This repository contains the hardware design files (Altium Designer) for a custom current sensing module designed for 36V DC systems. It features a high-side current measurement circuit using the INA240 amplifier and an integrated LM5017 DC-DC buck converter to power low-voltage logic circuits.
This module was designed to monitor the current consumption of DC motors in a robotic system (e.g., UAV or Mobile Robot). It acts as an interface between the high-voltage power source (36V Main Battery) and the control logic (STM32/Arduino).
- High-Side Current Sensing: Uses the TI INA240A2 (Gain: 50V/V) for precise measurement with excellent PWM rejection.
- Integrated Power Supply: Onboard LM5017 Buck Converter steps down 36V input to 5V (1A max) to power the sensor and external microcontrollers.
- Compact Design: 2-layer PCB designed for ease of integration.
| Feature | Description |
|---|---|
| Input Voltage | 36V DC Nominal |
| Sensing Method | High-Side Shunt Measurement |
| Current Amplifier | INA240A2DR |
| Shunt Resistor | 5mΩ (FCSL110R005FER) |
| DC/DC Converter | LM5017 (Iso-Buck capable, configured as Buck) |
| Output Voltage | 5V DC (for logic) |
| Signal Output | Analog Voltage (ADC Compatible) |
The system connects between the main battery and the motor driver. The sensed current is amplified and sent to the MCU's ADC pin.
The INA240 is configured to measure the voltage drop across the shunt resistor placed on the 36V line.
The 36V input is regulated down to 5V to ensure the sensor and connected MCU operate without an external power source.
Educational Project: This PCB was designed as part of an early engineering learning process to practice Altium Designer and Power Electronics concepts.
- Layout Considerations: While the circuit is functional, future iterations would benefit from optimized loop areas in the Buck Converter section for better EMI performance.
- Thermal Management: For continuous high-current applications, thermal vias under the shunt resistor could be increased.
Feel free to use this design as a reference for your own learning journey!
- U1: INA240A2DR (Current Sense Amp)
- U2: LM5017MR/NOPB (Buck Regulator)
- R1 (Shunt): FCSL110R005FER (5mΩ)
- L1: SRN8040-101M (100uH Inductor)
- D2: SS14 (Schottky Diode)
This project is open-source and available under the MIT License.