7Semi INA219 Triple-Channel DC Current Monitoring Sensor Breakout

Overview

The module is based on the INA219 current/power monitor IC, a high-side current and power monitoring IC.

• Measures:

  • Current (A)

  • Bus Voltage (V)

  • Power (W)

   

• Triple-channel breakout means:

  • Three independent INA219 circuits on one board

  • Each channel monitors a separate load

   

Designed for precise DC power monitoring in multi-channel systems.

Working Principle

1. Shunt Resistor Method (Current Measurement)

• A precision low-value shunt resistor is placed in series with the load

• Current flow creates a small voltage drop (shunt voltage)

Based on OhmrV_{shunt}}{R_{shunt}}I=Rshunt'Vshunt

The INA219 measures this tiny voltage very accurately.

2. High-Side Measurement

• Sensor is placed on the positive supply line (high side)

• Allows:

  • Accurate measurement without disturbing ground reference

  • Detection of load faults

3. Internal ADC & Processing

• Built-in 12-bit ADC converts analog signals into digital values

• Calculates:

  • Current

  • Bus voltage

  • Power (internally computed)

Measurement Capabilities

Current

• Typical range: up to 3.2 A (depends on shunt resistor)

• Resolution: up to 0.1 mA (configurable)

Voltage

• Bus voltage rangp>

  • Calculated internally:

    P=V'IP = V \times IP=V'I

  No external computation required.

  Electrical Characteristics

  • Supply voltage: 3V to 5.5V

  • Low current consumption

  • Operates with standard logic levels

  Communication Interface

  • Interface: I2C (digital communication)

  • Default address: 0x40 (configurable via pins)

  In triple-channel boards:

  • Each INA219 must have different I2C address

  Internal Features

  Programmable Gain Amplifier (PGA)

  • Amplifies small shunt voltages

  • Supports multiple ranges:

    • 40 mV to 320 mV

  Calibration Register

  • Allows scaling based on:

    nge

Built-in Power Calculation

• Automatically computes power values

• Reduces microcontroller load

Bidirectional Measurement

• Can measure:

  • Charging current

  • Discharging current

Triple-Channel Architecture

The breakout includes:

• 3 INA219 ICs

• 3 shunt resistors

• Shared I2C bus

Each channel:

• Works independently

• Can monitor separate loads simultaneously

Measurement Flow

• Current flows through shunt resistor

• Voltage drop is measured

• ADC converts signal

• Calibration applied

• Outputs:

  • Current

  • Voltage

  • erformance Characteristics

    • High accuracy due to:

      • Precision amplifier

      • Digital calibration

    • Good stability across temperature

    • Suitable for low-current measurement

    Limitations

    • Maximum current limited by:

      • Shunt resistor rating

    • Not suitable for:

      • Very high current (>10A without external modification)

    • Accuracy depends on:

      • Proper calibration

      • PCB layout

    Breakout Board Role (7Semi)

    The breakout board:

    • Integrates:

      • Three INA219 ICs