ADP1653

Rev. A | Page 15 of 24

UNUSED

UNUSED

UNUSED

OUT_SEL

OUTPUT SELECT

CONFIG

TIMER

CONFIGURATION

SW_STROBE

SOFTWARE STROBE

FAULT

FAULT

CONDITIONS

REG0

REG1

REG2

REG3

HPLED<4:0>

HIGH POWER

LED CURRENT

ILED<2:0>

INDICATOR LED

CURRENT

TMR_SET<3:0>

TIMER PERIOD

SETTING

TMR_CFG

TIMER

CONFIGURATION

SW_STROBE

SOFTWARE STROBE

ENABLE

FLT_OT

OVER TEMPERATURE

FAULT

FLT_OV

OVER VOLTAGE

FAULT

FLT_TMR

TIMEOUT FAULT

D7

D6

D5

D4

D3

D2

D1

D0

D7

D6

D5

D4

D3

D2

D1

D0

D7

D6

D5

D4

D3

D2

D1

D0

D7

D6

D5

D4

D3

D2

D1

D0

FLT_SCP

SHORT CIRCUIT

FAULT

The LED regulation current levels are controlled by writing to

the ILED and HPLED registers. If the ILED register is set to 0,

the ILED regulator is turned off and no current flows through

the indicator LED. If the ILED register is programmed from

1 (001 binary) to 7 (111 binary), the indicator LED is continuously

on, with a current scaled to the register setting given by

(2)

where Code is the ILED register setting. Therefore, the ILED

current can be programmed between 2.5 mA and 17.5 mA,

using the full range of codes.

If the HPLED register is set to 0, the HPLED regulator is turned

off, and no current flows through the high power LED(s). If the

HPLED register is programmed from 1 (00001 binary) to 11

(01011 binary), the regulator is in torch mode, and the HPLED

remains continuously on, independent of the state of STR. If the

HPLED register is programmed between 12 (01100 binary) and

31 (11111 binary), the HPLED regulator remains off until enabled

through the strobe input (STR) or a software strobe command.

To program a desired HPLED current with SETF tied high, use

the following equation:

(3)

where Code is the HPLED register setting.

Therefore, the HPLED torch current can be programmed between

50 mA and 200 mA for Code 1 to Code 11, and the HPLED flash

current can be programmed between 215 mA and 500 mA for

Code 12 to Code 31.

Additionally, the HPLED current can be adjusted with an external

resistor. This feature is primarily intended for limiting the LED

flash current in handset applications when the phone’s power

amplifier transmits, but it can also be used to modify the HPLED

current settings. If an external SETF resistor is present, the HPLED

current is given by

SETF

HPLED

R

Code

I

kΩ

50

mA)

15

mA

35

(

×

×

+

=

(4)

TURNING ON THE FLASH AND WATCHDOG TIMER

A watchdog timer is always active in flash mode to prevent

overstress of the HPLED.

In 2-bit logic interface mode, users select flash operation by

setting the CTRL1 pin and the CTRL0 pin high. The watchdog

timer in this mode is fixed at 0.82 sec. Bringing the CTRLx pins

to another state terminates the flash. If the state of the CTRLx

pins remains high for longer than 0.82 sec, flash is automatically

disabled by the watchdog timer, and the interrupt pin (INT)

goes low to indicate a fault.