] Furthermore, the AC power interface includes a first interface and a second interface. The input terminal of the indoor / outdoor power supply judgment module is connected to the live wire connection terminal of the first interface or the second interface, and the output terminal of the indoor / outdoor power supply judgment module is connected to the input terminal of the first control module.

[0010] The indoor / outdoor power supply determination module includes a Zener diode ZD12, capacitors C117, C118, and C116, resistors R268 and R269, capacitor C22, resistors R271 and R262, capacitor C115, operational amplifier U5B, resistors R266 and R267, transistor Q12, resistor 265, and resistor R263. The live wire connection terminal is connected to the negative terminal of the Zener diode, one end of capacitors C117, R268, R269, C118, and R262, and the non-inverting input terminal of operational amplifier U5B. The positive terminal of the diode, capacitor C117, and resistors R268 and R269 are also connected. The other end of capacitor C118 is grounded. The inverting input terminal of operational amplifier U5B is grounded through capacitor C22 and connected to a reference voltage through resistor R271. The other end of resistor R262 is connected to the output terminal of operational amplifier U5B through capacitor C115. The output terminal of operational amplifier U5B is connected to one end of resistor R267 and the base of transistor Q12 through resistor R266. The collector of transistor Q12 is connected to a 3.3V power supply through resistor R263 and outputs an indoor / outdoor power supply judgment signal through resistor R265. The other end of resistor R267 and the emitter of transistor Q12 are grounded. One end of capacitor C116 is connected to the indoor / outdoor power supply judgment signal output terminal, and the other end is grounded.

[0011] Furthermore, the PFC voltage regulation output circuit includes a PFC voltage regulation module, an output voltage acquisition module, a signal superposition module, and a conversion voltage output module. The input terminal of the PFC controller is connected to the output terminal of the signal superposition module, the output terminal of the PFC controller is connected to the input terminal of the conversion voltage output module, the output terminal of the conversion voltage output module is connected to the input terminal of the output voltage acquisition module, and the output terminal of the output voltage acquisition module and the output terminal of the indoor / outdoor power supply judgment module are respectively connected to the input terminal of the signal superposition module. The PFC controller controls the power output of the conversion voltage output module based on the superimposed waveform signal output by the signal superposition module.

[0012] Furthermore, the output voltage acquisition module includes an operational amplifier U12B, and the signal superposition module includes an adder U12A. The non-inverting input terminal of the operational amplifier U12B is connected to the output terminal of the conversion voltage output module through several series resistors. The inverting input terminal of the operational amplifier U12B is connected to its output terminal. The output terminal of the operational amplifier U12B and the output terminal of the indoor / outdoor power supply judgment module are connected through a resistor and then output to the input terminal of the adder U12A. The output terminal of the adder U12A is connected to the input terminal of the PFC controller through a resistor R107.

[0013] Furthermore, the relay timing control module includes a relay K1, resistors R123, R127, R55, R129, R131, transistor Q15, capacitors C84 and C163, and diode D20. One end of the coil of relay K1 is connected to power supply K1VCC via parallel resistors R123, R127, and R55. The other end of the coil is connected to the anode of diode D20 and the collector of transistor Q15, respectively. The cathode of diode D20 is connected to one end of the coil. The switch of relay K1 is connected between the live wire and the rectifier bridge to control the power supply switching of the power supply circuit. The emitter of transistor Q15 is connected to power ground, and its base is connected to the control terminal of the first control module via resistor R129. It is also connected to capacitor C84 and resistor R131, both connected to power ground.

[0014] Furthermore, the first conversion module includes an isolation drive unit, a drive unit, a full-bridge resonant unit, and an output rectification unit. The input terminal of the isolation drive unit is connected to the output terminal of the second control module, and the output terminal of the isolation drive unit is connected to the input terminal of the drive unit. The output terminal of the drive unit controls the full-bridge resonant unit, and the voltage output terminal of the full-bridge resonant unit outputs a 96V voltage through the output rectification unit.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: By monitoring indoor and outdoor scenarios, the present invention can make adaptive settings according to different application scenarios. When it is determined that the power supply is indoor, the rated power value is reduced in a targeted manner, avoiding the risk of softening and overheating of indoor lines during continuous high-power operation, and even causing fires. The present invention creatively solves the problem from the source of the power supply line, which not only improves the reliability of the switching power supply, but also improves the safety of users using the switching power supply.

[0016] This invention improves the stability of the conversion voltage of the first stage by using the PFC voltage regulation output circuit on the primary side, thereby improving the power factor of the entire circuit and thus improving the power utilization rate. By setting an output voltage and current detection module on the secondary side and using it as the input for the voltage and current loop closed-loop control, the working voltage output of the secondary side is made more stable through closed-loop control. Through the cooperation of the two, the accuracy and utilization rate of the output power of the entire switching power supply are improved.

