Abstract: The image sticking erasing circuit includes a detection circuit and a switching circuit connected to the detection circuit. The detection circuit is for use in detecting a first voltage signal, which closely follows the variation of the voltage source, and a reference voltage, which loosely follows the variation of the voltage source. When the detection circuit determines that the first voltage signal is lower than a first threshold value, the switching circuit switches the gate of a driving transistor to a second voltage signal, which loosely follows the voltage source. When the detection circuit determines that the reference voltage signal is lower than a second threshold value, the switching circuit switches the gate of a driving transistor to a low voltage state.

Abstract: A PWM (pulse width modulation) boost system includes a boost circuit, a voltage dividing circuit, a comparator, a PWM circuit, a pre-oscillator, and a current limit circuit. A start-up method of the PWM boost system includes (1) providing an error voltage; (2) generating a PWM signal according to the error voltage; (3) controlling a switch in a boost circuit with the PWM signal, so as to control an inductor current flowing through a boost inductor in the boost circuit; (4) charging a capacitor in the boost circuit with the inductor current, wherein charges stored in the capacitor define a DC output voltage; and (5) providing a feedback voltage according to the DC output voltage to adjust the error voltage.

Abstract: A PWM (pulse width modulation) boost system includes a boost circuit, a voltage dividing circuit, a comparator, a PWM circuit, a pre-oscillator, and a current limit circuit. A start-up method of the PWM boost system includes (1) providing an error voltage; (2) generating a PWM signal according to the error voltage; (3) controlling a switch in a boost circuit with the PWM signal, so as to control an inductor current flowing through a boost inductor in the boost circuit; (4) charging a capacitor in the boost circuit with the inductor current, wherein charges stored in the capacitor define a DC output voltage; and (5) providing a feedback voltage according to the DC output voltage to adjust the error voltage.