Isolation power supply circuit of sampling chip and electric vehicle

Abstract

The embodiment of the application discloses a power supply circuit of an isolated sampling chip and an electric automobile, and belongs to the technical field of automobile electronics. The circuit comprises a motor driving system and an isolated sampling chip. The isolated sampling chip is used for detecting a direct-current bus voltage in the motor driving system. The isolated sampling chip is powered by a driving power supply in the motor driving system. A primary power supply pin of the isolated sampling chip is connected with the driving power supply, and a primary ground pin of the isolated sampling chip is grounded. The power supply circuit provided by the embodiment of the application can save the power supply cost of the isolated sampling chip, reduce components and save more circuit board space.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the field of automobile electronics, in particular to a power supply circuit of an isolated sampling chip and an electric vehicle. BACKGROUND

[0002] The development of new energy vehicles is very rapid, and the biggest difference between new energy vehicles and fuel vehicles is electric drive, and the whole power system is a high-voltage electric drive system, that is, the DC bus voltage is as high as 400 or even 800V. Generally, the power system includes power battery, electric drive system and power supply system, and these high-voltage components need to detect the bus voltage at all times for control or over-voltage and under-voltage protection, therefore, an economical and reliable bus voltage detection scheme is particularly important.

[0003] The bus voltage detection scheme is designed based on an isolated sampling chip, and the primary and secondary sides of the isolated chip need to be powered. The primary side cannot use the control power supply of the secondary side because it is grounded with the negative pole of the bus,

[0004] In the related art, a separate power supply is used to power the primary side of the isolated sampling chip, which causes waste of electrical resources. SUMMARY

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

[0006] In one aspect, the embodiment of the present application provides a power supply circuit of an isolated sampling chip, which includes a motor drive system and an isolated sampling chip.

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

[0008] The isolated sampling chip is powered by a drive power supply in the motor drive system, the primary side power supply pin of the isolated sampling chip is connected with the drive power supply, and the primary side ground pin of the isolated sampling chip is grounded.

[0009] In another aspect, the embodiment of the present application provides an electric vehicle, which includes an isolated sampling chip for detecting the DC bus voltage, and the isolated sampling chip is powered by the power supply circuit as described in the above aspect.

[0010] In the embodiment of the present application, in the case of using the isolated sampling chip to detect the DC bus voltage in the motor drive system, the primary side of the isolated sampling chip is powered by the drive power supply in the motor drive system, which can save the power supply cost of the isolated sampling chip, reduce the components and save more circuit board space. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments will be briefly introduced. Obviously, the drawings in the following description only represent some of the embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

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

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

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

[0015] Figure 4 A connection schematic diagram of setting a voltage stabilizing capacitor provided by an example embodiment of the present application is shown.

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

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

[0018] The example embodiments will be described in detail below with reference to the drawings. Unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following example embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the present application as detailed in the appended claims.

[0019] The terms used in the present application are merely for the purpose of describing particular embodiments and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. 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. can be employed in this application to describe various information, these information should not be limited to these terms. These terms are only used to differentiate one piece of information from another piece of information. For example, a first parameter can also be termed a second parameter, and similarly, a second parameter can also be termed a first parameter, without departing from the scope of the present application. Depending on the context, the word "if' as used herein can be interpreted as meaning "when" or "upon" or "in response to determining.

[0021] Firstly, the terms involved in the embodiments of the present application are briefly introduced:

[0022] Motor drive system: is the core part of electric vehicle, including electric motor, power converter, controller, sensor and power supply and other parts. In electric vehicles, the role of motor drive system is to convert electrical energy into mechanical energy, drive the wheels to make the vehicle run. Compared with traditional internal combustion engine, electric motor structure is simple, mature technology, reliable operation. Electric motor can produce torque in a wide speed range, without complex transmission mechanism, convenient operation, low noise.

