TCA62723FMG Datasheet, PDF (5/13 Pages) Marktech Corporate – Three-Channel Constant-Current LED Driver

Output Current Dimming Control
1) Method of inputting analog voltage to terminal REXT
1. Precondition
Please set the range of the analog voltage input by 0 to 1.17V.
2. The maximum current is defined as αmA. (V_ADJ=0V)
α = 1.17×
R₁ + R_EXT
R₁×R_EXT
×460
3. The minimum current is defined as βmA. (V_ADJ=1.17V)
1
β =1.17× _REXT ×460
4. I_OUT can be set according to the next expression.
β-α
I_OUT = V_ADJ×
+α
1.17
(Example) Current Dimming from I_OUT=120mA to 60mA (Reference data)
V_IN
2.7V~5.5V
V_OUT
TCA62723FMG
V_ADJ
0~1.17V
TCA62723FMG
SHDN
CTL0
CTL1
CTL2
GND
VIN
OUT 0
OUT 1
OUT 2
REXT
R₁
R_EXT
Current Dimming Control (Reference data)
R1=24kΩ, REXT=9.1kΩ
140
120
100
80
60
40
20
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1
VADJ (V)
Note: These application examples are provided for reference only. Thorough evaluation and testing
should be implemented when designing your application's mass production design.
5
2010-06-10