4W/5V switching voltage regulator circuit diagram

 　　The picture shows a 4W/5V switching voltage regulator circuit . This circuit uses the T0P100 device of the TOPSwitch series . The TOPSwitch (Three TerminalOfflinePWMSwtich) series device is a three-terminal PWM switching power supply. Its characteristic is that the PWM controller and MOSFET power switch tube in the high-frequency switching power supply are integrated on the same chip. It is a A two-in-one device. This greatly simplifies circuit design, improves reliability, and makes power supply design simpler and faster. TOPSwitch devices come in a variety of packaging forms. They are packaged in DiP-8 and SMD-8. The four middle pins are empty. They can be connected to the copper foil of the printed circuit board to transfer the heat generated by the chip directly to the printed circuit board. There is no need to install a separate heat sink on the circuit board, which saves costs.