Protection circuit of switch charging chip and switch charging circuit

Abstract

The invention discloses a protection circuit of a switch charging chip and a switch charging circuit. A trigger unit is used for being switched on under the action of a first trigger voltage and generating and outputting a second trigger voltage according to an input voltage in the switched-on state. A detection unit is used for being switched on under the action of the first trigger voltage and comparing the voltage after voltage drop of a to-be-detected voltage with the second trigger voltage in the switched-on state. If the voltage after voltage drop of the to-be-detected voltage is higherthan the second trigger voltage, the detection unit outputs a control signal to make the gate voltage of a first switch tube in a switch charging chip pulled down to below the second trigger voltage.The first switch tube is used for controlling the on-off of the input and output ports of the switch charging chip. Through the circuit, the gate voltage of the first switch tube can be pulled down tobelow the second trigger voltage when the gate voltage of the first switch tube is too high, so that the switch charging chip is protected, and the normal operation of the switch charging chip is ensured.

Description

technical field [0001] The invention relates to the field of integrated circuits, in particular to a protection circuit for a switch charging chip and a switch charging circuit. Background technique [0002] With the diversified development of portable electronic products, the requirements for switching charging chips are also getting higher and higher. In addition to supporting basic 5V constant voltage charging, the current switch charging chip also supports 9V and 12V high voltage charging. [0003] During the charging process of the switch charging chip, abnormal situations may occur. Therefore, it is necessary to design a corresponding protection circuit for the switch charging chip. In the design of the protection circuit of the switch charging chip in the prior art, problems such as the positive and negative overshoot of the input terminal of the switch charging chip, the overheating of the switch charging chip and the short circuit of the output have been taken into...

AI Technical Summary

Problems solved by technology

In the design of the protection circuit of the switching charging chip in the prior art, the positive and negative overshoot of the input terminal of the switching charging chip, the overheating of the switching charging chip and the short circuit of the output have been considered.

However, when the protection circuit of the existing switching charging chip is designed, the situation that the input terminal is suddenly short-circuited to the ground is not considered.

[0004] During the charging process of the switch charging chip, when the input end is suddenly short-circuited to the ground, the gate-source voltage of the first switching tube in the switching charging chip is too high, resulting in breakdown of the gate oxide, causing damage to the first switching tube, and the switch The charging chip does not work properly

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