A circuit system is disclosed. The system comprises a master circuitry, at least one slave circuitry which has a battery sensor for checking battery status of a power supply battery and a shut down mechanism for controlled shut down upon detection of low battery by the battery sensor, and a battery sensor manipulation circuit controlled by the master circuitry. The battery sensor manipulation circuit is arranged to manipulate sensed battery status for the battery sensor of at least one of the at least one slave circuitry to force the controlled shut down of the at least one of the at least one slave circuitry upon provision of a shut down control signal from the master circuitry. A method of controlling power management of such a circuit system is also disclosed.