7W Digital Video Broadcasting – Circuit Design for Terrestrial (DVB-T) Power Supplies

7W-1.544MBE-T

Summary:

Way of working

The TOPSwitch-GX flyback power supply has an input voltage of 230 VAC ± 15% and an output of 4 channels with a power of 7 W. The chip uses a low-cost DIP-8 package TOP242PN, eliminating the need for an external heat sink. Resistor R7 sets the current limit of the TOP242PN to 78% of the nominal value just past the value required to reach the low voltage full load. This feature allows the transformer to be designed in a more continuous state, achieving better efficiency and cross regulation without requiring a larger core size.

design feature

• Meets CISPR22B/EN55022B conducted EMI limits when the output ground is connected to ground
• No-load power consumption <0.5 W
• 132 kHz operating frequency and configurable current limit allows the use of a small, low cost EF16 transformer for 7 W output
• Small component count, PCB size 80 × 30 × 16 mm
• Integrated soft-start feature reduces component stress during startup

See the PDF document for details (click on the PDF file to download)