LED driver plays an important role in unleashing many advantages of LED, such as high efficiency, long life-time. A constant current fly-back LED driver based on TOP222 is designed in this paper, and the transformer of the constant current power supply and the constant current feedback circuit are deeply researched. The experiment shows that, the output current of the LED driver is 1A, the output power is 10W, the power supply works in constant voltage mode within the low load situation. The result shows that the driver featured with good stability, constant-current characteristic, and high efficiency, is capable for driving LED.

Ozone is widely used in industry or even home nowadays, the power supply with frequency and duty cycle easy-adjust feature is very important to ozone production. An intelligent power supply based on MCU system is introduced in this paper, Intelligent Power Module (IPM) is used to compose a full bridge inverter circuit, and PWM technology is used to drive the IGBTs integrated in the IPM. The frequency and duty of the output AC can be adjusted manually or by auto tracking, and can be displayed synchronously on the LCD. The result shows that the power supply can adjust and display the output frequency and duty cycle by keyboard manually or by auto tracking based on detected current, and ozonizer have a higher efficiency with adjustable output frequency and duty cycle.

A high amplitude, fast rising time, and high isolating strength trigger signal is needed for triggering spark gap switch. A high voltage power supply scheme was verified by means of simulation in this paper. Proper parameters of power supply circuit were selected according to the simulation result. Finally, a pulsed power supply was developed. The experimental results show that a negative pulse with 25 kV isolating strength and 15 kV amplitude can be generated by the power supply, and this generated negative pulse can meet the demand of triggering spark gap switch.