Infineon XDPP1100, Technical Reference Manual

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User Manual 49 of 562 V 1.0
2021-08-25
XDPP1100 technical reference manual
Digital power controller
Current sense (IS)
Table 13 CE V
OUT
source
ceX_vout_sel CE0 (ISEN) associated V
OUT
CE1 (BISEN) associated V
OUT
0 Loop 0 V
OUT
Loop 0 V
OUT
1 Loop 0 V
OUT
CDR Loop 0 V
OUT
CDR
2 Loop 0 V
OUT
Loop 1 V
OUT
3 Loop 0 V
OUT
CDR Loop 1 V
OUT
CDR
Table 14 CE V
RECT
source
ceX_vrect_sel CE0 (ISEN) associated V
RECT
CE1 (BISEN) associated V
RECT
0 VS1 (VRSEN/VRREF) VS1 (VRSEN/VRREF)
1 VS2 (BVRSEN/BVRREF) VS2 (BVRSEN/BVRREF)
2 pid_ff_vrect_override pid_ff_vrect_override
3 PRISEN PRISEN
4 VS1 (VRSEN/VRREF) Loop 0 V
OUT
5 VS2 (BVRSEN/BVRREF) Loop 0 V
OUT
6 pid_ff_vrect_override Loop 0 V
OUT
7 PRISEN Loop 0 V
OUT
In a dual-loop system:
•
The ISEN/IREF pin pair must be used to sense the current for Loop 0, whereas the BISEN/BIREF pin pair can
be assigned for Loop 1, as shown in
Table 13 .
•
Loop 0 V
OUT
is allowed to be used as input voltage for Loop 1, as shown in Table 14 .
Current slope for secondary-side current sense
The slope estimation for buck-derived topologies (e.g., buck, forward, ACF, HB, FB) with secondary-side current
sense can be set through register
ceX_kslope_didv . The normalized current slope is defined according to
Equation (3.3), where the kslope_real is given in Equation (3.4) for secondary-side current sense.
𝑐𝑒𝑋_𝑘𝑠𝑙𝑜𝑝𝑒_𝑑𝑖𝑑𝑣 = 𝐼𝑁𝑇(𝑘𝑠𝑙𝑜𝑝𝑒_𝑟𝑒𝑎𝑙 ∗ 2
13
)
(3.3)
𝑘𝑠𝑙𝑜𝑝𝑒
𝑟𝑒𝑎𝑙
= 1.0 𝑉 ∗
10𝑛𝑠
𝐿
𝑂𝑈𝑇
∗𝐴𝑃𝐶
(3.4)
L
OUT
is the output inductance in nH, and AP C is the “amps per code” in amps as defined by PMBus command
MFR_IOUT_APC. However, in the real application the output inductance has a certain tolerance, and therefore,
its contribution to
ceX_kslope_didv has a variation. This tolerance can be corrected by:
•
The error tracking part of the CE
•
Setting parameter ceX_ladj_en to “1” , which enables the autocorrect for errors in ceX_kslope_didv based
on the incoming current sense waveform
In addition to the inductance tolerance, the inductor value may vary with the respect to the current. This
variation is typically non-linear, and the XDPP1100 provides a linear correction as illustrated in
Figure 27 .
Register ceX_dt_l_slope defines the L slope dependence on the current. As illustrated in the figure, the
compensation is specified by:
•
First point: use inductance value at 0 A
•
Second point: user definable based on the best fit curve for each application