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The PROG pin of the LTC4054 Lithium charger
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VanitarNordic:
I have a question regarding the PROG pin of this charger chip.

Pulling down the PROG pin with a proper resistor defines the charge current of the battery, but the question is that it defines the maximum current or the resistor value should be adjusted dependent the connected battery capacity?

for example, a 1.33K resistor should deliver around 900mA current maximum. then what happens if we connect a 300mA battery? it will get charged at 2C or 900mA or automatically it will get charged at a proper current?
Rerouter:
It will be charged at that 900mA while in the constant current phase of charging,

you need really smart chargers to normalize to 1C charge rate for all batteries, I've played with the Idea, using the mAh / mV scaling to adjust the rate of charge to get the most out of a battery that had to last 7 years, In the end my application allowed me to just lock it at 0.4C, and the datasheet was predicting that would suit its deterioration.
VanitarNordic:

--- Quote from: Rerouter on November 15, 2018, 09:04:23 am ---It will be charged at that 900mA while in the constant current phase of charging,

you need really smart chargers to normalize to 1C charge rate for all batteries, I've played with the Idea, using the mAh / mV scaling to adjust the rate of charge to get the most out of a battery that had to last 7 years, In the end my application allowed me to just lock it at 0.4C, and the datasheet was predicting that would suit its deterioration.

--- End quote ---

I am thinking of a method to tune this pin electronically rather than mechanically changing the pull-down resistor values
Rerouter:
Simplest way, use a few resistor values with mosfets to switch them in and out, by combining different ones you can get intermediate values.

Seeing as I cannot find a datasheet for your given chip, I cannot say if a DAC approach would be suitable.
VanitarNordic:

--- Quote from: Rerouter on November 15, 2018, 10:36:46 am ---Simplest way, use a few resistor values with mosfets to switch them in and out, by combining different ones you can get intermediate values.

Seeing as I cannot find a datasheet for your given chip, I cannot say if a DAC approach would be suitable.

--- End quote ---

The chip is LTC4054. I had made a typo mistake.
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