Current sampling circuit, chip and electronic device for high-side switch driving circuit

By introducing a voltage clamping circuit into the high-side switch drive circuit, the operating state of the high-side switch and the second transistor is adjusted, which solves the problem of low current sampling accuracy of the target transistor, and significantly improves the sampling accuracy, especially at small load currents.

CN119510855BActive Publication Date: 2026-06-02ZHUHAI NANXIN SEMICON TECH CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
ZHUHAI NANXIN SEMICON TECH CO LTD
Filing Date
2024-11-13
Publication Date
2026-06-02

AI Technical Summary

Technical Problem

In existing technologies, the current sampling accuracy of the target transistor in the high-side switch drive circuit is low, especially with large errors at small load currents, which cannot meet application requirements.

Method used

A voltage clamping circuit is introduced into the high-side switch driving circuit. The voltage clamping circuit, composed of a transconductance operational amplifier and a transistor driving circuit, adjusts the operating state of the high-side switch and the second transistor, so that they operate in the saturation region when the load current is small, thereby reducing the impact of offset voltage on current sampling.

Benefits of technology

It improves the current sampling accuracy under low load current, ensuring high-precision current monitoring under different load current conditions.

✦ Generated by Eureka AI based on patent content.

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Patent Text Reader

Abstract

The application relates to the technical field of switch driving, in particular to a current sampling circuit for a high-side switch driving circuit, a chip and electronic equipment. The current sampling circuit comprises a second transistor, a third transistor, an operational amplifier and a voltage clamping circuit. The operational amplifier is used to work in a linear amplification state, so that the second electrode of the high-side switch tube and the second electrode of the second transistor are in a virtual short state. The voltage clamping circuit is used to collect a first voltage on the second electrode of the high-side switch tube, and output a voltage clamping signal when the first voltage is greater than a preset second voltage. The voltage clamping signal is used to clamp the voltage difference between the first electrode and the second electrode of the high-side switch tube to a preset third voltage. In this way, when the load current of the branch where the high-side switch tube is located is small, the offset voltage can be negligible compared with the third voltage, so as to reduce the influence of the offset voltage on the load current and ensure the sampling accuracy of the load current.
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