Introduction
The MIP165 is a monolithic IC designed for power supply control applications. Compact and efficient, it offers a streamlined approach to creating power solutions for various electronic projects. In this article, we will build a small, efficient LED power supply using the MIP165 as the central component. This project is straightforward and perfect for hobbyists seeking to create a reliable power source for LED strips, individual high-power LEDs, or other low-voltage lighting applications.
Project Overview
This project focuses on constructing a 12V LED power supply capable of driving LED strips or high-power LEDs. The MIP165 provides the core functionality for managing input voltage, regulating output, and maintaining overall system stability. With a minimal number of external components, this project emphasizes simplicity and cost-effectiveness.
Components Required
● MIP165: Power supply controller IC
● Transformer: Step-down transformer with a secondary voltage of 18V
● Bridge Rectifier: Capable of handling the input current
● Electrolytic Capacitors: For smoothing and filtering (values detailed later)
● Ceramic Capacitors: For noise suppression
● Power Inductor: Inductor with suitable inductance for LED power supply
● Schottky Diode: For efficient rectification
● Resistors: For current sensing and setting parameters
● Heat Sink: For dissipating heat from the MIP165
● LED Strip or High-Power LEDs: Target load
● PCB and Connectors: For assembling and connecting components
Circuit Description
The LED power supply converts AC mains voltage to a stable DC output suitable for LEDs. Here's the process:
AC Input and Rectification: The AC mains voltage is stepped down using a transformer and rectified by a bridge rectifier. This produces a pulsating DC voltage.
Filtering and Smoothing: Large electrolytic capacitors filter the rectified DC voltage, smoothing it to a more constant level.
Regulation and Control with MIP165: The MIP165 manages the voltage regulation, output stabilization, and protection features.
Output Filtering: A combination of capacitors and inductors ensures minimal ripple at the output, providing clean DC power to the LEDs.
Step-by-Step Assembly
Step 1: Prepare the Transformer and Rectifier
● Select a transformer rated for 18V on the secondary side and enough current to handle your LED load.
● Solder the transformer leads to the bridge rectifier.
● Connect the output of the rectifier to an electrolytic capacitor (e.g., 470µF/25V) to smooth the voltage.
Step 2: Set Up the MIP165
● Mount the MIP165 onto a heat sink to manage heat dissipation during operation.
● Connect the input terminals of the MIP165 to the smoothed DC output from the rectifier.
● Configure the MIP165's control pins using resistors and ceramic capacitors. These components stabilize the IC and set operating parameters like voltage and current thresholds.
Step 3: Output Filtering
● Connect the output of the MIP165 to a power inductor (e.g., 100µH). This helps in reducing output ripple.
● Add a Schottky diode across the inductor for efficient energy transfer and improved response time.
● Place a second electrolytic capacitor (e.g., 220µF/16V) after the inductor for final smoothing of the DC output.
Step 4: Load Connection
● Attach connectors or terminal blocks to the output for connecting your LED load.
● Ensure the output voltage matches the specifications of your LEDs (e.g., 12V for most LED strips).
Step 5: Testing and Calibration
● Use a multimeter to verify the output voltage and ensure it remains stable under load.
● Gradually increase the LED load to verify the power supply's capacity.
● Check for excessive heat generation and ensure the heat sink is sufficient.
Safety Considerations
● High Voltage Handling: Be cautious when working with AC mains voltage. Always ensure power is disconnected during assembly.
● Heat Management: The MIP165 may generate heat under heavy loads. Use an appropriate heat sink and provide ventilation.
● Overcurrent Protection: Incorporate a fuse or circuit breaker on the primary side of the transformer to prevent damage in case of a short circuit.
● Insulation: Ensure all exposed conductive parts are insulated to prevent accidental contact.
Customizations and Improvements
Dimming Control: Add a potentiometer to adjust the output voltage and dim the LEDs.
Overvoltage Protection: Include a Zener diode or an additional control circuit to safeguard LEDs from voltage spikes.
Enclosure: Mount the entire assembly in a plastic or metal case with adequate ventilation for a professional finish.
Multiple Outputs: Design the PCB to include multiple output channels for powering different LED sections.
Troubleshooting Tips
No Output Voltage: Check connections and ensure the MIP165 is correctly mounted and powered.
Output Voltage Fluctuations: Verify the smoothing capacitors and ensure the power inductor is not undersized.
Excessive Heat: Confirm the heat sink's attachment and ensure the IC is not overloaded.
LED Flickering: Increase the capacitance of the output filter capacitors or use a higher-quality inductor.
Final Thoughts
Building a compact LED power supply with the MIP165 is an excellent DIY project for hobbyists and engineers looking to explore power electronics. The simplicity of the design, combined with the IC's features, makes it a versatile solution for various LED applications. Whether you're illuminating a workspace, creating decorative lighting, or powering functional displays, this project offers a reliable and customizable power source.