| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an LED power supply which can limit a load current so as not to exceed the maximum allowable current even if a load is connected suddenly from the open state of an LED load. <P>SOLUTION: The power supply device of an LED connected in parallel with an output capacitor C<SB POS="POST">3</SB>charged by a power supply power comprises a current limit resistor R<SB POS="POST">3</SB>connected in series with the LED, a switching element Q<SB POS="POST">2</SB>connecting the both ends of the resistor, a resistor R<SB POS="POST">2</SB>for load current detection, and a control circuit 4 of the switching element. The control circuit 4 has switching means 68 for switching the switching element, current presence determining means 64 for monitoring the load current value and determining that the LED is brought into connection state based on the presence of the load current, and current comparison means 66 for comparing a load current value I immediately after connection of the LED with a reference value I<SB POS="POST">0</SB>and determining the timing of the load current attenuating to the reference value. The switching means 68 switches the switching element to on state in that timing. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
