Hi,
I am looking at using the TPS40422 and i have 2 questions:
1 - What is the recommended voltage if i want to supply BPEXT with a external voltage source? Is a external voltage source recommened? I am planning to use 650KHz for the switching frequency and my mosfets have a Qghigh of 5.6nC and Qglow of 20nC. On page 18 of the data sheet it looks like the power dissapated by the TPS40422 if i am using the internal BP6 regulator would be (12V-6.5V) x 650KHz*(5.6nC + 20nC) which will give me about 91mV. Is this too much power for the TPS40422 to dissapate? I cannot seem to find the thermal data for this part on the datasheet.
2 - From the datasheet, it looks like the SMBus interface on this part needs a pull up to 3.3V. I only have 1.8V on my system, can i use the BP3 rail to supply the 3.3V pull up for the SMBus interface? I am not planning to use the SMBus interface, only for debugging so it will only be used with a external dongle.
Thanks
