| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an LED drive circuit which can drive to a high luminance by suppressing heating of the LED with a small size. <P>SOLUTION: In the LED drive circuit (1), the LED (5) is connected between the positive output side of an AC power supply rectifying circuit (3) and an FET (7), and a drive current detecting resistor (R2) is connected between the FET and the negative output side. An FET control circuit (11) applies a control voltage to a gate terminal (7g) to turn on the FET, receives the drive current detection of the detecting resistor, lowers the control voltage to less than the threshold voltage of the FET, and expedites discharging of the charge charged in the FET. The on-state of the FET is maintained by the discharge of the charge, and the drive current continuously flow during its period. This realizes the increase of the luminance of the LED. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
