| 摘要 |
A backlight driving circuit of an LCD(Liquid Crystal Display) is provided to control driving of backlight devices of various channels through one controller. A full bridge inverter(21) drives a main transformer(22) according as two switching units are alternatively driven by input gate pulses. First and second current equalization units(23A,23B) equally supply output currents of the main transformer to first to fourth LED(Light Emitting Diode) string units(26A,26B,26C,26D). First to fourth rectification units(24A,24B,24C,24D) rectifies sine waves outputted from the first and second current equalization units, and output the rectified sine wave in a half wave form. First to fourth filter units(25A,25B,25C,25D) filter ripple components of analog signals outputted from the first to fourth rectification units through a resonance frequency according to LC coupling, and output the filtered signal. The first to fourth LED string units are lighted by voltage outputted from the first to fourth filter units. An error voltage detection unit(27) compares an output current amount of the first LED string unit with a preset reference value, and outputs error voltage corresponding to the comparison result. An inverter driving control unit(28) compares the error voltage with output voltage of the full bridge inverter, and supplies a gate pulse of a duty ratio corresponding to the comparison result to a gate of the full bridge inverter. |
