Multiple RPM-Based PWM Fan Controller for Five Fans
Datasheet
Table 5.16 Error Range Options
ERR_RNGX[1:0]
1
0
OPERATION
0
0
1
1
0
1
0
1
0 RPM (default)
50 RPM
100 RPM
200 RPM
5.11
Gain Registers
Table 5.17 Gain Registers
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
Gain 1
Register
35h
45h
55h
65h
75h
R/W
R/W
R/W
R/W
R/W
-
-
GAIND1[1:0]
GAIND2[1:0]
GAIND3[1:0]
GAIND4[1:0]
GAIND5[1:0]
GAINI1[1:0]
GAINI2[1:0]
GAINI3[1:0]
GAINI4[1:0]
GAINI5[1:0]
GAINP1[1:0]
GAINP2[1:0]
GAINP3[1:0]
GAINP4[1:0]
GAINP5[1:0]
2Ah
Gain 2
Register
-
-
-
-
-
-
-
-
2Ah
2Ah
2Ah
2Ah
Gain 3
Register
Gain 4
Register
Gain 5
Register
The Gain registers store the gain terms used by the proportional and integral portions of each of the
RPM-based Fan Speed Control Algorithms. These gain terms are used as the KD, KI, and KP gain
terms in a classic PID control solution.
Bits 5 - 4 - GAINDX[1:0] - Controls the derivative gain term used by the FSC algorithm as shown in
Table 5.18.
Bits 3-2 - GAINIX[1:0] - Controls the integral gain term used by the FSC algorithm as shown in
Table 5.18.
Bits 1-0 - GAINP[1:0] - Controls the proportional gain term used by the FSC algorithm as shown in
Table 5.18.
Table 5.18 Gain Decode
GAIND OR GAINP OR GAINI [1:0]
1
0
RESPECTIVE GAIN FACTOR
0
0
0
1
1x
2x
Revision 1.1 (10-12-09)
SMSC EMC2305
DATA4S0HEET
SMSC [ SMSC CORPORATION ]