[0017] Through real-time monitoring by the first and second temperature detection modules, when the temperature of the power input interface exceeds the set value, or the temperature of the switching power supply exceeds the threshold, the current output or power output of the second control module is dynamically controlled, further improving the safety and reliability of the switching power supply. Attached Figure Description

[0018] To more clearly illustrate the solutions in this invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a structural block diagram of the present invention;

[0020] Figure 2 This is a flowchart of an embodiment of the indoor / outdoor power supply determination method of the present invention;

[0021] Figure 3 This is a circuit schematic diagram of an embodiment of a relay timing control module;

[0022] Figure 4 This is the schematic diagram of the microcontroller circuit for the first control module;

[0023] Figure 5 Circuit schematic diagram of an embodiment of an indoor / outdoor power supply determination module;

[0024] Figure 6 This is a circuit schematic diagram of an embodiment of a PFC voltage regulator module;

[0025] Figure 7 This is a circuit schematic diagram of an embodiment of the output voltage acquisition module and the signal superposition module;

[0026] Figure 8 This is a circuit schematic diagram of an embodiment of a PFC controller;

[0027] Figure 9 This is a circuit schematic diagram of an embodiment of a voltage conversion output module;

[0028] Figure 10 A circuit schematic diagram of an embodiment of the isolation drive unit of the second conversion module;

[0029] Figure 11 This is a circuit schematic diagram of one embodiment of the driving unit;

[0030] Figure 12 This is a circuit schematic diagram of an embodiment of a full-bridge resonant unit;

[0031] Figure 13 This is a circuit schematic diagram of an embodiment of the delay control module;

[0032] Figure 14 A circuit schematic diagram of an example of an auxiliary power supply branch. Detailed Implementation

[0033] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings are used to distinguish different objects, not to describe a particular order.

[0034] In this invention, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment to other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0035] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0036] like Figure 1 As shown, the present invention provides a more reliable switching power supply circuit, including a primary-side main control circuit, a secondary-side main control circuit, and an isolation communication module disposed between the primary-side and secondary-side main control circuits. The primary-side main control circuit includes a first control module, a relay timing control module connected to the first control module, a PFC voltage regulation output circuit, a second conversion module disposed at the output end of the PFC voltage regulation circuit, and a PFC controller. The secondary-side main control circuit includes a second control module, an indoor / outdoor power supply judgment module, and an output voltage and current detection module respectively connected to the second control module. The PFC controller controls the PFC voltage regulation output circuit to output a stable conversion voltage. Simultaneously, the second control module controls the output of the second conversion module based on the detection value of the output voltage and current detection module, realizing closed-loop control of the voltage and current loop. The second control module obtains the detection result of the indoor / outdoor power supply judgment module. When the power input terminal supplies power to the indoor power supply line, the second control module controls the current to be dated, thereby reducing the load on the indoor power supply line.

[0037] The primary-side main control circuit in this example also includes an AC power interface, a first conversion module connected to the output terminal of the AC power interface to convert external AC power into DC high voltage power, and the PFC voltage regulation output circuit is used to convert the DC high voltage power into a stable conversion voltage and output it.

[0038] This invention improves the stability of the conversion voltage of the first stage by using the PFC voltage regulation output circuit on the primary side, thereby improving the power factor of the entire circuit and thus improving the power utilization rate. By setting an output voltage and current detection module on the secondary side and using it as the input for the voltage and current loop closed-loop control, the working voltage output on the secondary side is made more stable through closed-loop control. Through the cooperation of the two, the accuracy and utilization rate of the output power of the entire switching power supply are improved.

[0039] like Figure 2 As shown, this invention uses an indoor / outdoor power supply judgment module to detect indoor / outdoor power supply, thereby improving the safety of indoor wiring. The specific processing method is as follows:

[0040] S1: Obtain AC input voltage and indoor / outdoor power supply judgment signals through the power input interface;

[0041] S2: Based on the collected indoor and outdoor power supply judgment signals, determine whether it is powered by the outdoor line or the indoor line. When the switching power supply determines that it is powered by the indoor line, execute step S3.

[0042] S3: Calculate the first current value that needs to be output based on the load information;

[0043] S4: Based on the first current value, determine the second current value output by the switching power supply, where the second current value is less than the first current value;

[0044] S5: The load is powered by a second current value, thereby limiting the current of the load.

[0045] In this example, the second current value can be 1 / 3 to 2 / 3 of the first current value. Preferably, in this example, 1 / 2 derating is selected.

