ADT7476 Analog Devices, Inc., ADT7476 Datasheet - Page 24

• Manufacturer Part Number: ADT7476
• Description: Dbcool Remote Thermal Controller And Voltage Monitor
• Manufacturer: Analog Devices, Inc.

ADT7476
Single-Channel ADC Conversions
Setting Bit 6 of Configuration Register 2 (0x73) places the
ADT7476 into single-channel ADC conversion mode. In this
mode, the ADT7476 can be made to read a single temperature
channel only. The appropriate ADC channel is selected by writing
to Bits [7:5] of the TACH1 minimum high byte register (0x55).
Table 14. Programming Single-Channel ADC Mode for
Temperatures
Register 0x55, Bits [7:5]
101
110
111
Configuration Register 2 (0x73)
Bit 4 = 1, averaging off.
Bit 6 = 1, single-channel convert mode.
TACH1 Minimum High Byte (0x55)
Bits [7:5] selects ADC channel for single-channel convert mode.
Overtemperature Events
Overtemperature events on any of the temperature channels can
be detected and dealt with automatically in automatic fan speed
control mode. Register 0x6A to Register 0x6C are the THERM
temperature limits. When a temperature exceeds its THERM
temperature limit, all PWM outputs run at the maximum PWM
duty cycle (Register 0x38, Register 0x39, and Register 0x3A).
This effectively runs the fans at the fastest speed allowed.
Channel Selected
Remote 1 temperature
Local temperature
Remote 2 temperature
Rev. B | Page 24 of 72
The fans run at this speed until the temperature drops below
THERM minus hysteresis. This can be disabled by setting the
BOOST bit in Configuration Register 3, Bit 2 (Register 0x78).
The hysteresis value for the THERM temperature limit is the
value programmed into the hysteresis registers (Register 0x6D
and Register 0x6E). The default hysteresis value is 4°C.
THERM can be disabled on specific temperature channels using
Bits [7:5] of Configuration Register 5 (0x7C). THERM can also
be disabled by:
•
•
THERM LIMIT
FANS
TEMPERATURE
In Offset 64 mode, writing −64°C to the appropriate
THERM temperature limit
In twos complement mode, writing −128°C to the
appropriate THERM temperature limit
Figure 28. THERM Temperature Limit Operation
100%
HYSTERESIS (°C)