LM3556

www.ti.com

SNVS796C – AUGUST 2011 – REVISED APRIL 2013

Configuration Register (0x07)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Strobe Pin

Torch Pin

TX Pin

TX Event Level

IVFM Enable

NTC Mode

Indicator Mode

Strobe Usage

Polarity

Polarity

Polarity

0 = Off

0 = Disabled

0 = Normal

0 = Internal

0 = Edge

0 = Active Low

0 = Active Low

0 = Active Low

1 = Torch Current

(default)

(default)

(default)

(default)

1 = Active

1 = Active

1 = Active

(default)

1 = Enabled

1 = Monitor

1 = External

1 = Level

High (default)

High (default)

High (default)

Strobe Usage Level or Edge. Flash will follow Strobe timing if Level and internal timing if Edge.

Strobe Polarity Active High or Active Low Select.

Torch Polarity Active High or Active Low Select.

TX Polarity Active High or Active Low Select.

TX Event Level Transition to Torch Current Level or Off if TX event occurs.

The TX Event Level "Off" setting is designed to only force a shutdown during a flash event. When Torch or

Indicator Mode is enabled, and a TX event occurs with the TX Event Level set to "Off", the LM3556 does

not shut down. The TX flag bit (bit7 in the Flags Register (0x0B)) will be set, and the mode bits (bit0 and

TX event is periodic and frequently occurring, clearing the fault register becomes more difficult. Depending

the Enable Register (0x0A)) to a '0' before clearing the fault register to prevent future flag sets.

IVFM Enable Enables Input Voltage Flash Monitoring.

NTC Mode Monitor Mode (Report Only) or Normal Mode (Reduce Current or Shutdown).

Indicator Mode Externally generated via TORCH Pin or internally generated PWM.

Flash Features Register (0x08)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Inductor Current Limit

Flash Ramp Time

Flash Time-Out Time

00 =1.7A

000 = 256 µs

000 = 100 ms

01 = 1.9A

001 = 512 µs

001 = 200 ms

10 = 2.5A

010 = 1.024 ms (default)

010 = 300 ms (default)

11 = 3.1A (default)

011 = 2.048 ms

011 = 400 ms

100 = 4.096 ms

100 = 500 ms

101 = 8.192 ms

101 = 600 ms

110 = 16.384 ms

110 = 700 ms

111 = 32.768 ms

111 = 800 ms

Current Control Register (0x09)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

RFU

Torch Current

Flash Current

000 = 46.88 mA (default)

0000 = 93.75 mA

001 =93.75 mA

0001 = 187.5 mA

010 =140.63 mA

0010 = 281.25 mA

011 = 187.5 mA

0011 = 375 mA

100 =234.38 mA

0100 = 468.75 mA

101 = 281.25 mA

0101 = 562.5mA

110 = 328.13 mA

0110 = 656.25 mA

111 =375 mA

0111 = 750 mA

1000 = 843.75 mA

1001 = 937.5 mA

1010 = 1031.25 mA

1011 = 1125 mA

1100 = 1218.75 mA

1101 = 1312.5 mA

1110 = 1406.25 mA

1111 = 1500 mA (default)

Copyright © 2011–2013, Texas Instruments Incorporated

Submit Documentation Feedback

21

Product Folder Links: LM3556