An Externally Trimmed Integrated DC Current Regulator Insensitive to Conducted EMI

This paper introduces a new integrated dc current regulator using external resistive trimming, which presents a high degree of immunity against conducted electromagnetic interference (EMI). While classic topologies generate erratic bias currents that are totally different from the expected value once EMI is injected into the circuit, this new topology succeeds in producing the same fixed dc current, whether EMI is present or not. Extra filtering requiring small on-chip capacitors ensures that the ripple on the output current due to the interference remains at a very low value.