Time-to-digital converter and comparator-based reference voltage generator

Abstract

A time-to-digital converter (TDC) that combines the energy efficiency of a successive approximation (SAR) design with the high speed of pipelined converters by leveraging the inherently pipelined nature of time-domain signaling. The TDC achieves high speed by removing a comparator decision from a signal path, instead using AND/OR gates to separate early and late edges. The TDC uses a pipelined SAR architecture to digitize a differential delay between two incoming clock edges with high speed and low power consumption. Described is a modular digital reference voltage generator that can be used for a capacitive digital-to-analog converter (DAC). The generator comprises a decoupling capacitor, one or more clocked comparators, and power transistor(s). A simplified digital low dropout (LDO) circuitry is used to provide fast reference voltage generation with minimal overhead. The LDO circuitry is arrayed using time-interleaved synchronous clocks or staggered asynchronous clocks to provide finer timing resolution.