Patent ID: 6650833
Filing Date: 2003-11-18
Classification: G03B

Abstract:
An exposure control drive apparatus comprising: a boosting circuit for boosting a voltage of a battery and outputting a boosted voltage; a capacitor charged by the boosted voltage; an actuator for driving an exposure control mechanism and having the capacitor as a power source; a detecting circuit for detecting a current flowing in the boosting circuit while the boosting circuit is boosting the voltage of the battery; and a control circuit for controlling operation of the boosting circuit in accordance with a magnitude of the detected current; wherein the boosting circuit has a transistor and a resistor through which an ON current of the transistor flows, the boosting circuit outputs the boosted voltage by a switching operation of the transistor, the resistor is connected to the transistor so that a voltage across the resistor is proportional to a magnitude of the ON current of the transistor, the magnitude of the ON current of the transistor corresponds to a current flowing from the battery, and the detecting circuit detects a voltage generated across the resistor in response to the ON current.