EMC2113 datasheet(82/88 Pages) MICROCHIP

82 / 88 page

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

Datasheet

DS20005251A-page 82

 2013 Microchip Technology Inc.

A.2

Example #2

This example uses the RPM-based Fan Speed Control Algorithm. The Spin Level (used by the Spin

Up Routine) should be changed to 40% drive for a total Spin Time of 1 second. For all other RPM

configuration settings, the default conditions are used.

For control inputs, it uses the External Diode 1 channel normally, the External Diode 2 channel

normally, and both Pushed Temperature registers in DTS format. The configuration is set as shown in

Table A.5, "Look Up Table Example #2 Configuration" while Table A.6, "Fan Speed Control Table

Example #2" shows how the table is loaded.

Note that when using DTS data, the USE_DTS_F1 and / or USE_DTS_F2 bits should be set. The

Pushed Temperature Registers are loaded with the normal DTS values as received by the processor.

When the DTS value is used by the Look Up Table, the value that is stored in the Pushed Temperature

against the Look Up Table thresholds normally. When programming the Look Up Table, it is necessary

to take this translation into account or else incorrect settings may be selected.

A.2.1

Fan Spin Up Configuration Bit Description

Bits 7-6 - DRIVE_FAIL_CNT[1:0] = ‘00b’ tells the circuitry that the drive fail detection circuitry is not

enabled. This is the default setting.

Bit 5 - NOKICK = ‘0b’ tells the circuitry that if than Spin Up Routine is invoked, it will drive to 100%

duty cycle for 25% of the spin up time. This is the default setting.

Bits 4-2 - SPIN_LVL[2:0] = ‘010b’ tells the circuitry that if the Spin Up Routine is invoked, it should run

at 40% drive.

Table A.4 Fan Speed Determination for Example #1 (using settings in Table A.3)

EXTERNAL

DIODE 1

TEMPERATURE

(CPU)

EXTERNAL

DIODE 2

TEMPERATURE

(GPU)

EXTERNAL

DIODE 3

TEMPERATURE

(SKIN)

INTERNAL DIODE

TEMPERATURE

(AMBIENT)

PWM RESULT

Example 1:

82°C

48°C

58°C

70% (CPU temp

requires highest drive)

Example 2:

82C°

97°C

62°C

58°C

80% (GPU and Skin

require highest drive)

Example 3:

82°C

97°C

62°C

75°C

100% (Internal temp

requires highest drive)

Table A.5 Look Up Table Example #2 Configuration

ADDR

SETTING

46h

Fan Spin Up

Configuration

DRIVE_FAIL_CNT

[1:0]

NOKICK

SPIN_LVL[2:0]

SPINUP_TIME [1:0]

0Ah

50h

LUT

Configuration

USE_

DTS_F1

USE_

DTS_F2

LUT_

LOCK

RPM /

PWM

PUSH1_

CFG

TEMP1_

CFG

TEMP3_

CFG

TEMP4_

CFG

E5h

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