Voltage Controlled Switches

Project Overview

Introduction:

  • Title: Voltage Controlled Switches
  • Duration: February 2024 - March 2024
  • Role: Project Engineer
  • Technologies Used: MOSFETs, LT Spice, Waveforms Software, Analog Discovery 2

Summary:
This project explored the design, simulation, and testing of two types of electronic switches using a combination of p-type and n-type MOSFETs. The primary goal was to understand the behaviors of ideal switches versus non-ideal switches under various conditions and to optimize the design for bidirectionality, low resistance when on, and high resistance when off.

Design Implementation and Testing (Switch 1):

  1. Circuit Features: Utilizes three voltage sources, two n-type and a p-type MOSFETs, and a 10k ohm resistor.
  2. Behavior Analysis: Focus on verifying bidirectionality and the switch's ability to handle different voltages, with maximum voltage tests conducted up to 10V using the AD2.
  3. Results: Demonstrated that the switch operates with zero resistance when on and a very high resistance when off, confirming the expected ideal switch behaviors.

Design Implementation and Testing (Switch 2):

  • Circuit Features: Similar setup to Switch Type 1 but with modifications to allow for output diversion to a secondary output when the switch is off.
  • Behavior Analysis: Tested for the same parameters as Switch Type 1, with additional focus on the switch's response to control voltages and its impact on secondary outputs.
  • Results: Confirmed that control actions lead to expected high or low outputs, validating the circuit's design and functionality under specified conditions.

Project Achievements

  • Bidirectional Switch Design: Successfully designed switches that operate bidirectionally, allowing current to flow in both directions with minimal resistance when on.
  • High and Low Resistance States: Demonstrated high resistance when off and zero resistance when on, confirming the switches' ideal behavior.
  • Control Voltage Responsiveness: Validated that the switches respond accurately to control voltages, achieving expected high and low outputs reliably.
  • Real-World Validation: Confirmed simulation results with practical tests, showing that the switches perform as designed under real-world conditions.

Gallery/Visuals

Switch 1 Schematic:

System Diagram

Switch 1 Real-Life Circuit:

System Diagram

Switch 2 Schematic:

System Diagram

Switch 2 Real-Life Circuit:

System Diagram

Voltage and Current Measurements for Both Switches

System Diagram

Challenges and Solutions

  • Challenge: Ensuring the switch designs provided both bidirectionality and the ability to handle specified voltage ranges effectively.
  • Solution: Iterative design adjustments using simulations in LTspice, followed by rigorous testing with Waveforms software and AD2 to ensure real-world operation aligned with theoretical expectations.

Future Directions

  • Higher Voltage Testing: Plan to test the switches with voltages exceeding the 10V limit of the AD2, using more robust testing equipment.
  • Design Optimization: Continuous improvement of switch designs to reduce non-idealities and enhance performance across various applications.