Clamping protection circuit with adjustable voltage

Abstract

The invention discloses a clamping protection circuit with adjustable voltage, which comprises a voltage regulation circuit and a clamping protection circuit body, the voltage regulation circuit is connected with the clamping protection circuit body, the voltage regulation circuit is used for automatically matching proper protection voltage according to voltage required to be protected and the clamping protection circuit body is used for generating a clamping voltage. The clamping position circuit is used in a charge pump, and can ensure that a gate oxide layer of a PMOS transistor is not broken down mainly when the high-voltage PMOS transistor is driven, so that the charge pump can work normally.

Description

technical field [0001] The invention relates to the technical field of protection circuits, in particular to a clamp protection circuit with adjustable voltage. Background technique [0002] In the prior art, there is usually a group of PMOS and NMOS transistors in the charge pump circuit, such as figure 1 As shown, one group of PMOS and NMOS transistors, that is, P0 and N0, form a charging and discharging circuit of the charge pump capacitor, which is used to determine the lower plate potential of the charge pump capacitor C0; when the PMOS transistor is turned on (the NMOS transistor is turned off) , the lower plate of the capacitor will be charged to the VDD potential; when the NMOS transistor is turned on (the PMOS transistor is turned off), the lower plate of the capacitor will be charged to the GND potential. Under the control of the frequency CK, the charge on the upper plate of the capacitor will also be raised to the required potential, which is the principle of th...

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Problems solved by technology

[0005] The traditional simple way is to use the Zener tube to directly clamp, such as figure 2 As shown, DZ0 and DZ1 are used to clamp the VG voltage. Although this method is simple in structure, it brings two problems. The clamping voltage of the first Zener tube will vary according to different process factories, and the clamping voltage of the second Zener tube The voltage is basically around 5.5V, and the adjustable clamping voltage cannot be realized. Therefore, a voltage-adjustable clamping protection circuit is proposed.

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