Power supply circuit of isolation sampling chip and electric vehicle

Abstract

The embodiment of the invention discloses a power supply circuit of an isolation sampling chip and an electric automobile, and belongs to the technical field of automobile electronics. The circuit comprises a motor driving system and an isolation sampling chip. The isolation sampling chip is used for detecting the direct current bus voltage in the motor driving system; the isolation sampling chip is powered by a driving power supply in the motor driving system, a primary side power supply pin of the isolation sampling chip is connected with the driving power supply, and a primary side grounding pin of the isolation sampling chip is grounded. By adopting the power supply circuit provided by the embodiment of the invention, the power supply cost of the isolation sampling chip can be saved, and more circuit board space is saved while components are reduced.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of automotive electronics technology, and in particular to a power supply circuit of an isolated sampling chip and an electric vehicle. Background Art

[0002] New energy vehicles are developing very rapidly, and the biggest difference between new energy vehicles and fuel vehicles is that they are electrically driven, and the entire power system is a high-voltage electric drive system, that is, the DC bus voltage is as high as 400 or even 800V. Usually the power system includes power batteries, electric drive systems, and power systems, and these high-voltage components need to detect the bus voltage at all times for control or over- and under-voltage protection. Therefore, an economical and reliable bus voltage detection solution is particularly important.

[0003] The bus voltage detection scheme is designed based on the isolation sampling chip. Both the primary and secondary sides of the isolation chip need to be powered. Since the primary side shares the same ground as the negative pole of the bus, the control power supply of the secondary side cannot be used.

[0004] In the related art, a separate power supply is used to power the primary side of the isolated sampling chip, resulting in a waste of electrical resources. Summary of the invention

[0005] The present application example provides a power supply circuit for an isolated sampling chip and an electric vehicle, and the technical solution is as follows.

[0006] On the one hand, an embodiment of the present application provides a power supply circuit for an isolated sampling chip, the circuit comprising a motor drive system and an isolated sampling chip;

[0007] The isolation sampling chip is used to detect the DC bus voltage in the motor drive system;

[0008] The isolation sampling chip is powered by a driving power supply in the motor driving system, a primary power supply pin of the isolation sampling chip is connected to the driving power supply, and a primary grounding pin of the isolation sampling chip is grounded.

[0009] On the other hand, an embodiment of the present application provides an electric vehicle, which includes an isolation sampling chip for detecting a DC bus voltage, and the isolation sampling chip is powered by the power supply circuit described in the above aspect.

[0010] In an embodiment of the present application, when an isolated sampling chip is used to detect the DC bus voltage in a motor drive system, the power supply cost of the isolated sampling chip can be saved by utilizing the driving power supply in the motor drive system to power the primary side of the isolated sampling chip. This can reduce components and save more circuit board space. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0012] Figure 1 A schematic diagram of a power supply circuit of an isolated sampling chip provided by an exemplary embodiment of the present application is shown;

[0013] Figure 2 A schematic diagram showing the connection between a driving power supply and an isolated sampling chip provided by an exemplary embodiment of the present application is shown;

[0014] Figure 3 A connection diagram including a current limiting resistor and a voltage stabilizing diode provided by an exemplary embodiment of the present application is shown;

[0015] Figure 4 A connection diagram of a voltage stabilizing capacitor provided by an exemplary embodiment of the present application is shown;

[0016] Figure 5 A schematic diagram of a power supply circuit for an isolated sampling chip provided by another exemplary embodiment of the present application is shown. DETAILED DESCRIPTION

[0017] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0018] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0019] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0020] It should be understood that, although the terms first, second, etc. may be used in the present application to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first parameter may also be referred to as the second parameter, and similarly, the second parameter may also be referred to as the first parameter. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0021] First, the nouns involved in the embodiments of the present application are briefly introduced:

[0022] Motor drive system: It is the core part of electric vehicles, including motors, power converters, controllers, sensors, and power supplies. In electric vehicles, the role of the motor drive system is to convert electrical energy into mechanical energy, drive the wheels to make the vehicle move. Compared with traditional internal combustion engines, electric motors have simple structures, mature technologies, and reliable operation. The motor can efficiently generate torque in a wide speed range, does not require a complex speed change mechanism, is easy to operate, and has low noise.

