Maxim introduces bi-directional current detection amplifiers

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

     Motor control system requires high precision current detection and current measurement of motor windings. The common method is to measure the winding current by grounding the bridge circuit or the reference end of the supply. Direct measurement of winding current is a simpler and more accurate measurement, but it is difficult to implement because of the high common-mode swing of PWM signal. Due to the poor PWM suppression performance and slow establishment speed, the current scheme restricts the popularity of this method.

     The MAX40056 can suppress PWM swing rates above 500V/µs and complete signal establishment within 500ns for full winding current measurement with accuracy up to 0.3%. Proprietary PWM suppression technology improves setup time by up to four times compared to competing products, allowing motor control designers to increase the motor's drive frequency or reduce the minimum duty cycle without reducing measurement accuracy. The higher PWM frequency helps to stabilize the current, reduce torque ripple, and achieve higher motor efficiency. Accurate measurement of low duty cycle winding current helps to reduce or basically eliminate the vibration of the motor at low speed.

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