20W 5V Evaluation Board with Quasi-Resonant CoolSET™ ICE2QR1765Z
Switching mode power supply evaluation board designed in a quasi resonant flyback converter topology using ICE2QR1765Z Quasi-resonant CoolSET™.With the CoolMOS™ integrated in this IC, it greatly simplifies the design and layout of the PCB. Due to valley switching, the turn on voltage is reduced and this offers higher conversion efficiency comparing to hard-switching flyback converter. With the DCM mode control, the reverse recovery problem of secondary rectify diode is relieved. And for its natural frequency jittering with line voltage, the EMI performance is better. Infineon’s digital frequency reduction technology enables a quasi-resonant operation till very low load. As a result, the system efficiency, over the entire load range, is significantly improved compared to conventional free running quasi resonant converter implemented with only maximum switching frequency limitation at light load. In addition, numerous adjustable protection functions have been implemented in ICE2QR1765Z to protect the system and customize the IC for the chosen application. In case of failure modes, like open control-loop/over load, output overvoltage, and transformer short winding, the device switches into Auto Restart Mode or Latch-off Mode. By means of the cycle-by-cycle peak current limitation plus foldback point correction, the dimension of the transformer and current rating of the secondary diode can both be optimized.Thus, a cost effective solution can be easily achieved.
- 650V avalanche rugged CoolMOS™ with built in depletion startup cell
- Quasi-resonant operation
- Digital frequency reduction with decreasing load
- Cycle-by-cycle peak current limitation with foldback point correction
- Built-in digital soft-start
- Direct current sensing with internal Leading Edge Blanking Time
- VCC under voltage protection: IC stop operation, recover with softstart
- VCC over voltage protection: IC stop operation, recover with softstart
- Openloop/Overload protection: Auto Restart
- Output overvoltage protection: Latch-off with adjustable threshold
- Short-winding protection: Latch-off
- Over temperature protection: Autorestart
The target application of ICE2QR1765Z are for set-top box, portable game controller, DVD player, netbook adapter and auxiliary power supply for LCD TV, etc.