Use of redundancy in sub-ranging time-to-digital converters to eliminate offset mismatch issues
AssigneeSilicon Laboratories Inc.
InventorsBrian G. Drost, Ankur Guha Roy
Life of this patent
Estimating the term…
Abstract
A time-to-digital converter utilizes both coarse and fine quantizers and addresses mismatch by using redundant bits in the coarse time representation and the fine time representation. The redundant bits are compared and if the redundant bits are the same, no mismatch correction is required but if the redundant bits are different a correction is applied to correct the redundant portion of the coarse time information. The redundant portion includes the most significant bit generated by the fine quantizer and the least significant bit of the coarse quantizer. The correction adds to or subtracts from the redundant information.
Claims20
An apparatus comprising:
- a fine time-to-digital converter (TDC) providing fine time information with a first resolution, wherein the fine TDC is configured to roll over from a maximum value to a minimum value;
- a coarse TDC providing coarse time information with a second resolution, the second resolution more coarse than the first resolution and the second resolution is less than a range of the fine TDC such that a first portion of the fine time information and a second portion of the coarse time information overlap and provide redundancy;
- a compare circuit to compare the first portion of the fine time information and the second portion of the coarse time information and supply a mismatch indication in response to the first portion and the second portion not matching;
- and
- a correction circuit to correct the second portion responsive to the mismatch indication.
A method comprising:
- providing fine time information from a fine time-to-digital converter that rolls over from a maximum value to a minimum value;
- providing coarse time information from a coarse time-to-digital converter;
- comparing a first portion of the fine time information and a second portion of the coarse time information and supplying a mismatch indication in response to the first portion and the second portion not being equal, wherein the first portion and the second portion overlap;
- and
- correcting the second portion responsive to the mismatch indication.
A sub-ranging time-to-digital converter comprising:
- a fine time-to-digital converter providing fine time information;
- a coarse time-to-digital converter providing coarse time information;
- a compare circuit to compare a most significant bit of the fine time information and a least significant bit of the coarse time information and supply a mismatch indication in response to the most significant bit and the least significant bit not being equal, wherein the most significant bit and the least significant bit overlap and provide redundancy;
- and
- a correction circuit to correct the least significant bit of the coarse time information responsive to the mismatch indication.
Dependencies are inferred from the claim text.