MIC2871 Datasheet, PDF (15/24 Pages) Micrel Semiconductor – 1.2A High-Brightness LED Flash Driver with Single-Wire Serial Interface

Micrel, Inc.
Table 4. Torch Current Register Mapping into Internal
TEN and TCUR Registers, and Relationship between
Torch Current as % of Maximum Current and the
TCUR Register Setting
Value
TEN/TCUR[4:0]
Dec. Binary
TEN[4]
TCUR[3:0] % of IMAX
0
00000
0
100.00
1
00001
0
88.96
2
00010
0
79.04
3
00011
0
70.72
4
00100
0
63.04
5
00101
0
56.00
6
00110
0
49.92
7
00111
0
44.64
8
01000
0
39.68
9
01001
0
35.52
10
01010
0
31.68
11
01011
0
28.16
12
01100
0
25.12
13
01101
0
22.40
14
01110
0
20.00
15
01111
0
17.92
16
10000
1
100.00
17
10001
1
88.96
18
10010
1
79.04
19
10011
1
70.72
20
10100
1
63.04
21
10101
1
56.00
22
10110
1
49.92
23
10111
1
44.64
24
11000
1
39.68
25
11001
1
35.52
26
11010
1
31.68
27
11011
1
28.16
28
11100
1
25.12
29
11101
1
22.40
30
11110
1
20.00
31
11111
1
17.92
MIC2871
Safety Timer Duration Register (STDUR: default 7)
The safety timer duration register sets the duration of the
flash and torch mode when the LED current exceeds the
programmed threshold current. Valid values are 0 for the
minimum timer duration to 7 for the maximum duration.
Table 5. Safety Timer Duration Register Setting and Safety
Timer Duration
Value
Dec. Binary
FDUR[2:0]
(binary)
Timeout (ms)
0
000
000
156.25
1
001
001
312.5
2
010
010
468.75
3
011
011
625
4
100
100
781.25
5
101
101
937.5
6
110
110
1093.75
7
111
111
1250
Low-Battery Threshold Register (LB_TH: default 7)
The LB_TH register sets the supply threshold voltage
below which the internal low battery flag is asserted and
flash functions are inhibited. Table 6 shows the threshold
values that correspond to the register settings. Setting 0
is reserved for disabling the function, and settings
between 1 and 9 inclusively enable and set the LB_TH
value between 3.0V and 3.8V with 100mV resolution.
Table 6. Low-Battery Threshold Register Setting and
Supply Threshold Voltage
Value
Dec. Binary
LB_TH[3:0]
VBAT Threshold (V)
0
0000
0000
Disabled
1
0001
0001
3.0
2
0010
0010
3.1
3
0011
0011
3.2
4
0100
0100
3.3
5
0101
0101
3.4
6
0110
0110
3.5
7
0111
0111
3.6
8
1000
1000
3.7
9
1001
1001
3.8
May 29, 2013
15
052913-1.0 (while in progress)
Revision 1.0 (final document)