Capacitive charge pump
DCFirst Claim
1. A charge pump, comprising:
- an output node;
a first capacitor having a first terminal coupled to a first circuit node; and
a first switch having a first current electrode coupled to the first circuit node, a control electrode coupled to receive a first switch control signal, and a second current electrode coupled to the output node, wherein the first switch control signal controls charge transfer between the first capacitor and the output node;
a second capacitor having a first terminal coupled to a second circuit node;
a second switch having a first current electrode coupled to the second circuit node, a second current electrode coupled to the output node;
a delay circuit having an input coupled to receive the first switch control signal and an output coupled to a control electrode of the second switch.
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Abstract
A capacitive charge pump that can be implemented in such devices as e.g. a phase locked loop (PLL). The charge pump includes at least one capacitor in the charge path and discharge path for limiting the amount of charge provided to or removed from a filter capacitor of a PLL. In one example, a second capacitor may be provided in the charge path or discharge path to reduce the capacitance (if provided in series) or increase the capacitance (if provided in parallel) to adjust the maximum amount of charge transferred to a filter capacitor. In one example, multiple capacitive stages may be implemented in parallel to increase the maximum amount of charge transferred to a filter capacitor. Each stage is enabled after a delayed period of time from when the previous stage was enabled.
38 Citations
43 Claims
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1. A charge pump, comprising:
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an output node;
a first capacitor having a first terminal coupled to a first circuit node; and
a first switch having a first current electrode coupled to the first circuit node, a control electrode coupled to receive a first switch control signal, and a second current electrode coupled to the output node, wherein the first switch control signal controls charge transfer between the first capacitor and the output node;
a second capacitor having a first terminal coupled to a second circuit node;
a second switch having a first current electrode coupled to the second circuit node, a second current electrode coupled to the output node;
a delay circuit having an input coupled to receive the first switch control signal and an output coupled to a control electrode of the second switch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A charge pump, comprising:
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an output node;
a first capacitor having a first terminal coupled to a first circuit node;
a first switch having a first current electrode coupled to the first circuit node, a control electrode coupled to receive a first switch control signal, and a second current electrode coupled to the output node, wherein the first switch control signal controls charge transfer between the first capacitor and the output node;
a potential setting circuit coupled to the first circuit node, wherein the potential setting circuit selectively sets, based on the first switch control signal, the first circuit node to a first potential;
wherein the potential setting circuit has a first current electrode coupled to a node whose voltage is dependent upon a voltage of the output node and a second current electrode coupled to the first circuit node, wherein the first potential is dependent upon on the voltage of the output node. - View Dependent Claims (10)
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11. A charge pump, comprising:
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an output node;
a first capacitor having a first terminal coupled to a first circuit node;
a first switch having a first current electrode coupled to the first circuit node, a control electrode coupled to receive a first switch control signal, and a second current electrode coupled to the output node, wherein the first switch control signal controls charge transfer between the first capacitor and the output node;
a second capacitor having a first terminal coupled to a second terminal of the first capacitor and a second terminal coupled to a first voltage supply. - View Dependent Claims (12)
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13. A charge pump, comprising:
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an output node;
a first capacitor having a first terminal coupled to a first circuit node;
a first switch having a first current electrode coupled to the first circuit node, a control electrode coupled to receive it first switch control signal, and a second current electrode coupled to the output node, wherein the first switch control signal controls charge transfer between the first capacitor and the output node;
a second capacitor having a first terminal coupled to a terminal of the first capacitor and a second terminal coupled to a first voltage supply;
a second switch having a first current electrode coupled to the first terminal of the second capacitor, a second current electrode coupled to the first voltage supply, and a control electrode coupled to receive an inverse of the first switch control signal.
