| T O P I C R E V I E W |
| Hugh_Davenport |
Posted - 05/25/2022 : 22:47:16
Hi guys, I have couple of question :
1.) by providing isolation to control IC by pulse xformer, then how the control IC is powered at the first time it powered? since the auxiliary windings doesn't have a voltage at that initial time
2.) do we need more winding to drive the high side mosfet? since we know that the voltage at the gate should be Vth+Main DC Voltage
Thank you |
| 1 L A T E S T R E P L I E S (Newest First) |
| Damien68 |
Posted - 05/26/2022 : 11:22:20
to be conductive, a P-Channel mosfet must have a negative Vgs voltage and under than the Vgsth (Vgsth is a negative value for P-chanel mosfet). so voltage of the gate must rather be drawn towards the GND.
compared to an N-Channel, with P-chanel (high side) everything is reversed.
what is a xformer? to make a switching mode power supply, a pulse/signal transformer is not suitable. |
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