To uniformize an optical output from a large number of LED and to suppress power consumption for uniformizing it, in a LED lighting circuit used for a luminaire.
A current flowing from a DC-DC converter 35 to a LED module 32 is detected by a current detecting resistance R2, it is compared with a reference voltage value Vref form a reference voltage source 38 in a comparison circuit 37, a control circuit 36 controls the DC-DC converter 35 in response to the comparison result, and constant current control of the currents flowing to the LED module 32 is collectively carried out. In addition, control elements Q1-Q3 composing a current mirror circuit are provided in series in respective load circuits U1-U3 composing the LED module 32, the circuit (U1) having the highest sum of the switching on voltages of the LED is used as a reference, a diode structure is given to the corresponding control element (Q1), the values of currents applied to the control elements (Q2, Q3) of the remaining circuits (U2, U3) are conjointly set, and the LED load circuits U1-U3 are thereby well-balanced between them.
SHIOHAMA EIJI
| JP2006165471A | 2006-06-22 | |||
| JP2005142137A | 2005-06-02 | |||
| JP2005174725A | 2005-06-30 | |||
| JP2006202855A | 2006-08-03 | |||
| JPH0664841A | 1994-03-08 | |||
| JP2005190899A | 2005-07-14 |
| WO2006001352A1 | 2006-01-05 |
Takao Ito
Jiro Higuchi