Exposure control drive apparatus

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 value, so that the boosting circuit is prevented from boosting the battery voltage when the detected current exceeds a predetermined level and permitted to boost the battery voltage when the detected current is below the predetermined level, to thereby prevent the current flowing from the battery from exceeding a maximum level;
• 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.

An exposure control drive apparatus for a comprising:

• a boosting circuit for boosting a voltage of a battery;
• a detecting circuit for detecting a voltage in the boosting circuit while the boosting circuit is boosting the voltage of the battery;
• and a control circuit for shutting off the boosting circuit when the detected voltage or current exceeds a predetermined value;
• 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.