A fixed voltage difference detection circuit

Abstract

The invention discloses a fixed voltage difference detection circuit, comprising: a bias circuit, a fixed voltage generating circuit, a hysteresis comparator circuit, a high voltage signal voltage dividing network and a low voltage signal voltage dividing network; the input terminal of the bias circuit is connected to a power supply voltage , the output terminal is connected to the fixed voltage generating circuit for generating a bias voltage signal; the input terminal of the low-voltage signal voltage dividing network receives the detected low-voltage signal, and the output terminal is connected to the fixed voltage generating circuit; the fixed voltage generating circuit The output terminal is connected to the input terminal of the hysteresis comparator circuit; the input terminal of the high-voltage signal voltage divider network receives the detected high-voltage signal, and the output terminal is connected to the input terminal of the hysteresis comparator circuit; the hysteresis comparator is used for two The voltage signal is detected to output the detection result. The invention can accurately detect whether the difference between two voltages is greater than the set voltage, and has the advantages of strong anti-noise ability, simple overall structure and the like.

Description

technical field [0001] The invention belongs to the technical field of analog integrated circuits, and in particular relates to a fixed voltage difference detection circuit. Background technique [0002] In the field of power management technology, it is sometimes necessary to detect whether the voltage difference between two voltages is greater than a set voltage. When the voltage difference is higher or lower than a preset value, a logic signal is output to switch the state of the circuit. For example, in a power management chip, it is sometimes necessary to switch the state of a circuit based on the voltage difference between the input and output voltages. [0003] figure 1 Shown is a common fixed voltage difference detection circuit, including four resistors R1, R2, R3, R4, an operational amplifier, a hysteresis comparator, and a bandgap reference source. Among them, R1, R2, R3 and R4 and the operational amplifier form a subtractor to obtain V H and V L Signal differ...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the defects and improvement needs of the prior art, the present invention provides a fixed voltage difference detection circuit, the purpose of which is to solve the problem that the existing fixed voltage difference detection circuit is greatly affected by the performance of the operational amplifier

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