BD1754HFN_12 Datasheet, PDF (12/19 Pages) Rohm – Constant Current LED Driver with 64 Dimming Steps for up to 4 LEDs

BD1754HFN
Datasheet
(7) Circuit example when connecting the two LEDs to each of the channels in series
Power Supply2=6.2~7V
Power Supply1
VIN
(Ex.)
On the assumption that Vf is 3 V
L1
L2
L3
L4
The voltage value of L* pin must
be VIN-1.4 V at the maximum
when the LED is powered ON.
(Maximum rating = 7.0 V)
0.1 µF
EN
UPIC
6
Current
DAC
GND
ISET
1 20k Ω
(When ILED-max =32mA)
Figure 22. Circuit example when connecting the two LEDs to each of the channels in series
This figure shows a circuit example when making 8 (2 x 4) LEDs available by connecting two LEDs to each of the
channels in series. In this example, when Vf is set to approx. 3 V in order to ensure the voltage to L1 through L4 pins, it
is necessary to apply a voltage of 6.2 V (3 V x 2 LED’s in series + 0.2 V of the minimum voltage value of the driver pin)
or higher to the LED anode pin as its power supply voltage. Pay attention that the voltage should not exceed the 7.0-V
maximum rating of the L1 through L4 pins. Determine the resistance value with which the LED current value is
maximized and then connect such resistor between the ISET and the GND pins. The power ON/OFF and the
brightness of the LEDs are controlled through the EN pin in accordance with the UPIC format.
www.rohm.com
© 2012 ROHM Co., Ltd. All rights reserved.
TSZ22111ï½¥15ï½¥001
12/16
TSZ02201-0G3G0C200060-1-2
9.NOV.2012 Rev.001