ADP1650 Analog Devices, ADP1650 Datasheet - Page 14

• Manufacturer Part Number: ADP1650
• Description: 1.5 A LED Flash Driver with I2C-Compatible Interface
• Manufacturer: Analog Devices

Specifications of ADP1650

• Product Description: 1.5 A LED Flash Driver with I2C-Compatible Interface
• Led #: 1
• Led Configuration: Serial
• Topology: Inductive
• Application: Flash
• I2c Support: Yes
• Max Iout (ma): 1500mA
• Brightness Control: I2C
• Peak Efficiency (%): 90%
• Switching Frequency: 3MHz
• Over Volt Protection (v): 5.5V
• Vin Min (v): 2.7V
• Vout (v): 4.575 to 5.425
• Synchronous: Yes
• Package: 12-Bump WLCSP

ADP1650
TORCH-TO-FLASH MODE
The driver can move directly from external torch mode (using
GPIO1) to flash mode by bringing STROBE high before GPIO1
= torch is brought low. Bringing torch low before STROBE goes
high prevents the flash from firing when STROBE goes high.
The ADP1650 returns to standby mode after a successful flash
and sets OUTPUT_EN = 0.
TxMASK OPERATION
When the ADP1650 is in flash mode, the TxMASK1 and
TxMASK2 functions reduce the battery load in response to the
system enabling a power amplifier. The device remains in flash
mode, but the LED driver output current reduces to the pro-
grammed TxMASK light level in less than 21 μs.
The device selects the TxMASK1 or TxMASK2 current level
based on whether the TxMASK1 or TxMASK2 input is used.
After a TxMASK1 or TxMASK2 occurs, a flag is set in the fault
information register. When the TxMASK signal goes low again,
the LED current goes back to the full flash level in a controlled
manner to avoid overshoots on the battery current. If both
TxMASK inputs are set high simultaneously, the TXMASK1
current level is used.
I
I
2
2
LED CURRENT
LED CURRENT
C DATA BUS
C D ATA BUS
I(TXMASK1)
REG 0x03, I_FL = XXXXX mA
REG 0x06, I_TX1 = XXXX mA
Figure 33. TxMASK1 Operation During Flash (Level-Sensitive) Mode
REG 0x02, FL_TIM = XXXX ms
TXMASK1
I(ASSIST)
I(FLASH)
REG 0x03, I_FL = XXXXX mA
STROBE
STROBE
REG 0x03, I_TOR = XXX mA
I(FLASH)
REG 0x02, IO1_CFG = 10
TORCH
(GPIO1)
Figure 32. Enabling Flash Mode from External Torch Mode
0A
IO1_CFG = 01, TORCH
0A
FL_TIM = XXXX ms
REG 0x04, OUTPUT_EN = 1
REG 0x04, OUTPUT_EN = 1
LED_MOD = 11
STR_LV = 1
LED_MOD = 00
STR_LV = 1
ADP1650 SETS OUTPUT_EN TO 0
ADP1650 SETS OUTPUT_EN TO 0.
ADP1650 SETS LED_MOD TO 00.
FL_TX1 = 1
Rev. C | Page 14 of 32
FREQUENCY FOLDBACK
Frequency foldback is an optional mode that optimizes
efficiency by reducing the switching frequency to 1.5 MHz
when VIN is slightly less than VOUT. Enable frequency
foldback by setting FREQ_FB = 1 in Register 0x04.
INDICATOR LED DRIVER
The indicator LED driver on GPIO2 provides a programmable
current source of between 2.75 mA and 11 mA for driving a red
privacy LED. The current level is programmed by the I_ILED
bits in Register 0x07. The circuit consists of a programmable
current source and a monitoring circuit that uses comparators
to determine whether the indicator LED is shorted or open. The
threshold for detection of a short is 1.2 V (maximum) and an
open circuit is 2.45 V (minimum). The indicator LED must not
be used at the same time as a flash or assist/torch event.
LOW BATTERY LED CURRENT FOLDBACK
As the battery discharges, the lower battery voltage results in
higher peak currents through the battery ESR, which may cause
early shutdown of the phone. The ADP1650 features an optional
low battery detection option, which reduces the flash current
(to a programmable level) when the battery voltage falls below a
programmable level.
I
Table 7. VDD Level at Which the VBAT Low Function Is
Enabled
Bit Name
V_VB_LO
Set V_VB_LO = 000 to disable the low battery current foldback.
2
C D ATA BUS
Figure 34. Register 0x09 Sets the Battery Voltage Threshold Level and the
V(V_VB_LO)
50mV HYS
REG 0x09, I_VB_LO = XXXX mA
STROBE
REG 0x04, OUTPUT_EN = 1
VIN
VDD Level
000 = disabled (default)
001 = 3.3 V
010 = 3.35 V
011 = 3.4 V
100 = 3.45 V
101 = 3.5 V
110 = 3.55 V
111 = 3.6 V
V_VB_LO = XXX V
LED_MOD = 10
Reduced LED Current Level
GLITCH < 50µs IGNORED
FL_VB_LO = 1
ADP1650 SETS OUTPUT_EN TO 0.
ADP1650 SETS LED_MOD TO 00.