Ring oscillator clock
A semiconductor integrated circuit comprising: a ring oscillator that produces periodic pulses; and a controller that uses the pulses as clock pulses to determine time.
1 . A method of measuring time comprising:
fabricating a semiconductor ring oscillator that produces periodic pulses; and
using the pulses as clock pulses to determine time.
2 . A method according to claim 1 and comprising periodically calibrating the ring oscillator pulses responsive to clock pulses characterized by a repetition frequency greater than a repetition frequency of the ring oscillator pulses.
3 . A method according to claim 2 wherein the calibration clock pulses are provided by a crystal clock.
4 . A method according to claim 3 wherein the crystal clock comprises semiconductor circuitry.
5 . A method according to claim 4 wherein the ring oscillator and the semiconductor circuitry of the crystal clock are comprised in a same semiconductor circuit or portions of a same semiconductor circuit.
6 . A method according to claim 2 and controlling the clock pulses used to calibrate the ring oscillator pulses responsive to the ring oscillator pulses.
7 . A method according to claim 6 wherein controlling the clock pulses used to calibrate the ring oscillator pulses comprises turning off the pulses responsive to time determined using the ring oscillator pulses.
8 . A method according to claim 6 wherein controlling the clock pulses used to calibrate the ring oscillator pulses comprises turning on the pulses responsive to time determined using the ring oscillator pulses.
9 . A method of controlling a function of a semiconductor integrated circuit, the method comprising:
measuring time according to any of claims 1 - 8 ; and
controlling a function of the semiconductor integrated circuit responsive to the measured time.
10 . A method according to claim 9 wherein controlling a function of the semiconductor integrated circuit comprises putting at least a portion of the semiconductor circuit into a sleep mode responsive to the measured time.
11 . A method according to claim 10 wherein the at least a portion of the semiconductor integrated circuitry comprises a timing circuit.
12 . A method according to claim 11 wherein the timing circuit comprises a resonant crystal
13 . A method according to claim 9 wherein controlling a function of the semiconductor integrated circuit comprises awakening at least a portion of the semiconductor circuit from a sleep mode responsive to the measured time.
14 . A method according to claim 13 wherein the at least a portion of the semiconductor integrated circuit comprises a timing circuit.
15 . A method according to claim 14 wherein the timing circuit comprises a resonant crystal.
16 . A method according to claim 9 wherein the semiconductor integrated circuit is comprised in a cell phone.
17 . A method according to claim 9 wherein the semiconductor integrated circuit is comprised in a receiver adapted to receive TV signal configured responsive to a DVBH standard.
18 . A semiconductor integrated circuit comprising:
a ring oscillator that produces periodic pulses; and
a controller that uses the pulses as clock pulses to determine time.
19 . A semiconductor integrated circuit according to claim 18 and comprising a crystal clock that provides clock pulses.
20 . A semiconductor integrated circuit according to claim 19 and comprising a calibration circuit that uses clock pulses provided by the crystal clock to calibrate the periodic pulses provided by the ring oscillator.
20 . An semiconductor integrated circuit according to claim 19 wherein the controller controls the crystal clock to enter a sleep mode or awake from a sleep mode responsive to the determined time.
21 . A semiconductor integrated circuit according to claim 20 wherein the integrated semiconductor circuit is comprised in a cell phone.
22 . A semiconductor integrated circuit according to claim 20 wherein the integrated circuit is comprised in a receiver adapted to receive TV signal configured responsive to a DVBH standard.