[0023] Drive power: It is the part that provides the motor with suitable electrical energy. It is responsible for converting the electrical energy in the power system (such as the battery pack) into the voltage and current required by the motor to drive the motor to rotate and perform the required work. The drive power plays a vital role in the motor drive system because it directly affects the performance, efficiency and reliability of the motor.

[0024] The drive power supply usually contains a DC-DC converter to convert the voltage of the power system to the voltage level required by the motor. In an electric vehicle, this may mean converting the voltage of the high-voltage battery pack to a voltage suitable for the motor. And the drive power supply needs to accurately control the current flowing to the motor to ensure that the motor can obtain the appropriate torque and speed under different operating conditions.

[0025] Lower bridge drive power supply: refers to the power supply part used to drive the lower bridge arm MOSFET or IGBT in the motor controller. In the H-bridge motor drive circuit, the lower bridge arm is opposite to the upper bridge arm, and they jointly control the forward and reverse rotation and braking of the motor. The lower bridge drive power supply needs to provide sufficient voltage and current to ensure that the power devices of the lower bridge arm can work normally, while also ensuring the stability and reliability of the power supply. In addition, in order to ensure the performance of the lower bridge drive power supply, it may also be necessary to consider using isolation technology to avoid potential electrical interference and ensure the stability and safety of the system.

[0026] DC bus: It is the core component of the motor drive system, responsible for transmitting electrical energy from the power supply to various components of the electric vehicle, including loads such as motors, to drive the vehicle. The DC bus consists of conductors, insulating materials and connectors. The conductors are usually made of highly conductive copper or aluminum materials to ensure efficient current transmission. Insulating materials are used to cover the conductors to prevent current leakage and short circuits.

[0027] DC bus voltage: It is the energy source of the motor drive system, providing the necessary electrical energy for the motor to ensure its normal operation. The stability of the DC bus voltage directly affects the operating performance of the motor, including the accuracy of speed control, the stability of torque output, and the response speed of the entire system.

[0028] In the motor drive system, the DC bus voltage usually needs to be maintained within a stable range to ensure that the motor can operate effectively under different load conditions. For example, in the electric drive system of an electric vehicle, the level of the DC bus voltage will directly affect the vehicle's power performance and charging speed. With the development of technology, the DC bus voltage level of electric vehicles is also gradually increasing to meet higher performance requirements. For example, some systems may use an 800V high-voltage platform to increase charging speed and driving range.

[0029] In addition, the stability of the DC bus voltage also has an important impact on the safety of the motor drive system. In the servo drive system, the fluctuation of the DC bus voltage may cause instability in the motor control, thus affecting the accuracy and reliability of the entire system. Therefore, some measures are usually taken to maintain the stability of the DC bus voltage, such as using capacitors for filtering, or adopting a closed-loop control strategy to adjust the bus voltage in real time.

[0030] Bus voltage detection: The DC bus voltage directly affects the output voltage and power of the inverter. By detecting the DC bus voltage, it can ensure that the voltage and power output of the inverter are within the set range, ensuring the stability and output performance of the system. In addition, by detecting the DC bus voltage, power failures can be discovered in time to prevent power short circuits, overloads and other failures, thereby improving the safety and stability of the system.

[0031] Optionally, bus voltage detection methods may include resistance voltage division method, photoelectric coupler isolation method, voltage sensor method, etc. Among them, the resistance voltage division method reduces the voltage to a measurable range by connecting a series resistor. This method has a simple structure and low cost, but may have certain defects, such as the inability to achieve electrical isolation, which may affect the insulation performance of the entire vehicle, generate leakage current, and have EMI (Electromagnetic Interference) problems and temperature drift characteristics. The photoelectric coupler isolation method uses a linear photoelectric coupler, such as HCNR200, to achieve electrical isolation between the high-voltage part and the low-voltage part, reduce electromagnetic interference, and improve sampling accuracy. This method achieves linear conversion and isolation of voltage signals through the coordinated work of light-emitting diodes and photodiodes.

