Fully Integrated CMOS EME-Suppressing Current Regulator for Automotive Electronics

In this paper, two circuit design techniques for lower electromagnetic emission (EME) are demonstrated based on shaping the supply current: 1) a discrete-time EME-SCR with a digital feedback loop to obtain more EME attenuation in the low frequency range starting from 150 kHz. It achieves maximum 30 dB di/dt reduction at high frequency with 60 μA quiescent current and a 230 pF on-chip capacitance. The cutoff frequency is shifted down to 100 kHz, which is about 10x lower compared with the continuous-time implementation. 2) The frequency modulation of the discrete-time EME-SCR's clock to further reduce the EME level in a wide frequency range. Measurement results show the effectiveness of these circuit techniques on the reduction of EME on chip level.