Wide voltage bus high side current detection circuit and detection method thereof
The discrete high-side current detection scheme, consisting of a floating power supply circuit and a transconductance amplifier, solves the accuracy and cost problems of current detection in traditional schemes. It achieves accurate acquisition of high-side current within the power supply platform range of 12V to 400V, reduces hardware development difficulty and cost, and improves system anti-interference capability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANJING WEIFU JINNING
- Filing Date
- 2026-05-18
- Publication Date
- 2026-07-21
AI Technical Summary
In traditional fuel vehicles and new energy vehicles, bus current detection solutions are prone to common-mode interference and have low accuracy, while high-side current detection is costly and limited by the bus voltage amplitude. Existing technologies make it difficult to achieve high-precision and economical current acquisition over a wide voltage range.
By employing a floating power supply circuit, a differential voltage-to-current signal circuit, and a current signal-to-voltage signal circuit, and using a discrete high-side current detection scheme composed of Zener diodes, transconductance amplifiers, and transistors, accurate acquisition of bus current within the 12V to 400V power platform range is achieved, avoiding the use of highly integrated current sampling chips.
It reduces the difficulty and cost of hardware development, improves the system's anti-interference capability, broadens the application range of bus voltage, and enables accurate acquisition of high-side current of wide-voltage buses.
Smart Images
Figure CN122430596A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of automotive electronics technology, and in particular to a wide-voltage bus high-side current detection circuit and its detection method. Background Technology
[0002] Controller bus current detection is an important safety monitoring method in the automotive electronics industry.
[0003] Traditional controllers for gasoline-powered vehicles employ either high-side or low-side current detection schemes. High-side detection often uses integrated chips, which are costly, while low-side current detection is cheaper but less accurate. Controllers for new energy vehicles, due to their higher bus voltages, often use expensive isolated integrated chips for high-side current detection, while low-side current detection schemes have poor interference immunity. Summary of the Invention
[0004] To address these issues, this invention provides a wide-voltage bus high-side current detection circuit and its detection method. It addresses the shortcomings of traditional low-voltage controllers in 12V systems of gasoline vehicles or high-voltage controllers in 400V systems of new energy vehicles, which suffer from low-side current detection schemes susceptible to common-mode interference and low accuracy, and high-side current detection schemes limited by bus voltage amplitude and expensive. Without requiring highly integrated current sampling chips, this invention can accurately and effectively acquire high-side current from a wide voltage bus within the 12V to 400V power supply platform range.
[0005] To solve the above-mentioned technical problems, the present invention provides a wide-voltage bus high-side current detection circuit, comprising: A floating power supply circuit, connected between the positive and negative terminals of the power supply, is used to clamp the high-side voltage signal of the bus to the supply voltage. A differential voltage to current signal circuit is connected to the floating power supply circuit. The differential voltage to current signal circuit is used to acquire the differential voltage across the sampling resistor set on the high side of the bus and convert the differential voltage into a current signal. A current signal to voltage signal circuit is connected to the output terminal of the differential voltage to current signal circuit. The current signal to voltage signal circuit is used to perform high voltage isolation on the current signal and output the current signal after high voltage isolation to the grounding resistor on the grounding side, so as to form a low voltage detection signal for the controller to sample on the grounding resistor.
[0006] In one embodiment of the present invention, the floating power supply circuit includes a Zener diode Z1, a first resistor R1, and a first capacitor C1; One end of the Zener diode Z1 connected in parallel with the first capacitor C1 is connected to one end of the first resistor R1. The other end of the first resistor R1 is connected to the negative terminal of the power supply; The cathode of the Zener diode Z1 is connected to the positive terminal of the power supply.
[0007] In one embodiment of the present invention, the differential voltage-to-current signal circuit includes a second resistor R2 and a transconductance amplifier U1; The second resistor R2 is configured as the sampling resistor; One end of the second resistor R2 is connected in series to the high side of the busbar, and the other end is grounded through the load; The two signal input terminals of the transconductance amplifier U1 are respectively connected to the two ends of the second resistor R2; The positive and negative terminals of the power supply of the transconductance amplifier U1 are connected to the cathode and anode of the Zener diode Z1, respectively. The transconductance amplifier U1 is used to convert the differential voltage across the sampling resistor R2 into the current signal according to a preset ratio.
