12-Channels Pre-programmable Constant Current LED Driver

Version:A.006

Page 15

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DM621

Driver Output Current

Constant-current value of each output channel is set by an external resistor, which is

connected between the REXT pin and GND. Varying the resistor value can adjust the

current scale ranging from 5mA to 90mA. The reference voltage (Vrext) of REXT

terminal is approximately 1.23V. The constant current formula is

100

*

)

(

Re

23

.

1

100

*

)

(

Re

)

(

)

(

Ω

=

Ω

=

k

xt

V

k

xt

V

Vrext

mA

IOUT

Figure 14.

IOUT V.S. VOUT curve

Figure 15.

IOUT V.S. Rext curve