The BOP and Limiter features utilize the information from the internal VBAT tracking and adjusts the output power accordingly to the configured setting. Since VBAT normally depletes after prolonged usage, it is necessary to implement such mitigating features. They serve as protections to system level collapse that may impact resources outside of the audio amplifier. Limiter can be enabled to adjust the output power above the BOP threshold. Typically, users would like to adjust the output power linearly with decrease in VBAT before it reaches the critical voltage threshold. BOP gives the user more control over how the amplifier can response in case of under-voltage. When VBAT drops bellows the threshold, there are two ways of which BOP can respond. Either attacks till max attenuation, or mute and shutdown the device. Attack Rate, Attack Step Size, Hold Time, Max Attenuation, Release Rate, and Release Step size are different parameters user can define to specify the manner in which BOP response. For more details each parameter, please refer to Battery Voltage Tracking Limiter and Brown-Out Protection and the Datasheet.

Figure 1-3 Brown-Out Protection (BOP).