Recently, Maxim Integrated announced the MAX40056 bidirectional current sense amplifier, a proprietary pulse width modulation (PWM) suppression technology that helps engineers improve motor efficiency and reduce vibration. This high-speed, wideband amplifier extends Maxim's leadership in high-precision, high-voltage current-sense to motor control applications.

The motor control system requires high precision current sensing and current measurement of the motor windings. A common method is to measure the winding current by grounding the bridge circuit or the power reference. Direct measurement of winding current is a simpler, more accurate measurement, but due to the high common-mode swing of the PWM signal, there are certain difficulties in implementation. The current scheme restricts the popularity of this method due to poor PWM suppression performance and slower setup speed.

The MAX40056 rejects PWM slew rates above 500V/μs and completes signal setup in 500ns for full-scale winding current measurements with up to 0.3% accuracy. Compared to competing products, proprietary PWM suppression technology increases setup time by a factor of four, allowing motor control designers to increase the drive frequency of the motor or reduce the minimum duty cycle without compromising measurement accuracy. In addition, the higher PWM frequency helps stabilize current and reduce torque ripple for higher motor efficiency.

The MAX40056 supports a wide common-mode voltage range of -0.1V to +65V with a -5V to 70V protection range to ensure that the inductor does not damage the IC during kickback. With its two-way detection capability, the MAX40056 is ideal for DC motor control, base stations, data centers, battery packs, and other applications that require high-precision current measurement in noisy environments.

For more information on this product, please refer to the Maxim Integrated website: