A circuit for sensing an open-circuit lamp is provided. The circuit includes a reference voltage output unit, a voltage sensor, and a comparator. The reference voltage output unit provides a reference voltage. The voltage sensor detects a sensed voltage corresponding to a status of a lamp. The status of the lamp includes an open-circuit status and a closed-circuit status. The comparator compares the sensed voltage with the reference voltage and outputs a result indicating the status of the lamp.