A control unit for a battery system includes a plurality of battery cells is provided. The control unit includes: an input node configured to receive a sensor signal indicative of a state of at least one of the plurality of battery cells; a microcontroller connected to the input node and configured to generate a first control signal based on the sensor signal; and a switch control circuit configured to control a power switch of the battery system by: receiving the sensor signal, the first control signal, and a fault signal indicative of an operational state of the microcontroller; generating a second control signal based on the sensor signal; and transmitting one of the first control signal and the second control signal to an output node of the control unit based on the received fault signal.