[0046] In this example, the power input of the switching power supply is connected to a three-phase AC power supply system. The three-phase AC power supply voltage is then converted into a high-voltage DC. This DC voltage is connected to the switching element and used as a switch in a high-frequency range of 20kHz to 100kHz. The high-voltage DC is then cut into a high-frequency square wave signal. This square wave signal passes through a power isolation transformer, where a pre-set voltage value is obtained on the secondary side. After rectification and filtering, the required DC output voltage is obtained. The DC output voltage is determined by the voltage required by the load, while the power supplied is mainly determined by the supply current and power factor. In this example, if the power supply is determined to be indoors and the power supplied is based on the load's required power, the indoor wiring may not be able to withstand the load for extended periods, thus posing a safety hazard.

[0047] This invention monitors indoor and outdoor scenarios and can make adaptive settings according to different application scenarios. When it is determined that the power supply is for indoor circuits, it reduces the rated power value by reducing the output current value, thereby avoiding the risk of softening and overheating of indoor circuits during continuous high-power operation, and even causing fires. This invention creatively solves the problem from the source of the power supply line, which not only improves the reliability of the switching power supply, but also improves the safety of users using the switching power supply.

[0048] like Figure 4 As shown, the first control module in this example includes a microcontroller U9 and a main control chip (not shown in the figure). The microcontroller only needs to collect signals and send PWM control signals, therefore it is compatible with most microcontrollers on the market, such as STM32H743 microcontrollers, STC series 51 microcontrollers, AT series 51 microcontrollers, etc. When a signal is abnormal, it can be indicated by LED1.

[0049] like Figure 5 As shown, the AC power interface in this example includes a first interface and a second interface. The input terminal of the indoor / outdoor power supply judgment module is connected to the live wire connection terminal of the first interface or the second interface, and the output terminal of the indoor / outdoor power supply judgment module is connected to the input terminal of the first control module.

[0050] The output of the indoor / outdoor power supply judgment module is connected to the input of the microcontroller. The microcontroller collects the output signal of the indoor / outdoor power supply judgment module to determine whether the power supply is indoor AC or outdoor. In this example, the first interface can be set as the access point for the indoor power supply line, and the second interface as the access point for the outdoor power supply line. Since both indoor and outdoor lines are powered by 220V AC, simply collecting the input voltage cannot identify the indoor / outdoor voltage. This invention creatively sets up distinct access interfaces, and then connects an indoor / outdoor power supply judgment module separately to the first or second interface, with its input connected to the live wire terminal. Thus, when one of the lines is connected, the corresponding line signal will be collected additionally, thereby realizing the identification of indoor / outdoor power supply and providing the hardware foundation for the power supply control of this invention.

[0051] As an embodiment of the present invention, the indoor / outdoor power supply judgment module includes a Zener diode ZD12, capacitors C117, C118, and C116, resistors R268 and R269, capacitor C22, resistors R271 and R262, capacitor C115, operational amplifier U5B, resistors R266 and R267, transistor Q12, resistor 265, and resistor R263. The live wire connection terminal is connected to the negative terminal of the Zener diode, one end of capacitor C117, resistors R268 and R269, capacitor C118, and resistor R262, and the non-inverting input terminal of operational amplifier U5B. The positive terminal of the diode, capacitor C117, and resistor R268... The other end of resistor R269 and capacitor C118 is grounded. The inverting input terminal of operational amplifier U5B is grounded through capacitor C22 and connected to a reference voltage through resistor R271. The other end of resistor R262 is connected to the output terminal of operational amplifier U5B through capacitor C115. The output terminal of operational amplifier U5B is connected to one end of resistor R267 and the base of transistor Q12 through resistor R266. The collector of transistor Q12 is connected to a 3.3V power supply through resistor R263 and outputs an indoor / outdoor power supply judgment signal through resistor R265. The other end of resistor R267 and the emitter of transistor Q12 are grounded. One end of capacitor C116 is connected to the indoor / outdoor power supply judgment signal output terminal, and the other end is grounded.

[0052] D3 is connected to the live wire terminal of the three-phase AC power supply. After being regulated by the Zener diode ZD12, the voltage is then filtered by resistors and capacitors before being sent to the non-inverting input of the operational amplifier U5B. The operational amplifier U5B compares the voltage with the 1.65V reference voltage source at the inverting input to output a high or low level signal. If the signal is high, it controls the conduction of the transistor Q12, pulling its collector low and outputting a low level signal to pin 25 of the microcontroller U9. The default state of pin 25 of the microcontroller U9 is a high level signal. When it is switched to a low level, it can detect the indoor power supply line connection.

