US Patent 11888499 Transition-state output device, time-to-digital converter, and analog-to-digital converter circuit

A transition-state output device includes: a ring oscillator circuit; a state machine changing in state according to a change in state of the ring oscillator circuit; a transition-state acquisition section acquiring and holding state information including a signal output from the ring oscillator circuit and a signal output from the state machine, synchronously with a reference signal; and an internal-state calculation section calculating an internal state corresponding to a number of changes in state of the ring oscillator circuit, based on the state information held by the transition-state acquisition section. A time until the internal state, after transitioning from a first internal state to a second internal state, transitions to the first internal state again is longer than a time interval of updating the state information held by the transition-state acquisition section.