We want to design the power supply for a LTE-Modem application. It should be a very low power application, witch would work for several years (ideally 10 years minimum). So we need to use lithium LI-SOCL2 batteries, because unfortunately all other rechargeable batterys or solar backup aren't possible.
The Lithium Primary Cells (for ex. LS33600) have the problem that they could only deliver 200mA (400mA pulse). On the other hand the modem needs short pulses up to 1,5A.
Our design components are:
- 2 Lithium Primary Cells in serie (7,2V) with 200mA continuous current
- 1 low power buck-boost converter (7,2V to 3,4V) with the needed capacitors and coils
- 1 LTE-Modem with a supply voltage from 3,4V to 4,3V with short pulses up to 1,5A and a maximum required peak-to-peak output ripple voltage of ideally 50mV.
- 1 MSP430 for the other functions on the PCB
Could you give us advises for the layout to use here. Witch power converter to use, in combination with two Lithium 3,6V Batteries in Serie. The Modem needs to have short pulses of 1,5A, but the batteries could only give 200mA continuous and 400mA pic. If it is possible, and it seems so, we would avoid the use of supercapacitors, and use normal electrolytic capacitor instead (longer lifetime).
Thanks for your Help.
Example of the power requirements of a similar modem
