A Time-Mode PWM 1st Order Low-Pass Filter

Abstract

In this work, a first-order low-pass filter is proposed as suitable for time-mode PWM signal processing. In time-mode PWM signal processing, the pulse width of a rectangular pulse is the processing variable. The filter is constructed using basic time-mode building blocks such as time registers and time adders and so it is characterized by low complexity which can lead to the modular and versatile design of higher-order filters. All the building blocks of the filter were designed and verified in a TSMC 65 nm technology process. The sampling frequency was 5 MHz, the gain of the filter at low frequencies was at −0.016 dB, the cut-off frequency was 1.2323 MHz, and the power consumption was around 59.1 μW.