charge circuit best option ?

[cybero]

Hello, I am designing a PCB with nRF51822 and I would like to know which is the best option to add battery charging to my PCB.

I think the most common options are these 2:

1- Charge IC which includes a DC-DC. The DC-DC is to get down the voltage to 1.8V to supply the MCU.

2- Charge IC + a diode to get down the voltage to <= 3.6V

What I'm looking for is energy efficiency.

[Øyvind Karlsen]

Hi,

You are probably going to be better off using a DC/DC IC than a diode if energy efficiency is your main concern. However if you are using a battery, why not consider a battery that gives less than 3.6V so that you can use the down-converters in the nRF51?

For the charge IC, energy efficiency is not as critical(you are always connected to some large power reservoir when charging), you will probably be fine with most charge ICs on the market.

Best regards,

Øyvind

[cybero]

Because I'm going to use a Li-ion battery (3.7V, Model: 18650) and a Li-ion battery are 4.2V when fully charged.

[Øyvind Karlsen]

In that case, look around for high efficiency DC/DC solutions, the one you linked is about 75-85% effective(from the datasheet), there are more efficient solutions on the market, but you might be fine with this module as it will save you BOM.

[cybero]

Can you recommend me a better charge IC with DC/DC please?

[Øyvind Karlsen]

For combined DCDC and charger ICs the module from TI that you linked seems to be the most effective I can find without thorough research. However there are more effective standalone DCDC converters. You also need to figure out what your expected current draws are to make sense out of the datasheets.