company blog about Supply TI Current-Sense Amplifiers:Analog Current-Sense Amplifier,Digital Power Monitors

Supply TI Current-Sense Amplifiers:Analog Current-Sense Amplifier,Digital Power Monitors

Shenzhen Mingjiada Electronics Co., Ltd. is a company specialising in the distribution of electronic components. With our extensive procurement channels and wealth of experience in supply chain management, we are committed to providing our customers with high-quality electronic component supply services.

Supply Advantages:

1. Genuine Products Guaranteed, Reliable Quality

Direct supply from manufacturers: We have established long-term authorised partnerships with over 500 leading global semiconductor brands, ensuring that all products are genuine and sourced directly from manufacturers.

Quality Management System: Certified to ISO 9001:2014 Quality Management System and ISO 14001:2014 Environmental Management System standards.

Strict Quality Control: End-to-end inspections ensure 100% genuine products, eliminating refurbished or bulk new items, and providing batch traceability.

2. Comprehensive Product Range and Ample Stock

Product Coverage: Our inventory comprises over 2 million SKUs, covering general-purpose, industrial, automotive and military integrated circuits, as well as niche and hard-to-find models.

Wide Range of Applications: Covering microcontrollers, memory, power management, communications, automotive electronics, sensors, artificial intelligence, 5G and all other categories.

Inventory Advantages: We maintain real-time global inventory synchronisation between our dual warehouses in Shenzhen and Hong Kong, effectively resolving issues such as stock-outs, discontinued products and extended lead times.

3. Efficient Delivery and Rapid Response

Express delivery: Standard orders are delivered within 1–3 days; urgent orders are dispatched within 4 hours and delivered within 24–48 hours.

Global network: With branches in Hong Kong, Japan, Russia, Taiwan and other locations, we support one-stop global order fulfilment.

Flexible transactions: We offer a variety of trade terms and settlement currencies to meet the needs of both domestic and international customers.

I. Core Principles of Current Detection

All TI current sensing devices utilise the shunt resistor sampling method, sharing the same core principle: a high-precision, low-value shunt resistor is connected in series with the load circuit; as current flows through the resistor, a minute voltage difference is generated; the device captures this differential voltage signal, which is then amplified, filtered and calibrated to calculate the current.

Compared to Hall-effect sensing solutions, the resistor-sampling approach has no hysteresis error, lower temperature drift, faster response times and a simpler structure. It is suitable for a wide range of applications, from low to high voltage and from small to large currents, and is the mainstream solution for high-precision industrial current sensing. Depending on the subsequent signal processing and output methods, the product range is divided into two main lines: analogue and digital architectures.

II. Analogue Current Sense Amplifier

1. Architecture and Operating Principle

An analogue current sense amplifier is a purely analogue device that integrates a high-precision differential operational amplifier, gain configuration circuitry, filter circuitry and common-mode rejection circuitry. The device samples the minute differential voltage across the shunt resistor; after amplification via a fixed or programmable gain, it directly outputs an analogue voltage signal, with the output voltage exhibiting a strictly linear relationship with the sensed current.

These devices require no clock or programming and are operational immediately upon power-up; current acquisition can be achieved simply by connecting an external microcontroller ADC, making them an extremely simple and highly real-time current sensing solution. It supports both high-side and low-side detection topologies: high-side detection enables monitoring of load earth faults, whilst low-side detection offers a simpler circuit design and lower cost.

2. Key Feature Advantages

- Ultra-high real-time response: With no ADC sampling delay or digital processing delay, the bandwidth can reach up to the MHz range, enabling the capture of transient current spikes and pulsed currents, and making it suitable for high-frequency dynamic applications such as switching power supplies and motor drives

- Wide common-mode voltage range: TI’s high-end analogue detection amplifiers support an ultra-wide common-mode voltage range of –5 V to 110 V, making them suitable for 12 V, 24 V and 48 V industrial buses and high-voltage DC systems; they maintain a high common-mode rejection ratio (CMRR) even during high-voltage operation, offering exceptional immunity to interference

- Low error and low drift: Featuring a zero-drift architecture, these amplifiers offer low temperature drift and low offset voltage, ensuring high measurement accuracy across the entire temperature range and meeting industrial-grade accuracy requirements without the need for complex calibration