[0008] In one embodiment of the present invention, the current signal to voltage signal circuit includes a transistor Q1 and a third resistor R3; The third resistor R3 is configured as the grounding resistor; The emitter of transistor Q1 is connected to the output of transconductance amplifier U1; The base of transistor Q1 is connected to the anode of Zener diode Z1; The collector of the transistor Q1 is connected to one end of the third resistor R3 and the ADC sampling pin of the controller, respectively. The other end of the third resistor R3 is connected to the negative terminal of the power supply.
[0009] In one embodiment of the present invention, the transistor Q1 is a PNP high-voltage transistor with a collector-emitter breakdown voltage greater than 400V.
[0010] In one embodiment of the present invention, the power supply voltage range is 5~15V.
[0011] In one embodiment of the present invention, the bus voltage range between the positive and negative terminals of the power supply is 12V~400V.
[0012] The present invention also provides a method for detecting high-side current of a wide-voltage bus, utilizing the aforementioned wide-voltage bus high-side current detection circuit, the detection method comprising: The high-side voltage of the bus is current-limited, clamped, and filtered by Zener diode Z1, first resistor R1, and first capacitor C1 in the floating power supply circuit, so that the voltage across Zener diode Z1 is clamped to 5V~15V, and the clamped voltage is used as the floating power supply of transconductance amplifier U1 in the differential voltage to current signal circuit. The transconductance amplifier U1 receives the differential voltage signal across the second resistor R2 connected in series on the high side of the bus, and converts the differential voltage signal into a current signal corresponding to the bus current according to a preset conversion ratio. The current signal is input to the emitter of transistor Q1 in the current signal to voltage signal circuit, and the current signal is output through the collector of transistor Q1, so as to achieve high voltage isolation between the floating high-side signal and the ground-side sampling signal through transistor Q1. The current signal flowing out from the collector of the transistor Q1 flows through the third resistor R3 and is converted into a low-voltage detection voltage on the third resistor R3; The low-voltage detection voltage is acquired through the ADC pin of the controller, and the bus current is calculated based on the conversion ratio of the transconductance amplifier U1 and the resistance value of the third resistor R3.
[0013] The technical solution of the present invention has the following advantages compared with the prior art: This invention discloses a wide-voltage bus high-side current detection circuit and method. It employs a discrete high-side current detection scheme powered by a floating power supply, replacing the low-side current detection schemes or high-side current detection schemes with highly integrated isolation chips used in traditional fuel or new energy vehicle controllers. This reduces hardware development difficulty and cost, improves system anti-interference capability, and broadens the application range of the system bus voltage. Addressing the shortcomings of low-side current detection schemes in traditional fuel vehicle 12V low-voltage controllers or new energy vehicle 400V high-voltage controllers, which are susceptible to common-mode interference and have low accuracy, and high-side current detection schemes which are limited by bus voltage amplitude and expensive, this invention can accurately and effectively collect high-side current data from a wide voltage bus range of 12V to 400V without requiring highly integrated current sampling chips. Attached Figure Description
[0014] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.
[0015] Figure 1 The diagram shows a module logic schematic of a wide-voltage bus high-side current detection circuit provided by an exemplary embodiment of the present invention.
[0016] Figure 2 The diagram shows a circuit schematic of a wide-voltage bus high-side current detection circuit provided by an exemplary embodiment of the present invention.
[0017] Explanation of reference numerals on the accompanying drawings: 110. Floating power supply circuit; 120. Differential voltage to current signal circuit; 130. Current signal to voltage signal conversion circuit. Detailed Implementation
[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.
[0019] In this invention, when directions (up, down, left, right, front, and back) are described, it is only for the convenience of describing the technical solution of this invention, and does not indicate or imply that the technical features referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.
[0020] In this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc., are understood to exclude the stated number; "above," "below," "within," etc., are understood to include the stated number. In the description of this invention, the terms "first" and "second" are used only to distinguish technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.
[0021] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; a fixed connection, a detachable connection, or an integrally formed connection; a mechanical connection, an electrical connection, or a connection capable of mutual communication; or the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention based on the specific content of the technical solution.
