i'm currently designing a device which uses GSM module. which works on 12V and if the main supply is not there, it will run on battery. right now i'm facing a problem in power supply circuit. i'm using a BLE module which works on 3.3V, the BLE module controls the GSM module switching it On and Off. the issue is the BLE module reboots every once in a while. when the BLE module reboots, the GSM module also reboots. i believe this occurs because i'm using the same supply for both GSM module and also the 3.3V regulator. it would be very helpful if some you can give me some suggestions. i have attached image of the power supply circuit power supply

  • \$\begingroup\$ .7V seems like a very narrow margin for your MIC, what is the LDO voltage for that device? How much bulk capacitance do you have on the 3.3v side? \$\endgroup\$ – Ron Beyer Jan 3 at 17:04
  • \$\begingroup\$ LDO for MIC5504-3.3v is 300mV at 600mA. i have connected 10uF close to regulator and 0.1uF close to BLE Module. i'm driving 4 LEDs,1 BLE Module and 1 Active GPS antenna with 3.3V \$\endgroup\$ – Paul Canon Jan 4 at 8:16
  • \$\begingroup\$ The LDO before the TP4056 seems like a bad idea. You're dropping from 12V to 5V, you dont need an LDO. Going from 4 to 3.3V, the MIC5504 supplies upto 300mA of current. That does not seem sufficient for powering the GSM Modules \$\endgroup\$ – Adi Jan 5 at 14:46
  • \$\begingroup\$ MIC5504 is not supplying the GSM Modules. GSM Module is powered through LM2596 if 12V is present and if it is absent then it is powered through Battery. MIC5504 is used supply power for BLE Module and 2 LED \$\endgroup\$ – Paul Canon Jan 6 at 18:29

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