Power supply isolation circuit, controller circuit board and vehicle
By combining signal modulation, transmission, and reception modules in the power isolation circuit and using an isolation power transformer to achieve the fusion transmission of signals and energy, the problem of high hardware cost in the prior art is solved, the stability and reliability of the power isolation circuit are improved, and the number of components and PCB design complexity are reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-02
- Publication Date
- 2026-04-07
AI Technical Summary
Existing signal isolation transmission methods increase hardware costs and suffer from problems such as a large number of components, large space occupation, complex design, and low reliability and security.
By combining a signal modulation module, a signal transmission module, and a signal receiving module in the power isolation circuit, and using an isolation power transformer for the fusion transmission of signals and energy, dedicated components such as optocouplers are eliminated. A PWM signal with a fixed duty cycle is used for signal modulation and parsing, enabling signal transmission at different reference grounds.
It reduces hardware costs, decreases the number of components and PCB design complexity, improves the stability and reliability of power isolation circuits, and ensures the integrity and security of signal transmission.
Smart Images
Figure CN121813871A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present disclosure relates to the technical field of signal transmission, and in particular to a power isolation circuit, a controller circuit board and a vehicle. BACKGROUND
[0002] In the fields of industrial control, automobile, power electronics, etc., signal isolation transmission is an indispensable key technology in high-low voltage mixing, cross-system communication, and harsh electromagnetic environment scenarios. By blocking the potential difference interference between different reference grounds and suppressing electromagnetic interference, while isolating high voltage and low voltage, surge and other dangerous signals, personnel and equipment safety can be guaranteed while avoiding signal distortion, error code and other problems.
[0003] However, in the related art, signal isolation transmission is mainly performed by adding dedicated signal isolation devices to the original power isolation circuit. The power isolation circuit is responsible for energy transmission and isolation, and the added signal isolation devices are used to realize signal isolation, such as using optical coupling, magnetic coupling and other devices or isolation bus modules to realize data interaction. Such a way increases the hardware cost and has the problem of high cost. SUMMARY
[0004] Therefore, it is necessary to provide a power isolation circuit, a controller circuit board and a vehicle capable of realizing signal isolation transmission and reducing hardware cost in view of at least one of the above technical problems.
[0005] In a first aspect, embodiments of the present disclosure provide a power isolation circuit, which includes a signal modulation module, a signal transmission module and a signal receiving module connected in sequence.
[0006] The signal modulation module is configured to modulate a PWM initial signal according to the to-be-transmitted signal data to obtain a PWM modulated signal, the PWM initial signal being a fixed duty cycle square wave signal, and the frequency of the PWM modulated signal having a corresponding relationship with the to-be-transmitted signal data.
[0007] The signal transmission module includes an isolation power supply topology unit and an isolation power supply transformer, the isolation power supply topology unit being configured to perform power amplification processing on the PWM modulated signal to obtain an amplified modulated signal and transmit the amplified modulated signal to the isolation power supply transformer.
[0008] The isolation power supply transformer is configured to perform electrical isolation processing on the amplified modulated signal to output an isolated transmission signal.
[0009] The signal receiving module is configured to receive the isolated transmission signal, perform signal analysis processing, and obtain the to-be-transmitted signal data.
[0010] In some embodiments, the signal modulation module is located on the low-voltage side of the power isolation circuit, and includes a low-voltage side controller configured to determine, according to the binary state identification information of the signal data to be transmitted, a corresponding PWM signal frequency of each binary bit according to a preset mapping relationship, and obtain a PWM modulation signal.
[0011] The preset mapping relationship is used to record the corresponding relationship between the binary state identification and the signal frequency.
[0012] In some embodiments, the signal receiving module is located on the high-voltage side of the power isolation circuit, and includes a level conversion circuit and a high-voltage side controller. The level conversion circuit is configured to filter and shape the isolation transmission signal from the isolation power transformer to obtain a PWM conversion signal. The high-voltage side controller is configured to receive and identify the PWM conversion signal from the level conversion circuit to obtain the signal data to be transmitted.
[0013] In some embodiments, the isolation power transformer includes a primary winding and a secondary winding. The primary winding is electrically connected to the isolation power topology unit, configured to receive the amplified modulation signal, and synchronously couple the amplified modulation signal to the secondary winding based on electromagnetic induction to obtain the isolation transmission signal.