[0022] Reference Figure 1 As shown, a wide-voltage bus high-side current detection circuit of the present invention includes: The floating power supply circuit 110 is connected between the positive and negative terminals of the power supply and is used to clamp the high-side voltage signal of the bus to the supply voltage. A differential voltage to current signal circuit 120 is connected to the floating power supply circuit 110. The differential voltage to current signal circuit 120 is used to acquire the differential voltage across the sampling resistor set on the high side of the bus and convert the differential voltage into a current signal. A current signal to voltage signal circuit 130 is connected to the output terminal of the differential voltage to current signal circuit 120. The current signal to voltage signal circuit 130 is used to perform high voltage isolation on the current signal and output the current signal after high voltage isolation to the grounding resistor on the grounding side, so as to form a low voltage detection signal for the controller (MCU) to sample on the grounding resistor.
[0023] In one embodiment, refer to Figure 2 As shown, the floating power supply circuit 110 includes a Zener diode Z1, a first resistor R1, and a first capacitor C1; One end of the Zener diode Z1 connected in parallel with the first capacitor C1 is connected to one end of the first resistor R1. The other end of the first resistor R1 is connected to the negative terminal of the power supply; The cathode of the Zener diode Z1 is connected to the positive terminal of the power supply.
[0024] In one embodiment, the differential voltage-to-current signal circuit 120 includes a second resistor R2 and a transconductance amplifier U1; The second resistor R2 is configured as the sampling resistor; One end of the second resistor R2 is connected in series to the high side of the busbar, and the other end is grounded through the load; The two signal input terminals of the transconductance amplifier U1 are respectively connected to the two ends of the second resistor R2; The positive and negative terminals of the power supply of the transconductance amplifier U1 are connected to the cathode and anode of the Zener diode Z1, respectively. The transconductance amplifier U1 is used to convert the differential voltage across the sampling resistor R2 into the current signal according to a preset ratio.
[0025] In one embodiment, the current signal to voltage signal circuit 130 includes a transistor Q1 and a third resistor R3; The third resistor R3 is configured as the grounding resistor; The emitter of transistor Q1 is connected to the output of transconductance amplifier U1; The base of transistor Q1 is connected to the anode of Zener diode Z1; The collector of the transistor Q1 is connected to one end of the third resistor R3 and the ADC sampling pin of the controller, respectively. The other end of the third resistor R3 is connected to the negative terminal of the power supply.
[0026] In one embodiment, the transistor Q1 is a PNP high-voltage transistor with a collector-emitter breakdown voltage greater than 400V.
[0027] In one embodiment, the power supply voltage ranges from 5 to 15V.
[0028] In one embodiment, the bus voltage between the positive and negative terminals of the power supply ranges from 12V to 400V.
[0029] The present invention also provides a method for detecting high-side current of a wide-voltage bus, utilizing the aforementioned wide-voltage bus high-side current detection circuit, the detection method comprising: The Zener diode Z1, the first resistor R1 and the first capacitor C1 in the floating power supply circuit 110 are used to limit, clamp and filter the high-side voltage of the bus, so that the voltage across the Zener diode Z1 is clamped to 5V~15V, and the clamped voltage is used as the floating working power supply of the transconductance amplifier U1 in the differential voltage to current signal circuit 120. The transconductance amplifier U1 receives the differential voltage signal across the second resistor R2 connected in series on the high side of the bus, and converts the differential voltage signal into a current signal corresponding to the bus current according to a preset conversion ratio. The current signal is input to the emitter of transistor Q1 in the current signal to voltage signal circuit 130, and the current signal is output through the collector of transistor Q1, so as to achieve high voltage isolation between the floating high-side signal and the ground-side sampling signal through transistor Q1. The current signal flowing out from the collector of the transistor Q1 flows through the third resistor R3 and is converted into a low-voltage detection voltage on the third resistor R3; The low-voltage detection voltage is acquired through the ADC pin of the controller, and the bus current is calculated based on the conversion ratio of the transconductance amplifier U1 and the resistance value of the third resistor R3.
[0030] In summary, this circuit adopts a discrete high-side current detection scheme powered by a floating power supply, replacing the low-side current detection scheme or the high-side current detection scheme with highly integrated isolation chip used in traditional fuel or new energy vehicle controllers. This reduces the difficulty and cost of hardware development, improves the system's anti-interference capability, and broadens the application range of the system bus voltage.
