| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To ensure a sensor operating voltage at the time of turning-off of an LED without increasing the power consumption at the time of turning-on of the LED, in an LED power-supply device with a sensor. <P>SOLUTION: An LED power-supply device with a sensor includes: a DC/DC conversion section 3; a load section 4 receiving an output of the DC/DC conversion section 3; a control section 6 controlling the output of the DC/DC conversion section 3; a secondary power-supply section 5 generating a voltage according to an output current of the DC/DC conversion section 3; and a sensor section 8 in which a voltage generated by the secondary power-supply section 5 is supplied as an operating voltage and which determines lighting-on or lighting-off of an LED 40 according to a detection state of a sensor circuit 80. The load section 4 is composed of a series circuit of the LED 40 and a first switch element and a series circuit of a bleeder resistor and a second switch element, brings the first switch into conduction and the second switch out of conduction when the sensor section 8 determines turning-on of the LED 40, and brings the second switch element into conduction and brings the first switch element out of conduction when the sensor section 8 determines turning-off of the LED. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