[0032] Isolation sampling chip: It is a special integrated circuit that can accurately sample high voltage signals while ensuring the safe transmission of signals between the isolation ends. This chip is usually used in situations where electrical isolation is required, such as measuring voltage and current in high voltage power management, motor drive systems or power grid infrastructure. The working principle of the isolation sampling chip is usually based on optocoupler technology or magnetic coupling technology. These technologies are used to isolate the input signal from the chip output, which can prevent electrical interference from the high voltage end from affecting the low voltage control and measurement circuits, thereby improving the stability and safety of the system.

[0033] Zener diode: Also known as Zener diode, it is a special semiconductor diode that can stabilize the voltage when the voltage across it exceeds a certain threshold. Its working principle is based on the Zener effect, that is, when the reverse voltage of the diode increases to a certain threshold (Zener voltage), the reverse current increases sharply, but the voltage remains almost unchanged. This characteristic enables the Zener diode to play a role in stabilizing voltage in the circuit.

[0034] The bus voltage detection solutions are all designed based on an isolated sampling chip, wherein the isolated sampling chip may include a primary side (Primary Side) and a secondary side (Secondary Side).

[0035] Optionally, the primary side refers to the part of the isolated sampling chip that is connected to the high voltage or input signal side. The primary side circuit is responsible for receiving the high voltage signal or power supply and converting it into a format suitable for isolated transmission.

[0036] Optionally, the secondary side refers to the output side of the isolated sampling chip, which is usually connected to a low voltage or signal processing circuit. The secondary side circuit receives the signal or power transmitted from the primary side through isolation and converts it into a usable low voltage signal for subsequent analog or digital circuits.

[0037] In the design of isolated sampling chips, electrical isolation is achieved between the primary side and the secondary side through an isolation layer to ensure the safety and reliability of signal transmission. Isolation technology can be achieved by optocouplers, magnetic coupling, capacitive coupling, etc. These technologies can effectively block the DC component and only allow the AC component to pass through, while providing high voltage isolation protection. In this way, the isolated sampling chip can prevent electrical interference or faults at the high voltage end from affecting the circuit at the low voltage end while ensuring signal integrity.

[0038] Optionally, the primary and secondary power supply of the isolated sampling chip is a key link to ensure the safe and accurate transmission of signals between the high and low voltage sides. And because the primary side is grounded with the negative pole of the DC bus, the primary side cannot be powered by the control power supply of the secondary side. That is, the primary side of the isolated sampling chip needs to be powered by a separate power supply.

[0039] In the embodiment of the present application, the primary side of the isolated sampling chip is powered by a driving power supply in the motor driving system. The embodiment of the present application does not limit the power supply mode of the secondary side of the isolated sampling chip.

[0040] Please refer to Figure 1 , which shows a schematic diagram of a power supply circuit of an isolated sampling chip provided by an exemplary embodiment of the present application.

[0041] like Figure 1 As shown, the isolated sampling chip U9 is used to detect the DC bus voltage in the motor drive system, and the isolated sampling chip U9 is powered by the driving power supply in the motor drive system. Since the output voltage of the driving power supply of the motor drive system is higher than the primary standard voltage of the isolated sampling chip U9, an LDO (Low Dropout Regulator) can be added between the isolated sampling chip U9 and the driving power supply VP12 to provide a stable voltage for the isolated sampling chip U9.

[0042] Optionally, a low dropout Zener diode is a DC voltage regulator whose function is to stabilize and reduce the input voltage to a lower and stable output voltage while providing a higher input-output voltage difference (ie, voltage drop) tolerance.

[0043] like Figure 1 As shown, the input voltage pin of the low-dropout voltage regulator U10 is connected to the driving power supply VP12, and the output voltage pin is used to provide a stable 5V output power supply HV, thereby supplying power to the isolation sampling chip U9 based on the 5V output power supply HV.

