Datasheet

A ON SELECT
A OFF SELECT
B ON SELECT
B OFF SELECT
EGEN A
EGEN B
EDGE GEN
PWM A
PWM B
B SELECT
A SELECT
INTRAMUX
A/B/C (N)
A/B/C (N+1)
C (N+2)
C (N+3)
A(N)
B(N)
A(N+1)
B(N+1)
UCD3138
www.ti.com SLUSAP2F –MARCH 2012–REVISED NOVEMBER 2013
4.13 DPWMC, Edge Generation, IntraMux
The UCD3138 has hardware for generating complex waveforms beyond the simple DPWMA and DPWMB
waveforms already discussed – DPWMC, the Edge Generation Module, and the IntraMux.
DPWMC is a signal inside the DPWM logic. It goes high at the Blanking A begin time, and low at the
Blanking A end time.
The Edge Gen module takes DPWMA and DPWMB from its own DPWM module, and the next one, and
uses them to generate edges for two outputs. For DPWM3, the DPWM0 is considered to be the next
DPWM. Each edge (rising and falling for DPWMA and DPWMB) has 8 options which can cause it.
The options are:
0 = DPWM(n) A Rising edge
1 = DPWM(n) A Falling edge
2 = DPWM(n) B Rising edge
3 = DPWM(n) B Falling edge
4 = DPWM(n+1) A Rising edge
5 = DPWM(n+1) A Falling edge
6 = DPWM(n+1) B Rising edge
7 = DPWM(n+1) B Falling edge
Where “n" is the numerical index of the DPWM module of interest. For example n=1 refers to DPWM1.
The Edge Gen is controlled by the DPWMEDGEGEN register. It also has an enable/disable bit.
The IntraMux is controlled by the Auto Config registers. Intra Mux is short for intra multiplexer. The
IntraMux takes signals from multiple DPWMs and from the Edge Gen and combines them logically to
generate DPWMA and DPWMB signals This is useful for topologies like phase-shifted full bridge,
especially when they are controlled with automatic mode switching. Of course, it can all be disabled, and
DPWMA and DPWMB will be driven as described in the sections above. If the Intra Mux is enabled, high
resolution must be disabled, and DPWM edge resolution goes down to 4 ns.
Here is a drawing of the Edge Gen/Intra Mux:
Here is a list of the IntraMux modes for DPWMA:
0 = DPWMA(n) pass through (default)
1 = Edge-gen output, DPWMA(n)
2 = DPWNC(n)
3 = DPWMB(n) (Crossover)
4 = DPWMA(n+1)
Copyright © 2012–2013, Texas Instruments Incorporated Functional Overview 45
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