Datasheet

18
24
14
38
18
KCompx
DPWMx Period
Loop_VFF
Filter YN (Duty %) Filter Duty
S0.23
14.0
14.0
14.0
14.0
S14.23
Resonant Duty
14.0
Round to
18 bits,
Clamp to
Positive
Clamp
Filter Output
Clamp High
Filter Output
Clamp Low
X
14.4
14.4
OUTPUT_MULT_SEL
14
Bits [17:4]
Filter Period
24
14
38 18
KCompx
DPWMx Period
Filter YN
S0.23
14.014.0
14.0
S14.23
Round to
18 bits,
Clamp to
Positive
Truncate
low 4 bits
X
14.0
PERIOD_MULT_SEL
14.4
UCD3138
SLUSAP2F –MARCH 2012 –REVISED NOVEMBER 2013 www.ti.com
There is a final section for the filter, which permits its output to be matched to the DPWM:
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.
4.14.1 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
• Cycle Adjustment (Current and flux balancing)
• Global Period
• Light Load (Burst Mode)
• Analog Peak Current Mode
48 Functional Overview Copyright © 2012–2013, Texas Instruments Incorporated
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