188.8.131.52 Pulse Width Modulation (PWM)
PWM is a powerful technique for digitally encoding analog signal levels. High-resolution counters are used to generate a square wave, and the duty cycle of the square wave is modulated to encode an analog signal. Typical applications include switching power supplies and motor control.
One PWM module is included, with four PWM generator blocks and a control block, for a total of eight PWM outputs. Each PWM generator block contains one timer (16-bit down or up/down counter), two comparators, a PWM signal generator, a dead-band generator, and an interrupt or ADC-trigger selector.
Each PWM generator block produces two PWM signals that can be either independent signals or a pair of complementary signals with dead-band delays inserted.
Each PWM generator has the following features:
- Four fault-condition handling inputs to quickly provide low-latency shutdown and prevent damage to the motor being controlled
- One 16-bit counter
- Runs in down or up/down mode
- Output frequency controlled by a 16-bit load value
- Synchronized load value updates
- Produces output signals at zero and load value
- Two PWM comparators
- Synchronized comparator value updates
- Produces output signals on match
- PWM signal generator
- Output PWM signal is constructed based on actions taken as a result of the counter and PWM comparator output signals.
- Produces two independent PWM signals
- Dead-band generator
- Produces two PWM signals with programmable dead-band delays suitable for driving a half-H bridge
- Can be bypassed, leaving input PWM signals unmodified
- Can initiate an ADC sample sequence
The control block determines the polarity of the PWM signals and which signals are passed through to the pins. The output of the PWM generation blocks are managed by the output control block before being passed to the device pins. The PWM control block has the following options:
- PWM output enable of each PWM signal
- Optional output inversion of each PWM signal (polarity control)
- Optional fault handling for each PWM signal
- Synchronization of timers in the PWM generator blocks
- Synchronization of timer/comparator updates across the PWM generator blocks
- Extended PWM synchronization of timer/comparator updates across the PWM generator blocks
- Interrupt status summary of the PWM generator blocks
- Extended PWM fault handling, with multiple fault signals, programmable polarities, and filtering
- PWM generators can be operated independently or synchronized with other generators