[0014] The secondary winding is electrically connected to the level conversion circuit.
[0015] In some embodiments, the power isolation circuit further includes a high-voltage side linear step-down power supply, and an output end of the high-voltage side linear step-down power supply is electrically connected to the high-voltage side controller. An output end of the secondary winding includes a power supply branch and a signal branch. The power supply branch is electrically connected to an input end of the high-voltage side linear step-down power supply, configured to provide power for the high-voltage side controller. The signal branch is electrically connected to the level conversion circuit, configured to transmit the isolation transmission signal.
[0016] In some embodiments, the power isolation circuit further includes a low-voltage side power module, and the low-voltage side power module includes a low-voltage side power supply and a low-voltage side step-down power supply. An output end of the low-voltage side step-down power supply is electrically connected to a power supply end of the low-voltage side controller, configured to provide a stable voltage power supply for the low-voltage side controller.
[0017] In some embodiments, the isolation power transformer is a coreless PCB transformer.
[0018] In some embodiments, the isolation power topology unit adopts a flyback power supply topology structure or a forward power supply topology structure.
[0019] In a second aspect, embodiments of the present disclosure provide a controller circuit board, characterized in that the controller circuit board comprises the power isolation circuit provided in any of the embodiments of the first aspect of the present disclosure.
[0020] In a third aspect, embodiments of the present disclosure provide a vehicle, characterized in that the vehicle comprises the power isolation circuit provided in any of the embodiments of the first aspect of the present disclosure, or the controller circuit board provided in any of the embodiments of the second aspect of the present disclosure.
[0021] The power isolation circuit, the controller circuit board and the vehicle described above, by using the power isolation circuit, realize signal transmission of the to-be-transmitted signal data on both sides (low-voltage side and high-voltage side) of the isolation power transformer. By modulating the to-be-transmitted signal data into the PWM control signal (PWM initial signal) of the isolation power in the form of a signal frequency, and then using the power topology unit to amplify the PWM modulated signal, and by means of the coupling characteristics of the isolation transformer, the amplified modulated signal is transmitted to the isolation side to obtain an isolation transmission signal, the signal receiving module realizes the receiving and analysis of the isolation transmission signal to obtain the to-be-transmitted signal data, and the transmission of the to-be-transmitted signal on different reference grounds is realized. By integrating signal transmission and power energy transmission, energy and signal transmission are realized simultaneously by using the isolation power transformer, special devices such as optocouplers and independent buses are saved, the number of devices and space are reduced, and the cost is reduced.
[0022] Meanwhile, the PWM initial signal adopts a fixed-duty-cycle square wave signal, which can ensure the stability of the output voltage of the isolation power supply and will not affect the amplitude of the output voltage due to frequency changes, thereby improving the stability and reliability of the power isolation circuit. BRIEF DESCRIPTION OF DRAWINGS
[0023] Figure 1 is a structural block diagram of the power isolation circuit in some embodiments; Figure 2 is a data format waveform diagram of the PWM modulated signal in some embodiments; Figure 3 is a structural block diagram of the power isolation circuit in some embodiments; Figure 4 is a circuit structure schematic diagram of the low-voltage side linear buck power supply in some embodiments; Figure 5 is a circuit structure schematic diagram of the level conversion circuit in some embodiments; Figure 6 is a circuit structure schematic diagram of the isolation power topology unit and the isolation power transformer in some embodiments. DETAILED DESCRIPTION
[0024] In order to make the technical solutions and advantages of the present disclosure clearer and more apparent, the following, in combination with the accompanying drawings and written description, further describes the embodiments of the present disclosure and related technical content in further detail. It should be understood that the embodiments described below are only used to explain the technical solutions of the embodiments of the present disclosure, and are not used to limit the more possible implementations of the present disclosure.
[0025] It should be noted that the terms of relationship such as "first", "second", etc. appearing in the present disclosure are only used to distinguish things, states or actions, and do not necessarily indicate or imply relative importance or sequential relationship. The terms "include", "contain" or any other variants thereof are used to represent non-exclusive inclusion, and the included objects can not be limited to the objects listed herein. The term "a plurality of" or other variants is used to represent the number of objects as two or more. The terms "mount", "connect", "connect" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements, or it can be wireless connection, or it can be wired connection. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.
