Voltage reference circuit with automatic protection

Abstract

The invention discloses a voltage reference circuit with automatic protection, comprising a band gap voltage reference source circuit, a first biasing circuit, a second biasing circuit, a starting control circuit and a protection control circuit, wherein the voltage output end of the first biasing circuit outputs one-time bipolar transistor base electrode and emitting electrode voltages VBE; the voltage output end of the second biasing circuit outputs double bipolar transistor base electrode and emitting electrode voltages VBE; when voltage reference output by the band gap voltage reference source circuit is lower than the VBE, the starting control circuit controls the voltage reference output by the band gap voltage reference source circuit to rise; and when the voltage reference output by the band gap voltage reference source circuit is higher than 2VBE, the protection control circuit controls the band gap voltage reference source circuit to close. The voltage reference circuit can realize the automatic detection protection when the output of the voltage reference is overhigh or excessive low.

Description

technical field [0001] The invention relates to a power supply circuit, in particular to a voltage reference circuit with automatic protection. Background technique [0002] The most classic voltage reference circuit in power management integrated circuits is the bandgap voltage reference source. The principle of the bandgap voltage reference is to use the base-emitter voltage V of the bipolar transistor (BJT) BE Equivalent thermal voltage V with negative temperature coefficient and positive temperature coefficient T The mutual cancellation of the zero temperature drift voltage reference. The traditional bandgap voltage reference Vbg generally consists of V BE +nV T Two parts, V BE is the base-emitter voltage of the negative temperature coefficient bipolar transistor (BJT), V T is the equivalent thermal voltage with positive temperature coefficient, n is a constant greater than 1, V BE The negative temperature coefficient is about -2mV / ℃, and V T The positive tempera...

AI Technical Summary

Problems solved by technology

[0005]The zero temperature drift voltage of the traditional bandgap voltage reference source is fixed at about 1.2 volts, and it is mainly used as a reference for other circuits. The traditional bandgap voltage reference circuit is only used as the core To control other circuits, the reference voltage will not be turned off even when a problem occurs. When the bandgap voltage reference circuit is not working properly and the voltage reference output is too high or too low, the automatic detection and protection function cannot be realized.

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