ADP1655ACBZ-R7 datasheet(13/24 Pages) AD

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ADP1655

Rev. 0 | Page 13 of 24

2-BIT LOGIC INTERFACE MODE (I2C/EN = 0)

In 2-bit logic interface mode, the two control pins, EN1 and

EN2, select whether the part is disabled or operating in assist

light mode or flash mode, as outlined in Table 6. Additionally,

the TORCH pin selects torch mode.

Figure 29 illustrates state transitions of 2-bit logic mode con-

trolled by digital inputs EN1, EN2, TORCH, and TX_MASK.

EXTERNAL

TORCH

FLASH

SHUTDOWN

ASSIST

LIGHT

EN2 = 1

EN2 = 0

EN1 = 0

EN1 = 1

EN2 = 1

EN1 = 0

EN2 = 1

TIMEOUT

EN1 = 1

EN2 = 1

EN1 = 0

EN2 = 0

TORCH = 0

TORCH = 1

Figure 29. 2-Bit Logic Mode State Transitions (I2C/EN = 0)

When the ADP1655 is in flash mode, the TX_MASK pin can

be used to reduce the battery load. The device remains in flash

mode, but the LED driver output current is reduced to the assist

light level.

Table 6. 2-Bit Logic Interface Mode Selection

Mode

I2C/

EN1

EN2

TORCH

Output Current

Shutdown

0 mA

Torch

One LED: 80 mA

Two LEDs: 40 mA

Assist light

One LED: 80 mA

Two LEDs: 40 mA

Reserved

0 mA

Flash

One LED: 500 mA

Two LEDs: 320 mA

I2C INTERFACE MODE (I2C/EN = 1)

The ADP1655 includes an I2C-compatible serial interface for

control of the LED current, as well as for a readback of system

status registers. The I2C chip address is 0x60 in write mode and

0x61 in read mode.

Table 7. I2C Interface Mode Selection

Mode

I2C/

SCL

SDA

TORCH

Output Current

Standby

0 mA

Torch

20 mA to 160 mA1, 2

Assist light

20 mA to 160 mA2

Flash

200 mA to 500 mA2

1 Torch mode has to be enabled from Register 0x04.

2 The output current value depends on the register settings.

Registers values are reset to the default values when VIN supply

falls below the undervoltage (UVLO) level.

Figure 30 illustrates the I2C write sequence to a single register.

The subaddress content selects which of the five ADP1655

registers is written to first. The ADP1655 sends an acknowl-

edgement to the master after the 8-bit data byte has been written.

The ADP1655 increments the subaddress automatically and starts

receiving a data byte to the following register until the master

sends an I2C stop as shown in Figure 31. Figure 32 shows the

I2C read sequence of a single register. ADP1655 sends the data

from the register denoted by the subaddress and increments

the subaddress automatically, sending data from the next reg-

ister until the master sends an I2C stop condition as shown in

Figure 33.

State transitions between standby, assist light, flash, and

external torch modes are described in the State Transitions

section and Figure 34.

The register definitions are shown in the I2C Register Map

section. The lowest bit number (0) represents the least

significant bit, and the highest bit number (7) represents

the most significant bit.

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