[0044] Although the power supply circuit of the above-mentioned isolation sampling chip reuses the driving power supply in the motor driving system, there is still a problem of resource waste when a single LDO is used to power the isolation sampling chip.

[0045] Therefore, in order to further save the power supply cost of the isolated sampling chip and avoid the waste of components, the embodiment of the present application provides another power supply circuit for the isolated sampling chip, which will be described below through several specific embodiments.

[0046] Please refer to Figure 2 , which shows a schematic diagram of the connection between a driving power supply and an isolated sampling chip provided by an exemplary embodiment of the present application.

[0047] Optionally, the power supply circuit includes a motor drive system 200 and an isolation sampling chip 202 . The isolation sampling chip 202 is used to detect the DC bus voltage in the motor drive system 200 .

[0048] Optionally, in order to ensure the safe and efficient operation of the motor drive system, it is usually necessary to sample and detect the DC bus voltage in the motor drive system. In a possible circuit design, the DC bus voltage of the motor drive system can be detected by an isolated sampling chip.

[0049] In a possible circuit design, in order to save power supply costs and optimize circuit design, the isolated sampling chip can be powered by a driving power supply in a motor drive system.

[0050] Indicatively, Figure 2 As shown, the driving power supply 201 in the motor driving system 200 supplies power to the isolation sampling chip 202 .

[0051] Optionally, the primary power supply pin of the isolated sampling chip is connected to the driving power supply, and the primary grounding pin of the isolated sampling chip is grounded.

[0052] Optionally, since the primary input signal of the isolated sampling chip is a sampling voltage obtained by resistor series voltage division, the primary ground pin of the isolated sampling chip and the negative pole of the DC bus in the motor drive system are at the same potential point.

[0053] To sum up, in the embodiments of the present application, when using an isolated sampling chip to detect the DC bus voltage in a motor drive system, by utilizing the driving power supply in the motor drive system to power the primary side of the isolated sampling chip, the power supply cost of the isolated sampling chip can be saved, and the components can be reduced while saving more circuit board space.

[0054] In some embodiments, since the output voltage of the driving power supply in the motor drive system is usually higher than the primary standard voltage of the isolated sampling chip, in order to use the driving power supply to provide a stable voltage for the isolated sampling chip, a voltage regulator diode can be added to the power supply circuit and a current limiting resistor can be set between the isolated sampling chip and the driving power supply.

[0055] Please refer to Figure 3, which shows a connection diagram including a current limiting resistor and a voltage stabilizing diode provided by an exemplary embodiment of the present application.

[0056] Indicatively, Figure 3 As shown, the current limiting resistor 302 is located between the driving power supply 304 and the isolation sampling chip 303 , and the current limiting resistor 302 is located between the driving power supply 304 and the voltage zener diode 301 , and the isolation sampling chip 303 and the voltage zener diode 301 are connected in parallel.

[0057] Optionally, the primary standard voltage of the isolated sampling chip refers to the voltage received at the primary input terminal of the isolated sampling chip. Optionally, the primary standard voltage of the isolated sampling chip is lower than the output voltage of the driving power supply in the motor drive system.

[0058] Alternatively, the working principle of the Zener diode is based on the Zener effect, that is, when the reverse voltage of the diode increases to a certain threshold (Zener voltage), the reverse current increases sharply, but the voltage remains almost unchanged.

[0059] Optionally, the output voltage of the driving power supply is higher than the Zener voltage of the voltage regulator diode. Therefore, when the voltage regulator diode is reversely broken down, it can be used to provide a stable voltage to the isolated sampling chip, and the stable voltage is close to the standard power supply of the isolated sampling chip.

[0060] Optionally, a current limiting resistor is provided between the isolation sampling chip and the driving power supply to achieve voltage division and voltage stabilization of the voltage stabilizing diode.

[0061] In some embodiments, in order to further ensure the stability and reliability of the voltage on both sides of the Zener diode, a Zener capacitor may be connected in parallel on both sides of the Zener diode.