[0026] The following explains some of the terms used in the embodiments of the present application. It should be noted that these explanations are for the convenience of those skilled in the art to understand, and do not limit the scope of protection required by the present application.
[0027] 1. PWM signal The PWM (Pulse Width Modulation) signal is a digital signal that carries information by adjusting the duty cycle, frequency or phase of the pulse. Its advantages are that it does not require complex digital-to-analog conversion, can be generated directly through hardware circuit, and can be restored to an analog signal through a simple filter circuit, or directly transmitted as a digital command.
[0028] 2. Isolation power transformer The isolation power transformer works on the principle of electromagnetic induction. When the primary (input) winding is energized, it generates a varying magnetic field, which is transmitted to the secondary (output) winding through the core, thereby inducing a corresponding voltage in the secondary winding. Unlike ordinary transformers, the primary and secondary windings of the isolation power transformer are not directly electrically connected, but energy is transmitted through electromagnetic induction.
[0029] 3. Isolation power topology The isolation power topology refers to the circuit structure form used in the isolation power supply to achieve electrical isolation between the input and output.
[0030] 4. Primary winding and secondary winding The primary winding and secondary winding are the core electromagnetic coupling components of an isolation power transformer. When an input voltage is applied to the primary winding, an alternating current (AC input) or a pulse current (DC input modulated by a switching transistor) is generated in the winding, which in turn excites an alternating magnetic field in the core. The alternating magnetic field passes through the secondary winding, and according to Faraday's law of electromagnetic induction, an induced electromotive force (voltage) is induced in the secondary winding. If the secondary circuit is closed (connected to a load), an induced current is formed, realizing the reverse conversion of magnetic energy to electrical energy and outputting energy to the load.
[0031] In fields such as industrial control, automotive, and power electronics, it is often necessary to divide the same PCB board into different ground references to achieve different functions. However, different ground references can prevent signals from being directly electrically connected. For example, in common high-voltage and low-voltage systems, direct communication cannot guarantee circuit safety and has weak signal immunity. For instance, the energy flow on the high-frequency side circuit can impact the low-voltage side circuit, easily causing damage. Furthermore, high voltage and current changes can generate signal spikes and disturbances, affecting signal quality and leading to information loss.
[0032] In related technologies, isolated signal transmission methods typically employ communication transformers, optocouplers, and dedicated digital isolators. By utilizing these dedicated isolators, high voltage can be effectively prevented from directly entering the low-voltage side, reducing the risk of damage to the low-voltage circuitry. Furthermore, by cutting off the common ground loop, signal immunity is also improved. However, these mainstream solutions all require additional isolators. Since these isolators are usually large, they not only increase material costs but also occupy a significant amount of board space, increasing PCB design complexity and cost, making it impossible to meet the requirements of ultra-thin product designs. Moreover, the more components used in a product, the more complex the design becomes, and the more potential system failures arise, ultimately reducing system reliability and security.
[0033] Based on this, the present disclosure provides a power isolation circuit and signal transmission method that can achieve signal isolation without increasing additional hardware costs.
[0034] In a first aspect, embodiments of this disclosure provide a power isolation circuit. For example... Figure 1 As shown, the circuit includes a signal modulation module 110, a signal transmission module 120, and a signal receiving module 130 that are connected in sequence.
[0035] The signal modulation module 110 is used to modulate the initial PWM signal according to the signal data to be transmitted to obtain the PWM modulated signal.
[0036] In this context, the frequency of the PWM modulation signal corresponds to the signal data to be transmitted.
[0037] Specifically, the signal modulation module 110 may include a low-voltage side controller.
[0038] In some specific examples, modulating the PWM initial signal based on the data to be transmitted can be achieved by inverting the high and low levels of the PWM initial signal to correspond to one bit of the data to be transmitted. For example, for data "0", a low-frequency PWM signal is output, and for data "1", a high-frequency PWM signal is output. Correspondingly, the waveform of the PWM modulation signal can be as follows: Figure 2 Waveforms 210 and 220 in the diagram represent low-frequency PWM signals used to transmit data "0", while waveforms 230 and 240 represent high-frequency PWM signals used to transmit data "1". Figure 2 The waveform shown can transmit data such as "0011".