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

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

[0025] Lower bridge drive power supply: refers to the power supply part used to drive the MOSFET or IGBT in the lower bridge arm of the motor controller. In the H-bridge motor drive circuit, the lower bridge arm is opposite to the upper bridge arm, which together controls the forward and reverse rotation and braking of the motor. Lower bridge drive power supply needs to provide sufficient voltage and current to ensure that the power devices in 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, isolation technology may also be considered to avoid potential electrical interference, to ensure the stability and safety of the system.

[0026] DC bus: 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 electric motors and other loads, to drive the vehicle. The DC bus is composed of conductors, insulating materials and connecting parts. The conductors are usually made of high-conductivity 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: 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 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 effectively operate under different load conditions. For example, in the electric drive system of an electric vehicle, the level of DC bus voltage directly affects the power performance and charging speed of the vehicle. With the development of technology, the DC bus voltage level of electric vehicles is gradually increasing to meet higher performance requirements. For example, some systems may use an 800V high-voltage platform to improve charging speed and 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 servo drive systems, fluctuations in DC bus voltage can cause instability in motor control, 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 using closed-loop control strategies to adjust the bus voltage in real time.

[0030] Bus voltage detection: The level of DC bus voltage directly affects the output voltage and power of the frequency converter. By detecting the DC bus voltage, we can ensure that the output voltage and power of the frequency converter are within the set range, ensuring the stability and output performance of the system. And by detecting the DC bus voltage, we can detect power supply failures in time to prevent power supply short circuits, overloads and other failures, improving the safety and stability of the system.

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

[0032] Isolation sampling chip: A special integrated circuit that can accurately sample high-voltage signals while ensuring safe transmission between isolated terminals. This chip is usually used in situations that require electrical isolation, 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 optical coupling technology or magnetic coupling technology, which realizes the isolation between the input signal and the chip output, preventing high-voltage interference from affecting low-voltage control and measurement circuits, thereby improving system stability and safety.

[0033] Zener diode: Also known as Zener diode, it is a special semiconductor diode that can stabilize 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 will increase sharply, but the voltage remains almost constant. This characteristic allows the Zener diode to stabilize the voltage in the circuit.

[0034] Bus voltage detection scheme is based on isolation sampling chip, which can include primary side and secondary side.

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

[0036] Optionally, the secondary side refers to the output side of the isolation sampling chip, usually connected to the low-voltage or signal processing circuit. The secondary circuit receives the signal or power transmitted by 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 the isolated sampling chip, the primary side and the secondary side are electrically isolated through the isolation layer to ensure the safety and reliability of signal transmission. Isolation technology can use optical coupling, magnetic coupling, capacitive coupling and other ways. These technologies can effectively block the direct current component and only allow alternating current component to pass through, while providing high voltage isolation protection. In this way, the isolated sampling chip can ensure signal integrity while preventing electrical interference or failure of the high voltage end from affecting the low voltage end circuit.

[0038] Optionally, the primary side and the secondary side of the isolated sampling chip are the key links to ensure the safe and accurate transmission of signals between high and low voltage sides. Moreover, since 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 embodiments of the present application, the primary side of the isolated sampling chip is powered by the drive power supply in the motor drive system. The embodiments of the present application do not limit the power supply mode of the secondary side of the isolated sampling chip.

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

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

[0042] Optionally, the low dropout regulator is a kind of DC voltage regulator, which functions to stabilize and reduce the input voltage to a lower and stable output voltage, while providing a higher input-output voltage difference (i.e. voltage drop) tolerance.

[0043] As shown in Figure 1 , the input voltage pin of the low dropout regulator U10 is connected with the drive power supply VP12, and the output voltage pin is used to provide a stable 5V output power supply HV, so as to supply power to the isolated sampling chip U9 based on the 5V output power supply HV.

[0044] Although the above power supply circuit of the isolated sampling chip reuses the drive power supply in the motor drive system, using a separate LDO to power the isolated sampling chip still has the problem of resource waste.

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

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

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

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

[0049] In a possible circuit design, in order to save the power supply cost and optimize the circuit design, the driving power supply in the motor driving system can be used to supply power to the isolation sampling chip.

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

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

[0052] Optionally, since the primary side input signal of the isolation sampling chip is a sampling voltage obtained by series voltage division through resistors, the primary side ground pin of the isolation sampling chip and the negative pole of the DC bus in the motor driving system are the same potential point.

