LM3553 Datasheet, PDF (11/26 Pages) National Semiconductor (TI) – 1.2A Dual Flash LED Driver System with I2C Compatible

LM3553
www.ti.com
SNVS414B – FEBRUARY 2008 – REVISED MAY 2013
MSB
ADR6
bit7
ADR5
bit6
ADR4
bit5
ADR3
bit4
ADR2
bit3
ADR1
bit2
ADR0
bit1
1
0
1
0
0
1
1
I²C Slave Address (chip address)
LSB
R/W
bit0
INTERNAL REGISTERS OF LM3553
Register
General Purpose Register
Multi-Function Pin Control Register
Current Step Time Register
Torch Current Control Register
Flash Current Control Register
Flash Duration Control Register
Internal Hex Address
0x10
0x20
0x50
0xA0
0xB0
0xC0
Power On Value
0001 1000
1110 0000
1111 1100
1000 0000
1000 0000
1111 0000
General Purpose Register
General Purpose Control
MSB
Register Address: 0x10
LSB
0
0
VFB
1
1
VM
EN1
EN0
bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
EN0-EN1: Set Flash LED mode
Indicator Mode sets I_LED = 20mA. In this mode, D1 is enabled and D2 is disabled.
VM: Enables Voltage Mode. Current sinks D1 and D2 are turned off and the LM3553 will operate in a regulated
voltage boost mode. Setting the VM bit to a '1' does not override the EN0 and EN1 bits stored in the general
purpose register. The default setting is '0'. If the LM3553 is in Voltage Mode and an indicator, torch or flash
command is issued, the LM3553 will turn on the D1 and D2 current sources and begin regulating the output
voltage to a value equal to VFB (350mV or 450mV) + VLED.
VM
EN1
EN0
Function
0
0
0
Shutdown
0
0
1
Indicator Mode
0
1
0
Torch Mode
0
1
1
Flash Mode
1
0
0
Voltage Mode
1
0
1
Indicator Mode
1
1
0
Torch Mode
1
1
1
Flash Mode
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