ADP8863 Analog Devices, ADP8863 Datasheet - Page 13

• 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

Soft Start Feature
At startup (either from UVLO activation or fault/standby
recovery), the output is first charged by I
until it reaches about 92% of V
the inrush current that is otherwise present when the output
capacitance is initially charged to V
reached, the controller enters G = 1× mode. If the output
voltage is not sufficient, then the automatic gain selection
determines the optimal point as defined in the Automatic Gain
Selection section.
OPERATING MODES
There are four different operating modes: active, standby,
shutdown, and reset.
Active Mode
In active mode, all circuits are powered up and in a fully
operational state. This mode is entered when Bit nSTBY (in
Register MDCR) is set to 1.
Standby Mode
Standby mode disables all circuitry except for the I
Current consumption is reduced to less than 1 μA. This mode is
entered when the nSTBY bit is set to 0 or when the nRST pin is
held low for more than 100 μs (maximum). When standby is
exited, a soft start sequence is performed.
STANDBY
nRST
V
OUT
V
IN
SHUTDOWN
V
IN
IN
. This soft start feature reduces
IN
V
. When this point is
IN
~100µs DELAY BETWEEN POWER-UP AND
WHEN I
CROSSES ~2.05V AND TRIGGERS POWER-ON RESET
SS
~3.75mA CHARGES
V
BIT nSTBY IN REGISTER
MDCR GOES LOW
OUT
(3.75 mA typical)
2
C COMMANDS CAN BE RECEIVED
TO V
SOFT START
IN
25µs TO 100µs NOISE FILTER
2
LEVEL
C receivers.
Figure 28. Typical Timing Diagram
Rev. A | Page 13 of 52
10µs 100µs
1×
1.5×
Shutdown Mode
Shutdown mode disables all circuitry, including the I
Shutdown occurs when V
When V
reset and the part is placed into standby mode.
Reset Mode
In reset mode, all registers are set to their default values and
the part is placed into standby. There are two ways to reset the
part: by power-on reset (POR) or using the nRST pin. POR is
activated any time that the part exits shutdown mode. After a
POR sequence is complete, the part automatically enters
standby mode.
After startup, the part can be reset by pulling the nRST pin low.
As long as the nRST pin is low, the part is held in a standby
state, but no I
kept at their default values). After releasing the nRST pin, all
registers remain at their default values, and the part remains in
standby; however, the part does accept I
The nRST pin has a 50 μs (typical) noise filter to prevent inad-
vertent activation of the reset function. The nRST pin must be
held low for this entire time to activate reset.
The operating modes function according to the timing diagram
in Figure 28.
2×
GAIN CHANGES OCCUR ONLY WHEN NECESSARY,
BUT HAVE A MIN TIME BEFORE CHANGING
IN
rises above V
nRST IS LOW, WHICH FORCES STANDBY
LOW AND RESETS ALL I
nRST MUST BE HIGH FOR 20µs (MAX)
BEFORE SENDING I
2
C commands are acknowledged (all registers are
IN(START)
IN
2
SOFT START
is below the undervoltage thresholds.
C COMMANDS
2
C REGISTERS
(2.05 V typical), all registers are
2
C commands.
ADP8863
2
C receivers.