The BQ25150 has three programmable ADC comparators that may be used to monitor any of the ADC channels. The comparators will send an interrupt whenever the ADC measurement the comparator is monitoring crosses the thresholds programmed in their respective ADC_ALARM_COMPx registers in the direction indicated by the x_ADCALARM_ABOVE bit. The comparators are only 12 bit compared to the 16 bits reported by the ADC, so only the first 12 bits of the ADC measurements are used to make the comparison. Note that the interrupts are masked by default and must be unmasked by the host to use this function.

When configuring the ADC comparators, it is recommended to first disable the comparator through the ADCCTRLx registers and allow the ADC to complete a measurement on the desired channel before enabling or reconfiguring the comparator by setting the ADC_COMPx_2:0 bits to the desired channel. This would prevent the comparator from sending an interrupt based on an outdated ADC reading when the comparator is enabled or reconfigured, especially in battery only operation where the ADC is not continuously performing measurements in all the channels.

ADC_COMP1 may be used to monitor critical conditions that need continuous and autonomous monitoring after a condition is detected. This comparator will force continuous ADC readings when the condition the ADC comparator is detecting is true regardless of ADC_READ_RATE setting until the condition is no longer present. Note that the continuous ADC reading will cause an increase in quiescent current, so it is recommended to disable ADC_COMP1 by setting the ADC_COMP1 bits to 000 if this function is not to be used .