US4636748A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Charge pump for use in a phase-locked loop
Assignee: EMC Corp
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Filing: 1985-06-26
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Granted: 1987-01-13
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Expires: 2005-06-26
Abstract
Abstract An improved charge pump for use in a phase-locked loop is disclosed in which there is only one current source, and in which all switching components pass current in the same direction. The charge pump may thus be constructed entirely of NPN transistors, which makes it possible to embody it in a single integrated circuit chip. The pump up and pump down currents inherently have the same magnitude and transient characteristics, thus minimizing steady-state errors.
Inventors
- 👤 II Paul W. Latham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:34
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/085; H03L7/089; H03L7/0891; H03L7/0895; H03L7/0896
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
94 words
A charge pump responsive to first and second commands for effecting in a current integrating means a change in voltage proportional to a difference in duration between the first and second commands, the charge pump comprising: a current source for producing a source current; a first switching means responsive to the first command for passing the source current through the integrating means in a first direction; and a second switching means responsive to the second command for passing the source current through the integrating means in a second direction opposite to the first direction.
Claim 2
Dependent Claim
94 words
A charge pump responsive to first and second commands for effecting in a current integrating means a change in voltage proportional to a difference in duration between the first and second commands, the charge pump comprising: a current source for producing a source current; a first switching means responsive to the first command for passing the source current through the integrating means in a first direction; and a second switching means responsive to the second command for passing the source current through the integrating means in a second direction opposite to the first direction.
Claim 3
Dependent Claim
174 words
A charge pump responsive to first and second commands for effecting in a current integrating means a change in voltage proportional to a difference in duration between the first and second commands, the charge pump comprising: a current source for producing a source current; a first switching means connected between the current source and the current integrating means and responsive to the first command for passing the source current to the current integrating means as a first current in a first direction; a second switching means responsive to the first command for completing a first current path for the first current from the current integrating means; a third switching means connected between the current source and the current integrating means and responsive to the second command for passing the source current to the current integrating means as a second current in a second direction opposite to the first direction; and a fourth switching means responsive to the second command for completing a second current path for the second current from the current integrating means.
Claim 4
Dependent Claim
174 words
A charge pump responsive to first and second commands for effecting in a current integrating means a change in voltage proportional to a difference in duration between the first and second commands, the charge pump comprising: a current source for producing a source current; a first switching means connected between the current source and the current integrating means and responsive to the first command for passing the source current to the current integrating means as a first current in a first direction; a second switching means responsive to the first command for completing a first current path for the first current from the current integrating means; a third switching means connected between the current source and the current integrating means and responsive to the second command for passing the source current to the current integrating means as a second current in a second direction opposite to the first direction; and a fourth switching means responsive to the second command for completing a second current path for the second current from the current integrating means.
Claim 5
Dependent Claim
31 words
The charge pump recited in claim 2, wherein: the first and third switching means pass the source current to a circuit ground when the first and second commands are simultaneously true.
Claim 6
Dependent Claim
31 words
The charge pump recited in claim 2, wherein: the first and third switching means pass the source current to a circuit ground when the first and second commands are simultaneously false.
Claim 7
Dependent Claim
46 words
The charge pump recited in claim 2, wherein: the charge pump is configured as a bridge circuit; the first, second, third, and fourth switching means each comprise one leg of the bridge circuit; and the current integrating means comprises a capacitor connected across the bridge circuit.
Claim 8
Dependent Claim
212 words
In a phase-locked loop comprising a voltage-controlled oscillator (VCO) responsive to a control voltage for producing a first signal which is periodic at a frequency proportional to the control voltage; means for detecting a phase difference between the first signal and a reference signal, and for producing first and second commands, a difference between whose durations is proportional to the phase difference; a charge pump responsive to the phase difference detecting means for producing a first current and a second current, a sum of the integrals of which is proportional to the difference between the durations of the first and second commands; and adjusting means including current integrating means responsive to the first current and the second current for adjusting the control voltage by an amount proportional to the sum of the integrals of the first current and the second current; the charge pump comprising a current source for producing a source current; a first switching means responsive to the first command for passing the source current through the current integrating means as a first current in a first direction; a second switching means responsive to the second command for passing the source current through the current integrating means as a second current in a second direction opposite to the first direction.
