Low voltage detection circuit

Abstract

The embodiment of the invention provides a low voltage detection circuit. The low voltage detection circuit is connected with the input voltage end and the grounding end of input voltage. A voltage dividing resistor array, a switch K, a level comparator circuit and an output circuit are also arranged between the input voltage end and the grounding end. Resistors R1, R2 and R3 are connected in the voltage dividing resistor array in turn. PMOS transistors PM1, PM2 and PM3, NPN triodes Q1 and Q2, resistors R4, R5, R6 and R8 and an NMOS transistor NM1 are arranged in the level comparator circuit. A PMOS transistor PM4 and a resistor R7 are arranged in the output circuit. Whether the power supply enters the normal working voltage area is detected by controlling the working state of the triodes. The complex degree of the circuit is simplified under the premise of accurately detecting the low voltage level.

Description

technical field [0001] The invention belongs to the field of integrated circuits, in particular to low-voltage detection circuits. Background technique [0002] ICs used in industrial control, transportation, and even some consumer areas often require a wide range of operating voltages. For example, the position control IC used for brushless motors may reach a maximum of 40V, and the minimum needs to be 3V to work normally. When the voltage is lower than the rated voltage, the circuit will not work normally, and it will cause serious consequences such as failure to start normally or affecting the stability of the circuit. [0003] The existing circuits are basically generated by generating a reference voltage and comparing it with the voltage to be detected. In this way, the entire circuit structure will be relatively complicated; and for the generation of the reference voltage, the power supply must reach the normal working voltage. If the voltage to be detected is also u...

AI Technical Summary

Problems solved by technology

In this way, the entire circuit structure will be relatively complicated; and for the generation of the reference voltage, the power supply must reach the normal working voltage. If the voltage to be detected is also used as the power supply, the voltage point lower than the normal working voltage will not be detected; or provide Another power supply, which virtually increases the complexity of the circuit and some inoperability

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