ShahbazAli
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sim300 vbat
I am building a module with SIM300 (supports both SIM300C and SIM300D). This contains micrcontroller and some other circuitry also besides SIM300. I intend to use SIM300 charging circuit to charge Li-ion battery. But I need to use the backup battery for all of the circuit and not only SIM300. VCHG is 5V coming from an LM317T, whereas VBAT is 4.2V coming from MC34063A. VBAT is VCC for all the circuit. So that when the 12V supply to regulator is gone, battery takes over the whole circuit.
Will this work? How will SIM300 gauge the charge on the battery when VBAT is coming from power supply?
Thanks.
I am building a module with SIM300 (supports both SIM300C and SIM300D). This contains micrcontroller and some other circuitry also besides SIM300. I intend to use SIM300 charging circuit to charge Li-ion battery. But I need to use the backup battery for all of the circuit and not only SIM300. VCHG is 5V coming from an LM317T, whereas VBAT is 4.2V coming from MC34063A. VBAT is VCC for all the circuit. So that when the 12V supply to regulator is gone, battery takes over the whole circuit.
Will this work? How will SIM300 gauge the charge on the battery when VBAT is coming from power supply?
Thanks.