Ring oscillator
First Claim
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1. An improved ring oscillator, comprising:
- first, second and third current starved inverters coupled in a ring;
a first fast inverter coupled between the second and third current starved inverters;
a second fast inverter coupled between the third and first current starved inverters, said first and second fast inverters having a speed of operation to conduct in a linear region insufficiently long at a frequency of operation of said ring oscillator to excite an analog oscillation mode; and
an output buffer coupled to the ring oscillator and outputting an output periodic waveform.
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Abstract
An improved ring oscillator (10, 70) includes a first, second and third current starved inverters (12, 14, 16) coupled in a ring, a first fast inverter (40) coupled between the second and third current starved inverters (14, 16), and a second fast inverter (45) coupled between the third and first current starved inverters (14, 16). An output buffer (30) coupled to the ring provides an output periodic waveform.
86 Citations
12 Claims
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1. An improved ring oscillator, comprising:
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first, second and third current starved inverters coupled in a ring; a first fast inverter coupled between the second and third current starved inverters; a second fast inverter coupled between the third and first current starved inverters, said first and second fast inverters having a speed of operation to conduct in a linear region insufficiently long at a frequency of operation of said ring oscillator to excite an analog oscillation mode; and an output buffer coupled to the ring oscillator and outputting an output periodic waveform. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An improved ring oscillator, comprising:
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first, second and third current starved CMOS inverters coupled in a ring; a first switch coupled between the second and third current starved inverters; a second switch coupled between the third and first current starved inverters;
said first and second switches closing at different times thereby not exciting an analog oscillation mode in said ring oscillator;wherein the first and second switches each comprises; a pMOS transistor coupled to a power supply voltage; and an nMOS transistor coupled to the pMOS transistor and ground; and an output buffer coupled to the ring oscillator and outputting an output periodic waveform. - View Dependent Claims (9, 10, 11)
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12. An improved ring oscillator, comprising:
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a first current starved inverter having an input and an output; a second current starved inverter having an input connected to said output of said first current starved inverter and an output; a first fast inverter having an input coupled to said output of said second current starved inverter and an output, said first fast inverter having a speed of operation to conduct in a linear region insufficiently long at a frequency of operation of said ring oscillator to excite an analog oscillation mode; a third current starved inverter having an input connected to said output of said first fast inverter and an output; a second fast inverter having an input coupled to said output of said third current starved inverter and an output connected to said input of said first current starved inverter, said second fast inverter having a speed of operation to conduct in a linear region insufficiently long at a frequency of operation of said ring oscillator to excite an analog oscillation mode; and an output buffer coupled to the ring oscillator and outputting an output periodic waveform.
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Specification