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BQ25504: When VSTOR is shorted to VBAT, VBAT_OK has no output signal

Part Number: BQ25504

Hi, I found several problems when using BQ25504, forgive my English expression.

1. I don't need battery overdischarge detection, ie VBAT_UV is not programmed and that pin is left floating. During charging, once the battery voltage exceeds the programmed VBAT_OK value, the VBAT_OK pin outputs a high level, which is sent to the enable pin of buck module. This all works fine. Since I don't need undervoltage monitoring, I short VSTOR to VBAT. When the solar power is disconnected, the VBAT_OK pin will never output a high level (VBAT=VSTOR=3V>VBAT_OK=2.5V). Is this normal situation? If I want to have the BQ25504 as a battery gauge without solar input, and judge by the output of the VBAT_OK pin. What should I do? Any help would be greatly appreciated.

  • Hi,

    We do not recommend to short VSTOR to VBAT. The device will not work properly with VSTOR short to VBAT.

    VBAT_OK only reports if the battery voltage exceeds or drop below the VBAT_OK threshold you programmed to. It will not report charge done. What type of gauging function are you designing for and what level of accuracy you need? Typically you will need a battery gauge IC to have an accurate gauging function.