Voltage comparator

Abstract

The embodiment of the invention provides a voltage comparator. The voltage comparator includes a reference circuit providing a reference output voltage; and a comparison unit, wherein the first inputend of the comparison unit receives the reference output voltage, the second input end of the comparison unit is connected with target voltage, and the output end of the comparison unit outputs a comparison result. The reference circuit comprises a voltage generation unit, an approximate zero temperature coefficient current source unit and a level shifting unit. The approximate zero temperature coefficient current source unit comprises a negative feedback voltage regulation unit, an average current unit, a first positive temperature coefficient current unit, a first negative temperature coefficient voltage unit, a first negative temperature coefficient current unit, a second negative temperature coefficient voltage unit and a second negative temperature coefficient current unit. Zero temperature coefficient can be realized by designing the resistance ratio of the first negative temperature coefficient current unit to the second negative temperature coefficient current unit; by designing the voltage on the current sharing unit, a smaller power supply working voltage can be realized.

Description

technical field [0001] The present invention relates to the field of analog circuits, and more specifically, to a voltage comparator. Background technique [0002] The reference circuit (reference voltage circuit), also known as the reference voltage source, is a circuit that can provide a stable output voltage when the process, power supply voltage, and temperature change. Voltage references are widely used in circuits such as data converters, smart sensors, and power converters. [0003] Conventional reference circuits generally adopt a bandgap circuit design. Since the bandgap voltage is generally about 1.21-1.22V, the output voltage is 1.21-1.22V, which requires the lowest power supply voltage to be greater than this voltage plus at least one Vds voltage to work. Generally, Vds needs at least 0.1V. Therefore, generally this kind of circuit requires a power supply voltage greater than 1.31V. In some applications, it is required to operate at a lower supply voltage, so ...

AI Technical Summary

Problems solved by technology

[0004] Due to the deviation of the generated reference voltage, the output result of the voltage comparator using such a reference circuit is also inaccurate

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