Chip over-current protection circuit with adjustable delay time

Abstract

The invention relates to the field of integrated circuit design. In order to solve the problems that over-current error judgment is caused by the large current generated by the moment of closing of a switch tube and a normal over-current protection function is affected in a traditional over-current protection technology, the invention adopts the technical scheme that the chip over-current protection circuit with the adjustable delay time comprises two parts, i.e. a leading-edge blanking (LEB) module and an over-current comparator; the sampled DRV current of the switch tube is converted into voltage through a resistor; the sampling voltage is transmitted to the front end of the comparator through the LEB module after a period of time is delayed; when the voltage is more than the reference voltage Vref of the comparator, the output ocp of the comparator is high level; the output ocp of the comparator controls the DRV of the switch tube to be low level, i.e. when the over-current situation occurs, the output ocp of the comparator controls the DRV of the switch tube to be cut off, the current is reduced; and when the over-current situation disappears, an over-current signal is automatically released. The chip over-current protection circuit with the adjustable delay time is mainly applied to the design and the manufacturing of integrated circuits.

Description

technical field [0001] The invention relates to the field of integrated circuit design, in particular to an overcurrent protection circuit with adjustable delay time of a PFC circuit, and specifically relates to a chip overcurrent protection circuit with adjustable delay time. Background technique [0002] With the ever-increasing requirements for green energy and the gradual implementation of regulations and standards aimed at the problem of rising grid current, power factor correction technology has become the key to the field of power management. The overcurrent protection circuit is an indispensable and important part of the PFC circuit. [0003] Picture 1-1 When the current of the switching tube is too large, it will cause the switching tube to burn out, and the turn-on and turn-off of the switching tube is very important to the input current waveform and output voltage, thus affecting the entire power factor correction circuit. [0004] The traditional overcurrent pr...

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Problems solved by technology

[0005] The present invention aims to overcome the deficiencies of the prior art, and solve the problem of overcurrent misjudgment caused by the large current at the moment the switch tube is closed in the traditional overcurrent protection technology and the problem of affecting the normal overcurrent protection function. The scheme is that the chip overcurrent protection circuit with adjustable delay time includes two parts: the leading edge blanking LEB module and the overcurrent comparator. After a delay, the sampling voltage is transmitted to the positive terminal of the comparator. When the voltage is greater than the reference voltage Vref of the comparator, the output ocp of the comparator is at a high level, and the output ocp of the comparator controls the switching tube DRV to be at a low level, that is, an overcurrent condition occurs , the comparator output ocp controls the switching tube DRV to disconnect, so that the current drops. When the over-current situation disappears, the over-current signal is automatically released

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