ADT6610 Datasheet, PDF (16/21 Pages) ADTech – 3-channel constant current LED driver that has a wide range of output currents

LOAD SUPPLY VOLTAGE( VLED )
The design of VLED should fulfill two targets
1. Less Power consumption and heat.
2. Sufficiently headroom for the LED and driver IC to operate in the constant current region.
The power dissipation in the driver is calculated by the equation.
PD = VDSA x IOUTA + VDSB x IOUTB + VDSC x IOUTC + VCC x ICC
By the spec, the max VCC = 18V, max ICC = 8mA => 144mW.
If VDSA = VDSB = VDSC = 1V, IOUTA=IOUTB=IOUTC=20mA.
PD is about 204mW.
If VDSA,VDSB,VDSC are over 1v then the power dissipation is more than 204mW.
This means, If VDSA,VDSB,VDSC drops too much voltage on the driver, it is necessary
to set external resistors( RA,RB,RC) to reduce the by V_R.
ADT6610
VLED
•
•
V_R R_A
R_B
R_C
Vf
VDSA ^VDSB
VDSC
IOUTA IOUTB
IOUTC
ADT6610
Aug. 25. 2011
* This specifications are subject to be changed without notice
16/21
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