UCC25600: Can I use it without external 12V supply (for start)?

ADAM JANICKI

Part Number: UCC25600
Other Parts Discussed in Thread: UCC2801,

Not much space I have.

Like for my old converters (Ucc2801 or similar):

Just high value resistor to 400V - charging Vcc cap, then for few ms this Vcc cap provides energy to UCC25600, then bias winding kicks in..

Possible?

over 6 years ago

0 Hong Huang over 6 years ago

TI__Guru 73955 points

UCC25600 needs up to 1.5mA for soft start compared to 0.1mA in UCC2801 case. The power losses will be high if using a resistor to start up this device. Unless you accept this high power losses, the resistor startup approach is not recommended.

0 ADAM JANICKI over 6 years ago in reply to Hong Huang

Prodigy 20 points

thx for quick answer.

2mA and 400V = about 1W

now bad, 2W resistor will do, or some other trick which will disconnect this resistor after AUX voltage is generated.

thx again

Power management

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UCC25600: Can I use it without external 12V supply (for start)?