AMC6821 Datasheet, PDF (42/54 Pages) Burr-Brown (TI) – Analog Monitor and Control Circuit

AMC6821
SBAS386C – MAY 2006 – REVISED JULY 2007
www.ti.com
Fan Spin Disable Bit: FSPD
This bit enables or disables the spin-up function.
PWM Frequency Bits: [PWM2:PWM0]
These bits specify the PWM frequency; the high range (1kHz–40kHz) has a default value of 25kHz, and the low
range (10Hz–94Hz) has a default value of 30Hz. The clock frequency is 3.2MHz. The PWM-MODE pin
determines which range is selected. When the PWM mode is tied to ground, the high range is selected;
otherwise, the low range is selected.
Spin-Up Time Bits: [STIME2:STIME0]
These bits specify a predetermined time period, or spin-up time, during which the 100% duty cycle is applied to
start the fan spinning. These bits are ignored when FSPD = 1.
DCY-LOW-TEMP Register (Address 0x21, Value After Power-On or Reset = 0x55, 33.2%)
Bit 7 (MSB)
L-DCY 7
Bit 6
L-DCY 6
Bit 5
L-DCY 5
Bit 4
L-DCY 4
Bit 3
L-DCY 3
Bit 2
L-DCY 2
Bit 1
L-DCY 1
Bit 0 (LSB)
L-DCY 0
This register specifies the duty cycle in Auto Temp-Fan Control mode when the control temperature is less than
or equal to the value of the Low-Temp bits in the TEMP-FAN Control Regsiter.
Local TEMP-FAN Control Register (Address 0x24, Value After Power-On or Reset = 0x41)
BIT
NAME DEFAULT
DESCRIPTION
7
L-TEMP4
0
Low Temperature Bit of Local Sensor
6
L-TEMP3
1
L-TEMP4 L-TEMP3 L-TEMP2 L-TEMP1 L-TEMP0
Low Temp
5
L-TEMP2
0
0
0
0
0
0
0°C
4
L-TEMP1
0
0
0
0
0
1
4°C
3
L-TEMP0
0
0
0
0
1
0
8°C
0
0
0
1
1
12°C
...
...
...
...
...
...
0
1
0
0
0
32°C (Default)
...
...
...
...
...
...
1
1
1
1
0
120°C
1
1
1
1
1
124°C
2
L-SLP2
0
Slope Bits of Local Sensor
1
L-SLP1
0
Slope
Temp Range in °C
0
L-SLP0
1
L-SLP2
L-SLP1
L-SLP0
LSB/°C
%/°C
(DCY 33.3% to 100%)
0
0
0
32
12.55
5.31
0
0
1
16
6.27
10.62 (default)
0
1
0
8
3.14
21.25
0
1
1
4
1.57
42.5
1
0
0
2
0.78
85
This register specifies the parameters of the local Temperature-Fan Control mode.
Low Temperature Bits: [L-TEMP4:L-TEMP0]
These bits specify the low temperature of the local temperature fan control loop. The calculated duty cycle is
equal to the value of the DCY-LOW-TEMP register when the local temperature is less than or equal to the value
defined by bits [L-TEMP4:L-TEMP0]. Refer to the Auto Temperature Fan Mode section for details.
Slope Bits: [L-SLP2:L-SLP0]
These bits define the increment of the duty cycle when the local temperature rises every 1°C in the auto local
temperature-fan control.
42
Submit Documentation Feedback
Product Folder Link(s): AMC6821
Copyright © 2006–2007, Texas Instruments Incorporated