[0039] In some specific examples, the initial PWM signal is a square wave signal with a fixed duty cycle, and the modulated PWM signal is also a fixed duty cycle signal. The isolated power supply is driven by the high-frequency and low-frequency signals. Specifically, the transformer in the power isolation circuit transfers energy according to a set frequency and conduction ratio, thus realizing the basic operation of the isolated power supply. A fixed duty cycle refers to the ratio of the high-level (switch on) duration in the square wave signal to the total duration of one cycle being constant. Specifically, the specific value of the fixed duty cycle can be determined based on the volt-second balance principle.
[0040] In some specific examples, the specific value of the fixed duty cycle can be preset by those skilled in the art, or it can be determined by the signal modulation module based on the circuit parameters in the power isolation circuit. For example, it can be determined based on the isolation power supply input voltage and output voltage in the power isolation circuit, where the isolation power supply input voltage can be the power supply voltage of the system to which the power isolation circuit belongs, and the output voltage can be the operating voltage of the corresponding load device.
[0041] The signal transmission module 120 includes an isolated power supply topology unit and an isolated power supply transformer.
[0042] The isolated power supply topology unit is electrically connected to the isolated power supply transformer, the isolated power supply topology unit is electrically connected to the output terminal of the signal modulation module 110, and the isolated power supply transformer is electrically connected to the input terminal of the signal receiving module 130.
[0043] The isolated power supply topology unit is used to amplify the PWM modulation signal, obtain the amplified modulation signal, and transmit it to the isolated power supply transformer.
[0044] An isolation power transformer is used to electrically isolate the amplified modulated signal and output an isolated transmission signal.
[0045] By using isolated power supply topology units to amplify the PWM modulation signal, the required power level for transformer driving can be met while preserving the information features embedded in the PWM modulation signal, thus providing energy support for subsequent signal transmission across the isolation domain.
[0046] In some specific examples, the isolation power transformer can consist of a primary winding coil1 and a secondary winding coil2.
[0047] The signal receiving module 130 is used to receive the isolated transmission signal from the isolated power transformer, perform signal parsing processing, and obtain the signal data to be transmitted.
[0048] The signal receiving module 130 is located on the high-voltage side of the power isolation circuit. Specifically, the signal receiving module 130 receives the isolated transmission signal and performs signal parsing processing, which may include preprocessing and demodulation / decoding of the isolated transmission signal.
[0049] In the aforementioned power isolation circuit, signal transmission of the signal data to be transmitted is achieved between the two sides (low-voltage side and high-voltage side) of the isolation power transformer. The signal data to be transmitted is modulated into the PWM control signal (PWM initial signal) of the isolation power supply at a specific frequency. The power topology unit then amplifies the PWM modulation signal. Utilizing the coupling characteristics of the isolation transformer, the amplified modulation signal is transmitted to the isolation side, resulting in an isolated transmission signal. The signal receiving module receives and analyzes this isolated transmission signal to obtain the signal data to be transmitted, thus achieving the transmission of the signal at different reference grounds. By integrating signal transmission with power energy transmission, and using the isolation power transformer to synchronously achieve energy and signal transmission, dedicated components such as optocouplers and independent buses are eliminated, reducing the number of components and space required, and lowering costs.
[0050] Meanwhile, the PWM initial signal uses a square wave signal with a fixed duty cycle, which ensures the stability of the isolated power supply's output voltage and prevents the amplitude of the output voltage from being affected by frequency changes, thus improving the stability and reliability of the power isolation circuit. The PWM signal modulation method of the above power isolation circuit only adjusts the frequency of the PWM signal and does not change the core operating logic of the isolated power supply (such as volt-second balance and core reset of flyback / forward power supplies). It can be adapted to mainstream isolated power supply topologies such as flyback and forward, without the need to redesign the modulation logic for different power supply topologies, and has strong versatility and compatibility.
[0051] In some embodiments, the signal modulation module 120 is located on the low-voltage side of the power isolation circuit and includes a low-voltage side controller for determining the PWM signal frequency corresponding to each binary bit according to a preset mapping relationship based on the binary state identification information of the signal data to be transmitted, thereby obtaining a PWM modulation signal.
[0052] The preset mapping relationship is used to record the correspondence between binary status identifiers and signal frequencies.
[0053] Specifically, the binary status identifiers include "0" and "1", and the signal frequencies include high frequency and low frequency. Correspondingly, a preset mapping table is used to record the correspondence between "0" and "1" and high frequency and low frequency.
