Protection circuit capable of working stably

Abstract

The invention discloses a protection circuit capable of working stably. The protection circuit comprises an insulated gate bipolar transistor T, a drive chip EXB841, a comparator A, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a diode D1, a diode D2 and a diode D3, wherein a non-inverting input of the comparator A is connected with one end of the resistor R3; the other end of the resistor R3 is connected with one end of the resistor R1; an inverting input end of the comparator A is connected with one end of the resistor R4; the other end of the resistor R4 is connected with a moving end c of the resistor R2; a fixed end a of the resistor R2 is simultaneously connected with one end of the resistor R1 and one end of the resistor R3; the resistor R6 is connected between a port 1 of the comparator A and a signal output end; the signal output end of the comparator A is connected with a cathode of the diode D2; an anode of the diode D2 is connected with a port 4 of the drive chip EXB841. According to the scheme, the condition that a forward voltage drop changes along with different currents can be eliminated through the circuit; and through the arrangement of the driver EXB841, the insulated gate bipolar transistor can be slowly turned off under the condition of overcurrent in the circuit; and the working stability and reliability of the circuit are ensured.

Description

technical field [0001] The invention relates to the field of voltage stabilizing circuits, in particular to a protection circuit with stable operation. Background technique [0002] Switching power supply is a kind of power supply that uses modern power electronic technology to control the time ratio of switching on and off to maintain a stable output voltage. Switching power supply is generally composed of pulse width modulation (PWM) control IC and MOSFET. With the development and innovation of power electronics technology, switching power supply technology is constantly innovating. At present, switching power supply is widely used in almost all electronic devices due to its small size, light weight and high efficiency. It is an indispensable power supply method for the rapid development of today's electronic information industry. With the rapid development of power electronics technology, the relationship between power electronic equipment and people's work and life is b...

AI Technical Summary

Problems solved by technology

In the existing switching power supply circuit, the forward voltage drop varies with the current. If the circuit is over-current, it is easy to damage the switching power supply and affect the stability of the work.

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