Shall i use Doubler circuit using MCP1640 with single AA battery power supply for nRF52832?

[vishal]

Hello Sir,

I have developed small and compact product using nRF52832 Soc. Due to size limitation and device is portable. I have attached snap shot of power supply circuit as per this circuit this switch is use only for ON device and after some period device will completely shut down not in sleep mode it achieve by MCP1640 EN pin = 0.

This doubler IC EN pin is control in nordic program by define on GPIO pin when momentary switch press EN high and nRF52832 chip ON and then quickly logic high is provide to MCP1640 EN pin in program. After some specified period it will automatically go to shut down by EN= GND. This logic we are using for power save to improve battery life. For controlling enable pin i am using n Channel Power MOSFET with very low VGSth. So sir please give me suggestion can i use this type of power source.

[MartinBL]

Hi,

1. Why do you need the MOSFET? To stop current flowing through the resistor divider when the MCP1640 is off? The datasheet claims that there is a "true" load disconnect when the device is disabled so I can't see why this would be a problem.
2. When you push the momentary switch the voltage on the GPIO will be 0.8-1.6V (Vin). Then, when the MCP1640 has started, it will supply the nRF52's VDD with 3.3V (Vout). When the nRF52 has started it will set the GPIO to high, in other words 3.3V (Vdd). This will probably all happen before the user has managed to release the switch and at a brief moment in time (probably a few 100s of milliseconds) the nRF52 will try to set the GPIO to Vdd while the switch forces it to Vin. This can damage the nRF52, but a resistor between the switch and the GPIO would probably make it a little safer.

[vishal]

Hi Martin, We have decide to use doubler circuit in my application, but as off now i am not use the above circuit for power source, My application is very simple simply collect sensor data and send to android mobile apps using BLE nRF52832. We have decide to use circuit for powering to Nordic using MCP1640 doubler IC as per given in their datasheet Herepage no 2 so please tell me is it right for long term application. My device is portable and communicate via BLE. In this given circuit is it need to add any other extra components add in my circuit e.g. reverse voltage protection or any other for power supply to nRF52832 chip. Please sir check this data sheet and if i use this circuit is it any extra current energy consumption. My device consume current upto 3-6mA. let me know for your valuable suggestion and any other thing. Thanks.........