[0031] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A wide-voltage bus high-side current detection circuit, characterized in that, include: The floating power supply circuit (110) is connected between the positive and negative terminals of the power supply and is used to clamp the high-side voltage signal of the bus to the supply voltage. A differential voltage to current signal circuit (120) is connected to the floating power supply circuit (110). The differential voltage to current signal circuit (120) is used to collect the differential voltage across the sampling resistor set on the high side of the bus and convert the differential voltage into a current signal. A current signal to voltage signal circuit (130) is connected to the output terminal of the differential voltage to current signal circuit (120). The current signal to voltage signal circuit (130) is used to perform high voltage isolation on the current signal and output the current signal after high voltage isolation to the grounding resistor on the grounding side to form a low voltage detection signal for the controller to sample on the grounding resistor.
2. The wide-voltage bus high-side current detection circuit according to claim 1, characterized in that, The floating power supply circuit (110) includes a Zener diode Z1, a first resistor R1, and a first capacitor C1; One end of the Zener diode Z1 connected in parallel with the first capacitor C1 is connected to one end of the first resistor R1. The other end of the first resistor R1 is connected to the negative terminal of the power supply; The cathode of the Zener diode Z1 is connected to the positive terminal of the power supply.
3. The wide-voltage bus high-side current detection circuit according to claim 2, characterized in that, The differential voltage-to-current signal circuit (120) includes a second resistor R2 and a transconductance amplifier U1; The second resistor R2 is configured as the sampling resistor; One end of the second resistor R2 is connected in series to the high side of the busbar, and the other end is grounded through the load; The two signal input terminals of the transconductance amplifier U1 are respectively connected to the two ends of the second resistor R2; The positive and negative terminals of the power supply of the transconductance amplifier U1 are connected to the cathode and anode of the Zener diode Z1, respectively. The transconductance amplifier U1 is used to convert the differential voltage across the sampling resistor R2 into the current signal according to a preset ratio.
4. The wide-voltage bus high-side current detection circuit according to claim 3, characterized in that, The current signal to voltage signal circuit (130) includes a transistor Q1 and a third resistor R3; The third resistor R3 is configured as the grounding resistor; The emitter of transistor Q1 is connected to the output of transconductance amplifier U1; The base of transistor Q1 is connected to the anode of Zener diode Z1; The collector of the transistor Q1 is connected to one end of the third resistor R3 and the ADC sampling pin of the controller, respectively. The other end of the third resistor R3 is connected to the negative terminal of the power supply.
5. The wide-voltage bus high-side current detection circuit according to claim 4, characterized in that, The transistor Q1 is a PNP high-voltage transistor with a collector-emitter breakdown voltage greater than 400V.
6. The wide-voltage bus high-side current detection circuit according to claim 1, characterized in that, The power supply voltage range is 5~15V.
7. The wide-voltage bus high-side current detection circuit according to claim 1, characterized in that, The bus voltage range between the positive and negative terminals of the power supply is 12V~400V.
8. A method for detecting high-side current on a wide-voltage bus, characterized in that, The detection method using the wide-voltage bus high-side current detection circuit of claim 4 includes: The Zener diode Z1, the first resistor R1 and the first capacitor C1 in the floating power supply circuit (110) are used to limit, clamp and filter the high-side voltage of the bus, so that the voltage across the Zener diode Z1 is clamped to 5V~15V, and the clamped voltage is used as the floating working power supply of the transconductance amplifier U1 in the differential voltage to current signal circuit (120). The transconductance amplifier U1 receives the differential voltage signal across the second resistor R2 connected in series on the high side of the bus, and converts the differential voltage signal into a current signal corresponding to the bus current according to a preset conversion ratio. The current signal is input to the emitter of transistor Q1 in the current signal to voltage signal circuit (130), and the current signal is output through the collector of transistor Q1, so as to achieve high voltage isolation between the floating high-side signal and the ground-side sampling signal through transistor Q1. The current signal flowing out from the collector of the transistor Q1 flows through the third resistor R3 and is converted into a low-voltage detection voltage on the third resistor R3; The low-voltage detection voltage is acquired through the ADC pin of the controller, and the bus current is calculated based on the conversion ratio of the transconductance amplifier U1 and the resistance value of the third resistor R3.