This document describes a 60W adapter application using the L6668 fixed frequency current mode PWM controller and the STSR30 smart driver for flyback synchronous rectification. This chipset guarantees low no-load consumption and high efficiency, making it easy to comply with world-wide mandatory and voluntary energy saving requirements.
This document describes a 60W AC-DC adapter application using the L6668 fixed frequency current mode PWM controller and the STSR30 smart driver for flyback synchronous rectification. The chipset guarantees low no-load consumption and high efficiency, making it easy to comply with world-wide mandatory and voluntary energy saving requirements.
The demo board, EVALSTSR30-60W, implements a flyback topology with synchronous rectification to improve efficiency. It operates in both Continuous and Discontinuous conduction modes depending on input voltage and load. The document details the circuit description, electrical performance, functional checks, thermal measurements, bill of materials, PCB layout, and transformer specifications.
| Input Voltage | 88 ~ 264 VRMS |
|---|---|
| Input Frequency | 45 ~ 66 Hz |
| Output Voltage | 12V DC ± 2% |
| No-Load Consumption | Pin below 0.3W |
| Safety Standard | EN60065 |
| EMI Compliance | EN55022 - Class B |
| Switching Frequency | 68-kHz |
| Transformer Core | ETD34 ferrite |
| Reflected Voltage | 95V |
The STSR30 is a smart driver for flyback synchronous rectification that substitutes the output diode with a power MOSFET to reduce conduction losses.
The converter works in both Continuous and Discontinuous conduction mode depending on the input voltage and the output load.