[0053] In summary, in the embodiment of the application, in the case of using the isolation sampling chip to detect the DC bus voltage in the motor driving system, by using the driving power supply in the motor driving system to supply power to the primary side of the isolation sampling chip, the power supply cost of the isolation sampling chip can be saved, and more circuit board space can be saved while reducing components.

[0054] In some embodiments, since the output voltage of the driving power supply in the motor driving system is usually higher than the standard voltage of the primary side of the isolation sampling chip, in order to be able to use the driving power supply to provide stable voltage to the isolation sampling chip, a voltage stabilizing diode can also be added in the power supply circuit, and a current limiting resistor can be arranged between the isolation sampling chip and the driving power supply.

[0055] Please refer to Figure 3Fig. 1 shows a connection diagram provided by an exemplary embodiment of the present application, which shows a connection diagram containing a current-limiting resistor and a voltage stabilizing diode.

[0056] As shown in Fig. 1, 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 stabilizing diode 301, and the isolation sampling chip 303 and the voltage stabilizing diode 301 are connected in parallel. Figure 3

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

[0058] Optionally, the working principle of the voltage stabilizing 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 will increase 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 stabilizing diode. Therefore, in the case of reverse breakdown of the voltage stabilizing diode, it can be used to provide a stable voltage to the isolation sampling chip, and the stable voltage is close to the standard power supply of the isolation sampling chip.

[0060] Optionally, by setting the current-limiting resistor between the isolation sampling chip and the driving power supply, the voltage dividing and voltage stabilizing effects of the voltage stabilizing diode can be achieved.

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

[0062] Fig. 2 shows a connection diagram provided by an exemplary embodiment of the present application, which shows a connection diagram containing a voltage stabilizing capacitor. Figure 4 Figure 4 As shown in Fig. 2, the voltage stabilizing capacitor 305 is connected in parallel on both sides of the voltage stabilizing diode 301, that is, the voltage stabilizing capacitor 305 is also connected in parallel on both sides of the isolation sampling chip 303.

[0063] Optionally, the voltage stabilizing capacitor can be a filter capacitor, a bypass capacitor, or a parallel capacitor combined with a filter capacitor and a bypass capacitor.

[0064] In the above embodiments, in the case that the output voltage of the driving power supply in the motor driving system is higher than the primary-side standard voltage of the isolation sampling chip, by adding a voltage stabilizing diode in the power supply circuit, the working principle of the voltage stabilizing diode can be used to provide a stable voltage to the isolation sampling chip, saving the power supply cost of the isolation sampling chip, and saving more circuit board space while reducing the number of circuit components. ​​

[0065] And, by connecting a voltage stabilizing capacitor in parallel with the voltage stabilizing diode, the stability and reliability of the voltage on both sides of the voltage stabilizing 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 by means of a specific circuit schematic diagram.

[0067] Please refer to Figure 5 , which shows the schematic diagram of the power supply circuit of the isolated sampling chip according to 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 in FIG. 6, and the secondary side pins of the isolated sampling chip U9 are not shown. For the secondary side power supply mode of the isolated sampling chip U9, the embodiments of the present application do not make any limitation.

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

[0070] Illustratively, as shown in Figure 5 , the first resistance pin 501 of the current limiting resistor R75 is connected with the driving power supply VP12, and the second resistance pin 502 is connected with the primary side power supply pin VDD1 of the isolated 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 voltage stabilizing diode, the cathode pin of the voltage stabilizing diode needs to be connected with the primary side power supply pin of the isolated sampling chip, and the cathode pin is connected with the second resistance pin of the current limiting resistor, so that the voltage after voltage division by the current limiting resistor flows from the cathode into the voltage stabilizing diode.

[0072] Optionally, the anode pin of the voltage stabilizing diode is grounded.

[0073] Illustratively, as shown in Figure 5 , the cathode pin 503 of the voltage stabilizing diode D21 is connected with the primary side power supply pin VDD1 of the isolated sampling chip U9, and the cathode pin 503 of the voltage stabilizing diode D21 is connected with the second resistance pin 502 of the current limiting resistor R75, and the anode pin 504 of the voltage stabilizing diode D21 is grounded N-.

