| 摘要 |
A brightness control circuit in an LCD inverter is provided to stably control duty against noises or in-rush currents by having a capacitor and a varistor of high capacity between a brightness control voltage input terminal and a controller. A transformer(T) changes input voltage and outputs to an LCD panel. An FET(Field Effect Transistor,Q1) switches operation of the transformer. A controller(100) variably outputs a duty of a pulse width modulation signal supplied to the FET according to the level of brightness control voltage(Vbr) supplied from the outside. A capacitor(C1) is installed in parallel between a brightness control voltage input terminal and the controller for removing noises included in the brightness control voltage. A varistor(VT1) is installed between the brightness control voltage input terminal and the controller for removing static electricity components included in the brightness control voltage. |
