Application of Schottky diodes in switching power supplies

Application of Schottky diodes in switching power supplies

The switching power supply is composed of high-frequency transformer, high-frequency capacitor, high-voltage high-power transistor, power rectifier diode, control IC and other main components. Secondary rectifier diode as an energy-consuming component, large loss, (about 30% of the power consumption), high heating, its selection of the power supply efficiency and reliability indicators is a very critical factor, which requires the rectifier diode in the high-speed and high-current working state should have the characteristics of small forward voltage drop VF, small reverse leakage IR, short recovery time Trr.

For low-voltage and high-current high-frequency rectification, Schottky diodes are the choice (at this time due to their low reverse withstand voltage), commonly used as ±5V, ±12V, ±15V rectifier output tubes. (For example, the +5V output of the computer power supply mostly adopts SR3040, and the +12V output adopts SR1660) coupled with the forward voltage drop VF of the Schottky diode and the junction temperature TJ present a negative temperature coefficient, so the switching power supply manufactured by it has high efficiency, low temperature rise, low noise and high reliability.