Other Parts Discussed in Thread: UCC24650,
Hello
I designed flyback power supply based on UCC28730D and UCC24650. Design is made in TI WEBENCH designer and prototype was made according to the design.
Everything is checked with SLUC579 UCC28730 design calculator tool.
When connected to mains power supply simply doesnt start.
Image below is from osciloscope and signals are:
yellow: mosfet gate
green: VDD
orange: CS pin
blue: VS pin
VDD voltage has kind of sawtooth form, with a time between max cca 1.3s.
Gate has burst of 6 pulses with f=25kHz
I made changes on:
- VDD capacitor
- Rcs resistor
- VS divider
Without any luck.
Attached is webench design, prototype is made by this design.
UCC28730 - WBENCH-Design-01.pdf
Can anyone help what can be wrong?
Sincerely
Ciril M.