| 摘要 |
<p>An LED backlight source comprises a boosting circuit (210) used for boosting and outputting the input direct-current voltage (Vin); a plurality of LED strings (220) connected in parallel, wherein each LED string (220) comprises a plurality of LEDs connected in series and receives the direct-current voltage output from the boosting circuit (210); a plurality of constant-current driving circuits (230) connected in parallel and used for controlling the magnitude of current flowing through each LED string (220), wherein each constant-current driving circuit (230) controls the magnitude of current of at least one LED string (220), and a first constant-current driving circuit (231) controls the on-off of the boosting circuit (210); a low-voltage protection control circuit (240) outputting low-voltage protection voltage to each constant-current driving circuit (230), each constant-current driving circuit (230) determining, according to the received low-voltage protection voltage, whether to stop operating, wherein the low-voltage protection voltage output to the first constant-current driving circuit (231) is less than the low-voltage protection voltage output to the other constant-current driving circuits. The backlight source can turn off or on multiple LED strings (220) simultaneously to improve the optical grade of the LED backlight source. A liquid-crystal display device using the LED backlight source is also disclosed.</p> |
