EMC2113 datasheet(23/88 Pages) MICROCHIP

23 / 88 page

RPM-Based Fan Controller with Multiple Temperature Zones & Hardware Thermal Shutdown

Datasheet

 2013 Microchip Technology Inc.

DS20005251A-page 23

6.1

Critical/Thermal Shutdown

The EMC2113 provides a hardware Critical/Thermal Shutdown function for systems. Figure 6.2 is a

block diagram of this Critical/Thermal Shutdown function. The Critical/Thermal Shutdown function

accepts configuration information from the pullup resistor of the SHDN_SEL pin.

The analog portion of the Critical/Thermal Shutdown function monitors the hardware determined

shutdown channel. This measured temperature is then compared with TRIP_SET point. This

TRIP_SET point is set by the system designer with a single external resistor.

The SYS_SHDN is asserted when the indicated temperature meets or exceeds the temperature

threshold (TTRIP) established by the TRIP_SET input pin for a number of consecutive measurements

defined by the fault queue.

Each of the software programmed temperature limits can be optionally configured to act as inputs to

the Critical/Thermal Shutdown independent of the hardware shutdown operation. When configured to

operate this way, the SYS_SHDN pin will be asserted when the temperature meets or exceeds the

programmed Tcrit Limit for the enabled channel (see Section 7.10).

6.1.1

SYS_SHDN Pin

The SYS_SHDN pin is an active low dedicated system interrupt. This pin is asserted low when:

1. The programmed temperature channel (see Section 6.1.2) exceeds the hardware set limit (see

Section 6.1.3).

2. Any of the measured temperature channels meet or exceed their programmed TCRIT limits and

have been linked to the SYS_SHDN pin (see Section 7.10).

3. Any of the measured temperature channels meet or exceed their programmed High limits and have

been linked to the SYS_SHDN pin (see Section 7.11).

Figure 6.2 Block Diagram of Critical/Thermal Shutdown

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