[0053] like Figure 1 , Figures 6-7 As shown, the PFC voltage regulation output circuit in this example includes a PFC voltage regulation module, an output voltage acquisition module, a signal superposition module, and a conversion voltage output module. The input terminal of the PFC controller is connected to the output terminal of the signal superposition module, the output terminal of the PFC controller is connected to the input terminal of the conversion voltage output module, the output terminal of the conversion voltage output module is connected to the input terminal of the output voltage acquisition module, and the output terminals of the output voltage acquisition module and the indoor / outdoor power supply judgment module are respectively connected to the input terminal of the signal superposition module. The PFC controller controls the power output of the conversion voltage output module based on the superimposed waveform signal output by the signal superposition module.

[0054] Because switching power supplies are capacitor-input circuits, the phase difference between their current and voltage leads to power loss. To reduce this loss and improve power efficiency, a power factor correction (PFC) circuit is introduced into switching power supplies. The PFC circuit improves the power factor of the power supply, enabling it to effectively manage reactive power while consuming active power, thereby reducing unnecessary losses on the power grid and improving the overall efficiency of the power system.

[0055] like Figure 6 As shown, in this example, pin 15 of the microcontroller outputs a voltage-regulated PWM signal, which is then processed by the PFC voltage regulation module before being output.

[0056] like Figure 7 and Figure 8 As shown, the output voltage acquisition module includes operational amplifier U12B, and the signal superposition module includes adder U12A. The non-inverting input terminal of operational amplifier U12B is connected to the output terminal of the conversion voltage output module through several series resistors. The inverting input terminal of operational amplifier U12B is connected to its output terminal. The output terminal of operational amplifier U12B and the output terminal of the indoor / outdoor power supply judgment module are connected through a resistor and then output to the input terminal of adder U12A. The output terminal of adder U12A is connected to pin 4 of the PFC controller through resistor R107.

[0057] In this example, the voltage conversion output module preferably uses a cross-controlled output power module, and the specific circuit is as follows: Figure 9 As shown, the system mainly includes power transistors IC1 and IC2, transformers T6 and T7, and switching transistors Q16, Q17, Q4, and Q6. Pins 14 and 17 of the PFC controller are connected to the input terminals of power transistors IC1 and IC2, respectively, sending control signals to the two power transistors to control the cross-on / off switching of switching transistors Q16 and Q17. Pin 9 of the PFC controller is connected to the primary side of transformer T6, and pin 8 is connected to the primary side of transformer T7, enabling cross-output of the set voltage. In this example, an adjustable DC voltage of 360-400V can be achieved. The gates of switching transistors Q16 and Q17 are also connected to the main controller of the switching power supply, enabling the main controller's conduction control. The gates of switching transistors Q4 and Q6 are connected to the control terminal of the main controller, enabling the discharge of the secondary capacitor and energy storage capacitor. This allows the switching power supply to quickly discharge the approximately 400V DC high voltage to below a safe voltage when the power supply is disconnected, improving the safety of the switching power supply.

[0058] The processing method for the PFC voltage regulation step in this example is as follows:

[0059] (1) Obtain the conversion voltage of the switching power supply from AC input voltage to DC high voltage. This step is generally implemented by the output voltage acquisition module. By acquiring the output voltage, it is possible to detect whether the output voltage fluctuates within the set range in real time. When the requirements are not met, PFC voltage regulation is performed.

[0060] (2) When voltage regulation is required, the microcontroller will generate a signal to acquire the PFC voltage regulation waveform;

[0061] (3) The collected conversion voltage signal and the PFC voltage regulation waveform signal will be superimposed to obtain the superimposed waveform signal, which will then be output to the PFC controller;

[0062] (4) The PFC controller controls the PFC output voltage based on the superimposed waveform signal.

[0063] PFC (Power Factor Correction) is primarily used to improve the power factor, reduce harmonic pollution, and address electromagnetic interference (EMI) and electromagnetic compatibility (EMC) issues caused by severe current waveform distortion due to capacitive loads. PFC reduces energy loss during power conversion, improving power efficiency. This invention superimposes and samples the PFC voltage regulation waveform signal with the output square wave signal. This simplifies circuit design by reusing a single microcontroller acquisition port, reducing cost and failure rate. Furthermore, merging the acquired signals into a single path avoids delay differences and deviations caused by circuit hardware noise, eliminating inter-channel delay differences and phase distortion in the error signal, thus improving signal anti-interference capabilities. Additionally, since the PFC voltage regulation waveform signal is generally weak, this invention, through signal fusion, can accurately read the signal without noise reduction or amplification, thereby improving conversion efficiency and further enhancing the overall power factor (PF) of the circuit, thus increasing power utilization.

