Fault indicator whole bridge turning circuit

Abstract

The invention provides a fault indicator whole bridge turning circuit, which comprises a controller, wherein an electrode G of an NMOS tube is connected to a 27th lead pin of the controller through aresistor R7, and is connected to a base electrode of a triode T1 through a resistor R3; a collector electrode of the triode T1 is connected to an electrode G of a PMOS tube G4 through a resistor R2 toform a turning control circuit; an electrode of an NMOS tube G2 is respectively connected to a 30th lead pin of a controller through a resistor R9 and a base electrode of a triode T2 through a resistor R4; a collecting electrode of the triode T2 is connected to an electrode G of a PMOS tube G3 through a resistor R1; and an electrode D of a PMOS tube is connected with an electrode D of a PMOS tubeG4 through a driving coil L1 for forming a rest control circuit. The fault indicator whole bridge turning circuit uses the NMOS tubes and the PMOS tubes for replacing controlled silicon; the on-off states of the MOS tubes are controlled, so that the charging and discharging are faster; the conduction resistance of the MOS tubes is very small; the voltage drop is almost zero, so that the capacitorvoltage can be sufficiently used; therefore a circuit is simplified; the plate material pace is saved; and the economic cost is reduced.

Description

technical field [0001] The invention belongs to the field of indicator circuits, in particular to a fault indicator full-bridge turnaround circuit. Background technique [0002] The principle of the existing external fault indicator overturning circuit is that after the indicator detects a line fault, the CPU sends a overturning signal, and the MCR16-100 thyristor turns on the corresponding capacitor to discharge, so that the indicator overturns, but the current existence is as follows: 1. The turn-off point of the SCR is harsh, and the capacitor discharge must be lowered to the turn-off point voltage before the turn-over action can be performed; 2. Two capacitors are used for turn-over and reset, which wastes board space; 3. The voltage drop of the SCR tube is large, The available voltage is small; 4. At high temperature, the leakage current of the capacitor increases, and the capacitor is not fully charged; at low temperature, the capacitor capacity decreases, which will a...

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Problems solved by technology

[0002] The principle of the existing external fault indicator overturning circuit is that after the indicator detects a line fault, the CPU sends a overturning signal, and the MCR16-100 thyristor turns on the corresponding capacitor to discharge, so that the indicator overturns, but the current existence is as follows: 1. The turn-off point of the SCR is harsh, and the capacitor discharge must be lowered to the turn-off point voltage before the turn-over action can be performed; 2. Two capacitors are used for turn-over and reset, which wastes board space; 3. The voltage drop of the SCR tube is large, The available voltage is small; 4. At high temperature, the leakage current of the capacitor increases, and the capacitor is not fully charged; at low temperature, the capacitor capacity decreases, which will affect the capacitor capacity under high and low temperature conditions and cause unreliable turnaround

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