Current-shunt monitor improves efficiency and accuracy

22nd November 2016

Daisy Stapley-Bunten

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Datasheet

Texas Instruments (TI) has introduced a current-sense amplifier for in-line motor phase current measurement that improves overall motor efficiency, compared to existing current-sense amplifiers. The INA240 offers enhanced Pulse-Width Modulation (PWM) rejection for systems running at up to 80V to support a variety of applications such as motor control, solenoid control and power delivery systems.

Key features and benefits;

Enhanced PWM rejection for improved motor efficiency: The presence of high-speed in-line PWM motor control systems requires high AC and DC accuracy. The INA240’s enhanced PWM rejection improves transient suppression and gives designers the ability to reduce their blanking time, optimize the motor-control algorithm and ultimately improve motor efficiency.
Flexible for a variety of motor applications: The INA240 operates at PWM rates in excess of 100kHz, with switching-edge rates as high as 10V/ns while enabling system voltages as high as 80V. In addition, to address the needs for a wide range of systems, this device supports the negative voltages (-4V) induced by the inductive kickback of the motor.
Industry-leading performance and accuracy: The INA240 has the industry’s best combination of low offset voltage (5µV), offset drift (50nV/°C), gain error and drift performance (0.05% and 0.5ppm/°C, respectively). The device also provides an excellent AC Common-Mode Rejection Ratio (CMRR) of 93dB at 50kHz. The INA240 delivers performance over a wide range of operating conditions.
Enhanced performance for any motor-control solution: The INA240’s precision is showcased in a 48-V 10-A In-Line Three-Phase High-Frequency Gallium Nitride (GaN) Inverter for Brushless Motors Reference Design. This BoosterPack plug-in module reference design is paired with a C2000 LaunchPad kit, demonstrating how designers can use the INA240 and LMG5200 GaN half-bridge power stage to reduce switching losses over an extended temperature range up to 125°C, facilitate the use of higher PWM frequencies and reduce heat sinking requirements.

The INA240 will be on display at the SPS IPC Drives exhibition in Booth 6-441 starting November 22^nd.

Tools and support to jump-start design
Short, use-case technical notes called TI TechNotes offer engineers implementation techniques related to low-drift in-line motor current phase measurement and current monitoring for overcurrent protection.

Support is available in the TI E2E Community Current Sensing forum, where engineers can search for solutions, get help, share knowledge, and solve problems with fellow engineers and TI experts. As with TI’s entire current-sensing portfolio, designers have access to a full suite of support resources, including a complete library of TI Designs reference designs, evaluation modules (EVMs), online training series and SPICE models.