Current gain adjustment
STP1612PW05
22/35
Doc ID 15819 Rev 4
12
Current gain adjustment
The bit 9 to bit 2 of the configuration register set the gain of output current, i.e., G. Being 8-
bit in total, ranging from 8’b00000000 to 8’b11111111, these bits allow the user to set the
output current gain up to 256 levels. These bits can be further defined in the configuration
register as follows:
Configuration register
1.
Bit 9 is HC bit. The setting is in the low current range when HC=0, and in the high
current range when HC=1.
2.
Bit 8 to bit 2 are DA6 ~ DA0.
The relationship between these bits and current gain G is:
HC = 1, D = (256G-128)/3
HC = 0, D = (1024G-128)/3
and D in the above decimal numeration can be converted to its equivalent in binary form by
the following equation:
D = DA6x2
6
+ DA5x2
5
+ DA4x2
4
+ DA3x2
3
+ DA2x2
2
+ DA1x2
1
+ DA0x2
0
In other words, these bits can be looked as a floating number with 1-bit exponent HC and 7-
bit mantissa DA6~DA0.
Figure 13.
Gain vs DA6 - DA0
MSB
LSB
F
E
D
C
B
A
9
8
7
6
5
4
3
2
1
0
-
-
-
-
-
-
HC
DA6
DA5
DA4
DA3
DA2
DA1
DA0
-
-
