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

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

vishal — Fri, 29 Dec 2017 13:39:10 GMT

OK... Thanks.

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

MartinBL — Fri, 29 Dec 2017 13:21:25 GMT

Let us continue here: devzone.nordicsemi.com/.../

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

vishal — Tue, 26 Dec 2017 08:48:52 GMT

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.........

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

MartinBL — Wed, 22 Nov 2017 10:23:01 GMT

The resistor value needs to be large enough to limit the current drawn from the GPIO and protect the GPIO protection diodes inside the SoC. A value between 1k-10k should be fine. If you add the resistor the system will not draw more current. If anything, it will reduce the current since you won't get the short circuit between Vdd and Vin.

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

vishal — Wed, 22 Nov 2017 08:29:02 GMT

Ya write, nRF52 is restart and it is ON upto specific time define in program after that it again restart. If i use MOSFET i will shut down completely and when i press momentary switch it will ON. Can you suggest me resistor value.

Thanks..

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

MartinBL — Wed, 22 Nov 2017 08:16:38 GMT

Are you saying that the nRF52 is restarting after you have disabled the MCP? Shouldn't you have a clean discharge curve on Vout after you disable the MCP?

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

vishal — Tue, 21 Nov 2017 14:06:22 GMT

MOSFET is use because when i shut down MCP1640 in nordic program mean GPIO GND = EN pin at that time vout of MCP1640 volatge is slowly decrease at the same time nRF52832 again ON because it operate upto 1.7V. Thats why for avoid again ON nordic we are using MOSFET, Can you suggest me alternate solution for the same. How to stop current flowing the resistor divider when the MCP1640 is off? For safer nRF52832 chip which value resistor i use between the switch and the GPIO. If i add resistor nordic chip is safe should i use in my final design. If i add resistor is it increase any extra current consumption or not.

Thanks.........

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

MartinBL — Tue, 21 Nov 2017 13:38:10 GMT

Hi,

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.
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.