Abstract: A voltage converter includes a voltage converting circuit, a pulse width modulation (PWM) controller, a feedback circuit, an adjusting circuit, and a measuring circuit. The voltage converting circuit converts an input voltage to a low output voltage for a load. The PWM controller includes a comparator and a triangular-wave oscillator. The comparator is connected to the voltage converting circuit and outputs a PWM voltage to the voltage converting circuit. The triangular-wave oscillator is connected to an inverting terminal of the comparator, and outputs a sawtooth-wave voltage to the comparator. The feedback circuit is connected to a non-inverting terminal of the comparator and outputs a feedback voltage to the comparator. The measuring circuit measures current output from the voltage converting circuit and controls the adjusting circuit to provide a pull-up voltage to the triangular-wave oscillator when the measured current decreases, thereby increasing the duty ratio of the PWM voltage.

Abstract: An overcurrent protection circuit includes an input terminal, an output terminal, a first resistor, a second resistor, a current source and a comparator. The first resistor, the second resistor and the current source are connected in series in that order between the input terminal and ground. A first input pin of the comparator is connected to a first node between the second resistor and the current source. A second input pin of the comparator is connected to the input terminal An output pin of the comparator is connected to the output terminal. When current input through the input terminal is greater than a predetermined value, the overcurrent protection circuit outputs a signal indicative of the current being greater than the predetermined value through the output terminal.

Abstract: A standby power supply circuit includes a pulse width modulation controller, first to fourth metal-oxide-semiconductor field effect transistors (MOSFETs), and an inductor. A gate of the first MOSFET and a gate of the second MOSFET are connected to a first and a second general purpose terminals of a power management chip, respectively. A drain of the first MOSFET is connected to a source of the third MOSFET. A gate of the fourth MOSFET is connected to a lower gate terminal of the controller. A phase terminal of the controller is grounded via the inductor and a capacitor in series. The drain of the second MOSFET is connected to a node between the inductor and the capacitor via a resistor.

Abstract: An exemplary power supply system for a CPU, includes a power managing module and a computer system module. The power managing module supplies a current operating voltage to the CPU. The computer system module electrically communicates with the power managing module and the CPU, obtains a next operating voltage required in a next program carried out by the CPU, and controls the power managing module to adjust the current operating voltage to be the next operating voltage before the next program is carried out.

Abstract: A voltage converter includes a voltage converting circuit, a pulse width modulation (PWM) controller, a feedback circuit, an adjusting circuit, and a measuring circuit. The voltage converting circuit converts an input voltage to a low output voltage for a load. The PWM controller includes a comparator and a triangular-wave oscillator. The comparator is connected to the voltage converting circuit and outputs a PWM voltage to the voltage converting circuit. The triangular-wave oscillator is connected to an inverting terminal of the comparator, and outputs a sawtooth-wave voltage to the comparator. The feedback circuit is connected to a non-inverting terminal of the comparator and outputs a feedback voltage to the comparator. The measuring circuit measures current output from the voltage converting circuit and controls the adjusting circuit to provide a pull-up voltage to the triangular-wave oscillator when the measured current decreases, thereby increasing the duty ratio of the PWM voltage.

Abstract: A standby power supply circuit includes a pulse width modulation controller, first to fourth metal-oxide-semiconductor field effect transistors (MOSFETs), and an inductor. A gate of the first MOSFET and a gate of the second MOSFET are connected to a first and a second general purpose terminals of a power management chip, respectively. A drain of the first MOSFET is connected to a source of the third MOSFET. A gate of the fourth MOSFET is connected to a lower gate terminal of the controller. A phase terminal of the controller is grounded via the inductor and a capacitor in series. The drain of the second MOSFET is connected to a node between the inductor and the capacitor via a resistor.