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Bias Winding Reduces No-Load Input Power |
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| 2019年7月8日 | |
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A bias winding reduces the no-load consumption to < 30 mW
- IC supply current is no longer provided from the DRAIN pin - Select resistor value to provide the supply current (IS1&IS2) specified in TinySwitch-4 datasheet - Internal clamp limits maximum BP/M pin voltage 
Reduces No-Load Input Power RBP1 ≈ ( V1 – V2) / IS1 ≈ ( V1 – VSHUNT) / IS1 - V1 voltage is measured from no load condition RBP2 ≈ ( V1 – V2) / IS2 ≈ ( V1 – VSHUNT) / IS2 - V1 voltage is measured from no load condition - Normally the switching frequency is below 132kHz - This means the IS2 can compromise with switching frequency here Choose the smaller one resistor value to meet both request - Calculate with maximum value to cover all device tolerance 
This's a application note for TinySwitch & innoswitch family |