A Simple Area-Efficient Ripple-Rejection Technique for Chopped Biosignal Amplifiers

Chopping is an effective way to mitigate transistor flicker noise in biosignal amplifiers. However, chopping creates a ripple at the output of the amplifier, which is due to the upmodulated amplifier offset and flicker noise. Many techniques have been suggested in the literature to reduce these ripples. This brief presents a ripple-reduction technique that is far simpler than previous techniques, yet effective and area efficient while consuming no additional power. Simulations using a 65-nm complementary metal-oxide-semiconductor process show that the output ripples are attenuated by 78 dB, whereas all other performance parameters of the amplifier remain unchanged.