Hello E2E Experts,
Good day.
The project I'm working on is designing a Wireless Power Transfer System. I was wondering if the UCC27611 would be a suitable choice to drive an EPC2019 or EPC2207. It will be driven at either 13.56 MHz or 27.12 MHz (this one is a bit of a stretch). Ideally, the LMG1020 would be used as it is a much more attractive option; however, it is not available.
Thank you in advance for your help.
Regards,
CSC
Hello,
Thank you for reaching out on E2E!
Yes UCC27611 should be a suitable device if LMG1020 is not available.
The maximum frequency that the device can operate at is based on the maximum power dissipation of the device with respect to the ambient temperature. Below I will link a maximum frequency calculator that can be used to calculate the maximum frequency that a device can operate at based on its datasheet as well as the FET's, along with the ambient temperature that the device will be operating in. It works with both Half-bridge and low-side drivers.
Maximum operating frequency calculator: https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1025075/faq-ucc27282-how-to-calculate-the-max-operating-frequency-of-a-gate-driver
Another way to calculate if a device can handle a certain frequency is by using the power dissipation formula. The formulas I will use are referenced from section 8.2.2.4 of the UCC27611 datasheet. For UCC27611 power dissipation is equal to Psw * Pdc. In the case of UCC27611 Pdc is negligible.
Psw = Qg * fsw * Vref * 2 (assuming no external gate resistors for a worst case calculation)
Psw = 2.4nC (typical gate charge EPC2019) * 13.56MHz * 5V * 2
Psw = 2.410^-9 * 13.56 * 10^6 * 5 *2 = 0.325 W
Pdiss = 0.325W + 0
Pdiss = 0.325W
Based on Junction-to-Ambient Thermal Resistance RΘJA of 80.3 C/W, we can calculate the thermal increase in the device by multiplying it with the the calculated power dissipation.
T = 80.3 C/W * 0.325 W = 26.1 C
We can take this temperature and add it to the ambient temperature and get our Tj.
Tj = 26.1 C + 25 C (Assumed ambient temperature) = 51.1 C
This Tj is within the maximum Tj of 140C which means that it can operate at that given frequency.
I hope this helps!
Thank you,
Donaldo