[0064] Preferably, in sub-step (4) of the PFC voltage regulation step in this example, the PFC controller controls the two parallel power output circuits to cross-output the conversion voltage. Through the control of the two switches, a high-frequency square wave signal can be output.

[0065] like Figure 1As shown, the primary-side main control circuit also includes a first temperature detection module connected to the first control module, and the secondary-side main control circuit also includes a second temperature detection module connected to the second control module. Through real-time monitoring by the first and second temperature detection modules, when the power input interface temperature exceeds a set value, or the switching power supply temperature exceeds a threshold, it indicates that the power value of the switching power supply may be too high, posing a safety hazard. Therefore, this invention can reduce the second current value in step S4 and adjust the PFC voltage regulation waveform signal to dynamically adjust the output power. Simultaneously, this example also controls the cooling fan to turn on, improving heat dissipation. By dynamically controlling the current output or power output of the second control module, the safety and reliability of the switching power supply are further improved. When the first and / or second temperature detection modules exceed their absolute limits, the power supply is directly cut off, and an alarm is issued through the alarm signal output module.

[0066] like Figure 1 and Figure 12 As shown, the second conversion module in this example includes an isolation drive unit, a drive unit, a full-bridge resonant unit, and an output rectifier unit. The input terminal of the isolation drive unit is connected to the output terminal of the second control module, and the output terminal of the isolation drive unit is connected to the input terminal of the drive unit. The output terminal of the drive unit controls the full-bridge resonant unit, and the voltage output terminal of the full-bridge resonant unit outputs a 96V voltage through the output rectifier unit.

[0067] like Figure 10 As shown, the isolation drive unit in this example includes an isolation chip U2 and an isolation transformer T3. The drive chip U2 in this example has a first input terminal (pin 2) and a second input terminal (pin 4) connected to the controller, and also has a first output terminal (pin 7) and a second output terminal (pin 5). The first output terminal is connected to the same-name terminal of the primary side of the isolation transformer T3, and the second output terminal is connected to the opposite-name terminal of the primary side of the isolation transformer T3. The first set of output terminals on the secondary side of the isolation transformer includes a first same-name terminal DRVA-H1 and a first opposite-name terminal DRVA-G1, and the second set of output terminals includes a second opposite-name terminal DRVA-L1 and a second same-name terminal DRVA-G2. The first same-name terminal DRVA-H1 and the second opposite-name terminal DRVA-L1 are respectively connected to the positive voltage drive units of the two drive branches, and the first opposite-name terminal DRVA-G1 and the second same-name terminal DRVA-G2 are respectively connected to the negative voltage drive units of the two drive branches.

[0068] In this example, one drive branch drives one switch transistor, and two drive branches drive two switch transistors. This is suitable for forming a half-bridge circuit that includes upper and lower power transistors. In this example, four switch transistors of the full bridge need to be driven, so four drive branches are required. Correspondingly, two drive chips and two isolation transformers are needed. The four drive branches in this example have the same structure.

[0069] like Figure 11 As shown, in one embodiment of the present invention, the positive pressure drive unit includes a voltage divider unit, a transient suppression unit, an energy storage unit, and an output unit. The transient suppression unit and the energy storage unit are connected in parallel between the voltage divider unit and the output unit. The output unit is provided with a positive drive output pin, and the negative pressure drive unit is provided with a negative drive output pin.

[0070] Furthermore, the voltage divider unit is one or more voltage divider resistors, the transient suppression unit is a transient suppression diode or an electrostatic discharge tube, and the energy storage unit includes one or more energy storage capacitors connected in parallel.

[0071] This example uses the second drive branch of the power transistor as an example for specific explanation. The output unit of this example is an RC filter, including capacitor C9, resistor R13, resistor R114, and resistor R19. Among them, capacitor C9 and resistor R13 are connected in series, one end of which is connected to the output terminal of the energy storage unit, and the other end is connected to the negative drive output pin. Resistors R114 and R19 are connected in parallel, one end of which is connected to the output terminal of the energy storage unit, and the other end is connected to the positive drive output pin.

[0072] The negative voltage drive unit in this example includes an isolation unit, a transient suppression unit, and a first switching unit. The first opposite-name terminal DRVA-G1 and the second same-name terminal DRVA-G2 are connected to the positive terminal of the isolation unit and the negative terminal of the transient suppression unit, respectively. The negative terminal of the isolation unit is connected to the control terminal of the first switching unit. The positive terminal of the transient suppression unit is connected to one end of the first switching unit and the negative drive output pin. The other end of the first switching unit is connected to the input terminal of the energy storage unit through a resistor. In this example, the transient suppression unit is a transient suppression diode ZD4, and the first switching unit is a MOSFET. The negative voltage drive unit in this example also includes a resistor R16 connected in parallel with the isolation unit.

