EMC2104 datasheet(53/101 Pages) SMSC

53 / 101 page

Dual RPM-Based PWM Fan Controller with Hardware Thermal Shutdown

Datasheet

SMSC EMC2104

Revision 1.74 (05-08-08)

DATASHEET

6.6

Beta Configuration Registers

The Beta Configuration Registers control advanced temperature measurement features for each

External Diode channel. The Beta Configuration Registers are software locked. The External Diode 1

Beta Configuration Register Is hardware locked if the SHDN_SEL pin is not set to disable the Critical

/ Thermal Shutdown functionality (see Table 6.1).

Bit 4 - AUTO - Enables the Automatic Beta detection algorithm.

‘0’ - The Automatic Beta detection algorithm is disabled. The BETAx[3:0] bit settings will be used

to control the beta compensation circuitry.

‘1’ (default) - The Automatic Beta detection algorithm is enabled. The circuitry will automatically

detect the transistor type and beta values and configure the BETAx[3:0] bits for optimal

performance.

Bits 3 - 0 - BETAx[3:0] - hold a value that corresponds to a range of betas that the Beta Compensation

circuitry can compensate for. These four bits will always show the current beta setting used by the

circuitry. If the AUTO bit is set (default), then these bits may updated by the device with every

temperature conversion. If the AUTO bit is not set, then the value of these bits is used to drive the

beta compensation circuitry. In this case, these bits should be set with a value corresponding to the

lowest expected value of beta for the PNP transistor being used as a temperature sensing device.

See Table 6.9 for supported beta ranges. A value of 1111b indicates that the beta compensation

circuitry is disabled. In this condition, the diode channels will function with default current levels and

will not automatically adjust for beta variation. This mode is used when measuring a discrete 2N3904

transistor or AMD thermal diode.

All of the Beta Configuration Registers are Software Locked.

Table 6.8 Beta Configuration Registers

ADDR

R/W

DEFAULT

14h

R/W

External Diode 1

Beta

Configuration

AUTO

BETA1[3:0]

10h

15h

R/W

External Diode 2

Beta

Configuration

AUTO

BETA2[3:0]

10h

16h

R/W

External Diode 3

Beta

Configuration

AUTO

BETA3[3:0]

10h

Table 6.9 Beta Compensation Look Up Table

AUTO

BETAX[3:0]

MINIMUM BETA

3210

0000

0.050

0001

0.066

0010

0.087

0011

0.114

0100

0.150

EMC2104 Fiches technique(PDF) 53 Page - SMSC Corporation

EMC2104 Fiches technique(HTML) 53 Page - SMSC Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Fiches technique Télécharger

Lien URL