My company is using the identical battery charger circuit used in your evaluation board BQ24610EVM. In testing the charger circuit we found that if the battery is removed, yet a resistor simulating the thermistor that is meant to detect battery heat is left in the circuit, and if the DC input voltage at terminal ACPWR falls below that of the programmed battery voltage, the resulting SYS output voltage oscillates around 20Hz and passes only half of the DC input voltage. Probing the circuit shows us that the BATDRV signal out of the charger periodically (20Hz rate) attempts to connect the battery that isn’t there to the SYS output until the attempt fails.
Is there a simple way to prevent the BQ24610 from attempting to drive the battery MOSFET and test for the presence of a battery for the combination of the following three events?
- Battery is removed
- A resistor simulating the thermistor is present in the circuit
- The DC input voltage is below the expected battery voltage
