EMC2106 Datasheet, PDF (29/106 Pages) SMSC Corporation – Dual RPM-Based Linear Fan Controller with Hardware Thermal Shutdown

Dual RPM-Based Linear Fan Controller with Hardware Thermal Shutdown
Datasheet
„ The TACH / DRIVE bit in the Look Up Table Configuration Register MUST be set to ‘0’ or
the TACH Target values will be incorrectly set. Setting this bit to ‘0’ ensures tha the settings
will be RPM settings (Tachometer counts).
APPLICATION NOTE: It is important that the TACH Target settings are in the proper format when using the RPM
based Fan Speed Control Algorithm.
DIRECT SETTING
MODE
Fan Driver Setting
(read / write)
EDGES[1:0]
-
UPDATE[2:0]
(Fan Configuration)
LEVEL
(Spin Up
Configuration)
SPINUP_TIME[1:0]
(Spin Up
Configuration)
Fan Step
-
Valid TACH Count
-
TACH Reading
-
-
Table 5.3 Fan Controls Active for Operating Mode
FSC MODE
Fan Driver Setting (read
only)
EDGES[1:0]
(Fan Configuration)
RANGE[1:0]
(Fan Configuration)
UPDATE[2:0]
(Fan Configuration)
LEVEL
(Spin Up Configuration)
DIRECT SETTING W/ LUT
MODE
FSC W/ LUT MODE
Fan Driver Setting (read
only)
EDGES[1:0]
Fan Driver Setting (read
only)
EDGES[1:0]
-
UPDATE[2:0]
(Fan Configuration)
LEVEL
(Spin Up Configuration)
RANGE[1:0]
(Fan Configuration)
UPDATE[2:0]
(Fan Configuration)
LEVEL
(Spin Up Configuration)
SPINUP_TIME[1:0]
(Spin Up Configuration)
SPINUP_TIME[1:0]
(Spin Up Configuration)
SPINUP_TIME[1:0]
(Spin Up Configuration)
Fan Step
Fan Minimum Drive
Valid TACH Count
TACH Target (read / write)
Fan Step
Valid TACH Count
-
TACH Reading
-
DRIVE_FAIL_CNT[1:0] and
Drive Band Fail Registers
TACH Reading
Look Up Table Drive /
Temperature Settings (read
only)
-
Fan Step
Fan Minimum Drive
Valid TACH Count
TACH Target (read
only)
TACH Reading
Look up Table Drive /
Temperature Settings
(read only)
DRIVE_FAIL_CNT[1:0]
and Drive Band Fail
Registers
5.3
5.3.1
High Side Fan Driver
The EMC2106’s contains a 5V, 600mA, linear high side fan driver to directly drive a 5V fan. By fully
integrating the linear fan driver, the typical requirement for the discrete pass device and other external
linearization circuitry is completely eliminated. The linear fan driver is driven by an 8-bit DAC providing
better than 20mV resolution between steps.
Over Current Limit
The High Side Fan Driver contains circuitry to allow for significant over current levels to accommodate
transient conditions on the FAN pins. The over current limit is dependent upon the output voltage with
the limit dropping as the voltage nears 0V.
SMSC EMC2106
29
DATASHEET
Revision 1.72 (11-01-07)