The LED illumination circuit and the lighting equipment null 1 which uses

摘要

PPROBLEM TO BE SOLVED: To homogenize light output from numerous LEDs, and to suppress power consumption for the homogenization in an LED lighting circuit used for an illumination fixture or the like. PSOLUTION: By detecting a current from a DC-DC converter 35 to an LED module 32 by a current detecting resistor R2, comparing it with the reference voltage Vref from the reference voltage source 38 by a comparing circuit 37, and controlling the DC-DC converter 35 in response to the comparison result, a control circuit 36 collectively constant current controls a current to flow into the LED module 32. Furthermore, in the respective LED load circuits U1 to U3 constituting the LED module 32, control elements Q1 to Q3 constituting a current mirror circuit are installed in series, homogenize the light output, and achieve low power consumption by making its reference current by the LED load circuit U1. Moreover, when a disconnection detecting circuit 42 detects disconnection of the LED load circuit U1, an impedance circuit 42 is inserted and light-out of other LED load circuits U2, U3 due to disappearance of the reference current is prevented. PCOPYRIGHT: (C)2008,JPO&INPIT