Abstract: A power supply apparatus is provided. When an electronic apparatus coupled to the power supply is in standby mode, a microprocessor delivers a standby control pulse. A feedback circuit receiving the standby control pulse directs a pulse width modulation (PWM) controller to deliver a periodic intermittent signal. A switching device of the power supply apparatus reduces its switching action to reduce switching power lost upon receipt of activated periodic intermittent signal.

Abstract: A discharge lamp circuit for ignition time control and overvoltage protection. The discharge lamp circuit includes drive circuitry, a sensing circuit, a timing circuit and a start-up circuit. The drive circuitry produces a strike voltage for a discharge lamp and provides a lamp current through the discharge lamp. The sensing circuit is provided to detect the lamp current. During lamp start-up, the timing circuit will develop a threshold voltage at the end of a predetermined period if the discharge lamp has not been lit yet, thereby controlling an ignition time of the drive circuitry. The start-up circuit allows the drive circuitry to keep on applying the strike voltage for the ignition time in order to start the discharge lamp before the threshold voltage is developed. Once the sensing circuit detects the absence of the lamp current, the start-up circuit also causes the drive circuitry shutdown.

Abstract: A discharge lamp circuit for ignition time control and overvoltage protection. The discharge lamp circuit includes drive circuitry, a sensing circuit, a timing circuit and a start-up circuit. The drive circuitry produces a strike voltage for a discharge lamp and provides a lamp current through the discharge lamp. The sensing circuit is provided to detect the lamp current. During lamp start-up, the timing circuit will develop a threshold voltage at the end of a predetermined period if the discharge lamp has not been lit yet, thereby controlling an ignition time of the drive circuitry. The start-up circuit allows the drive circuitry to keep on applying the strike voltage for the ignition time in order to start the discharge lamp before the threshold voltage is developed. Once the sensing circuit detects the absence of the lamp current, the start-up circuit also causes the drive circuitry shutdown.