A comparator antistatic circuit and its working method

Abstract

The invention discloses a comparator anti-static circuit and a working method thereof. The comparator anti-static circuit comprises a bipolar transistor Q1, a bipolar transistor Q2, a resistor R1, a resistor R2 and a tail current source IP; the tail current source IP is connected with a ground AGND; and the bipolar transistor Q1 and the bipolar transistor Q2 are respectively connected with a powersupply voltage AVDD, the tail current source IP, a comparator positive end input signal INP and a comparator reverse end input signal INN through an anti-static protective circuit. The comparator anti-static circuit and the working method thereof, which are disclosed by the invention, are applicable to most of comparator circuits which use an NPN type transistor as an input pair transistor, and are very high in flexibility and universality.

Description

technical field [0001] The invention belongs to the technical field of integrated circuit design, and in particular relates to a comparator antistatic circuit and a working method thereof. Background technique [0002] In recent years, with the miniaturization of integrated circuits and the continuous innovation of technology, comparator chips have developed by leaps and bounds. However, the antistatic protection circuit structure of comparators is single and develops slowly, which cannot guarantee that the chip pins are exposed to the outside world. After being damaged by certain static electricity in the environment, the functional performance parameters of the chip will not be affected. Therefore, it is very important to design an electrostatic protection network that can greatly improve the antistatic ability of the comparator port. [0003] figure 1 It is an antistatic circuit structure between any two input / output ports and positive and negative power supplies of a t...

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Problems solved by technology

[0004] However, if figure 1 The antistatic circuit shown has the following disadvantages: when any electrostatic damage occurs between any two ports in the circuit, the antistatic structure of the PAD1 port and the antistatic structure of the PAD2 port will form as follows: figure 2 The PNPN four-layer structure shown in the figure, if the structure is not fully opened when external static electricity occurs, the N-type input tube inside the circuit will absorb a large amount of electrostatic energy, causing the comparator circuit itself to bear a huge discharge current, and the input to the tube The BE junction suffers damage and cannot work properly or even fail to function

In addition, there are certain requirements for the input differential mode range of the comparator, so the common antistatic structure is difficult to be directly applied to the comparator circuit with NPN as the input pair tube

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