Other Parts Discussed in Thread: UCC28911, TPS63802,
We are looking to power a device with GSM modem which takes 2A peak current for 0.6 us every 4.6 ms whenever it is communicating (2-3s). The two power sources that we are considering for this application are a buck DC-DC converter such as UCC28911 (70V Vin and 5V out with 0.5A max) and a Li-Ion battery (4.2-3.2V, 3.8V nominal). These two sources are to be selected automatically with DC-DC as higher priority. The output of the PPM is given to a buck-boost TPS63802 to give a stable 4V for GSM module. This is as shown in block diagram below.
1. What is the Vout drooping characteristics of UCC28911 when it is overloaded?
2. Based on this drooping of Vout and battery power path being enabled, how would TPS2116 hysteresis react in the 0.6 ms 2A current draw duration?
3. Would the two power paths come to an equilibrium to share power to the buck-boost regulator?
4. Any other issues possible with this configuration?
Thanks and regards, Prithvi