Abstract: An improved structure of a power supply is based on an emitter-switched PWM controller and special structure transformer. An improved structure of a power supply mainly describes two primary side regulation (here called “PSR”) solutions based on above PWM controller that is used in charger/adapter solutions. These PSR solutions employ a transformer with special winding structure. It is required that adjacent reeling between its input bias winding and output winding, in which the input side of the transformer is connected to an AC input and an emitter-switched PWM controller, and the output side of the transformer is connected to a rectified diode. The present invention further provides low cost PSR solutions with higher system reliability, better line/load regulation, and short circuit characteristic.

Abstract: An improved structure of a power supply mainly discloses three PSR solutions based on a PWM controller that is used in charger/adapter solutions, in which a low voltage PNP transistor and zener diode composes error signal amplification circuit, or ?431 typed shunt regulators senses and amplifies the input error signal caused by the changes of load or line voltage, or one diode and two resistors form sense circuit of error signal. These PSR solutions employ a transformer, in which the input side of the transformer is connected to an AC input and PWM controller, and the output side of the transformer is connected to a rectified diode. The present invention further provides low cost PSR solutions with higher system reliability, better line/load regulation, and short circuit characteristic.

Abstract: The present invention discloses a transformer used in a charger circuit, in which the input side of the transformer is connected to an AC input and PWM control circuit of the charger circuit, the output side of the transformer is connected to a constant current and/or constant voltage control circuit of the charger circuit. The AC input, PWM control circuit, the constant current and/or constant voltage control circuit are coupled through an optical coupling element, wherein the transformer includes a main output winding and an auxiliary output winding, and the auxiliary output winding is used to supply power for the optical coupling element and the constant current and/or constant voltage control circuit. The present invention further provides a high performance charger circuit adopting the transformer described above for improving electromagnetic compatibility, conversion efficiency and short circuit characteristic.

Abstract: A PWM controller includes a short circuit mode circuit which has input ends connecting simultaneously to a power supply input end and an output end of an output driving circuit, and an oscillator which has a temperature compensation circuit that includes a medium value multi-transistor resistor of a negative temperature coefficient and a well resistor of a positive temperature coefficient. The invention also provides a charger circuit which includes the PWM controller set forth above and a constant voltage/current control circuit coupling with the PWM controller through a transformer. A system adopting the PWM controller circuit and charger circuit of the invention does not need a voltage stabilization diode now equipped in many conventional designs. The invention provides an improved short circuit protection and eliminates low frequency harmonic waves.

Abstract: The present invention discloses a transformer used in a charger circuit, in which the input side of the transformer is connected to an AC input and PWM control circuit of the charger circuit, the output side of the transformer is connected to a constant current and/or constant voltage control circuit of the charger circuit. The AC input, PWM control circuit, the constant current and/or constant voltage control circuit are coupled through an optical coupling element, wherein the transformer includes a main output winding and an auxiliary output winding, and the auxiliary output winding is used to supply power for the optical coupling element and the constant current and/or constant voltage control circuit. The present invention further provides a high performance charger circuit adopting the transformer described above for improving electromagnetic compatibility, conversion efficiency and short circuit characteristic.

Abstract: A PWM controller includes a short circuit mode circuit which has input ends connecting simultaneously to a power supply input end and an output end of an output driving circuit, and an oscillator which has a temperature compensation circuit that includes a medium value multi-transistor resistor of a negative temperature coefficient and a well resistor of a positive temperature coefficient. The invention also provides a charger circuit which includes the PWM controller set forth above and a constant voltage/current control circuit coupling with the PWM controller through a transformer. A system adopted the PWM controller circuit and charger circuit of the invention does not need a voltage stabilization diode now equipped in many conventional designs. The invention provides an improved short circuit protection, eliminates low frequency harmonic waves, packages power transistors and the controller into a single TO-94, increases the cluster density and enhances the reliability of small packages.