LM3556_15 Datasheet, PDF (24/39 Pages) Texas Instruments – Synchronous Boost LED Flash Driver With High-Side Current Source

LM3556
SNVS796D – AUGUST 2011 – REVISED OCTOBER 2015
www.ti.com
7.6.1.9 Flash Features Register (0x08)
Bit 7
Bit 6
Inductor Current Limit
00 =1.7 A
01 = 1.9 A
10 = 2.5 A
11 = 3.1 A (default)
Table 10. Flash Features Register Description
Bit 5
Bit 4
Bit 3
Flash Ramp Time
000 = 256 µs
001 = 512 µs
010 = 1.024 ms (default)
011 = 2.048 ms
100 = 4.096 ms
101 = 8.192 ms
110 = 16.384 ms
111 = 32.768 ms
Bit 2
Bit 1
Flash Time-Out Time
000 = 100 ms
001 = 200 ms
010 = 300 ms (default)
011 = 400 ms
100 = 500 ms
101 = 600 ms
110 = 700 ms
111 = 800 ms
Bit 0
7.6.1.10 Current Control Register (0x09)
Bit 7
RFU
Table 11. Current Control Register Description
Bit 6
Bit 5
Torch Current
000 = 46.88 mA (default)
001 =93.75 mA
010 =140.63 mA
011 = 187.5 mA
100 =234.38 mA
101 = 281.25 mA
110 = 328.13 mA
111 =375 mA
Bit 4
Bit 3
Bit 2
Bit 1
Flash Current
0000 = 93.75 mA
0001 = 187.5 mA
0010 = 281.25 mA
0011 = 375 mA
0100 = 468.75 mA
0101 = 562.5mA
0110 = 656.25 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)
Bit 0
7.6.1.11 Enable Register (0x0A)
Table 12. Enable Register Description
Bit 7
Bit 6
Bit 5
NTC Enable
0 = Disabled
(default)
1 = Enabled
TX Pin Enable
0 = Disabled
(default)
1 = Enabled
STROBE Pin
Enable
0 = Disabled
(default)
1 = Enabled
NTC EN Enables NTC block.
Bit 4
TORCH Pin
Enable
0 = Disabled
(default)
1 = Enabled
Bit 3
Bit 2
PreCharge Mode
Enable
0 = Normal
(default)
1 = PreCharge
Pass-Mode
Only Enable
0 = Normal
(default)
1 = Pass Only
Bit 1
Bit 0
Mode Bits: M1, M0
00 = Standby (default)
01 = Indicator
10 = Torch
11 = Flash
TX EN
Allows TX events to change the current.
Strobe EN Enables STROBE pin to start a flash event.
Torch EN Enables TORCH pin to start a torch event.
PreCharge Mode EN Enables Pass Mode to pre-charge the output cap.
Pass-Only Mode EN Only allows Pass Mode and disallows Boost Mode.
If Pass-Only Mode is enabled during any LED mode (Indicator, Torch or Flash), it remains enabled
until the LM3556 enters the standby state regardless of whether the Pass-Only Mode bit is reset or
not during the following command.
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