NCP81255
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11
GENERAL
The NCP81255 is a single phase IMVP8 Intel proprietary
interface controller with a built in gate driver. The controller
makes use of a digitally enhanced high performance current
mode RPM control method that provides excellent transient
response while minimizing transient aliasing. The average
operating frequency is digitally stabilized to remove
frequency drift under all continuous mode operating
conditions. At light load the NCP81255 automatically
transitions into DCM operation to save power.
Serial VID Interface (Intel proprietary interface)
For Intel proprietary interface communication details
please contact Intel
®
, Inc.
Switching Frequency, Intel proprietary interface
Address, and Boot Voltage Programming
F
SW
, address, and VBOOT are during power up on
a single pin. A 10 mA current is sourced from the pin and the
resulting voltage is measured. This is compared with the
thresholds and the corresponding values for F
SW
, VBOOT,
and Intel proprietary interface address are configured. These
values are programmed on power up and cannot be changed
after the initial power up sequence is complete.
Table 5. SWITCHING FREQUENCY
Resistor F
SW
Address VBOOT
1
10 kW
1.2 MHz 0 0V
2
13 kW
1.1 MHz 0 0V
3
16 kW
1.0 MHz 0 0V
4
19.2 kW
900 kHz 0 0V
5
22.5 kW
800 kHz 0 0V
6
26 kW
700 kHz 0 0V
7
29.6 kW
600 kHz 0 0V
8
33.5 kW
1.2 MHz 1 0V
9
37.4 kW
1.1 MHz 1 0V
10
41.5 kW
1.0 MHz 1 0V
11
45.8 kW
900 kHz 1 0V
12
50.2 kW
800 kHz 1 0V
13
54.8 kW
700 kHz 1 0V
14
59.5 kW
600 kHz 1 0V
15
64.5 kW
1.2 MHz 2 1.05 V
16
69.6 kW
1.1 MHz 2 1.05 V
17
75 kW
1.0 MHz 2 1.05 V
18
80.6 kW
900 kHz 2 1.05 V
19
86.5 kW
800 kHz 2 1.05 V
20
92.6 kW
700 kHz 2 1.05 V
21
99 kW
600 kHz 2 1.05 V
22
105.5 kW
1.2 MHz 3 0V
23
112.5 kW
1.1 MHz 3 0V
24
119.6 kW
1.0 MHz 3 0V
25
127 kW
900 kHz 3 0V
26
134.8 kW
800 kHz 3 0V
27
143 kW
700 kHz 3 0V
28
151.4 kW
600 kHz 3 0V
29
160.3 kW
700kHz 0 1.05 V
30
169.5 kW
700kHz 1 1.05 V
31
180 kW
700 kHz 2 0V
32
210 kW
700 kHz 3 1.05 V