[0073] The working principle of this example is as follows:

[0074] The driver chip U2 alternately outputs the drive voltage through pins 5 and 7, thereby generating a voltage difference between the two terminals of the primary side of the isolation transformer T3. The secondary side of the isolation transformer T3 outputs two sets of complementary square waves. One set is input to the first drive branch to drive the upper switch of the half-bridge, and the other set is input to the second drive branch to drive the lower switch of the half-bridge.

[0075] If pin 7 of driver chip 2 outputs a drive signal, then the same-name terminal of the primary side of isolation transformer T3 is positive, the first same-name terminal DRVA-H1 and the second opposite-name terminal DRVA-L1 of the secondary side are positive, and the first opposite-name terminal DRVA-G1 and the second same-name terminal DRVA-G2 are negative. When the second opposite-name terminal DRVA-L1 is positive and the second same-name terminal DRVA-G2 is negative, the voltage charges the energy storage unit through the positive voltage drive unit. The energy storage unit outputs a drive voltage to the positive drive output pin DRA_L, driving the subsequent switching transistor to conduct.

[0076] When the second opposite-name terminal DRVA-L1 is negative and the second same-name terminal DRVA-G2 is positive, the MOSFET is turned on, forming a negative voltage loop through the MOSFET. The negative-name terminal drives the output pin with a negative voltage, which can cancel out the high-level interference signal generated during the circuit driving process, preventing the subsequent switching transistor from being interfered with by the high level, effectively avoiding the mis-turn-on of the subsequent switching transistor, and improving the anti-interference capability and stability of the isolation drive circuit.

[0077] The full-bridge resonant unit in this example includes switching transistors Q1, Q2, Q3, and Q5, a resonant inductor L1A, transformer T1A, and transformer T1B. The gates of switching transistors Q1, Q2, Q3, and Q5 are respectively connected to the output terminals of the four drive arms of the drive unit. The source of switching transistor Q1 is connected to the drain of switching transistor Q2, the drain of switching transistor Q1 is connected to the voltage output terminal of the PFC voltage regulation output circuit, and the source of switching transistor Q1 is connected to the power supply ground. The source of switching transistor Q3 is connected to... The drains of switching transistor Q5 are connected together, and the drain of switching transistor Q3 is connected to the voltage output terminal of the PFC voltage regulation output circuit. The source of switching transistor Q5 is connected to the power supply ground. The resonant inductor L1A, the primary side of transformer T1A, and the primary side of transformer T1B are connected in series. One end is connected to the source of switching transistor Q1 and the drain of switching transistor Q2 through several parallel capacitors, and to the drive signal DRA-G of the drive unit. The other end is connected to the source of switching transistor Q3 and the drain of switching transistor Q5, and is also connected to the drive signal DRB-G of the drive unit. The secondary sides of transformers T1A and T1B are rectified by the output rectifier unit to output a 96V operating voltage.

[0078] like Figure 3As shown, the relay timing control module includes a relay K1, resistors R123, R127, R55, R129, and R131, a transistor Q15, capacitors C84 and C163, and a diode D20. One end of the coil of relay K1 is connected to power supply K1VCC via parallel resistors R123, R127, and R55. The other end of the coil is connected to the anode of diode D20 and the collector of transistor Q15, respectively. The cathode of diode D20 is connected to one end of the coil. The switch of relay K1 is connected between the live wire and the rectifier bridge to control the power supply of the switching power supply circuit. The emitter of transistor Q15 is connected to power ground, and its base is connected to the control terminal of the first control module via resistor R129. It is also connected to capacitor C84 and resistor R131, both connected to power ground.

[0079] This example also includes a third conversion module that converts the converted voltage to a 24V DC voltage. The switching power supply circuit also has several operation buttons and auxiliary power supply branches connected to the 24V DC voltage. The second conversion module is used to convert the converted voltage to a 96V DC operating voltage. Of course, the third conversion module can also output other rated voltages lower than the human body safety voltage.

[0080] like Figure 14 As shown, the auxiliary power supply branch in this example includes a power management chip U3, which, through circuit processing, outputs a stable 24V voltage for user use. This example...

[0081] like Figure 1 and Figure 13 As shown, this example also includes a delay control module. The input terminal of the delay control module is connected to the output terminal of the third conversion module, and the output terminal of the delay control module is connected to the enable terminal of the power management chip of the auxiliary power supply branch.

[0082] The delay control module includes an optocoupler U8 and a transistor Q19. The primary side of the optocoupler U8 is connected to the control terminal of the second control module. The secondary side pin 1 of the optocoupler U8 is connected to the base of the transistor Q19 through a resistor R306. The collector is connected to the enable terminal of the power management chip through a resistor R303. The emitter is connected to the power ground. In this example, the output control and protection are performed through the transistor Q19.

