E
NGINEERING
D
EPARTMENT
706679 Rev 09-26-18
8 of 9
READ_IOUT 0x8C
The A/D count is linear from zero to 125% of nominal output current resulting in a full scale count of 1023d.
Rated output current occurs at a count of 818d. 100% of rated currents are equal to 270-watts divided by the
above output voltages. The coefficient parameters used to translate the data to the actual percentage value of
rated output current information are given below.
Parameter Value
m
8184d
b
0
R
-3d
Table 10 PMBus direct format coefficient parameters for READ_IOUT
READ_TEMPERATURE_1 0x8D
Returns a 10-bit unsigned integer of the temperature near main transformer. The sensor measurement range is
from -40 °C to 125 °C. The XL270 will shut down when the temperature reaches around 110 °C (data value of
930d). The parameters used to translate the data to the actual temperature information are given below.
Parameter Value
m
620d
b
24800d
R
-2d
Table 11 PMBus direct format coefficient parameters for READ_TEMPERATURE_1
MFR_SPECIFIC_01 0xD1 – Fan Speed Control, Read/Write Byte
Note: During non-default mode, internal thermostat control will override other modes and turn the fan
on at 100% duty cycle if the transformer temperature is above 85 °C.
Data Byte
Fan Speed Control Mode
0x00
100% duty cycle (power-on default mode)
0x01
Fixed speed at 0% PWM duty cycle (off)
0x02
Fixed speed at 25% PWM duty cycle
0x03
Fixed speed at 50% PWM duty cycle
0x04
Fixed speed at 75% PWM duty cycle
0x05
Fixed speed at 100% PWM duty cycle (on)
0x06
Internal automatic PWM control:
transformer Temp
Duty Cycle
Above 74°C
100% duty cycle (on)
61°C-73°C
75% duty cycle
48°C-60°C
50% duty cycle
35°C-47°C
25% duty cycle
Below 35°C
0% duty cycle (off)
Table 12 Fan Speed Control Data Byte Usage
