ADP8861ACPZ-R7 Analog Devices Inc, ADP8861ACPZ-R7 Datasheet - Page 15

• Manufacturer Part Number: ADP8861ACPZ-R7
• Description: Charge Pump Based Backlight Controller
• Manufacturer: Analog Devices Inc
• Series: -r

Specifications of ADP8861ACPZ-R7

• Constant Current: -
• Constant Voltage: -
• Topology: Switched Capacitor (Charge Pump)
• Number Of Outputs: 7
• Internal Driver: Yes
• Type - Primary: Backlight, LED Blinker
• Type - Secondary: RGB, White LED
• Frequency: 800kHz ~ 1.32MHz
• Voltage - Supply: 2.5 V ~ 5.5 V
• Voltage - Output: 4.3 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 20-WFQFN Exposed Pad, CSP
• Operating Temperature: -40°C ~ 85°C
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

BACKLIGHT TURN ON/TURN OFF/DIM
With the device in active mode (nSTBY = 1), the backlight can
be turned on using the BL_EN bit in Register 0x01. Before
turning on the backlight, the user should ensure that the
maximum and dim settings are programmed. The backlight
turns on when BL_EN = 1. The backlight turns off when
BL_EN = 0.
While the backlight is on (BL_EN = 1), the user can change to
the dim setting by programming DIM_EN = 1 in Register 0x01.
If DIM_EN = 0, the backlight reverts to its maximum setting.
BACKLIGHT
MAX
MAX
DIM
BACKLIGHT
CURRENT
CURRENT
30
25
20
15
10
5
0
Figure 30. Comparison of the Dimming Transfers Laws
0
Figure 32. Backlight Turn On/Dim/Turn Off
BL_EN = 1
Figure 31. Backlight Turn On/Turn Off
BL_EN = 1
0.25
DIM_EN = 1
UNIT FADE TIME
SQUARE
0.50
LINEAR
DIM_EN = 0
BL_EN = 0
CUBIC 10
0.75
CUBIC 11
BL_EN = 0
1
.00
Rev. A | Page 15 of 40
AUTOMATIC DIM AND TURN OFF TIMERS
The user can program the backlight to dim automatically by
using the DIMT bits in Register 0x07. The dim timer has
127 settings ranging from 1 sec to 127 sec. Program the dim
timer (DIMT) before turning on the backlight. If BL_EN = 1,
the backlight turns on to its maximum setting and the dim
timer starts counting. When the dim timer expires, the internal
state machine sets DIM_EN = 1, and the backlight enters its
dim setting.
If the user clears the DIM_EN bit, the backlight reverts to its
maximum setting and the dim timer begins counting again.
When the dim timer expires, the internal state machine again
sets DIM_EN = 1, and the backlight enters its dim setting. The
backlight can be turned off at any point during the dim timer
countdown by clearing BL_EN.
The user can also program the backlight to turn off automati-
cally by using the OFFT bits in Register 0x06. The off timer has
127 settings ranging from 1 sec to 127 sec. Program the off
timer (OFFT) before turning on the backlight. If BL_EN = 1,
the backlight turns on to its maximum setting and the off timer
starts counting. When the off timer expires, the internal state
machine clears the BL_EN bit, and the backlight turns off.
The backlight can be turned off at any point during the off
timer countdown by clearing BL_EN.
MAX
BACKLIGHT
DIM
CURRENT
MAX
BACKLIGHT
SET BY USER
SET BY INTERNAL STATEMACHINE
CURRENT
SET BY USER
SET BY INTERNAL STATE MACHINE
BL_EN = 1
DIM TIMER
RUNNING
DIM_EN = 1
Figure 33. Dim Timer
BL_EN = 1 BL_EN = 0
Figure 34. Off Timer
OFF TIMER
RUNNING
DIM_EN = 0 DIM_EN = 1
DIM TIMER
RUNNING
BL_EN = 0
ADP8861