Patent ID: 8058821

Claim:
A light emitting apparatus comprising: a DC/DC converter including a switching transistor which allows step-up voltage operation to be controlled by performing on/off control for said switching transistor; a control circuit which performs on/off control for said switching transistor; a light emitting element driven by the output voltage of said DC/DC converter; and a microprocessor for controlling the light-emission state of said light emitting element, wherein said control circuit outputs a signal, which corresponds to the comparison signal, to said microprocessor so as to control whether or not light emission of said light emitting element is permitted, wherein said control circuit comprises: a hysteresis comparator which compares a detection voltage that corresponds to the output voltage of said DC/DC converter with two threshold voltages, and outputs a first-level comparison signal when the detection voltage is smaller than the lower threshold voltage, and outputs a second-level comparison signal when the detection voltage is greater than the lower threshold voltage; and a switching control unit which controls the switching operation of a switching element included in said DC/DC converter according to the comparison signal output from said hysteresis comparator, and instructs the switching element of said DC/DC comparator to perform switching operation during a period when the comparison signal is at the first level, and suspends the switching operation of the switching element of said DC/DC comparator during a period when the comparison signal is at the second level.