[0054] By employing a modulation rule that corresponds binary status identifiers to frequencies, the low-voltage side controller eliminates the need for complex encoding algorithms. It only needs to identify the binary bit status of the signal data to be transmitted to directly match the corresponding frequency and generate a PWM modulation signal, significantly reducing the software algorithm complexity and hardware computing power requirements of the controller. Furthermore, it eliminates the need for additional modulation chips, reducing the number of circuit components, lowering hardware costs, PCB layout complexity, and the probability of failure.
[0055] Furthermore, frequency-based transmission of signal data has the advantage of strong anti-interference capability. Compared with modulation dimensions such as duty cycle and level amplitude, which are susceptible to interference, frequency is more stable. In the complex electromagnetic environment of vehicle scenarios, even if the PWM modulation signal has small level disturbances or line voltage drops, the signal receiving module 130 can still accurately identify high frequency / low frequency through simple methods such as filtering and counting, avoiding binary bit misjudgment and improving the reliability of signal transmission in isolated scenarios.
[0056] In some embodiments, the signal receiving module 120 is located on the high-voltage side of the power isolation circuit and includes a level conversion circuit and a high-voltage side controller; The level conversion circuit is used to filter and shape the isolated transmission signal from the isolated power transformer to obtain the PWM conversion signal.
[0057] In related technologies, PWM signals are prone to waveform distortion after being transmitted through transformer isolation, such as blurred edges, level jitter, and glitches. Filtering the isolated transmission signal using a level conversion circuit can specifically remove electromagnetic interference and power supply noise. Shaping processing can repair distorted waveforms and restore the standard PWM square wave. This physically ensures that the PWM conversion signal input to the high-voltage side controller meets the requirements of a standard waveform and is free from noise interference, avoiding subsequent demodulation errors caused by signal distortion.
[0058] In some specific examples, the level conversion circuit can also be used to synchronously adapt the signal level, that is, to convert the non-standard level output by the transformer into the 3.3V / 5V logic level supported by the high-voltage side controller. This solves the problem of the signal level not matching the controller input threshold after isolated transmission, and ensures that the controller can accurately identify the core characteristics of the PWM signal, such as frequency and period.
[0059] The high-voltage side controller is used to receive and identify the PWM conversion signal from the level conversion circuit to obtain the signal data to be transmitted.
[0060] The high-voltage side controller receives and identifies the PWM conversion signal. Specifically, it can extract the information carried in the PWM conversion signal based on a preset demodulation algorithm to obtain the signal data to be transmitted. The preset demodulation algorithm is matched with the signal modulation method of the signal modulation module 120.
[0061] In some embodiments, the isolation power transformer includes a primary winding and a secondary winding.
[0062] The primary winding is electrically connected to the isolated power supply topology unit to receive the PWM modulation signal and synchronously couples the PWM modulation signal to the secondary winding based on electromagnetic induction to obtain the isolated transmission signal. The secondary winding is electrically connected to the level conversion circuit to transmit the isolated transmission signal to the level conversion circuit.
[0063] The primary and secondary windings of an isolation power transformer have no direct electrical connection; energy or signals are transferred only through electromagnetic induction. This achieves signal transmission from the isolation power topology unit to the level conversion circuit while simultaneously cutting off the electrical loop between the high and low voltage sides. It avoids the conduction of risks such as voltage surges and leakage between the high and low voltage sides, thus achieving isolated signal transmission.
[0064] In some embodiments, the power isolation circuit further includes a high-voltage side linear buck power supply, the output of which is electrically connected to the high-voltage side controller.
[0065] The output terminals of the secondary winding include a power supply branch and a signal branch.
[0066] The power supply branch is used to connect to the input of the high-voltage side linear step-down power supply to provide power to the high-voltage side controller.
[0067] The signal branch is electrically connected to the level conversion circuit and is used to transmit isolated signals.
[0068] The power supply branch provides power to the high-voltage side linear step-down power supply, while the signal branch transmits isolated signals. The two branches are physically independent and functionally separated, which can prevent the power supply ripple and current fluctuations in the power supply circuit from affecting the purity of the isolated transmission signal. At the same time, it can prevent electromagnetic interference during signal transmission from intruding into the power supply circuit, ensuring that the power supply stability and signal transmission integrity do not interfere with each other.