[0062] Please refer to Figure 4 , which shows a connection diagram of a voltage stabilizing capacitor provided by an exemplary embodiment of the present application. Figure 4 As shown, the voltage stabilizing capacitor 305 is connected in parallel to both sides of the voltage stabilizing diode 301 , that is, the voltage stabilizing capacitor 305 is also connected in parallel to both sides of the isolation sampling chip 303 .

[0063] Optionally, the voltage stabilizing capacitor may be a filter capacitor, a bypass capacitor, or a parallel capacitor combining a filter capacitor and a bypass capacitor.

[0064] In the above embodiment, when the output voltage of the driving power supply in the motor driving system is higher than the primary standard voltage of the isolated sampling chip, by adding a Zener diode in the power supply circuit, the working principle of the Zener diode can be used to provide a stable voltage for the isolated sampling chip, thereby saving the power supply cost of the isolated sampling chip and saving more circuit board space while reducing circuit components.

[0065] Furthermore, by connecting a stabilizing capacitor in parallel on both sides of the zener diode, the stability and reliability of the voltage on both sides of the zener diode can be further ensured.

[0066] In combination with the above embodiments, the power supply circuit of the isolated sampling chip will be described below through a specific circuit schematic diagram.

[0067] Please refer to Figure 5 , which shows a schematic diagram of a power supply circuit of an isolated sampling chip provided by another exemplary embodiment of the present application.

[0068] It should be noted that Figure 5 Only the primary side pins of the isolated sampling chip U9 are shown, and the secondary side pins of the isolated sampling chip U9 are not shown. The embodiment of the present application does not limit the secondary side power supply method of the isolated sampling chip U9.

[0069] Optionally, the current limiting resistor is located between the driving power supply and the isolated sampling chip, the first resistor pin of the current limiting resistor is connected to the driving power supply, and the second resistor pin of the current limiting resistor is connected to the primary power supply pin of the isolated sampling chip.

[0070] Indicatively, Figure 5 As shown, the first resistor pin 501 of the current limiting resistor R75 is connected to the driving power supply VP12, and the second resistor pin 502 is connected to the primary power supply pin VDD1 of the isolation sampling chip U9. The resistance value of the current limiting resistor R75 is 1KΩ.

[0071] Optionally, in order to provide a stable voltage for the isolated sampling chip based on the Zener effect of the Zener diode, the cathode pin of the Zener diode needs to be connected to the primary power pin of the isolated sampling chip, and the cathode pin is connected to the second resistor pin of the current limiting resistor, so that the voltage after voltage division by the current limiting resistor flows from the cathode into the Zener diode.

[0072] Optionally, the anode pin of the Zener diode is connected to ground.

[0073] Indicatively, Figure 5 As shown, the cathode pin 503 of the Zener diode D21 is connected to the primary power pin VDD1 of the isolation sampling chip U9, and the cathode pin 503 of the Zener diode D21 is connected to the second resistor pin 502 of the current limiting resistor R75, and the anode pin 504 of the Zener diode D21 is grounded N-.

[0074] Optionally, the primary standard voltage of the isolated sampling chip may be 5V.

[0075] Optionally, the model of the isolated sampling chip can be AMC1200B. AMC1200B is a fully differential isolation amplifier with an input voltage range of ±250mV, suitable for current detection applications directly connected to shunt resistors, and has extremely low nonlinearity (maximum 0.075% at 5V), low offset error (maximum 1.5mV), low noise (typical value 3.1mVRMS), low high-side supply current (maximum 8mA at 5V), minimum 60kHz input bandwidth, fixed gain of 8 (accuracy 0.5%), high common-mode rejection ratio (108dB), and 3.3V low-side operating voltage.

[0076] Optionally, the voltage regulator diode needs to be selected according to the primary standard voltage of the isolation sampling chip, and the Zener voltage of the voltage regulator diode can be 5.1V, that is, the voltage regulator diode D21 can be a 5.1V voltage regulator tube.

