Abstract: The invention provides an output control apparatus for adjusting the output level of a pulse width modulation (PWM) signal by changing the amplitude level of the output PWM signal. The output control apparatus comprises a control signal generator, a digital-to-analog converter (DAC), and an output circuit. The control signal generator generates a digital control signal. The DAC outputs a predetermined level according to the digital control signal. The output circuit with a negative feedback loop receives the PWM signal and receives the predetermined level by the negative feedback loop. While the PWM signal is logic number “0”, the negative feedback loop is not switched on, so as to control the level of the PWM signal at a base level. While the PWM signal is logic number “1”, the negative feedback loop is switched on, so as to control the level of the PWM signal at the predetermined level.

Abstract: The invention provides an output control apparatus for adjusting the output level of a pulse width modulation (PWM) signal by changing the amplitude level of the output PWM signal. The output control apparatus comprises a control signal generator, a digital-to-analog converter (DAC), and an output circuit. The control signal generator generates a digital control signal. The DAC outputs a predetermined level according to the digital control signal. The output circuit with a negative feedback loop receives the PWM signal and receives the predetermined level by the negative feedback loop. While the PWM signal is logic number “0”, the negative feedback loop is not switched on, so as to control the level of the PWM signal at a base level. While the PWM signal is logic number “1”, the negative feedback loop is switched on, so as to control the level of the PWM signal at the predetermined level.