Abstract: A low visual noise, jitterized pulse width modulation brightness control circuit is provided. The circuit uses a brightness control signal generating unit to receive a brightness adjusting signal and to generate a brightness control signal in response to the brightness adjusting signal. The brightness control pulse signal has a duty cycle or frequency varying in a predetermined range. An inverter coupled to the brightness control signal generating unit drives the fluorescent lamp in response to the brightness control pulse signal to reduce the visual interference due to the adjustment of the current beam density.

Abstract: A pulse width modulator and a loading system thereof are disclosed. The pulse width modulator comprises an amplitude-adjustable triangle-wave generator, an error signal generator and a pulse signal generator. The triangle-wave generator is adapted to perform an amplitude operation according to the reference voltage and the feedback voltage for generating an amplitude-adjustable triangle wave according to a variation of the feedback voltage. The error signal generator is adapted to perform an error operation according to the feedback voltage and the reference voltage for outputting an error signal. The pulse signal generator is adapted to receive and compare the error signal and the amplitude-adjustable triangle wave for outputting a pulse controlling signal for the loading system.

Abstract: A LCD lighting control system comprises a lamp, a self-oscillation inverter, a sampling-frequency generating circuit, a detecting-feedback circuit, a modulator and a buck circuit. The LCD lighting control system samples at the preset sampling location in the self-oscillation inverter or the preset sampling location between the self-oscillation inverter and the buck circuit to synchronize the control signal from the modulator and the self-oscillation frequency, to suppress high-voltage ripple effect, and to enhance stability of the system.

Abstract: A low visual noise, jitterized pulse width modulation brightness control circuit is provided. The circuit uses a brightness control signal generating unit to receive a brightness adjusting signal and to generate a brightness control signal in response to the brightness adjusting signal. The brightness control pulse signal has a duty cycle or frequency varying in a predetermined range. An inverter coupled to the brightness control signal generating unit drives the fluorescent lamp in response to the brightness control pulse signal to reduce the visual interference due to the adjustment of the current beam density.

Abstract: A low visual noise, jitterized pulse width modulation brightness control circuit is provided. The circuit uses a brightness control signal generating unit to receive a brightness adjusting signal and to generate a brightness control signal in response to the brightness adjusting signal. The brightness control pulse signal has a duty cycle or frequency varying in a predetermined range. An inverter coupled to the brightness control signal generating unit drives the fluorescent lamp in response to the brightness control pulse signal to reduce the visual interference due to the adjustment of the current beam density.

Abstract: A pulse width modulation (PWM) illumination control circuit with low visual noise for driving a light-emitting diode (LED) is provided. An illumination control pulse-generating unit is used to generate an illumination control pulse signal according to an illumination-adjusting signal. The duty cycle or frequency of the illumination control pulse signal varies within a predetermined scope for controlling a DC/DC converter to drive the light-emitting diode so that overall visual noise level of the PWM illumination control circuit is improved.

Abstract: A pulse width modulator and a loading system thereof are disclosed. The pulse width modulator comprises an amplitude-adjustable triangle-wave generator, an error signal generator and a pulse signal generator. The triangle-wave generator is adapted to perform an amplitude operation according to the reference voltage and the feedback voltage for generating an amplitude-adjustable triangle wave according to a variation of the feedback voltage. The error signal generator is adapted to perform an error operation according to the feedback voltage and the reference voltage for outputting an error signal. The pulse signal generator is adapted to receive and compare the error signal and the amplitude-adjustable triangle wave for outputting a pulse controlling signal for the loading system.

Abstract: A low visual noise, jitterized pulse width modulation brightness control circuit is provided. The circuit uses a brightness control signal generating unit to receive a brightness adjusting signal and to generate a brightness control signal in response to the brightness adjusting signal. The brightness control pulse signal has a duty cycle or frequency varying in a predetermined range. An inverter coupled to the brightness control signal generating unit drives the fluorescent lamp in response to the brightness control pulse signal to reduce the visual interference due to the adjustment of the current beam density.