Switch control circuit and load switch

Abstract

The invention discloses a switch control circuit and a load switch. The switch control circuit comprises a signal input end, a power voltage input end, a first voltage control output end, a first capacitor, a first switching tube, a first current source and a second switching tube; and due to the fact that the characteristic of the first capacitor is that when the voltage at the two ends of the first capacitor changes, the capacitor is caused to release or absorb charges, and the capacitor has a high-pass characteristic, namely, the current passing through the capacitor and the change rate ofthe voltage at the two ends of the capacitor is of a directly proportional relationship. The current is coupled to a first end of the first switching tube through the first capacitor, namely a controlend of the second switching tube, so that the current passing through the second switching tube becomes large, and the voltage of the first voltage control output end is pulled down in a short time,thus a main switch in the load switch is controlled, and then the purpose of fast turn-off is achieved. The switch control circuit provided by the invention is simple in circuit structure, does not increase more power consumption, and can perform fast response under the condition of faster voltage change.

Description

technical field [0001] The invention relates to the technical field of analog circuits, in particular to a switch control circuit and a load switch. Background technique [0002] In higher-end electronic equipment, such as mobile phones and other equipment, an external power supply charger and other power supply equipment are often connected through a load switch, and the instability of the power grid and external equipment often causes rapid and large changes in the input power supply voltage, so , This type of load switch usually adds OVP (Over Voltage Protection, overvoltage protection) function, that is, when the input voltage exceeds the set voltage value, the load switch will be turned off, thereby protecting the internal circuit from external high voltage impact. [0003] The turn-off time Toff of the load switch is an important indicator. The faster the turn-off speed means that an external overvoltage of the same condition occurs, the smaller the internal voltage ri...

AI Technical Summary

Problems solved by technology

[0006] In view of this, the present invention provides a switch control circuit and a load switch to solve the problem that the load switch in the prior art cannot respond in time when a rapid overvoltage event occurs, resulting in low system reliability and safety, and low power consumption. Big, costly problems

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