Over-voltage and under-voltage protection circuit, electronic ballast and over-voltage and under-voltage detection method thereof

Abstract

The application discloses an over-voltage and under-voltage protection circuit comprising a diode (D2), a first capacitor (C4), a first resistor (R1) and a second resistor (R2). The diode (D2) detects a maximum voltage after rectification to realize peak value sampling; the first capacitor (C4) filters a ripple wave of an input voltage after the peak value sampling; the first resistor (R1) and the second resistor (R2) carry out voltage division on the input voltage after the ripple wave filtering and a division voltage is outputted to an input terminal of a microprocessor at the common terminal of the first resistor (R1) and the second resistor (R2). In addition, the application also discloses an electronic ballast and over-voltage and an under-voltage detection method thereof. According to the scheme, because of arrangement of the over-voltage and under-voltage protection circuit, the effect that automatic lighting can be realized without the need of manual processing after the power grid voltage is recovered can be realized; and the impact on surge currents of the power grid and the electronic ballast when the power-on situation is started again after the low-voltage recovery is realized can be reduced.

Description

technical field [0001] The application relates to the lighting field, in particular to an overvoltage and undervoltage protection circuit, an electronic ballast and an overvoltage and undervoltage detection method thereof. Background technique [0002] At present, in the lighting system, a fuse of appropriate specification is usually connected in series with the power input terminal of the electronic ballast. When the rated current of the fuse is reached, the fuse operates to protect the electronic ballast. [0003] see figure 1 , figure 1 It is a structural schematic diagram of an implementation mode of the lighting system in the prior art. [0004] The lighting system includes sequentially connected: a fuse 100, an electronic ballast 200, and a load 300, wherein the electronic ballast 200 includes: a rectification and filtering unit 210, a power factor correction (Power Factor Correction, PFC) unit 220, a switching power supply unit 230 , a microcontroller unit 240 , a...

AI Technical Summary

Problems solved by technology

[0010] 1. After the fuse is activated, manual processing is required;

[0011] 2. After the fuse operates, when the grid voltage returns to normal, the electronic ballast cannot work normally;

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