Abstract: A speaker control system includes a speaker; an audio amplifier electrically connected to the speaker and used for driving the speaker, the audio amplifier having a shutdown pin and a reference voltage input pin; a switch circuit, a first end of the switch circuit being electrically connected to the shutdown pin and a second end of the switch circuit being connected to the reference voltage input pin; and a processor electrically connected to the shutdown pin and the first end, when the processor outputs a first voltage signal, the audio amplifier being enabled and the reference voltage input pin being kept at a reference voltage, when the processor outputs a second voltage signal, the audio amplifier being disabled and the switch circuit switching the reference voltage input pin from the reference voltage to a low voltage level.

Abstract: A speaker control system includes a speaker; an audio amplifier electrically connected to the speaker and used for driving the speaker, the audio amplifier having a shutdown pin and a reference voltage input pin; a switch circuit, a first end of the switch circuit being electrically connected to the shutdown pin and a second end of the switch circuit being connected to the reference voltage input pin; and a processor electrically connected to the shutdown pin and the first end, when the processor outputs a first voltage signal, the audio amplifier being enabled and the reference voltage input pin being kept at a reference voltage, when the processor outputs a second voltage signal, the audio amplifier being disabled and the switch circuit switching the reference voltage input pin from the reference voltage to a low voltage level.

Abstract: A high efficiency audio amplifier is disclosed. The high efficiency audio amplifier includes an input end for receiving an input audio signal, an output end for outputting an output audio signal, a signal generator coupled to the input end for determining a frequency of an oscillating signal according to the distribution of the input audio signal and a reference voltage, and generating the oscillating signal accordingly, a waveform transformer coupled to the input end and the signal generator for comparing the input audio signal with the oscillating signal to generate a pulse width modulation (PWM) signal, a pre-drive circuit for generating a pre-drive signal according to the PWM signal, an output stage coupled to the pre-drive circuit for generating an output signal, and a filter coupled to the output stage for filtering the output signal to generate the output audio signal to the output end.

Abstract: A high efficiency audio amplifier is disclosed. The high efficiency audio amplifier includes an input end for receiving an input audio signal, an output end for outputting an output audio signal, a signal generator coupled to the input end for determining a frequency of an oscillating signal according to the distribution of the input audio signal and a reference voltage, and generating the oscillating signal accordingly, a waveform transformer coupled to the input end and the signal generator for comparing the input audio signal with the oscillating signal to generate a pulse width modulation (PWM) signal, a pre-drive circuit for generating a pre-drive signal according to the PWM signal, an output stage coupled to the pre-drive circuit for generating an output signal, and a filter coupled to the output stage for filtering the output signal to generate the output audio signal to the output end.

Abstract: A remote control setting method for an electronic device for setting a plurality of functions of the electronic device to be controlled by a plurality of keypads of a remote controller includes displaying an indication message according to a control signal, to indicate codes of a function of the plurality of functions and ask a user to press a keypad of the plurality of keypads, receiving a triggering signal generated by pressing the keypad, and storing codes including relation between the triggering signal and the function according to the control signal.

Abstract: A power supply device of a LCD display device comprising an AC rectifier; a square wave generator; an AC voltage converting module, coupled to the square wave generator, for providing an AC voltage to a backlight module of the LCD display device; and a plurality of DC voltage converting modules, for providing a plurality of voltage sources to a plurality of load circuits of the LCD display device, each DC voltage converting module comprising a control circuit for masking off the first oscillating signal, to generate a second oscillating signal according to a feedback signal of a corresponding load circuit; a voltage converting unit, coupled to the control circuit and the load circuit, for transforming the second oscillating signal into a voltage source for the load circuit; and a feedback control unit, coupled to the control circuit and the load circuit, for generating the feedback signal.