| 摘要 |
A dimming mode selecting circuit ( 25 ) includes a switch circuit ( 251 ) and a compensation circuit ( 252 ). The switch circuit selects a first input voltage or a second input voltage according to an input signal. The compensation circuit connects to the switch circuit, for compensating voltage loss of the first input voltage or the second input voltage in the dimming mode selecting circuit, and outputting a first compensated input voltage or a second compensated input voltage according to the switch circuit. In the invention, the dimming mode selecting circuit combines a hysteresis circuit ( 250 ) with the compensation circuit, to make the input signal stably and the output signal reliably. The structure of the circuit is simple.
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