The enhanced PWM rejection feature of the INA241x provides increased attenuation of large common-mode ΔV/Δt transients. Large ΔV/Δt common-mode transients associated with PWM signals are employed in applications such as motor or solenoid drive and switching power supplies. The disturbances that can occur at the output of a current sense amplifier from common-mode transients causes erroneous measurements and impose limitations when the output is valid. The INA241x is designed with high common-mode rejection techniques to reduce large ΔV/Δt transients before the system is disturbed. As a result, this makes system design simple with INA241x. The high AC CMRR, in conjunction with signal bandwidth, allows the INA241x to minimize output disturbances and ringing during common-mode transitions when compared against traditional current-sensing amplifiers.

Figure 7-1 Enhanced PWM Rejection Performance

Figure 7-1 shows the INA241x PWM enhancement performance. When INA241x senses the large common-mode ΔV/Δt transients, the device holds the output for 1μs, thereby preventing the common-mode disturbance from propagating to the output. If another common-mode transient occurs during the following 3μs, the INA241x relies on high BW and AC CMMR to attenuate the effect of common-mode transient. The enhanced PWM rejection is achieved up to a PWM frequency of 125kHz or if common-mode transient edges are separated by a 3μs interval or more.