An overcurrent detection circuit based on hall sensors

Abstract

The utility model discloses a kind of overcurrent detection circuit based on hall sensor, it is related to charging detection technical field, including hall sensor and power module connection, for current sampling;Voltage follower module is connected with the output end of hall sensor;Voltage division circuit module is connected with voltage follower module, for voltage division to voltage follower module output voltage;Amplifier circuit module is connected with the output end of voltage division circuit module, for the voltage amplified to voltage division circuit output;Filter module is connected with amplifier circuit module, for the output of amplifier circuit module is filtered and output to back stage after back.This utility model weak low-voltage signal is collected to output to hall sensor, carries out voltage following, voltage division, negative feedback amplification and filtering processing, then, it can be accurately detected by processor such as single-chip microcontroller.This utility model uses the active filter circuit of two-stage operational amplifier composition, output detection signal is pure, error is extremely small.Circuit uses few devices, and cost is low.

Description

Technical Field

[0001] This utility model relates to the field of charging detection technology, and more particularly to the field of new energy vehicle charging technology. Specifically, it is an overcurrent detection circuit based on a Hall sensor. Background Technology

[0002] Current sampling circuits typically come in three types: "high-side current sampling," "low-side current sampling," and "Hall sensor sampling." High-side current sampling suffers from drawbacks such as high common-mode voltage, the use of numerous non-dedicated discrete components, complex design, and high cost. Low-side current sampling introduces ground level interference, which becomes more pronounced as the current increases. Hall sensor sampling isolates the sampling signal, making it particularly suitable for high-power applications. However, current Hall sensor sampling circuits generally employ passive filtering technology, resulting in unclean detection signals and thus large detection errors. Utility Model Content

[0003] The purpose of this invention is to provide an overcurrent detection circuit based on a Hall sensor, which solves the problems of large detection error and unstable operation in the current sampling circuit based on a Hall sensor in the prior art.

[0004] The present invention solves the above problems through the following technical solution:

[0005] An overcurrent detection circuit based on a Hall sensor includes:

[0006] Hall effect sensors, connected to the power module, are used to sample current.

[0007] A voltage follower module is connected to the output terminal of the Hall sensor;

[0008] The voltage divider circuit module is connected to the voltage follower module and is used to divide the output voltage of the voltage follower module.

[0009] An amplifier circuit module is connected to the output terminal of the voltage divider circuit module and is used to amplify the voltage output by the voltage divider circuit.

[0010] A filtering module, connected to the amplifier circuit module, is used to filter the output of the amplifier circuit module before outputting it to the next stage.

[0011] Working principle:

[0012] The Hall sensor's primary stage samples the external input current, while its secondary stage outputs a weak, low-voltage signal. This signal is then divided by a voltage follower module and a voltage divider module before being fed into an amplifier module. The amplifier module's output is filtered, allowing the high-current detection signal to be accurately detected by a microcontroller or other processor after conditioning.

[0013] Furthermore, the voltage follower module includes a first operational amplifier and a resistor R1. The non-inverting input of the first operational amplifier is connected to the output of the Hall sensor. The first end of the resistor R1 is connected to the inverting input of the first operational amplifier, and the second end of the resistor R1 is connected to the output of the first operational amplifier.

[0014] Furthermore, the voltage divider circuit module includes resistors R2 and R3. The first end of resistor R2 is connected to the output terminal of the voltage follower module, the second end of resistor R2 is connected to the first end of resistor R3 and an input terminal of the amplifier circuit module, and the second end of resistor R3 is grounded.

[0015] Furthermore, the amplifier circuit module includes a second operational amplifier, resistors R4 and R5, and capacitor C3. The non-inverting input of the second operational amplifier is connected to the second end of resistor R2, and the inverting input of the second operational amplifier is connected to the first end of resistor R4, the first end of resistor R5, and the first end of capacitor C3. The second end of resistor R4 is grounded, and the second ends of resistor R5 and capacitor C3 are connected to the output of the second operational amplifier.

[0016] Furthermore, the filtering module includes a resistor R6 and a capacitor C4. The first end of the resistor R6 is connected to the output end of the amplifier circuit module, the second end of the resistor R6 is connected to the first end of the capacitor C4 and serves as the signal output end, and the second end of the capacitor C4 is grounded.

[0017] Furthermore, filter capacitors are connected between the Hall sensor and the power module, and between the Hall sensor and ground.

[0018] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0019] This invention acquires weak low-voltage signals from Hall effect sensors, performs voltage following, voltage division, negative feedback amplification, and filtering, allowing for accurate detection by microcontrollers and other processors. This invention cleverly utilizes an active filter circuit composed of two operational amplifier stages, resulting in a pure output detection signal with minimal error. Furthermore, the circuit uses few components, leading to low cost. Attached Figure Description

[0020] Figure 1 This is the circuit schematic diagram of this utility model;

[0021] Among them, U1 is a Hall sensor; U2A is the first operational amplifier; and U2B is the second operational amplifier. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0023] Example 1:

[0024] An overcurrent detection circuit based on a Hall sensor includes:

[0025] Hall sensor U1 is connected to the power module and is used to sample the current.

[0026] A voltage follower module is connected to the output terminal of the Hall sensor U1;

[0027] The voltage divider circuit module is connected to the voltage follower module and is used to divide the output voltage of the voltage follower module.

[0028] An amplifier circuit module is connected to the output terminal of the voltage divider circuit module and is used to amplify the voltage output by the voltage divider circuit.

