Other Parts Discussed in Thread: TIDA-01159, , SN6505B, UCC21540
Hi Team,
We have received this inquiry from our customer,
I am working on a synchronous boost converter project with the UCC21520 and TIDA-01159. The TIDA-01159 is a good demo driver board for a synchronous boost converter. However, it needs a special transformer which is not really attainable on the market, especially for our research lab. It made me to decide on the alternate plan on the driver card.
Hence, I tried to redesign a driver card using the UCC21520. For the VDDs at the gate side, I chose the isolated DC-DC converter other than the SN6505B + transformer. Other parts of the driver card design follow the same schematic and layout from the TIDA-01159 solution. My design works fine with a low output current ( Iout = ~2A). With the output current increasing, the gate signal became extremely abnormal. Especially the low-side gate signal, it becomes the multiple pulses other than the square wave.
I have a guess on this unexpected wave: the TIDA-01159 design used the SN6505B transformer driver. It has a nominal oscillating frequency at 420 kHz. But the isolated DC/DC converter I used in my design is only ~40 kHz. This frequency is very close to my boost converter's switching frequency which is exactly 50 kHz.
So, I wonder if my guess is correct or there is anything else that makes the driver card being unstable?
In the real board, I used jump wires passed the isolator U2 and 5V-5V converter PS3. And rest of the schematic is the design I applied to the boost converter test.
Regards,
Danilo