[0069] In some specific examples, the power supply branch includes a first power supply branch and a second power supply branch. The first power supply branch is electrically connected to the input of the high-voltage side linear buck power supply to provide power to the high-voltage side controller, and the second power supply branch is connected to other loads (such as power drive circuits) to provide power to other loads.
[0070] In some embodiments, the power isolation circuit further includes a low-voltage side power module, which includes a low-voltage side power supply and a low-voltage side step-down power supply. The output terminal of the power supply is electrically connected to the input terminal of the low-voltage side step-down power supply and the input terminal of the isolation power supply topology unit, respectively, to provide input power.
[0071] The output terminals of the low-voltage side step-down power supply are electrically connected to the power supply terminals of the low-voltage side controller to provide regulated power to the low-voltage side controller.
[0072] In some embodiments, the isolation power transformer is a coreless PCB transformer.
[0073] A coreless PCB transformer can consist of mutually coupled helical coils on a PCB board. Its parameters, such as self-inductance, leakage inductance, coupling coefficient, turns ratio, operating frequency, and number of PCB layers, can be designed according to actual circuit requirements. The PWM modulation signal is transmitted from the primary winding to the secondary winding of the coreless PCB transformer. Compared to traditional isolated communication solutions, this further reduces the use of transformers, lowers hardware material costs, and avoids the bulky packaging of independent transformers, significantly reducing the PCB board area.
[0074] In some embodiments, the isolated power supply topology unit adopts a flyback power supply topology or a forward power supply topology.
[0075] In some specific examples, the schematic diagram of the power isolation circuit can be as follows: Figure 3 As shown. The power isolation circuit includes a low-voltage side power supply 310, a low-voltage side linear buck power supply 320, a low-voltage side controller 330, an isolation power supply topology unit 340, an isolation power supply transformer 350, a level conversion circuit 360, a high-voltage side linear buck power supply 370, and a high-voltage side controller 380, which are connected in sequence.
[0076] in, Figure 3 The arrows in the diagram are used to indicate the direction of signal or electrical energy transmission.
[0077] Specifically, the low-voltage side power supply 310 can be the power supply for the control circuit on the low-voltage side of the power isolation circuit, used to provide input power for the low-voltage side linear buck power supply 320 and the isolation power topology unit 340.
[0078] The low-voltage side linear buck power supply 320 is used to provide power to the low-voltage side controller 330.
[0079] The high-voltage side linear buck power supply 370 is used to provide power to the high-voltage side controller 380.
[0080] The low-voltage side controller 330 can be a control unit on the low-voltage side, providing PWM control signals to other loads in the circuit (e.g., power drive circuitry) (not shown) and the isolated power supply topology unit 340. In this embodiment, the low-voltage side controller 330 provides PWM modulation signals to the isolated power supply topology unit 340.
[0081] The high-voltage side controller 380 can be a control unit on the high-voltage side, receiving the PWM conversion signal output from the level conversion circuit 360 and parsing and identifying the signal as signal data to be transmitted.
[0082] The isolated power supply topology unit 340 can be the main power device of an isolated power supply such as a flyback or forward converter, used to condition the electrical energy input from the low-voltage side power supply 310 to the voltage required by the high-voltage side of the load.
[0083] The isolation power transformer 350 can be a magnetic component of an isolation power supply, serving as part of the isolation power supply to achieve isolated power transmission.
[0084] The level conversion circuit 360 is used to shape and convert the signal output from the secondary winding of the transformer into a signal that can be recognized by the high-voltage side controller 380, namely the PWM conversion signal.
[0085] In some specific examples, the circuit structure diagram of the low-voltage side linear buck power supply 320 can be shown as follows: Figure 4 As shown.
[0086] Figure 4 U4 is an LDO power supply chip, R44 and R45 are current-limiting resistors, and C26, C27, C28, and C29 are input and output decoupling capacitors, respectively.
[0087] In some specific examples, the circuit diagram of the high-voltage side linear buck power supply 370 can be compared with the circuit diagram of the low-voltage side linear buck power supply 320. Figure 1 To.
[0088] In some specific examples, the circuit structure diagram of the level conversion circuit 360 can be as follows: Figure 5 As shown.
