UCD3138A_15 Datasheet, PDF (43/83 Pages) Texas Instruments – Highly Integrated Digital Controller for Isolated Power

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UCD3138A
SLUSC66B – MARCH 2015 – REVISED MAY 2015
The final section for the filter, which permits its output to be matched to the DPWM is shown in Figure 6-
13.
Filter YN
24 S0.23
KCompx 14.0
DPWMx Period 14.0
X 38
S14.23
Round to
18 bits, 18 Truncate 14 Filter Period
Clamp to _14.4 low 4 bits _{Bits [17:4] 14.0}
Positive
14
14.0
PERIOD_MULT_SEL
Figure 6-13. Final Section for the Filter
This permits the filter output to be multiplied by a variety of correction factors to match the DPWM Period,
to provide for Voltage Feed Forward, or for other purposes. After this, there is another clamp. For resonant
mode, the filter can be used to generate both period and duty cycle.
Filter Output
Clamp High
Filter YN (Duty %)
24 S0.23
KCompx ^14.0
DPWMx Period 14.0
Loop_VFF _14.0
Resonant Duty _14.0
X 38
S14.23
14
14.0
Round to
18 bits, ¹⁸
Clamp to _14.4
Positive
Clamp
18 ^{Filter Duty}
14.4
Filter Output
Clamp Low
OUTPUT_MULT_SEL
Figure 6-14. Resonant Mode
6.9.1 Loop Multiplexer
The Loop Mux controls interconnections between the filters, front ends, and DPWMs. Any filter, front end,
and DPWM can be combined with each other in many configurations.
It also controls the following connections:
• DPWM to Front End
• Front End DAC control from Filters or Constant Current/Constant Power Module
• Filter Special Coefficients and Feed Forward
• DPWM synchronization
• Filter to DPWM
The following control modules are configured in the Loop Mux:
• Constant Power/Constant Current
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Detailed Description
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