RPM-Based Fan Controller with Multiple Temperature Zones & Hardware Thermal Shutdown
Datasheet
6.10.2
6.11
6.12
Continuous Operation
When configured to operate in Continuous Operation, the Watchdog timer will start immediately. It can
be disabled by any access (read or write) to the SMBus register set. Upon completion of SMBus
activity, the Watchdog timer is reset and restarted.
Fault Queue
The EMC2113 contains a programmable fault queue on all fault conditions. The fault queue defines
how many consecutive out-of-limit conditions must be reported before the corresponding status bit is
set (and the ALERT pin asserted).
ALERT Pin
The ALERT pin acts as an active low open drain interrupt that flags several conditions. It will be
asserted low when:
1. The FSC Algorithm detects a stalled fan.
2. The measured temperature meets or exceeds its programmed high limit or drops below its
programmed low limit.
3. A diode fault is detected.
4. The PWM input duty cycle has exceeded its programmed limit.
Once asserted, the ALERT pin will remain asserted until the status bits have been cleared or the MASK
bit has been set.
6.13
Temperature Monitoring
The EMC2113 can monitor the temperature of up to three (3) externally connected diodes as well as
the internal or ambient temperature. Each channel is configured with Resistance Error Correction, BJT
Transistor model support, and Averaging enabled or disabled based on user settings and system
requirements. All temperature channels offer 1°C accuracy and 0.125°C resolution.
6.13.1
Dynamic Averaging
The EMC2113 supports dynamic averaging. When enabled, this feature changes the conversion time
for all channels based on the selected conversion rate. This essentially increases the averaging factor
as shown in Table 6.4, "Dynamic Averaging Behavior". The benefits of Dynamic Averaging are
improved noise rejection due to the longer integration time as well as less random variation on the
temperature measurement.
Table 6.4 Dynamic Averaging Behavior
AVERAGING FACTOR (RELATIVE TO 11-BIT CONVERSI0N)
CONVERSION RATE
DYNAMIC AVERAGING
ENABLED
DYNAMIC AVERAGING
DISABLED
1 / sec
2 / sec
8x
4x
2x
1x
1x
1x
1x
1x
4 / sec
Continuous
Revision 1.2 (10-08-09)
SMSC EMC2113
DATA3S4HEET
SMSC [ SMSC CORPORATION ]
