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ADP5062 Recharge happening too often

Question asked by GEDavid on Jun 14, 2017
Latest reply on Jun 15, 2017 by Leo_Liu

While I was testing and debugging for ADP5062 Overcharging, I noticed that on some units, the recharge cycles are occurring much more frequently than they should. I've attached logs from 2 units showing the battery voltage and charger state once the battery is charged - one (EOC-A) runs a recharge cycle after 22 hours, after a voltage drop of around 61mV, and one (EOC-B) runs a recharge cycle after around 30 minutes, after a voltage drop of only 26mV. Both units were configured identically (read during initial CC period of charging cycle):

 

ParameterValueComments
Manufacturer and model ID0x19
Silicon revision0x05
VINx pin settings0x06500mA
Termination settings0x8F
Charging current settings0x1F400mA/80mA
Voltage thresholds0x1A
Timer settings0x18
Functional Settings 10x05
Functional Settings 20x07
Interrupt enable0x00
Interrupt active0x00
Charger Status 10x62CC
Charger Status 20xE4Thermistor ok, Sense > Weak
Charger Status Pin0x00
Charger Sys En Pin0x00

 

The batteries being charged are 1900mAh Li-Ion cells, and the capacity measure is read from a gas gauge, which is forced to 100% at the end of a charge cycle (that's the step you can see at 5:45 in EOC-B). I have other logs which show the same pattern of increasingly-regular recharge cycles as EOC-B, but repeated multiple times.

 

The charger chip doesn't seem to be waiting for the 80mV recharge voltage threshold before starting a recharge cycle. This doesn't seem to match the behaviour specified in the datasheet - what could cause this?

 

David

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