BQ24074: Big electrolytic capacitor on OUT pin

Tomasz,

Electrolytic capacitors typically have high ESR. This ESR and high capacitance form a low frequency small signal zero which could cause the feedback loops to be unstable. TI has not tested the charger with a high ESR electrolytic capacitors. You can quickly test the CV loop stability by removing the battery and forcing a fast transient load (1A/us) on OUT and measuring the voltage ringing at OUT on an oscilloscope. If there is a lot of ringing at your highest or lowest expected ambient temperature, then there is a chance of instability. You can test the CC loop stability by replacing the battery or simulated battery, with charge current at you maximum and starting with the voltage lower than SYSMIN and then increase above SYSMIN, monitoring the battery charge current for ringing during the transition above and below SYSMIN. I also recommend performing this test at high and low temperature.