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BD1754HFN

Datasheet

TSZ02201-0G3G0C200060-1-2

10.Dec.2015 Rev.002

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© 2012 ROHM Co., Ltd. All rights reserved.

TSZ22111･15･001

2.

Application Circuit Examples

(1) Circuit example when the power supply is separated

IN

ISET

GND

Current

DAC

UPIC

6

EN

L4

L3

L2

L1

Power Supply2=5V

0.1µF

120k

Ω

The voltage value of L* pin must

when the LED is powered ON.

Power Supply1

(Maximum rating = 7.0 V)

(Ex.)

Figure 13. Circuit Example when the Power Supply is separated

(threshold voltage value of a white LED) or higher to the LED. In this case, please note that when the LED is powered

V is applied to L* pin, a desired current value cannot be obtained. Also, please pay attention to the voltage application

procedure at start-up. Be sure to power the current driver ON using the UPIC after applying power supply voltages to

the IN and the LED-anode pins. If the current driver is powered ON prior to applying power supply voltages to the LED,

a rush current occurs in the LED. 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.

(2) Circuit example when using only two LEDs

120k

Ω

IN

ISET

GND

Current

DAC

UPIC

6

EN

L2

L1

0.1µF

Connect to the GND pin.

(When

L4

L3

Figure 14. Circuit Example when using only Two

LED’s

This figure shows a circuit example when none of L3 and L4 LED’s are used. Connect both of the unused L3 and L4

pins to the GND pin. Likewise, it is possible to make the L1 and/or the L2 pins unused, which allows the back lights to

be used with the one or three LED(s) turned ON. In all cases, connect the unused L* pin to the GND pin. 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 LED’s are controlled through the EN pin in accordance

with the UPIC format.