UCC35706P

The UCC35706P is a Universal Off-Line Secondary Regulator with high- and low-side remote sensing suitable for use in either dual secondary flyback or forward and flyback converters. It has predictable, low cost protection from short circuits, feed-forward voltage and current limiting, and provides adjustable current limiting.

Application Field

This power management device provides high performance and cost-effective solutions for small and medium AC/DC offline power supplies. It is mainly used for powering a range of domestic appliances such as washing machines, refrigerators and air conditioners.

Working Principle

The UCC35706P uses a two-transistor topology to perform its power conversion. It supports two different secondary winding turns ratios: 3:1 and 1:1. The first winding of the transformer is connected to the rectified AC input, and the second winding is connected to an output filter capacitor and the load. The output voltage is set by comparing the output voltage on the drain and source pins. With the 3:1 winding ratio, the output voltage is held to a constant voltage, while for the 1:1 winding ratio, it is regulated by the control loop.

The UCC35706P provides a constant current limit, adjustable through the closed loop. When the voltage at the drain and source pins go over the set point, the device enters into latch mode where the primary winding current is limited to the set current limit. The device also provides a feed forward voltage capability, where the output voltage is provided directly to the primary winding, resulting in a more stable output voltage.

The output voltage is continuously monitored by the drain and source pins and any changes in the output voltage due to changes in load current or other external influences can be detected immediately. The on-board oscillator keeps the output current constant by switching the power MOSFET on and off.

Conclusion

The UCC35706P from Infineon is a versatile and efficient power management device for small and medium AC/DC offline power supplies. It offers a cost-effective and comprehensive solution for addressing the needs of the market. Its intelligent design and robust protection features make it well-suited for a wide range of applications.