[0083] This example demonstrates how the relay timing control module and the delay control module work together to achieve reliable timing control from power input to power output. Specifically, the timing control process of the switching power supply circuit is as follows:

[0084] When the switching power supply circuit is powered on, a resistor is provided between the live wire terminal L3 and the input terminal AC1 of the rectifier bridge in this example. This resistor has a certain impedance, which enables the entire circuit to start with a small current, avoiding the impact of a large current on the entire circuit and preventing damage to the components. At the same time, the power supply is supplied to the first control module. When the first delay time is reached, the transistor Q15 in the relay timing control module controlled by the microcontroller is turned on, the relay coil is energized, and the switch is closed. Then, the live wire terminal L3 and the power supply terminal AC1 are connected, and the live wire terminal L3 directly outputs power to the power supply terminal, which speeds up the charging speed of the internal capacitors of the switching power supply and improves the working efficiency.

[0085] When the second delay time is up, power is supplied to the PFC controller, and the PFC controller starts working. When the third delay time is up, communication is established with the second control module. The second control module outputs a control signal to the optocoupler U8, which controls the level of the transistor Q19 to flip, and sends a trigger signal to the enable terminal of the power management chip. The power management chip then outputs its operating voltage.

[0086] In this example, the first delay time can be set to 600ms, the second delay time to 100ms, and the third delay time to 500ms, etc. Through timing control, power can be supplied to each control chip first, and power can be supplied only after each chip is working normally, thus ensuring smooth control. In addition, the auxiliary power supply branch and other circuits should work last after the entire circuit is stable, improving the efficiency and accuracy of the entire switching power supply regulation.

[0087] The specific embodiments described above are preferred embodiments of the present invention and are not intended to limit the specific scope of the present invention. The scope of the present invention includes, but is not limited to, these specific embodiments. All equivalent changes made in accordance with the present invention are within the protection scope of the present invention.

Claims

1. A switching power supply circuit with higher reliability, characterized in that: The system includes a primary-side main control circuit, a secondary-side main control circuit, and an isolation communication module between them. The primary-side main control circuit includes a first control module, a relay timing control module connected to the first control module, a PFC voltage regulation output circuit, a second conversion module located at the output of the PFC voltage regulation output circuit, and a PFC controller. The secondary-side main control circuit includes a second control module, an indoor / outdoor power supply judgment module, and an output voltage / current detection module connected to the second control module. The PFC controller controls the PFC voltage regulation output circuit to output a stable conversion voltage. Simultaneously, the second control module adjusts the output voltage accordingly. The detection value of the voltage and current detection module controls the output of the second conversion module to realize closed-loop control of the voltage and current loop. The output terminal of the indoor and outdoor power supply judgment module is connected to the input terminal of the second control module. The second control module obtains the detection result of the indoor and outdoor power supply judgment module. When the power input terminal supplies power to the indoor power supply line, the second control module controls the current to be dated, thereby reducing the load on the indoor power supply line. After the first control module controls the power-on operation, when the first delay time is reached, it controls the relay timing control module to conduct, and directly outputs AC power to the subsequent stage through the relay branch of the relay timing control module to accelerate the charging speed of the internal capacitor of the switching power supply. The PFC voltage regulation output circuit includes a PFC voltage regulation module, an output voltage acquisition module, a signal superposition module, and a conversion voltage output module. The input terminal of the PFC controller is connected to the output terminal of the signal superposition module, the output terminal of the PFC controller is connected to the input terminal of the conversion voltage output module, the output terminal of the conversion voltage output module is connected to the input terminal of the output voltage acquisition module, and the output terminals of the output voltage acquisition module and the indoor / outdoor power supply judgment module are respectively connected to the input terminal of the signal superposition module. The PFC controller controls the power output of the conversion voltage output module based on the superimposed waveform signal output by the signal superposition module.

2. The switching power supply circuit according to claim 1, characterized in that: The primary-side main control circuit also includes a first temperature detection module connected to the first control module, and the secondary-side main control circuit also includes a second temperature detection module connected to the second control module.

3. The switching power supply circuit according to claim 1, characterized in that: The primary-side main control circuit also includes an AC power interface, a first conversion module connected to the output terminal of the AC power interface to convert external AC power into DC high voltage power, a PFC voltage regulation output circuit for converting the DC high voltage power into a stable conversion voltage and outputting it, and a third conversion module for converting the conversion voltage into 24V DC voltage. The switching power supply circuit also has several operation buttons and auxiliary power supply branches connected to the 24V DC voltage, and a second conversion module for converting the conversion voltage into 96V DC operating voltage.

