High-precision high-side current detection circuit

Abstract

The invention relates to a high-precision high-side current detection circuit comprising a pair of transistors formed by a first triode and a second triode and a pair of transistors formed by a third triode and a fourth triode. The first triode and the second triode have the same PNP type; and the third triode and the fourth triode have the same NPN type. The collector of the first triode is connected with a grid electrode of a Mosfet tube; the base electrode of the third triode is connected with a control terminal; the emitter of the first triode is connected with a load voltage input terminal; the emitter of the second triode is connected with a load voltage output terminal; and a current detection resistor is connected between the load voltage input terminal and the load voltage output terminal. The source electrode of the Mosfet tube is connected with a current detection signal output terminal. According to the invention, the high-side current detection circuit with the low cost is provided; and the detection precision is high and the stable current detection precision can be maintained in the environment with obvious temperature and voltage changes. When the circuit module is in a sleep mode, the circuit can be switched off by the control terminal, thereby reducing the quiescent current.

Description

Technical field: [0001] The invention relates to the field of electricity, in particular to a vehicle-mounted electrical appliance, in particular to a current detection technology in the vehicle-mounted electrical appliance, in particular to a high-precision high-side current detection circuit. Background technique: [0002] There are more and more electronic devices installed and used in automobiles. In order to monitor the state of the load and diagnose open circuit, short circuit and overload conditions, it is necessary to detect various types of load current with high precision. In the prior art, the circuit for detecting the load current has the following technical solutions: [0003] (1) Use the smart switch chip to provide the current detection function. Although the circuit of this solution is simple, the cost is high and the detection accuracy is low, especially in the detection of small current, the detection accuracy will have a deviation of more than 50%, which ...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide a high-precision high-side current detection circuit. The high-precision high-side current detection circuit should solve the technical problems of high cost and low detection accuracy of the circuit for detecting load current in the prior art.

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