| 摘要 |
PURPOSE:To prolong the operating time of battery by automatically deciding battery drive when a liquid crystal display is driven with a battery and reducing power of back light. CONSTITUTION:Power supply drive section 18 for a back light 5 comprises an AC/DC converter 12, a power supply decision unit 16, an inverter 14, and an inverter control section 17. When only a battery 15 is connected, the power supply decision unit 16 delivers a decision signal automatically to the inverter control section 17 which then reduces at least one of driving conditions of the inverter 14, i.e., duty, driving frequency, current value, thus reducing power of back light. Consequently, power consumption of the battery is reduced and the operating time of battery is prolonged. |