4. The switching power supply circuit according to claim 3, characterized in that: It also includes a delay control module, the input of which is connected to the output of the third conversion module, and the output of which is connected to the enable terminal of the power management chip of the auxiliary power supply branch.

5. The switching power supply circuit according to claim 4, characterized in that: The delay control module includes an optocoupler U8 and a transistor Q19. The primary side of the optocoupler U8 is connected to the control terminal of the second control module. The secondary pin 1 of the optocoupler U8 is connected to the base of the transistor Q19 through a resistor R306. The collector is connected to the enable terminal of the power management chip through a resistor R303. The emitter is connected to the power ground. The timing control process of the switching power supply circuit is as follows: when the switching power supply circuit is powered on, the first control module supplies power. When the first delay time is reached, the relay timing control module is turned on, and AC power is directly output to the subsequent stage through the relay branch. When the second delay time is reached, power is supplied to the PFC controller, and the PFC controller starts working. When the third delay time is reached, communication is established with the second control module. The second control module outputs a control signal to the optocoupler U8, controls the level of the transistor Q19 to flip, and sends a trigger signal to the enable terminal of the power management chip. The power management chip outputs the operating voltage.

6. The switching power supply circuit according to claim 3, characterized in that: The AC power interface includes a first interface and a second interface. The input terminal of the indoor / outdoor power supply determination module is connected to the live wire of either the first or second interface. The indoor / outdoor power supply determination module includes a Zener diode ZD12, capacitors C117, C118, and C116, resistors R268 and R269, capacitor C22, resistors R271 and R262, capacitor C115, operational amplifier U5B, resistors R266 and R267, transistor Q12, resistor 265, and resistor R263. The live wire connection terminal is connected to the negative terminal of the Zener diode, one end of capacitors C117, R268, R269, C118, and R262, and the non-inverting input terminal of operational amplifier U5B. The positive terminal of the diode, capacitor C117, and resistors R268 and R269 are also connected. The other end of capacitor C118 is grounded. The inverting input terminal of operational amplifier U5B is grounded through capacitor C22 and connected to a reference voltage through resistor R271. The other end of resistor R262 is connected to the output terminal of operational amplifier U5B through capacitor C115. The output terminal of operational amplifier U5B is connected to one end of resistor R267 and the base of transistor Q12 through resistor R266. The collector of transistor Q12 is connected to a 3.3V power supply through resistor R263 and outputs an indoor / outdoor power supply judgment signal through resistor R265. The other end of resistor R267 and the emitter of transistor Q12 are grounded. One end of capacitor C116 is connected to the indoor / outdoor power supply judgment signal output terminal, and the other end is grounded.

7. The switching power supply circuit according to any one of claims 1-4, characterized in that: The output voltage acquisition module includes an operational amplifier U12B, and the signal superposition module includes an adder U12A. The non-inverting input terminal of the operational amplifier U12B is connected to the output terminal of the conversion voltage output module through several series resistors. The inverting input terminal of the operational amplifier U12B is connected to its output terminal. The output terminal of the operational amplifier U12B and the output terminal of the indoor / outdoor power supply judgment module are connected through a resistor and then output to the input terminal of the adder U12A. The output terminal of the adder U12A is connected to the input terminal of the PFC controller through a resistor R107.

8. The switching power supply circuit according to any one of claims 1-4, characterized in that: The relay timing control module includes a relay K1, resistors R123, R127, R55, R129, and R131, a transistor Q15, capacitors C84 and C163, and a diode D20. One end of the coil of the relay K1 is connected to the power supply K1VCC through resistors R123, R127, and R55 in parallel. The other end of the coil is connected to the anode of diode D20 and the collector of transistor Q15, respectively. The cathode of diode D20 is connected to one end of the coil. The switch of the relay K1 is connected between the live wire and the rectifier bridge to control the power supply of the switching power supply circuit. The emitter of transistor Q15 is connected to the power supply ground, and the base is connected to the control terminal of the first control module through resistor R129. It is also connected to capacitor C84 and resistor R131, which are connected to the power supply ground.

9. The switching power supply circuit according to any one of claims 1-4, characterized in that: The second conversion module includes an isolation drive unit, a drive unit, a full-bridge resonant unit, and an output rectification unit. The input terminal of the isolation drive unit is connected to the output terminal of the second control module, and the output terminal of the isolation drive unit is connected to the input terminal of the drive unit. The output terminal of the drive unit controls the full-bridge resonant unit, and the voltage output terminal of the full-bridge resonant unit outputs a 96V voltage through the output rectification unit.

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