INA219 I2C BI-Directional Hight Side DC Current / Power Monitor Sensor

CJMCU-219 INA219 Bi-directional Current/Power Supply Monitor Module is an exceptionally precise sensor solution designed to measure current and power flowing in both directions on a high-side bus. Built around the highly accurate Texas Instruments INA219 chip, this module enables system designers to monitor bus voltage, shunt voltage, and calculated power using a convenient I²C digital interface. Consequently, it eliminates the complexity of analog sensing methods and delivers high accuracy with a maximum error of only ±1% over the extended temperature range. This versatile module easily integrates into various embedded systems, providing essential diagnostics for energy management. Furthermore, its small form factor and low-power operation make it an ideal choice for monitoring battery life and optimizing power consumption in portable devices and servers.

Key Features:

• High-Side Bi-directional Sensing: The INA219 architecture measures current flowing into and out of the bus line (bi-directional), supporting common-mode voltages up to +26 V.
• I²C Digital Interface: This module uses a 2-wire I²C/Two-Wire Interface (TWI) for seamless communication and configuration with microcontrollers, simplifying wiring and reducing pin count.
• Integrated Calibration Register: The chip includes a programmable calibration register that allows you to configure the internal multiplier, thereby directly outputting current in Amperes and power in Watts.
• High Accuracy: The device boasts a maximum initial offset voltage of ±100 μV and a maximum gain error of ±1.0%, guaranteeing reliable measurements.
• Wide Bus Voltage Range: The measurement circuit handles bus voltages from 0 V up to +26 V, accommodating 3.3V, 5V, 12V, and 24V systems.

Technical Specifications:

• Sensing Chip: Texas Instruments INA219
• Operating Voltage (V_CC): 3.0 V to 5.5 V (Logic Supply)
• Bus Voltage Range (V_BUS): 0 V to +26 V
• Maximum Current Measurement: ±3.2 A (Default maximum, depends on calibration)
• Internal Shunt Resistor (R_SHUNT): 0.1 Ω (1%)
• Communication Interface: I²C (Adjustable Address: 4 possible addresses)
• Current Resolution: Varies based on configuration (typically down to 0.8 mA)
• Accuracy (Max Error): ±1.0% (Gain Error)

Mechanical Specifications:

• Module Name: CJMCU-219
• Package Type: Small PCB Breakout Module
• Mounting: Solderable header pins (typically included but may require soldering)
• LED Indicator: Power On LED (typically)

Dimensions:

• PCB Length: ≈ 25 mm
• PCB Width: ≈ 13 mm
• PCB Thickness: ≈ 1.6 mm
• Weight: ≈ 2 g (Extremely lightweight for portable integration)

Pinout and Wiring:

• VCC: Connect the 3V-5.5V logic power supply for the INA219 chip.
• GND: Connect to the circuit ground reference.
• SDA: The I²C Serial Data line; connect to the microcontroller’s SDA pin.
• SCL: The I²C Serial Clock line; connect to the microcontroller’s SCL pin.
• VBUS: Connect the positive terminal of the power line being monitored (the load’s supply input).
• GND (Load Side/Shunt): Connect the negative terminal of the power line being monitored (the load’s supply output, after the shunt).
• Wiring Note: Always connect the shunt resistor in series with the positive high-side bus line to measure the current accurately.

Datasheet Reference:

• Download Texas Instruments INA219 Datasheet

Commonly Used in:

• Battery Management Systems (BMS): Provides continuous monitoring of charge/discharge cycles and remaining battery capacity.
• Server and Telecom Equipment: Used for power optimization, redundancy management, and fault detection in infrastructure.
• Solar Power Monitoring: Essential for tracking energy harvesting efficiency and load usage in off-grid systems.

Applications:

• Energy Auditing: Accurately measuring the real-time power consumption of complex electronic circuits.
• Fault Detection: Detecting overcurrent conditions by continuously monitoring the bus line current.
• Load Profiling: Creating precise usage profiles for motors, solenoids, or other varying loads.
• Portable Devices: Implementing smart power management features in handheld and wearable electronics.

Equivalent Models:

• INA226: A pin-compatible upgrade with higher precision (16-bit resolution) and lower offset voltage.
• MAX471: An older, analog-output current sensor, however, it lacks the digital interface and power calculation capabilities of the INA219.
• INA219-based modules from other manufacturers: Modules utilizing the same INA219 chip but sold under different breakout board names (e.g., Adafruit INA219, SparkFun INA219).

Package Includes:

• 1 x CJMCU-219 INA219 Current/Power Supply Monitoring Module