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App note: High-Speed PWM module on PIC24E and dsPIC33E

Posted on Sunday, December 25th, 2011 in Uncategorized by DP

Here’s a reference guide from Microchip about the high-speed PWM modules found on some PIC24E and dsPIC33E microcontrollers and digital signal processors.

This module is a advanced version of the standard ECCP pulse-width modulator on PIC microcontrollers. It’s designed mainly for power conversion and electric motor control. The feature list is impressive:

  • Up to seven PWM generators, each with an individual time base.
  • Two PWM outputs per PWM generator.
  • Individual period and duty cycle for each PWM output.
  • Duty cycle, dead time, phase shift and frequency resolution equal to the system clock source (TOSC).
  • Independent fault and current-limit inputs for up to 14 PWM outputs.
  • Redundant Output mode.
  • Independent Output mode (this feature is not available on all devices).
  • Push-Pull Output mode.
  • Complementary Output mode.
  • Center-Aligned PWM mode.
  • Output override control.
  • Special Event Trigger.
  • PWM capture feature.
  • Prescaler for input clock.
  • ADC triggering with PWM.
  • Independent PWM frequency, duty cycle and phase shift changes.
  • Leading-Edge Blanking (LEB) functionality.
  • Dead time compensation.
  • Output clock chopping.

The resolution of this module is just 7.14nS, which means it can output a PWM signal at 500KHz with a resolution of 8bits.

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