Bipolar NPN type band-gap reference voltage circuit

Abstract

The invention discloses a bipolar NPN type band-gap reference voltage circuit. On the basis of the structure of the traditional bipolar NPN type band-gap reference voltage circuit, a fixed bias circuit and a protective control circuit are added; by using the characteristic that the output reference voltage, which is about 1.2v, of a standard bipolar NPN type band-gap reference voltage source is always smaller than the base emitter voltage, which is about 1.4v, of a dual bipolar junction transistor (BJT), that the base emitter voltage of the dual BJT is about 1.4v is realized in the fixed biascircuit; the comparison and control of the base emitter voltage of the dual BJT and the output reference voltage of the band-gap reference source are realized by the comparator; and thus, both the start of the band-gap reference voltage source is taken into consideration and the over-voltage protection function of the band-gap reference voltage source is realized. The bipolar NPN type band-gap reference voltage circuit can realize the automatic protection of the circuit when the output reference voltage is over high and is suitable to be manufactured by a process in which all kinds of bipolartransistors and metal-oxide-field effect tubes are compatible.

Description

technical field [0001] The invention relates to a power supply circuit, in particular to a bipolar NPN bandgap reference voltage circuit. Background technique [0002] The most classic voltage reference circuit in power management integrated circuits is the bipolar NPN bandgap reference voltage source. The principle of the bipolar NPN bandgap reference voltage source is to use the base-emitter voltage V of the bipolar transistor (BJT) BE Negative temperature coefficient and equivalent thermal voltage V T The positive temperature coefficients cancel each other out for a zero-drift voltage reference. The traditional bipolar NPN bandgap voltage reference is generally composed of V BE +kV T Two parts, V BE is a negative temperature coefficient of approximately -2mV / °C, while V T is a positive temperature coefficient of about 0.086mV / °C, V BE About 0.7V, plus k times (k>1) equivalent thermal voltage V T , V T The difference between the base emitter voltage and the sam...

AI Technical Summary

Problems solved by technology

[0010] The zero temperature drift voltage of the traditional bandgap reference voltage source is fixed at about 1.2 volts. It is mainly used as a reference for other circuit parts. When the output reference voltage is too high, it will not be turned off, and the automatic protection of the circuit cannot be realized.

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