UCD3138A Datasheet, PDF (38/87 Pages) Texas Instruments – Highly-Integrated Digital Controller for Isolated Power

UCD3138A
SLUSC66C – MARCH 2015 – REVISED SEPTEMBER 2016
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7.5.3 DPWMC, Edge Generation, IntraMux
The UCD3138A 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 an auxillary signal inside the DPWM logic. It can be generated using the Blanking A begin
time, and 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 output a
generated edge.
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.
The IntraMux (short for intra multiplexer) is controlled by the Auto Config registers. 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. When disabled, DPWMA and DPWMB are driven as described
in the Section 7.5.2 section. If the Intra Mux is enabled, the high-resolution feature must be disabled, and
the DPWM edge resolution falls to 4 ns.
The Edge Gen/Intra Mux is shown in Figure 7-5.
A/B/C (N)
A/B/C (N+1)
C (N+2)
C (N+3)
EDGE GEN
INTRAMUX
PWM A
PWM B
A(N)
B(N)
A(N+1)
B(N+1)
A ON SELECT
A OFF SELECT
B ON SELECT
B OFF SELECT
EGEN A
EGEN B
B SELECT
A SELECT
Figure 7-5. Edge Gen/Intra Mux
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