[0077] In some embodiments, in the process of using a voltage stabilizing diode to provide a stable voltage for the isolated sampling chip, in order to ensure the stability and reliability of the voltage, a voltage stabilizing capacitor may also be provided in the power supply circuit.

[0078] Optionally, the voltage stabilizing capacitor includes a filter capacitor and a bypass capacitor, that is, the filter capacitor and the bypass capacitor are connected in parallel on both sides of the voltage stabilizing diode.

[0079] Optional filter capacitors and bypass capacitors are used to maintain the voltage stability on both sides of the Zener diode.

[0080] Optionally, a first filter capacitor pin of the filter capacitor is connected to a cathode pin of a voltage regulator diode, and a second filter capacitor pin is connected to an anode pin of the voltage regulator diode.

[0081] Indicatively, Figure 5 As shown, the filter capacitor C81 is connected in parallel with the Zener diode D21, the first filter capacitor pin 505 of the filter capacitor C81 is connected to the cathode pin 503 of the Zener diode D21, and the second filter capacitor pin 506 is connected to the anode pin 504 of the Zener diode D21.

[0082] Optionally, a first bypass capacitor pin of the bypass capacitor is connected to a cathode pin of the Zener diode, and a second bypass capacitor pin is connected to an anode pin of the Zener diode.

[0083] Indicatively, Figure 5 As shown, the bypass capacitor C83 is connected in parallel with the Zener diode D21, the first bypass capacitor pin 507 of the bypass capacitor C83 is connected to the cathode pin 503 of the Zener diode D21, and the second bypass capacitor pin 508 is connected to the anode pin 504 of the Zener diode D21.

[0084] In a possible circuit design, the capacitance specification of the filter capacitor is 0.1u / 50V, and the capacitance specification of the bypass capacitor is 1u / 50V.

[0085] In some embodiments, considering that the primary ground pin of the isolation sampling chip and the negative pole of the DC bus in the motor drive system are at the same potential point, the drive power supply can be the lower bridge drive power supply in the motor drive system.

[0086] The lower bridge drive power supply refers to the power supply part used to drive the lower bridge arm MOSFET or IGBT in the motor controller. In the H-bridge motor drive circuit, the lower bridge arm is opposite to the upper bridge arm, and they jointly control the forward and reverse rotation and braking of the motor. The lower bridge drive power supply needs to provide sufficient voltage and current to ensure that the power devices of the lower bridge arm can work normally, while also ensuring the stability and reliability of the power supply.

[0087] Optionally, the output voltage of the lower bridge driving power supply may be 15 to 25V.

[0088] Optionally, when the driving power supply is a three-phase IGBT full-bridge, the lower bridge driving power supply can be the lower bridge driving power supply of any phase. The specific selection method can be determined according to the actual circuit design, and the embodiment of the present application is not limited to this.

[0089] Optionally, the primary side of the isolated sampling chip includes an inverting analog input pin and a non-inverting analog input pin in addition to a primary power pin and a primary ground pin.

[0090] The inverting analog input pin and the non-inverting analog input pin are connected to a bus voltage detection circuit of the motor drive system.

[0091] Optionally, an inverting analog input pin and a non-inverting analog input pin are used to receive input signals of a bus voltage detection circuit to measure a DC bus voltage in a motor drive system.

[0092] Optionally, the inverting analog input pin is usually labeled VINN and the non-inverting analog input pin is usually labeled VINP. Figure 5 As shown, the inverting analog input pin and the non-inverting analog input pin are connected to the left bus voltage detection circuit.

[0093] In the isolated sampling chip, the inverting analog input pin and the non-inverting analog input pin work together to form a differential input pair for receiving external signals. Among them, the non-inverting analog input pin is used to receive the positive part of the input signal, and the inverting analog input pin is used to receive the inverting part of the input signal, thus forming a differential input pair together, which can suppress common mode noise and improve the signal-to-noise ratio of the signal.

[0094] Optionally, the inverting analog input pin and the non-inverting analog input pin of the isolated sampling chip can be directly connected to a shunt resistor or a voltage divider for current or voltage measurement.