[0089] in, Figure 5 The pull-up resistor R46 provides the turn-on voltage for switch Q1. Series resistors R47 and R49, along with the controller signal RX, jointly control the on / off state of switch Q1. When switch Q1 is on, the voltage at pin 1 of switch Q3 is the same as the voltage at pin 3 of switch Q1. When the voltage at pin 1 of switch Q3 is higher than that at pin 2, switch Q3 is on; conversely, when the voltage at pin 1 is lower, switch Q3 is off, thus controlling the on / off state of switch Q3.
[0090] The pull-up resistor R48 is aligned with the voltage level of the high-voltage side controller 380. When the controller signal RX is high, switch Q1 is off, and the voltage at pin 1 of switch Q3 is the same as the voltage at pin 2 of switch Q3, so switch Q3 is also off. Due to the presence of the pull-up resistor R48, the RX signal output by the controller MCU is high. When the RX signal is low (0V, zero potential or reference ground potential), switch Q1 is on, and the voltage at pin 1 of switch Q3 is 3.3V, which is higher than the 0V at pin 2, so switch Q3 is on, and the controller MCU outputs a low level.
[0091] In some specific examples, the circuit structure diagrams of the isolated power supply topology unit 340 and the isolated power supply transformer 350 can be as follows: Figure 6 As shown.
[0092] in, Figure 6 The isolated power supply topology unit in the diagram is a forward power supply topology. Figure 6 The input power supplies C34, C35, C37, and L1 of the forward converter form a Π-type filter (a passive filter circuit based on a "capacitor-inductor-capacitor" or "resistor-inductor-resistor" topology), which reduces noise entering the power supply. Diode D11 is used to achieve magnetic reset and prevent the transformer from becoming magnetically saturated. The drive resistor R53 is used to match the impedance between the drive chip and the power device. The pull-down resistor R54 is used to accelerate the turn-off of the power device. The rectifier diode D3 is used to rectify the output voltage of the transformer secondary side. Resistor R50 and capacitor C30 form the peak absorption circuit of rectifier diode D3 to prevent overvoltage breakdown of diode D3. Resistor R52 and capacitor C38 form the peak absorption circuit of power device U5 to prevent overvoltage breakdown of power device U5. Capacitors C33, C32, C31, and C36 are all Zener capacitors used to maintain stable output voltage. The current-limiting resistor R52 is used to protect diode D12 from overcurrent damage. Zener diode D12 is used to maintain the stability of the output voltage.
[0093] In some specific examples, the specific value of the fixed duty cycle of the PWM initial signal can be calculated based on the volt-second balance principle.
[0094] Specifically, given a fixed input voltage, output voltage, diode voltage drop, and transformer turns ratio, the duty cycle can be calculated based on the volt-second balance principle.
[0095] When the isolated power supply topology is a flyback power supply topology, the following flyback power supply formula can be used for calculation: ; Where n = N1 / N2, N1 is the number of turns in the primary winding of the transformer, N2 is the number of turns in the secondary winding of the transformer, D is the duty cycle of the initial PWM signal, Vin is the input voltage, Vout is the output voltage, and Vf is the diode voltage drop.
[0096] Based on this flyback power supply formula, given a fixed transformer turns ratio and diode voltage drop, the input and output voltages of the flyback power supply are related to the duty cycle.
[0097] Taking an input voltage Vin of 12V, an output voltage Vout of 20V, a diode voltage drop Vf of 0.7V, and a turns ratio of 0.1 as an example, the duty cycle can be calculated to be 17.25%.
[0098] When the isolated power supply topology unit is a forward power supply topology, the following forward power supply formula can be used for calculation: ; Where n = N1 / N2, N1 is the number of turns in the primary winding of the transformer, N2 is the number of turns in the secondary winding of the transformer, D is the duty cycle of the initial PWM signal, Vin is the input voltage, Vout is the output voltage, and Vf is the diode voltage drop.
[0099] In some examples, with an input voltage Vin of 12V, an output voltage Vout of 20V, a diode voltage drop Vf of 0.7V, and a turns ratio of 0.1, the duty cycle can be calculated to be 14.74%.
[0100] Those skilled in the art will understand that Figure 1 and Figure 3 The structures shown are merely block diagrams of some structures related to the embodiments of this disclosure and do not constitute a limitation on the power isolation circuits applied thereto. Specific power isolation circuits may include more or fewer components than those shown in the figures, or combine certain components, or have different component arrangements.
