Microchip Technology DM183021 Data Sheet

 2010 Microchip Technology Inc.

DS39616D-page 173

The Power Control PWM module simplifies the task of
generating multiple, synchronized Pulse-Width
Modulated (PWM) outputs for use in the control of
motor controllers and power conversion applications.
In particular, the following power and motion control
applications are supported by the PWM module:
• Three-Phase and Single-Phase AC Induction 

Motors

• Switched Reluctance Motors
• Brushless DC (BLDC) Motors
• Uninterruptible Power Supplies (UPS)
• Multiple DC Brush Motors

The PWM module has the following features:
• Up to eight PWM I/O pins with four duty cycle 

generators. Pins can be paired to get a complete 
half-bridge control.

• Up to 14-bit resolution, depending upon the PWM 

period.

• “On-the-fly” PWM frequency changes.
• Edge and Center-Aligned Output modes.
• Single-Pulse Generation mode.
• Programmable dead-time control between paired 

PWMs.

• Interrupt support for asymmetrical updates in 

Center-Aligned mode.

• Output override for Electrically Commutated 

Motor (ECM) operation; for example, BLDC.

• Special Event Trigger comparator for scheduling 

other peripheral events.

• PWM outputs disable feature sets PWM outputs 

to their inactive state when in Debug mode.

The Power Control PWM module supports three PWM
generators and six output channels on
PIC18F2331/2431 devices, and four generators and
eight channels on PIC18F4331/4431 devices. A simpli-
fied block diagram of the module is shown in

 and 

 show how

the module hardware is configured for each PWM
output pair for the Complementary and Independent
Output modes.
Each functional unit of the PWM module will be
discussed in subsequent sections.