Other Parts Discussed in Thread: UCC27519
Hi,
I am developing an insulated DC-DC converter using UCC256303 QR controller.
Two UCC27519 are inserted between the UCC256303 high side gate and low side gate wires and the MOSFET, as shown below, to improve the driver current. The UCC27519 drivers aren’t powered by the controller but by an external source. Can it generate problems?
In the schematic the components vales are for a 390Vin 160Vout QR power supply but for the first test (to avoid to burn components!) we are working from 70Vin and 25Vout, changing consequentially the components. The following screen is in this condition.
As you can see in the below screen the high side MOSFET switches correctly whereas the lower MOSFET practically doesn’t switch; why? It switches only at power-up to charge, correctly, the high side boost cap; in yellow the high side gate referred to GND, in green the low side gate, and in blue the current in the transformer primary winding.
Thank you for your attention!
Best regards
Lorenzo Dellacorna
Mobile: 0039 3356214871
Email: lorenzo.dellacorna@l-f.it
