L16B45AG-R24-R Datasheet, PDF (8/12 Pages) Unisonic Technologies – Schmitt trigger input

L16B45A
Preliminary
CMOS IC
 APPLICATION INFORMATION
Constant Current
To design LED displays, UTC L16B45A provides nearly no variations in current from channel
to channel and from IC to IC. This can be achieved by:
1) The maximum current variation between channels is less than ±2.5%, and that between ICs is less than ±3%.
2) In addition, the current characteristic of output stage is flat and users can refer to the figure as shown below.
The output current can be kept constant regardless of the variations of LED forward voltages (V_F). This performs as
a perfection of load regulation.
Adjusting Output Current
The output current of each channel (I_OUT) is set by an external resistor, R_ext. The relationship between I_OUT and R_ext
is shown in the following figure.
Also, the output current can be calculated from the equation:
V_R-EXT=1.24V; I_OUT=V_R-EXT*( 1/Rext )x15; R_ext=(V_R-EXT/I_OUT)x15
where R_ext is the resistance of the external resistor connected to R-EXT terminal and V_R-EXT is the voltage of R-EXT
terminal. The magnitude of current (as a function of R_ext) is around 25mA at 744Ω and 10mA at 1860Ω.
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
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QW-R102-071.a