ADP8863 Analog Devices, ADP8863 Datasheet - Page 16

• Manufacturer Part Number: ADP8863
• Description: Charge Pump, 7-Channel Fun Lighting LED Driver
• Manufacturer: Analog Devices

Specifications of ADP8863

• Vin Range: 2.5 to 5.5V
• Vout (v): 4.3 to 5.5
• Synchronous: No
• Package: 20-Lead LFCSP,20-Lead WLCSP
• Led Configuration: Parallel
• Topology: Capacitive
• I2c Support: Yes
• Max Iout (ma): 60mA
• Brightness Control: I2C
• Peak Efficiency (%): 89%
• Switching Frequency: 1.32MHz
• Over Volt Protection (v): 5V

ADP8863
BACKLIGHT OPERATING LEVELS
Backlight brightness control operates at three distinct levels:
daylight (L1), office (L2), and dark (L3). The BLV bits in
Register 0x04 control the specific level at which the backlight
operates. These bits can be changed manually or, if in automatic
mode (CMP_AUTOEN is set high in Register 0x01), by the
ambient light sensor (see the Ambient Light Sensing section).
By default, the backlight operates at daylight level (BLV = 00),
where the maximum brightness is set using Register 0x09
(BLMX1). A daylight dim setting can also be set using Register
0x0A (BLDM1). When operating at office level (BLV = 01), the
backlight maximum and dim brightness settings are set using
Register 0x0B (BLMX2) and Register 0x0C (BLDM2). When
operating at the dark level (BLV = 10), the backlight maximum
and dim brightness settings are set using Register 0x0D (BLMX3)
and Register 0x0E (BLDM3).
30mA
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, select the level (daylight (L1), office
(L2), or dark (L3)) to operate in and ensure that maximum and
dim settings are programmed for that level. 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.
0
DAYLIGHT_MAX
BACKLIGHT
MAX
CURRENT
DAYLIGHT (L1)
DAYLIGHT_DIM
BL_EN = 1
Figure 34. Backlight Turn On/Turn Off
Figure 33. Backlight Operating Levels
BACKLIGHT OPERATING LEVELS
OFFICE_MAX
OFFICE (L2)
OFFICE_DIM
BL_EN = 0
DARK_MAX
DARK (L3)
DARK_DIM
Rev. A | Page 16 of 52
The maximum and dim settings can be set from 0 mA to 30 mA;
therefore, it is possible to program a dim setting that is greater
than a maximum setting. For normal expected operation,
ensure that the dim setting is programmed to be less than the
maximum setting.
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
BACKLIGHT
MAX
DIM
CURRENT
MAX
BACKLIGHT
DIM
CURRENT
SET BY USER
SET BY INTERNAL STATEMACHINE
BL_EN = 1
DIM TIMER
RUNNING
Figure 35. Backlight Turn On/Dim/Turn Off
BL_EN = 1
DIM_EN = 1
Figure 36. Dim Timer
DIM_EN = 1
DIM_EN = 0 DIM_EN = 1
DIM TIMER
RUNNING
DIM_EN = 0
BL_EN = 0
BL_EN = 0