User Manual
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V 1.0
2021-08-25
XDPP1100 technical reference manual
Digital power controller
Current sense (IS)
Therefore, assuming L
0
is the inductance at zero current, the parameter
ceX_dt_l_slope
is computed according
to Equation (3.5).
𝑐𝑒𝑋_𝑑𝑡_𝐼_𝑠𝑙𝑜𝑝𝑒 = 𝐼𝑁𝑇 (2
14
∗ ((
𝐿
0
𝐿
1
) − 1) ∗
𝐴𝑃𝐶
𝐼
1
)
,
(3.5)
Where:
•
L
0
= inductance at 0 A
•
L
1
= inductance at user-selected I
1
•
APC = amps per code from MFR_IOUT_APC.
Figure 27
Inductance variation with the current
Current slope for primary-side current sense
The primary-side and secondary-side current waveforms are different, as illustrated in
. The
continuous secondary-side current can be sensed during any PWM state. However, the primary-side current can
be sensed only while PWM is in the on-state. This means that in the off- and HIZ states, tracking through the
ADC is not possible. Thefore, the tracking should be disabled by setting both register values,
ce_ktrack_off
and
ce_ktrack_hiz
, to zero. The slope estimator correctly places the DAC at the beginning of the next on-state.
Current
In
du
ct
an
ce
I
0
I
1
L
0
L
1
L vs. I curve from manufacturer
s datasheet
XDPP1100 linear approximation