[0029] A filtering module, connected to the amplifier circuit module, is used to filter the output of the amplifier circuit module before outputting it to the next stage.

[0030] Working principle:

[0031] The Hall sensor U1 samples the external input current at the primary stage and outputs a weak low-voltage signal at the secondary stage. After being divided by a voltage follower module and a voltage divider module, the signal is sent to an amplifier module. The output of the amplifier module is filtered, so that the high-current detection signal can be accurately detected by a microcontroller or other processor after conditioning.

[0032] Example 2:

[0033] Based on Example 1, combined with Appendix Figure 1 As shown, PIN1 and PIN2 of Hall sensor U1 are connected to the positive terminal L_IN of the input current, and PIN3 and PIN4 of Hall sensor U1 are connected to the positive terminal N_IN of the input current.

[0034] One end of the filter capacitor C1 is connected to PIN8 of the Hall sensor U1 via the +5V power supply module;

[0035] A filter capacitor C2 is connected between PIN6 and PIN5 of the Hall sensor;

[0036] The Hall sensor's PIN7 is connected to the non-inverting input of op-amp U2 channel A;

[0037] The voltage follower module includes a first operational amplifier U2A and a resistor R1. The non-inverting input of the first operational amplifier U2A is connected to the output of the Hall sensor U1. The first end of the resistor R1 is connected to the inverting input of the first operational amplifier U2A, and the second end of the resistor R1 is connected to the output of the first operational amplifier U2A. Resistor R1 is a balancing resistor.

[0038] The voltage divider circuit module includes resistors R2 and R3. The first end of resistor R2 is connected to the output terminal of the voltage follower module (i.e., the output terminal of the first operational amplifier U2A). The second end of resistor R2 is connected to the first end of resistor R3 and an input terminal of the amplifier circuit module (i.e., the non-inverting input terminal of the second operational amplifier U2B). The second end of resistor R3 is grounded.

[0039] Furthermore, the amplifier circuit module includes a second operational amplifier U2B, resistors R4 and R5, and capacitor C3. The non-inverting input of the second operational amplifier U2B is connected to the second terminal of resistor R2, and the inverting input of the second operational amplifier U2B is connected to the first terminals of resistors R4, R5, and C3. The second terminal of resistor R4 is grounded, and the second terminals of resistor R5 and C3 are connected to the output of the second operational amplifier U2B. Resistor R5 and capacitor C3 form a feedback network.

[0040] Furthermore, the filtering module includes a resistor R6 and a capacitor C4. The first end of the resistor R6 is connected to the output end of the amplifier circuit module (i.e., the output end of the second operational amplifier U2B). The second end of the resistor R6 is connected to the first end of the capacitor C4 and serves as the signal output end to output the detection signal OCP_DET. The second end of the capacitor C4 is grounded.

[0041] Although the present invention has been described herein with reference to illustrative embodiments, the above embodiments are merely preferred embodiments of the present invention, and the implementation of the present invention is not limited to the above embodiments. It should be understood that those skilled in the art can design many other modifications and implementations, which will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. A Hall sensor-based overcurrent detection circuit, characterized by, include: Hall effect sensors, connected to the power module, are used to sample current. A voltage follower module is connected to the output terminal of the Hall sensor; The voltage divider circuit module is connected to the voltage follower module and is used to divide the output voltage of the voltage follower module. An amplifier circuit module is connected to the output terminal of the voltage divider circuit module and is used to amplify the voltage output by the voltage divider circuit. A filtering module, connected to the amplifier circuit module, is used to filter the output of the amplifier circuit module before outputting it to the next stage.

2. The overcurrent detection circuit based on a Hall sensor according to claim 1, characterized in that, The voltage follower module includes a first operational amplifier and a resistor R1. The non-inverting input of the first operational amplifier is connected to the output of the Hall sensor. The first end of the resistor R1 is connected to the inverting input of the first operational amplifier, and the second end of the resistor R1 is connected to the output of the first operational amplifier.

3. The overcurrent detection circuit based on Hall sensor according to claim 1, characterized in that, The voltage divider circuit module includes resistors R2 and R3. The first end of resistor R2 is connected to the output terminal of the voltage follower module, and the second end of resistor R2 is connected to the first end of resistor R3 and an input terminal of the amplifier circuit module. The second end of resistor R3 is grounded.

4. The overcurrent detection circuit based on a Hall sensor according to claim 3, characterized in that, The amplifier circuit module includes a second operational amplifier, resistors R4 and R5, and capacitor C3. The non-inverting input of the second operational amplifier is connected to the second end of resistor R2. The inverting input of the second operational amplifier is connected to the first end of resistor R4, the first end of resistor R5, and the first end of capacitor C3. The second end of resistor R4 is grounded. The second ends of resistor R5 and capacitor C3 are connected to the output of the second operational amplifier.

5. The overcurrent detection circuit based on Hall sensor according to claim 1, characterized in that, The filtering module includes a resistor R6 and a capacitor C4. The first end of the resistor R6 is connected to the output end of the amplifier circuit module, the second end of the resistor R6 is connected to the first end of the capacitor C4 and serves as the signal output end, and the second end of the capacitor C4 is grounded.

6. The overcurrent detection circuit based on Hall sensor according to claim 1, characterized in that, Filter capacitors are connected between the Hall sensor and the power module, and between the Hall sensor and ground.

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