User Manual
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V 1.0
2021-08-25
XDPP1100 technical reference manual
Digital power controller
Voltage control
Figure 42
Multi-segment droop: V
OUT
vs. I
OUT
The first positive segment (SEG1) is the standard operating droop, which is programmed through the PMBus
command VOUT_DROOP. The higher-current segments (SEG2 and SEG3) allow a linear approximation to
constant current and constant power operation before the output is clamped to VOUT_MIN. The negative
current segment allows the negative current droop to be independently programmed according to the system
requirements.
5.4.1
Droop voltage computation
The droop resistance parameters are computed for each segment using the PMBus commands according to the
following equations:
•
SEG1: Equations (5.6) and (5.7)
•
SEG2: Equations (5.8) and (5.9)
•
SEG3: Equations (5.10) and (5.11)
•
Negative segment: Equations (5.12) and (5.13)
𝑣𝑐_𝑣𝑎𝑣𝑝_𝑟𝑙𝑙 =
𝑉𝑂𝑈𝑇_𝐷𝑅𝑂𝑂𝑃∗𝑉𝑂𝑈𝑇_𝑆𝐶𝐴𝐿𝐸_𝐿𝑂𝑂𝑃
2
(𝑦+9)
(5.6)
𝑦 = −1 ∗ 𝐿𝐼𝑁𝐸𝐴𝑅11 𝑒𝑥𝑝𝑜𝑛𝑒𝑛𝑡 𝑜𝑓 𝑉𝑂𝑈𝑇_𝐷𝑅𝑂𝑂𝑃
(5.7)
𝑣𝑐_𝑣𝑎𝑣𝑝_𝑟𝑙𝑙_𝑠𝑒𝑔2 =
𝑀𝐹𝑅_𝑅𝐷𝑅𝑂𝑂𝑃_𝑅𝐿𝐿_𝑆𝐸𝐺2∗𝑉𝑂𝑈𝑇_𝑆𝐶𝐴𝐿𝐸_𝐿𝑂𝑂𝑃
2
(𝑦+15)
(5.8)
𝑦 = −1 ∗ 𝐿𝐼𝑁𝐸𝐴𝑅11 𝑒𝑥𝑝𝑜𝑛𝑒𝑛𝑡 𝑜𝑓 𝑀𝐹𝑅_𝑅𝐷𝑅𝑂𝑂𝑃_𝑅𝐿𝐿_𝑆𝐸𝐺2
(5.9)
𝑣𝑐_𝑣𝑎𝑣𝑝_𝑟𝑙𝑙_𝑠𝑒𝑔3 =
𝑀𝐹𝑅_𝑅𝐷𝑅𝑂𝑂𝑃_𝑅𝐿𝐿_𝑆𝐸𝐺3∗𝑉𝑂𝑈𝑇_𝑆𝐶𝐴𝐿𝐸_𝐿𝑂𝑂𝑃
2
(𝑦+15)
(5.10)
𝑦 = −1 ∗ 𝐿𝐼𝑁𝐸𝐴𝑅11 𝑒𝑥𝑝𝑜𝑛𝑒𝑛𝑡 𝑜𝑓 𝑀𝐹𝑅_𝑅𝐷𝑅𝑂𝑂𝑃_𝑅𝐿𝐿_𝑆𝐸𝐺3
(5.11)
I
OUT
(A)
0
V
O
U
T
(V
)
MFR_RDROOP_RLL_NEG
MFR_RDROOP_RLL_SEG2
MFR_RDROOP_RLL_SEG3
VOUT_DROOP (SEG1)
VOUT_MAX
VOUT_MIN
VOUT_COMMAND
