CV/CC flyback charger circuit design using TNY276PN

1206 red anti-stick

Photocoupler

Summary:

The CV/CC charger circuit is a flyback converter designed using the TNY276PN (U1). The four source pins are on the side of the 8-pin package, simplifying the layout of the PCB copper foil for heat dissipation. In addition, the value of C3 is determined to select the current limit point of U1 reduction. These two factors allow the U1 to deliver full load power in a sealed enclosure with an external ambient temperature of 40 °C. In applications where heat is not critical, TNY275PN can be used, operating at standard current limit (C3 = 0.1μF) to reduce costs, and others do not need to be changed.

design feature

• Simple design, low cost, and low component count
• Low no-load power consumption: no-load power consumption <260 mW at 265 VAC input
• Efficiency >65% at 90 VAC input
• Meet CEC/Energy Star requirements for efficiency of on-load operation mode (66.8% vs 62.6% requirement)
• Compact design, small size, low cost EE16 core
• EMI margin >15 dBμV compared to EN55022B conducted EMI limits
• No Y capacitor: power frequency leakage current <10 μA

4.5W, 5.7V CV/CC charger circuit diagram using TNY276PN

See the uploading documentation for details (click to download)