- Strong PWM immunity: Some high-end models incorporate enhanced PWM suppression, effectively cancelling out PWM switching noise from motors and inverter circuits to prevent signal jitter and distortion

- Bidirectional current sensing: Supports both forward and reverse current sampling, suitable for applications such as battery charging and discharging, and bidirectional power conversion

3. Typical TI product models

- INA241A: Flagship high-precision analogue current amplifier with a common-mode voltage range of –5 V to 110 V; supports bidirectional sensing and features integrated enhanced PWM suppression; suitable for high-voltage motor drives and industrial inverter systems

- INA225: 36 V programmable-gain analogue monitoring amplifier; supports independent supply voltage monitoring and bidirectional current sampling; suitable for low-voltage battery management and compact power modules

- INA2290: Dual-channel ultra-precision monitoring amplifier; operates over a wide supply voltage range of 2.7 V to 120 V with a high bandwidth of 1.1 MHz; suitable for industrial equipment requiring simultaneous monitoring of multiple current channels

4. Typical Application Scenarios

Primarily used in real-time closed-loop control, high-speed overcurrent protection and dynamic current monitoring scenarios, including constant-current control in switching power supplies, current-loop regulation in servo motors, fast charging and discharging control for lithium-ion batteries, instantaneous overcurrent protection in industrial equipment, and current sampling in high-frequency inverter circuits.

III. Digital Power Monitor

1. Architecture and Operating Principles

The Digital Power Monitor is an integrated intelligent sensing device which, building upon an analogue front-end sampling circuit, incorporates a high-precision Σ-Δ ADC, a microprocessor, a memory unit and a digital communication interface. After acquiring the voltage signal from the shunt resistor, the device autonomously performs analogue-to-digital conversion, data processing and error calibration, directly outputting digital parameters such as current, voltage, power, energy and temperature, without the need for an external ADC.

These devices support functions such as programmable sampling rates, averaging filters, threshold alarms and energy integration, enabling comprehensive, independent monitoring of power supply systems. They communicate with microcontrollers and host computers via standard buses such as I²C and SPI, significantly simplifying the system’s hardware architecture.

2. Key Features and Advantages

- Integrated multi-parameter monitoring: A single chip simultaneously acquires shunt current and bus voltage, automatically calculating instantaneous power, cumulative energy and charge; certain models support chip temperature monitoring, enabling comprehensive status monitoring of the power supply system

- Ultra-high measurement accuracy: Equipped with a 16–20-bit high-precision ADC, offering a dynamic range of up to 120 dB, supporting high-precision measurement across a wide range from minute to high currents, making it suitable for precision power consumption metering applications

- Extensive intelligent functions: Supports programmable sampling intervals, multi-average filtering, overcurrent/overvoltage/undervoltage threshold alarms, data latching and energy accumulation, enabling autonomous fault diagnosis and data storage

- Minimalist Bus Communication: Standardised I²C and SPI interfaces support multi-device bus networking; monitoring multiple power supplies requires no extensive analogue wiring, significantly reducing hardware complexity and wiring interference

- Low-Power Operation: Supports sleep mode with extremely low operating and shutdown currents, making it suitable for battery-powered and low-power IoT monitoring devices

3. Typical TI Product Models

- INA238: 85V, 16-bit high-precision digital power monitor with an I²C interface; supports current, voltage and power monitoring as well as threshold alarms; suitable for industrial power supplies and server power monitoring

- INA229: 20-bit ultra-high-precision monitor with a high-speed SPI interface; supports energy and charge accumulation with a programmable conversion rate; suitable for precision instruments and high-end energy storage equipment

- INA4230: Four-channel, 16-bit digital current monitor with multi-channel synchronous sampling, suitable for batch monitoring scenarios involving multiple power supplies and multi-branch equipment

4. Typical Application Scenarios

Primarily used in high-precision power consumption metering, power supply status diagnostics and intelligent energy consumption monitoring scenarios, including power supply monitoring for servers and data centres, energy consumption statistics for energy storage batteries, power consumption analysis of industrial equipment, power supply monitoring for IoT terminals, and battery health status detection.