LM3S1960 Luminary Micro, Inc, LM3S1960 Datasheet - Page 391

• Manufacturer Part Number: LM3S1960
• Description: Lm3s1960 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

16
16.1
July 25, 2008
Pulse Width Modulator (PWM)
Pulse width modulation (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.
The Stellaris
PWM generator block contains one timer (16-bit down or up/down counter), two PWM comparators,
a PWM signal generator, a dead-band generator, and an interrupt selector. The control block
determines the polarity of the PWM signals, and which signals are passed through to the pins.
Each PWM generator block produces two PWM signals that can either be independent signals
(other than being based on the same timer and therefore having the same frequency) or a single
pair of complementary signals with dead-band delays inserted. The output of the PWM generation
blocks are managed by the output control block before being passed to the device pins.
The Stellaris
such as those required by a simple charge pump. It can also generate paired PWM signals with
dead-band delays, such as those required by a half-H bridge driver. Three generator blocks can
also generate the full six channels of gate controls required by a 3-phase inverter bridge.
Block Diagram
Figure 16-1 on page 391 provides the Stellaris
392 provides a more detailed diagram of a Stellaris
contains three generator blocks (PWM0, PWM1, and PWM2) and generates six independent PWM
signals or three paired PWM signals with dead-band delays inserted.
Figure 16-1. PWM Unit Diagram
PWM Clock
Fault
System Clock
Interrupts
Triggers
®
®
PWM module provides a great deal of flexibility. It can generate simple PWM signals,
PWM module consists of three PWM generator blocks and a control block. Each
Control and
PWMSTATUS
PWMENABLE
PWMINVERT
PWMFAULT
PWMINTEN
PWMSYNC
Interrupt
PWMCTL
PWMRIS
PWMISC
Output
Status
Preliminary
®
PWM module unit diagram and Figure 16-2 on page
Generator 0
Generator 1
Generator 2
®
PWM generator. The LM3S1960 controller
PWM
PWM
PWM
PWM0_A
PWM0_B
PWM0_Fault
PWM1_A
PWM1_B
PWM1_Fault
PWM2_A
PWM2_Fault
PWM2_B
LM3S1960 Microcontroller
Control
Output
PWM
Logic
PWM 0
PWM 1
PWM 2
PWM 3
PWM 4
PWM 5
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