Detection circuit based on bandgap reference voltage and bandgap reference voltage circuit

Abstract

The invention discloses a detection circuit based on a bandgap reference voltage and a bandgap reference voltage circuit. The detection circuit includes: a second MOS tube, and a power supply voltage V DD and bandgap reference voltage V BG The first MOS transistor between them constitutes a first current mirror, which is used to copy the current in the first MOS transistor; the first detection resistor is arranged in series with the second MOS transistor; the third MOS transistor and the fourth MOS transistor, the The third MOS transistor is arranged in parallel with the second MOS transistor, and the third MOS transistor and the fourth MOS transistor form a second current mirror; the second detection resistor is arranged in series with the fourth MOS transistor. The present invention can judge whether the output of the bandgap reference voltage is correct without introducing a reference voltage into the bandgap reference voltage circuit through the setting of the detection circuit, and the bandgap reference voltage V BG After the output is correct, a high-level logic level signal BG_OK is output, which can be applied to the case of low power supply voltage.

Description

technical field [0001] The invention belongs to the technical field of power supply circuits, and in particular relates to a detection circuit based on a bandgap reference voltage and a bandgap reference voltage circuit. Background technique [0002] The most classic voltage reference circuit in power management integrated circuits is the bandgap reference voltage source. The principle of the bandgap reference voltage source is to use the base-emitter PN junction 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. Traditional bandgap voltage reference V BG Generally by V BE +kV T Two parts, V BE It is a negative temperature coefficient of about -2mV / ℃, while VT is a positive temperature coefficient of about 0.086mV / ℃, V BE About 0.7V, plus k times (k>1) equivalent thermal voltage V T , V T It is also related ...

AI Technical Summary

Problems solved by technology

When judging whether the bandgap reference voltage is correct, there is no reference voltage to use, so usually the method of judging whether the bandgap reference voltage is correct is very rough, and it is impossible to ensure that the bandgap reference is correct before outputting the indicator signal BG_OK

In addition, under low input voltage application conditions, it is necessary to output the BG_OK signal as close to the correct output of the bandgap reference voltage as possible, such as figure 1 In the A position, but to avoid in the figure 1 The BG_OK signal is only output in the B position, because in the B position V DD The voltage may have exceeded the minimum input voltage defined in the specification, at this time V DD The judgment of the minimum input voltage is inaccurate and meaningless, and if the input voltage is just the minimum input voltage, the BG_OK signal cannot be output, and the chip will not start

Images