Abstract: A rectifier circuit includes: a switching circuit having an input end, an output terminal and a control end, wherein the input end of the switching circuit receives an input voltage; a control circuit electrically connected to the control end of the switching circuit, wherein, when a load current is smaller than a reference current, the rectifier circuit is situated at a light-load state and the control circuit reduces a switching frequency of the switching circuit; and a filtering circuit which is electrically connected between the output end of the switching circuit and an output terminal of the rectifier circuit, and includes at least one inductive component of which a current is formed by superposition of the load current and a ripple current, wherein, when the load current is smaller than the reference current, an inductance of the inductive component increases with the decrease of the load current.

Abstract: A power converting device including a pulse width modulation circuit, a switch unit, a power output unit and a voltage start unit is provided. The pulse width modulation circuit increases a start voltage in a soft start mode and is operated under the start voltage to generate a pulse width modulation signal. The switch unit is for receiving an input voltage, and forming a charge path and a discharge path alternately according to the pulse width modulation signal. The power output unit converts the input voltage to a core voltage in accordance with the charge path and the discharge path. The voltage start unit is for detecting the start voltage, and for transmitting a control signal to interrupt the formation of the discharge path when the start voltage is smaller than the core voltage.

Abstract: A voltage regulating circuit including an error signal generator, a comparator, a switch unit, a low-pass filter and a modulating unit is provided. The error signal generator respectively receives a reference voltage signal and a feedback signal, and generates an error signal. The comparator respectively receives the error signal and a comparing signal, and generates a pulse width modulation signal. The switch unit regulates an input voltage signal to generate an output voltage signal according the pulse width modulation signal. The low-pass filter filters out the high frequency of the output signal and produces the feedback signal. The modulating unit is coupled to the low-pass filter and the error signal generator for regulating a transient voltage of the output voltage signal.

Abstract: A power converting device including a pulse width modulation circuit, a switch unit, a power output unit and a voltage start unit is provided. The pulse width modulation circuit increases a start voltage in a soft start mode and is operated under the start voltage to generate a pulse width modulation signal. The switch unit is for receiving an input voltage, and forming a charge path and a discharge path alternately according to the pulse width modulation signal. The power output unit converts the input voltage to a core voltage in accordance with the charge path and the discharge path. The voltage start unit is for detecting the start voltage, and for transmitting a control signal to interrupt the formation of the discharge path when the start voltage is smaller than the core voltage.

Abstract: A feedback and comparison apparatus applicable to a DC-DC voltage converter is provided. The feedback and comparison apparatus includes a comparator and a voltage feedback circuit. The voltage feedback circuit includes a first voltage dividing component and a second voltage dividing component. The comparator compares a feedback voltage with a first reference voltage, and outputs a control signal to the DC-DC voltage converter according to the comparing result. One end of the first voltage dividing component is coupled to an output voltage output by the DC-DC voltage converter and the other end of the first voltage dividing component is coupled to one end of the second voltage dividing component, for providing the feedback voltage. The other end of the second voltage dividing component is coupled to a second reference voltage. The present invention is applicable to a situation that the output voltage is smaller than the reference voltage.

Abstract: A power factor correction circuit including a boost converter, a first capacitor, a first resistor, and a boost control unit is provided. The boost control unit includes a signal generator and a frequency controller. The boost converter transforms a rectified voltage to a correction voltage according to a pulse width modulation (PWM) signal. The first capacitor and the first resistor are coupled between an input terminal and a ground terminal of the boost converter. The boost control unit is adapted to generate the PWM signal, and adjust a duty cycle and a frequency of the PWM signal according to a current flowing through the first resistance, the rectified voltage and the correction voltage. Wherein, the signal generator is adapted to generate a ramp signal and adjust a slope of the ramp signal according to a charging current. The frequency controller adjusts the charging current according to the rectified voltage.

Abstract: A power supply and a bootstrap circuit thereof are provided. The bootstrap circuit includes a transistor, a first capacitor, a first impedance and a regulator circuit. The collector and the emitter of the transistor respectively serve as the input terminal and the output terminal of the bootstrap circuit. A terminal of the first capacitor is coupled to the collector of the transistor. A terminal of the first impedance is coupled to another terminal of the first capacitor. The regulator circuit is coupled to another terminal of the first impedance and the base of the transistor for clamping the voltage of the above-mentioned base at a predetermined voltage level.

Abstract: A power factor correction circuit including a boost converter, a first capacitor, a first resistor, and a boost control unit is provided. The boost control unit includes a signal generator and a frequency controller. The boost converter transforms a rectified voltage to a correction voltage according to a pulse width modulation (PWM) signal. The first capacitor and the first resistor are coupled between an input terminal and a ground terminal of the boost converter. The boost control unit is adapted to generate the PWM signal, and adjust a duty cycle and a frequency of the PWM signal according to a current flowing through the first resistance, the rectified voltage and the correction voltage. Wherein, the signal generator is adapted to generate a ramp signal and adjust a slope of the ramp signal according to a charging current. The frequency controller adjusts the charging current according to the rectified voltage.

Abstract: A linear step-down voltage regulator is provided. The linear step-down voltage regulator is grounded with a ground terminal. The ground terminal is electrically connected to a digital ground terminal of a switching circuit. The linear step-down voltage regulator includes a pass element, a voltage dividing resistor, an error amplifier, a metal oxide semiconductor (MOS) transistor, and a low-pass filter. The employment of the low-pass filter effectively adjusts and restricts the switching noise to pass therethrough, so as to decrease the output of the switching noise and thus eliminating the problems due to the noise.

Abstract: A voltage regulating circuit including an error signal generator, a comparator, a switch unit, a low-pass filter and a modulating unit is provided. The error signal generator respectively receives a reference voltage signal and a feedback signal, and generates an error signal. The comparator respectively receives the error signal and a comparing signal, and generates a pulse width modulation signal. The switch unit regulates an input voltage signal to generate an output voltage signal according the pulse width modulation signal. The low-pass filter filters out the high frequency of the output signal and produces the feedback signal. The modulating unit is coupled to the low-pass filter and the error signal generator for regulating a transient voltage of the output voltage signal.

Abstract: A feedback and comparison apparatus applicable to a DC-DC voltage converter is provided. The feedback and comparison apparatus includes a comparator and a voltage feedback circuit. The voltage feedback circuit includes a first voltage dividing component and a second voltage dividing component. The comparator compares a feedback voltage with a first reference voltage, and outputs a control signal to the DC-DC voltage converter according to the comparing result. One end of the first voltage dividing component is coupled to an output voltage output by the DC-DC voltage converter and the other end of the first voltage dividing component is coupled to one end of the second voltage dividing component, for providing the feedback voltage. The other end of the second voltage dividing component is coupled to a second reference voltage. The present invention is applicable to a situation that the output voltage is smaller than the reference voltage.

Abstract: A power measuring apparatus including a voltage transformer, a voltage-current measuring circuit, and an operation unit is provided. The voltage transformer converts an input voltage signal into an output voltage signal. The voltage-current measuring circuit includes an inductor, a first resistor, a first capacitor and a second capacitor. A first end of the first inductor herein receives the output voltage signal and a second end thereof generates a voltage feedback signal. The operation unit performs an operation on the voltage feedback signal and a terminal current signal between the first terminal and the second terminal of the first capacitor so as to calculate a power signal. In this way, the accuracy of thermal test is effectively increased by the presented invention.