omarmongy/pwm

Omar Mongy

Pulse Width Modulation (PWM) Verilog Controller

Overview

This GitHub repository contains a Verilog project that implements a configurable Pulse Width Modulation (PWM) controller. The PWM controller is a widely used technique for efficiently controlling the power delivered to loads and regulating signals. The project includes two modules: PWM and timer_counter_inp, providing users with a versatile and customizable PWM solution for various applications.

PWM Module

The PWM module generates the PWM signal based on the duty cycle value and the timer. The module takes user-defined parameters, such as resolution (R) and timer width (Timer), to tailor the PWM controller for specific requirements. This module utilizes two internal registers, Q_reg and D_reg, to store the current values for the counter and the duty cycle comparison.

Inputs

• clk: Clock signal used for synchronization.
• reset_n: Asynchronous active-low reset signal.
• Final_Value: Timer value representing the PWM period.
• duty: Duty cycle value.

Outputs

• pwm_out: The PWM output signal.

Operation

• The PWM module continuously monitors the tick signal generated by the timer_counter_inp module to determine the appropriate time to update the PWM signal.
• On each clock edge, the PWM module increments the current PWM timer value (Q_reg) and compares it with the duty cycle value. If the current timer value is less than the duty cycle value, the PWM output (pwm_out) is set to high, otherwise low.
• When the counter reaches the Final_Value, it generates a done signal to indicate that a complete PWM period has elapsed. At this point, the counter is reset, and the next PWM period starts.
• The reset_n input is used to initialize the PWM module and counter to a known state when the reset is asserted.
• Overall, the PWM module generates a PWM signal with a variable duty cycle specified by the duty input, where the duty cycle is a value between 0 and (2^R - 1). The counter counts up to Final_Value, and the PWM output is high (1) when the counter value is less than the duty cycle, and low (0) otherwise. The PWM signal repeats with the frequency of the clock.

Timer Counter Module

The timer_counter_inp module is a configurable timer counter that counts from 0 to the user-defined final_value. It provides a simple and efficient way to generate timing signals for various applications.

Inputs

• clk: Clock signal used for synchronization.
• reset_n: Asynchronous active-low reset signal.
• enable: Control signal to enable the timer.
• final_value: The final value for the timer counter.

Outputs

• done: Indicates when the timer has reached the final_value.

Operation

The timer counter module uses an always block triggered on the positive clock edge and negative reset signal to update the counter's value when the enable signal is high. When the counter reaches the final_value, the done output is set high, indicating that the desired timing interval has elapsed ,One of the key features of the timer_counter_inp module is its ability to control the frequency of the output PWM signal. By configuring the final_value parameter, users can adjust the timer's counting value, which directly affects the PWM frequency. The PWM frequency is inversely proportional to the timer's counting value. A larger final_value will result in a slower counting rate, leading to a lower PWM frequency. Conversely, a smaller final_value will increase the counting rate and raise the PWM frequency.

Applications and Uses of PWM

The PWM controller implemented in this project has a wide range of applications and uses across various industries and electronic systems. Some of the key applications include:

• Motor Control: Efficient speed control of DC motors, servo motors, and brushless DC motors.
• LED Dimming: Precise brightness control for LED lighting systems.
• Switching Power Supplies: Core component for regulating output voltage in power supply circuits.
• Audio Amplification: Used in Class D audio amplifiers for high-efficiency audio signal amplification.
• Heating Control: Temperature regulation in heating systems.
• Battery Charging: Efficient charging of batteries in various applications.
• Communication Systems: PWM used as a modulation technique in some wireless communication systems.
• Voltage Regulation: Regulating output voltage in voltage regulator circuits.
• Robotics: Control of actuators and servos in robotic systems.
• Solar Power Systems: Charging regulation in solar charge controllers.
• Frequency Regulation: Control of output signal frequency in certain applications.
• Temperature Control: Power regulation for heating or cooling elements in temperature control systems.

Repository Structure

The repository contains the following files:

• Source: Verilog source file containing the PWM and the timer_counter_inp module code.
• Sim: Verilog testbench for the PWM module including the simulation results.
• README.md: Detailed explanation of the project, its modules, and their applications.