| 摘要 |
PROBLEM TO BE SOLVED: To provide a load drive device capable of minimizing a loss of a constant current source even in the case where the number of columns of loads is increased.SOLUTION: A load drive device 1 includes: a converter 3 for supplying power to a plurality of LED columns 2-1, 2-2, ..., 2-n; a constant current source 4 connected in series with the LED columns 2-1, 2-2, ..., 2-n and incorporating switch elements Q1-1, Q1-2, ..., Q1-n, respectively; and a microcomputer 6 which generates a monitor value M[0] by using source voltages S1-1, S1-2, ..., S1-n of the switch elements Q1-1, Q1-2, ..., Q1-n corresponding to currents Iout-1, Iout-2, ..., Iout-n flowing to the LED columns 2-1, 2-2, ..., 2-n and detects a change point of the monitor value M[0] in the case where an output voltage Vout from the converter 3 is changed, thereby controlling the output voltage Vout while defining the change point as a target value of the monitor value M[0]. |