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

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

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

[0077] In some embodiments, in the process of providing stable voltage for the isolation sampling chip by using the voltage stabilizing diode, in order to ensure the stability and reliability of the voltage, a voltage stabilizing capacitor can also be arranged 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] Optionally, the filter capacitor and the bypass capacitor are used to maintain the stability of the voltage on both sides of the voltage stabilizing diode.

[0080] Optionally, 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.

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

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

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

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

[0085] In some embodiments, the primary-side ground pin of the isolation sampling chip is at the same potential point as the negative pole of the DC bus in the motor driving system, and therefore the driving power supply can be selected as the lower bridge driving power supply in the motor driving system.

[0086] The lower bridge driving power supply refers to a power supply part for driving MOSFET or IGBT of the lower bridge arm in the motor controller. In the H-bridge motor driving circuit, the lower bridge arm and the upper bridge arm are opposite to each other and jointly control the forward and reverse rotation and braking of the motor. The lower bridge driving power supply needs to provide sufficient voltage and current to ensure that the power device of the lower bridge arm can work normally, and also needs to ensure the stability and reliability of the power supply.

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

[0088] Optionally, in the case of a three-phase IGBT full bridge driving power supply, the lower bridge driving power supply can be the lower bridge driving power supply of any phase, and the specific selection manner can be determined according to actual circuit design, which is not limited in the embodiments of the application.

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

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

[0091] Optionally, the inverting analog input pin and the non-inverting analog input pin are used to receive the input signal of the bus voltage detection circuit to measure the DC bus voltage in the motor driving system.

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

[0093] In the isolation 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. 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 inverted part of the input signal, thereby 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 embodiments, when detecting the DC bus voltage in the motor drive system by using the isolated sampling chip, 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 stabilizing diode is arranged in the power supply circuit to provide a stable voltage for the isolated sampling chip, and the filter capacitor and the bypass capacitor are connected in parallel across the voltage stabilizing diode to further ensure the stability and reliability of the voltage in the power supply circuit.

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

[0097] Those skilled in the art can understand that all or part of the steps of the above embodiments can be completed by hardware, or by a program instructing relevant hardware to complete, and the program can be stored in a computer readable storage medium, such as a read-only memory, a magnetic disk or an optical disk.

[0098] The above are only optional embodiments of the present application, and are not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall 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 isolated sampling chip is used to detect the DC bus voltage in the motor drive system; The isolation sampling chip is powered by the drive power supply in the motor drive system. The primary power supply pin of the isolation sampling chip is connected to the drive power supply, and the primary ground 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 Zener 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-side 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 Zener diode is used to provide a stable voltage to the isolation sampling chip in the event of reverse breakdown, and the stable voltage is close to the primary-side standard voltage of the isolation sampling chip.

3. The power supply circuit according to claim 2, characterized in that, 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-side power supply pin of the isolation sampling chip. The cathode pin of the Zener diode is connected to the primary power supply pin of the isolation sampling chip, and the cathode pin is connected to the second resistance pin of the current limiting resistor. The anode pin of the Zener diode is grounded.

4. The power supply circuit according to claim 2, characterized in that, The primary-side standard voltage of the isolation sampling chip is 5V, and the Zener voltage of the Zener 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 across the Zener 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 Zener diode, and the second filter capacitor pin is connected to the anode pin of the Zener diode. The first bypass capacitor pin of the bypass capacitor is connected to the cathode pin of the Zener diode, and the second bypass capacitor pin is connected to the anode pin of the Zener diode.

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

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

9. The power supply circuit according to claim 1, characterized in that, The isolated sampling chip also includes inverting analog input pins and non-inverting analog input pins; The inverting analog input pin and the non-inverting analog input pin are connected to the 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 the input signal of 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 includes an isolated sampling chip for detecting DC bus voltage, the isolated sampling chip being powered by a power supply circuit as described in any one of claims 1 to 9.

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