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TI INA219BIDR Zero-Drift Bidirectional Current Power Monitor With I2C Interface

In today's electronic system design, precise current and power monitoring has become a critical factor in improving energy efficiency and optimising system performance. Shenzhen Mingjiada Electronics Co., Ltd., as a leading domestic supplier of electronic components, provides TI genuine INA219BIDR zero-drift bidirectional current/power monitors for industries such as industrial automation, new energy, and consumer electronics.

INA219BIDR Product Overview and Technical Highlights

The INA219BIDR is a high-precision bidirectional current and power monitor housed in an SOIC-8 package, featuring an I2C or SMBus-compatible interface, specifically designed for applications requiring precise power management. The INA219BIDR device simultaneously monitors the voltage drop across the shunt resistor and the bus power supply voltage, achieving high-precision measurements through its built-in 16-bit ADC and programmable gain amplifier (PGA).

Zero-drift architecture is one of the core technical advantages of the INA219BIDR. Compared to traditional current monitoring solutions, its input offset voltage (Vos) is as low as 50 μV, ensuring high-precision measurements of 0.5% accuracy across a wide temperature range of -40°C to +125°C, eliminating measurement errors caused by temperature changes. This feature makes it particularly suitable for industrial applications with long-term operation and significant environmental temperature fluctuations.

Key technical specifications of the INA219BIDR include:

Bus voltage range: 0V to 26V, covering the requirements of most low-voltage systems

Supply voltage: 3V to 5.5V single-supply operation, with maximum current consumption of only 1mA

Communication interface: Standard I2C/SMBus interface, supporting 16 programmable addresses

Package type: Industrial-standard SOIC-8, facilitating PCB layout and soldering

Functional features and system integration advantages of the INA219BIDR

The INA219BIDR integrates multiple advanced features, significantly simplifying system design and enhancing measurement reliability. Its programmable calibration values combined with an internal multiplier enable direct reading of current values (amps) and calculation of power values (watts) via an additional multiplier register. This integrated design eliminates the need for external calculation circuits, reducing BOM costs and PCB area.

Bidirectional current monitoring capability enables the device to simultaneously measure both forward and reverse current flow, making it particularly suitable for applications such as battery charge/discharge management and motor drives that require monitoring of bidirectional energy flow. By configuring the internal PGA (gain programmable to ±40 mV, ±80 mV, ±160 mV, or ±320 mV), designers can flexibly adapt to different values of shunt resistors, optimising measurement range and accuracy.

The INA219BIDR's I2C interface supports standard mode (100kHz) and fast mode (400kHz) communication, with 16 programmable addresses (configured via the A0 and A1 pins), facilitating the connection of multiple monitoring nodes on the same bus. Internal filtering options can be programmed to effectively suppress high-frequency noise and improve measurement stability.

The INA219BIDR's low-power characteristics (typical operating current of 1mA) make it ideal for portable and battery-powered devices. Its wide operating temperature range (-40°C to +125°C) ensures reliable operation in harsh environments, meeting industrial and automotive application requirements.

Electrical characteristics of the INA219BIDR:

Bus voltage measurement: 0V to 26V range, resolution 3.2mV/LSB  

Shunt voltage measurement: Depends on PGA settings, up to ±320mV full scale  

Current calculation: Current = Shunt voltage / Shunt resistance value  

Power calculation: Power = Bus voltage × Current value  

ADC resolution: 16-bit, conversion time configurable from 84μs to 8.244ms

PCB design recommendations for the INA219BIDR:

Shunt resistor layout: Place the shunt resistors as close as possible to the IN+ and IN- pins of the INA219BIDR, using Kelvin connections to minimise the impact of parasitic resistance

Power decoupling: Place a 1μF ceramic capacitor near the Vs pin to ensure stable power supply

Thermal management: Although the INA219BIDR has low power consumption, heat dissipation should still be considered in high ambient temperature applications

I2C wiring: Keep the SCL and SDA signal lines as short as possible, and add appropriate pull-up resistors if necessary

Typical application scenarios for the INA219BIDR

1. Industrial automation and motor control

In PLC systems, servo drives, and industrial robots, the INA219BIDR can monitor motor phase current and bus voltage in real time, enabling precise closed-loop control and overcurrent protection. Its high-side current detection capability avoids ground loop interference, while the wide temperature range ensures stable operation in factory environments.

2. Renewable Energy and Energy Storage Systems

In photovoltaic inverters, battery management systems (BMS), and charging stations, the INA219BIDR device is used for energy flow monitoring, accurately measuring charging and discharging currents and power to optimise system efficiency. Its bidirectional measurement capability is particularly suitable for energy storage systems, enabling simultaneous monitoring of grid power supply and battery charging/discharging status.

3. Consumer Electronics and Smart Devices

For laptops, smartphone chargers, and smart home devices, the INA219BIDR's compact size and low power consumption make it an ideal choice for power management. It can monitor device power consumption, implement intelligent power-saving strategies, and transmit data to the main control MCU via the I2C interface.

4. Communication Infrastructure

In 5G base stations, routers, and switches, the INA219BIDR device is used to monitor current and power in power distribution networks, helping to optimise energy usage and detect faults. Its high precision ensures the reliability of power management in communication equipment.