Overcurrent protection circuit without static power consumption

Abstract

The invention discloses an overcurrent protection circuit without static power consumption. The circuit comprises a resistor, a PMOS transistor, an NMOS transistor, an internal circuit and a shaping circuit, wherein one end of the resistor is connected with a powers supply VDD while the other end is connected with an A point, a grid of the PMOS transistor is connected with the A point connected with the resistor, a source of the PMOS transistor is connected with the power supply VDD, a drain of the PMOS is connected with a drain of the NMOS transistor, a source of the PMOS transistor is connected with a ground potential, and the drains of the PMOS transistor and the NMOS transistor are connected with the input of the shaping circuit. According to the circuit provided by the invention, thefunction of overcurrent protection is achieved via a subject circuit composed of one resistor and two MOS transistors, no static current exists, fewer devices are used than a conventional circuit, anadditional reference voltage and an operational amplifier are not needed, the function of overcurrent protection is achieved, and the purposes of reducing working current of the circuit and reducing layout area of the overcurrent protection function are achieved.

Description

technical field [0001] The invention belongs to the technical field of integrated circuits and relates to an overcurrent protection circuit, in particular to an overcurrent protection circuit without static power consumption. Background technique [0002] The over-current protection function of the chip is integrated in many types of chips, especially in power management chips. Most of the existing overcurrent protection circuits are implemented by circuits such as operational amplifiers and comparators. The advantage of this circuit is that it can control the value of the overcurrent trip point more accurately. The disadvantage is that the circuit is too complicated, the quiescent current is relatively large, and it is not suitable for the situation where the difference between the working current value and the overcurrent current setting value is relatively large. [0003] For example, in the patent CN2009101109865 "An Overcurrent Protection Circuit", an overcurrent prote...

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Problems solved by technology

It can be seen that the quiescent current is relatively large, and an additional reference voltage is required, and the circuit is relatively complicated.

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