DISCONNECTION DETECTION CIRCUIT

PROBLEM TO BE SOLVED: To provide a configuration capable of turning current to be made to flow to a load when detecting disconnection to an appropriate current value suited to an impedance of the load, and reliably preventing a malfunction of the load when detecting the disconnection and erroneous detection of a disconnection state and a non-disconnection state.SOLUTION: A disconnection detection circuit 1 comprises: an impedance detection circuit for detecting the impedance of a load 3; a current level determination circuit for determining a current level corresponding to the detected load impedance so as to lower the current level to be set as the load impedance detected by the impedance detection circuit is larger; an energizing circuit for supplying current to the load 3 according to the current level determined by the current level determination circuit; and a disconnection determination circuit for determining whether or not the load 3 is in the disconnection state on the basis of a state of voltage applied to the load 3 when the current according to the load impedance is supplied to the load 3 by the energizing circuit.