BD6066GU_11 Datasheet, PDF (9/16 Pages) Rohm – White Backlight LED Drivers for Medium to Large LCD Panels (Switching Regulator Type)

BD6066GU,BU6066EKN
Technical Note
●Start control and select constant current driver
BD6066GU/EKN can control the start conditions by EN1, 2 terminal and PWM terminal, and sets 0.2V or below EN1, 2
terminal or sets 0.2 or below PWM terminal and IC can power off by being 0V LED terminal selected EN1, 2. PWM, EN
power on at more than 1.4V, constant current can select ON/OFF by the combination of EN as shown below table. When
there is unused constant current driver, connect unused LED terminal to VREG terminal or connect to fixed voltage of more
than 1V. And, EN1, 2 are changed with PWM=H and it is prohibited to change a constant current driver.
Enable
EN1
EN2
PWM
H
H
H
L
H
H
H
L
H
L
L
H
H
H
L
L
H
L
H
L
L
L
L
L
LED1
OFF
OFF
ON
Constant current driver
LED2
LED3
OFF
ON
ON
ON
ON
ON
LED4
ON
ON
ON
OFF
(As for these setups, power-off IC.)
●Off sequence
Off sequence controls power off timing of each block, LED terminal may not exceed the pressure.
After EN or PWM terminal set H→L, it continues electric current by the current value decided with ISET terminal until all the
LED terminals selected with EN are less than 40mV and output voltage reduces. On that occasion, the DC/ DC power-off is
given and it doesn't have a charge to the output capacitor. After that, LED driver is turned off, built-in REG is turned off, and
power-off is completed. If the VF tolerance of the LED is large, it doesn't need to examine VF not to exceed pressure of the
LED terminal by this sequence.
EN
DCDC_EN
DRV_EN
REG_EN
LED Terminal Voltage is high.
LED Terminal Voltage is low.
Terminal voltage is detected, and turned off.
EN1, 2,PWM
Power
Control
REG_EN
REG
5V
DCDC_EN
DCDC ^SW
LED
10 lights
LED
9 lights
DRV_EN
DRV
LED4
LED3
LED2
LED1
Terminal voltage is low
Terminal voltage is high
Fig.30 Block diagram of off sequence
www.rohm.com
© 2011 ROHM Co., Ltd. All rights reserved.
9/15
2011.06 - Rev.B