| 摘要 |
<p>An LED backlight source drive circuit, an LED backlight source and a liquid crystal display. The LED backlight source drive circuit comprises: a direct-current voltage input (11) used for inputting a direct-current voltage; a booster circuit (12) used for boosting the direct-current voltage input by the direct-current voltage input (11) and outputting the boosted direct-current voltage; an LED string (13) comprising a plurality of LEDs connected in series and a first resistor (R1), the LED string (13) being used for receiving the boosted direct-current voltage from the booster circuit (12), wherein the direct-current voltage when the LED string (13) normally emits light is less than or equal to the boosted direct-current voltage output by the booster circuit (12); and a constant current drive circuit (14) used for outputting a level signal to the booster circuit (12) according to the voltages of both ends of the first resistor (R1) and a voltage of a triangular wave signal. By making the frequency of the drive signal to change back and forth in the vicinity of a centre frequency, the frequency spectrum energy of the drive signal is dispersed, the situation where the peak value of the drive signal exceeds the standard is difficult to occur in the process of an EMl test, and the EMI test result is improved.</p> |