[0101] In a second aspect, embodiments of the present disclosure provide a controller circuit board that includes the power isolation circuit provided in any embodiment of the first aspect of the present disclosure.
[0102] In some specific examples, the controller circuit board may be a vehicle controller circuit board.
[0103] In a third aspect, embodiments of this disclosure provide a vehicle that includes a power isolation circuit provided in any embodiment of the first aspect of this disclosure, or a controller circuit board provided in an embodiment of the second aspect.
[0104] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this disclosure.
[0105] The above embodiments merely illustrate several implementation methods of this disclosure, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of protection of this disclosure. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this disclosure, and these all fall within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the appended claims.
Claims
1. A power isolation circuit, characterized in that, The power isolation circuit includes a signal modulation module, a signal transmission module, and a signal receiving module that are electrically connected in sequence. The signal modulation module is used to modulate the initial PWM signal according to the signal data to be transmitted, and output the PWM modulation signal to the signal transmission module. The initial PWM signal is a square wave signal with a fixed duty cycle, and the frequency of the PWM modulation signal has a corresponding relationship with the signal data to be transmitted. The signal transmission module includes an isolated power supply topology unit and an isolated power supply transformer. The isolated power supply topology unit is used to amplify the PWM modulation signal to obtain an amplified modulation signal and transmit it to the isolated power supply transformer. The isolated power supply transformer is used to electrically isolate the amplified modulation signal and output an isolated transmission signal. The signal receiving module is used to receive the isolated transmission signal, perform signal parsing processing, and obtain the signal data to be transmitted.
2. The power isolation circuit according to claim 1, characterized in that, The signal modulation module is located on the low-voltage side of the power isolation circuit and includes a low-voltage side controller, which is used to determine the PWM signal frequency corresponding to each binary bit according to the binary state identification information of the signal data to be transmitted and according to a preset mapping relationship, so as to obtain the PWM modulation signal. The preset mapping relationship is used to record the correspondence between binary state identifiers and signal frequencies.
3. The power isolation circuit according to claim 1, characterized in that, The signal receiving module is located on the high-voltage side of the power isolation circuit and includes a level conversion circuit and a high-voltage side controller; The level conversion circuit is used to filter and shape the isolated transmission signal from the isolated power transformer to obtain a PWM conversion signal; The high-voltage side controller is used to receive and identify the PWM conversion signal from the level conversion circuit to obtain the signal data to be transmitted.
4. The power isolation circuit according to claim 3, characterized in that, The isolation power transformer includes a primary winding and a secondary winding; The primary winding is electrically connected to the isolation power supply topology unit to receive the amplified modulation signal and synchronously couple the amplified modulation signal to the secondary winding based on electromagnetic induction to obtain the isolation transmission signal. The secondary winding is electrically connected to the level conversion circuit.
5. The power isolation circuit according to claim 4, characterized in that, The power isolation circuit also includes a high-voltage side linear buck power supply, the output terminal of which is electrically connected to the high-voltage side controller. The output terminal of the secondary winding includes a power supply branch and a signal branch; The power supply branch is used to electrically connect to the input terminal of the high-voltage side linear step-down power supply, and is used to provide power to the high-voltage side controller; The signal branch is electrically connected to the level conversion circuit and is used to transmit the isolated transmission signal.
6. The power isolation circuit according to claim 1, characterized in that, The power isolation circuit also includes a low-voltage side power module, which includes a low-voltage side power supply and a low-voltage side step-down power supply. The output terminal of the power supply is electrically connected to the input terminal of the low-voltage side step-down power supply and the input terminal of the isolation power supply topology unit, respectively, to provide input power. The output terminal of the low-voltage side step-down power supply is electrically connected to the power supply terminal of the low-voltage side controller, and is used to provide a regulated power supply for the low-voltage side controller.
7. The power isolation circuit according to claim 1, characterized in that, The isolation power transformer is a coreless PCB transformer.
8. The power isolation circuit according to claim 1, characterized in that, The isolated power supply topology unit adopts either a flyback power supply topology or a forward power supply topology.
9. A controller circuit board, characterized in that, The controller circuit board includes a power isolation circuit as described in any one of claims 1-8.
10. A vehicle, characterized in that, The vehicle includes a power isolation circuit as described in any one of claims 1-8, or a controller circuit board as described in claim 9.