Adaptive time-to-digital converter and method

Abstract

Systems, methods, and circuitries are disclosed for controlling an adaptive time-to-digital converter (TDC) that determines a phase difference between a reference signal and a phase locked loop (PLL) feedback signal. Adaptive TDC circuitry includes a chain of n delay elements each characterized by an incremental delay. Gate circuitry outputs a gated PLL feedback signal while a gating enable signal has an enable value. N sampling elements, each associated with a delay element, are enabled by the reference signal arriving at the input of the associated delay element to store a value of the gated PLL feedback signal. Adaptive gating circuitry is configured to generate the gating enable signal based on the incremental delay and a period of the PLL feedback signal. A supply voltage for the delay elements may be controlled to cause the delay elements to exhibit a desired incremental delay.