UCD3138128 datasheet(23/80 Pages) TI

23 / 80 page

UCD3138128, UCD3138A64

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SLUSBZ8A – JUNE 2014 – REVISED SEPTEMBER 2014

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Dead-time between DPWM A and B outputs

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High Resolution PWM capability – 250 ps

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Pulse cycle adjustment of up to ±8.192 µs ( 32768 × 250 ps)

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Active high/ active low output polarity selection

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Provides events to trigger both CPU interrupts and start of ADC12 conversions.

9.3.2.1.3

DPWM Events

Each DPWM can control the following timing events:

1. Sample Trigger Count–This register defines where the error voltage is sampled by the EADC in relationship

to the DPWM period. The programmed value set in the register should be one fourth of the value calculated

based on the DPWM clock. As the DCLK (DCLK = 62.5 MHz max) controlling the circuitry runs at one fourth

of the DPWM clock (PCLK = 250MHz max). When this sample trigger count is equal to the DPWM Counter,

it initiates a front end calculation by triggering the EADC, resulting in a CLA calculation, and a DPWM

update. Over-sampling can be set for 2, 4 or 8 times the sampling rate.

2. Phase Trigger Count–count offset for slaving another DPWM (Multi-Phase/Interleaved operation).

3. Period–low resolution switching period count. (count of PCLK cycles)

4. Event 1–count offset for rising DPWM A event. (PCLK cycles)

5. Event 2–DPWM count for falling DPWM A event that sets the duty ratio. Last 4 bits of the register are for

high resolution control. Upper 14 bits are the number of PCLK cycle counts.

6. Event 3–DPWM count for rising DPWM B event. Last 4 bits of the register are for high resolution control.

Upper 14 bits are the number of PCLK cycle counts.

7. Event 4–DPWM count for falling DPWM B event. Last 4 bits of the register are for high resolution control.

Upper 14 bits are the number of PCLK cycle counts.

8. Cycle Adjust–Constant offset for Event 2 and Event 4 adjustments.

Basic comparisons between the programmed registers and the DPWM counter can create the desired edge

placements in the DPWM. High resolution edge capability is available on Events 2, 3 and 4.

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