[0095] In the above embodiment, when the isolated sampling chip is used to detect the DC bus voltage in the motor drive system, the primary side of the isolated sampling chip is powered by the lower bridge drive power supply in the motor drive system, and a voltage regulator diode is arranged in the power supply circuit to provide a stable voltage for the isolated sampling chip. At the same time, the filter capacitor and the bypass capacitor are connected in parallel on both sides of the voltage regulator diode, thereby further ensuring the stability and reliability of the voltage in the power supply circuit.

[0096] The solutions shown in the above embodiments of the present application can be applied to electric vehicles. Specifically, the present application also provides an electric vehicle, which includes an isolation sampling chip for detecting a DC bus voltage, and the isolation sampling chip is powered by a power supply circuit as shown in the above embodiments.

[0097] A person skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0098] The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A power supply circuit for an isolated sampling chip, characterized in that: The circuit includes a motor drive system and an isolation sampling chip; The isolation sampling chip is used to detect the DC bus voltage in the motor drive system; The isolation sampling chip is powered by a driving power supply in the motor driving system, a primary power supply pin of the isolation sampling chip is connected to the driving power supply, and a primary grounding pin of the isolation sampling chip is grounded.

2. The power supply circuit according to claim 1, characterized in that: The circuit also includes a current limiting resistor and a voltage stabilizing diode, wherein the current limiting resistor is located between the isolation sampling chip and the driving power supply; The output voltage of the driving power supply is higher than the primary standard voltage of the isolation sampling chip, and the output voltage of the driving power supply is higher than the Zener voltage of the voltage regulator diode; The voltage stabilizing diode is used to provide a stable voltage to the isolation sampling chip when it is reversely broken down, and the stable voltage is close to the primary standard voltage of the isolation sampling chip.

3. The power supply circuit according to claim 2, characterized in that: The first resistance pin of the current limiting resistor is connected to the driving power supply, and the second resistance pin of the current limiting resistor is connected to the primary power supply pin of the isolation sampling chip; The cathode pin of the voltage stabilizing diode is connected to the primary power pin of the isolation sampling chip, and the cathode pin is connected to the second resistor pin of the current limiting resistor, and the anode pin of the voltage stabilizing diode is grounded.

4. The power supply circuit according to claim 2, characterized in that: The primary standard voltage of the isolation sampling chip is 5V, and the Zener voltage of the voltage regulator diode is 5.1V.

5. The power supply circuit according to claim 2, characterized in that: The circuit also includes a filter capacitor and a bypass capacitor; The filter capacitor and the bypass capacitor are used to maintain the stability of the voltage on both sides of the voltage regulator diode.

6. The power supply circuit according to claim 5, characterized in that: The first filter capacitor pin of the filter capacitor is connected to the cathode pin of the voltage stabilizing diode, and the second filter capacitor pin is connected to the anode pin of the voltage stabilizing diode; A first bypass capacitor pin of the bypass capacitor is connected to a cathode pin of the voltage stabilizing diode, and a second bypass capacitor pin is connected to an anode pin of the voltage stabilizing diode.

7. The power supply circuit according to claim 5, characterized in that: The capacitance specification of the filter capacitor is 0.1u / 50V, and the capacitance specification of the bypass capacitor is 1u / 50V.

8. The power supply circuit according to claim 1, characterized in that: The driving power supply of the motor driving system is a lower bridge driving power supply, and the output voltage of the lower bridge driving power supply is 15-25V.

9. The power supply circuit according to claim 1, characterized in that: The isolation sampling chip also includes an inverting analog input pin and a non-inverting analog input pin; The inverting analog input pin and the non-inverting analog input pin are connected to a bus voltage detection circuit of the motor drive system; The inverting analog input pin and the non-inverting analog input pin are used to receive input signals from the bus voltage detection circuit to measure the DC bus voltage in the motor drive system.

10. An electric vehicle, characterized in that: The electric vehicle comprises an isolation sampling chip for detecting a DC bus voltage, and the isolation sampling chip is powered by a power supply circuit as described in any one of claims 1 to 9.

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