EMC2305 Datasheet, PDF (40/55 Pages) SMSC Corporation – Multiple RPM-Based PWM Fan Controller for Five Fans

Multiple RPM-Based PWM Fan Controller for Five Fans
Datasheet
5.11
Table 5.16 Error Range Options
ERR_RNGX[1:0]
1
0
0
0
0
1
1
0
1
1
Gain Registers
OPERATION
0 RPM (default)
50 RPM
100 RPM
200 RPM
ADDR R/W
35h
R/W
45h
R/W
55h
R/W
65h
R/W
75h
R/W
REGISTER
Gain 1
Register
Gain 2
Register
Gain 3
Register
Gain 4
Register
Gain 5
Register
Table 5.17 Gain Registers
B7
B6 B5
B4
B3
B2 B1 B0 DEFAULT
-
-
GAIND1[1:0] GAINI1[1:0] GAINP1[1:0]
2Ah
-
-
GAIND2[1:0] GAINI2[1:0] GAINP2[1:0]
2Ah
-
-
GAIND3[1:0] GAINI3[1:0] GAINP3[1:0]
2Ah
-
-
GAIND4[1:0] GAINI4[1:0] GAINP4[1:0]
2Ah
-
-
GAIND5[1:0] GAINI5[1:0] GAINP5[1:0]
2Ah
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
1x
0
1
2x
Revision 1.1 (10-12-09)
40
DATASHEET
SMSC EMC2305