Claim 9
Dependent Claim
212 words
In a phase-locked loop comprising a voltage-controlled oscillator (VCO) responsive to a control voltage for producing a first signal which is periodic at a frequency proportional to the control voltage; means for detecting a phase difference between the first signal and a reference signal, and for producing first and second commands, a difference between whose durations is proportional to the phase difference; a charge pump responsive to the phase difference detecting means for producing a first current and a second current, a sum of the integrals of which is proportional to the difference between the durations of the first and second commands; and adjusting means including current integrating means responsive to the first current and the second current for adjusting the control voltage by an amount proportional to the sum of the integrals of the first current and the second current; the charge pump comprising a current source for producing a source current; a first switching means responsive to the first command for passing the source current through the current integrating means as a first current in a first direction; a second switching means responsive to the second command for passing the source current through the current integrating means as a second current in a second direction opposite to the first direction.
Claim 10
Dependent Claim
283 words
In a phase-locked loop comprising a voltage-controlled oscillator (VCO) responsive to a control voltage for producing a first signal which is periodic at a frequency proportional to the control voltage; means for detecting a phase difference between the first signal and a reference signal, and for producing first and second commands, a difference between whose durations is proportional to the phase difference; a charge pump responsive to the phase difference detecting means for producing a first current and a second current, a sum of the integrals of which is proportional to the difference between the durations of the first and second commands; and adjusting means including current integrating means responsive to the first current and the second current for adjusting the control voltage by an amount proportional to the sum of the integrals of the first current and the second current; the charge pump comprising a current source for producing a source current; a first switching means connected between the current source and the current integrating means and responsive to the first command for passing the source current to the current integrating means as a first current in a first direction; a second switching means responsive to the first command for completing a first current path for the first current from the current integrating means; a third switching means connected between the current source and the current integrating means and responsive to the second command for passing the source current to the current integrating means as a second current in a second direction opposite to the first direction; and a fourth switching means responsive to the second command for completing a second current path for the second current from the current integrating means.
Claim 11
Dependent Claim
283 words
In a phase-locked loop comprising a voltage-controlled oscillator (VCO) responsive to a control voltage for producing a first signal which is periodic at a frequency proportional to the control voltage; means for detecting a phase difference between the first signal and a reference signal, and for producing first and second commands, a difference between whose durations is proportional to the phase difference; a charge pump responsive to the phase difference detecting means for producing a first current and a second current, a sum of the integrals of which is proportional to the difference between the durations of the first and second commands; and adjusting means including current integrating means responsive to the first current and the second current for adjusting the control voltage by an amount proportional to the sum of the integrals of the first current and the second current; the charge pump comprising a current source for producing a source current; a first switching means connected between the current source and the current integrating means and responsive to the first command for passing the source current to the current integrating means as a first current in a first direction; a second switching means responsive to the first command for completing a first current path for the first current from the current integrating means; a third switching means connected between the current source and the current integrating means and responsive to the second command for passing the source current to the current integrating means as a second current in a second direction opposite to the first direction; and a fourth switching means responsive to the second command for completing a second current path for the second current from the current integrating means.
Claim 12
Dependent Claim
31 words
The phase-locked loop recited in claim 7, wherein: the first and third switching means pass the source current to a circuit ground when the first and second commands are simultaneously true.
Claim 13
Dependent Claim
31 words
The phase-locked loop recited in claim 7, wherein: the first and third switching means pass the source current to a circuit ground when the first and second commands are simultaneously false.
Claim 14
Dependent Claim
46 words
The phase-locked loop recited in claim 7, wherein: the charge pump is configured as a bridge circuit; the first, second, third, and fourth switching means each comprise one leg of the bridge circuit; and the current integrating means comprises a capacitor connected across the bridge circuit.
References Cited (Backward Citations)
US4546330A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-01-12 | 1990-07-14 | 1991-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-12 | 1994-07-14 | 1995-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-12 | 1998-07-14 | 1999-01-13 | $7700.00 | Window Closed / Lapsed |