| 摘要 |
<p>Provided is an LED drive circuit whereby direct driving with an AC input is possible, flicker occurrences are alleviated, and low power consumption is achieved. An LED drive circuit which drives an LED unit comprising a plurality of LEDs which are connected in series comprises: a rectifier which rectifies AC input; a constant current circuit, further comprising an op amp and a plurality of drive transistors which are connected via a partial resistor to an output row of the op amp; and resistors as voltage detectors, which are respectively inserted between emitters of the plurality of drive transistors. The LED drive circuit is further configured such that one end of the rectifier on the output side is connected to the input side of the LED unit, and one end of the output side of each of the plurality of transistors are connected to connection points of different LED row numbers in the LED unit, whereby the plurality of transistors selectively drive the LED unit according to the AC input voltage, and also the current which flows through the selectively driven LED unit fluctuates according to the AC input voltage.</p> |
