| 摘要 |
An LED backlight drive circuit comprises a plurality of LED lamp strings connected in parallel, a constant-current control circuit for controlling magnitudes of currents flowing through the LED lamp strings to be the same, and a plurality of constant-voltage units. The number of the constant-voltage units is the same as that of the LED lamp strings. The constant-voltage units are connected between the LED lamp strings and the constant-current control circuit respectively. Each constant-voltage units comprises an MOS transistor and a first operational amplifier. The MOS transistor has a drain connected to a cathode of a corresponding LED lamp strings, a gate connected to an output terminal of the first operational amplifier and a source connected to the constant-current control circuit. The first operational amplifier has a positive input terminal connected to a reference voltage and an inverting input terminal connected to the source of the MOS transistor.
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