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14. A charge pump, comprising:
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an output node;
a first capacitor having a first terminal coupled to a first circuit node;
a first switch having a first current electrode coupled to the first circuit node, a control electrode coupled to receive a first switch control signal, and a second current electrode coupled to the output node, wherein the first switch control signal controls charge transfer between the first capacitor and the output node;
a second capacitor having a first terminal coupled to a second circuit node; and
a second switch having a first current electrode coupled to the second circuit node, a control electrode coupled to receive a second switch control signal, and a second current electrode coupled to the output node, wherein the second switch control signal controls charge transfer between the second capacitor and the output node;
a first potential setting circuit coupled to the first circuit node, wherein the first potential setting circuit selectively sets, based on the first switch control signal, the first circuit node to a first potential, wherein the first potential is dependent upon on a voltage of the output node a second potential setting circuit coupled to the second circuit node wherein the second potential setting circuit selectively sets, based on the second switch control signal, the second circuit node to a second potential, wherein the second potential is dependent upon on the voltage of the output node. - View Dependent Claims (15, 16, 17)
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18. A charge pump, comprising:
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an output node;
a first capacitor having a first terminal coupled to a first circuit node;
a first switch having a first current electrode coupled to the first circuit node, a control electrode coupled to receive a first switch control signal, and a second current electrode coupled to the output node, wherein the first switch control signal controls charge transfer between the first capacitor and the output node;
a second capacitor having a first terminal coupled to a first supply voltage;
a second switch having a control electrode coupled to receive the first switch control signal, a first current electrode coupled to a second terminal of the first capacitor, and a second current electrode coupled to a second terminal of the second capacitor wherein, the second switch selectively couples, based on the first switch control signal, the first capacitor and the second capacitor in series. - View Dependent Claims (19, 20, 21, 22, 23)
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24. A phase locked loop (PLL) circuit comprising:
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a filter capacitor;
a phase frequency detector circuit having a first input to receive a first clack, a second input to receive a second clock, and a first output to provide a first clock control signal based on the first clock and the second clock, wherein the phase frequency detector circuit has a second output to provide a second clock control signal based on the first clock and the second clock;
a voltage controlled oscillator having an input coupled to a first terminal of the filter capacitor and an output to provide an output clock;
a charge pump having a first input to receive the first clock control signal and an output coupled to the first terminal of the filter capacitor and the input of the voltage controlled oscillator, the charge pump comprising;
a first capacitor having a first terminal;
a first switch having a first current electrode coupled to the first terminal of the first capacitor, a control electrode coupled to receive the first clock control signal, and a second current electrode coupled to the first terminal of the filter capacitor, tho first switch selectively coupling the first capacitor to the filter capacitor, based on the first clock control signal;
a second capacitor;
a second switch having a first current electrode coupled to a first terminal of the second capacitor, a second current electrode coupled to the first terminal of the filter capacitor, and a control electrode coupled to receive the second clock control signal, the second switch selectively coupling the second capacitor to the filter capacitor, based on the second clock control signal;
a potential setting circuit coupled to the first terminal of the first capacitor, wherein the potential setting circuit selectively sets, based on the first clock control signal, the first terminal of the first capacitor to a first potential;
a second potential setting circuit coupled to the first terminal of the second capacitor, wherein the second potential setting circuit selectively sets, based on the second clock control signal, the first terminal of the second capacitor to a second potential;
wherein the first and second potentials are dependent upon a voltage of the output node. - View Dependent Claims (25, 26, 27, 28, 29, 30)
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31. A charge pump, comprising:
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an output node;
a first capacitor having a first terminal coupled to a first circuit node;
a first switch having a first current electrode coupled to the first circuit node, a control electrode coupled to receive a first switch control signal, and a second current electrode coupled to the output node, wherein the first switch control signal controls charge transfer between the first capacitor and the output node;
wherein the first switch includes a pass gate, the pass gate having a second control electrode coupled to receive an inverse of the first switch control signal.
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32. A charge pump comprising:
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an output node;
a charge path including a first capacitor;
a first switch including a control electrode coupled to receive a first charge control signal, wherein the first capacitor selectively provides charge based on the first charge control signal, to the output node via the first switch;
a discharge path including a second capacitor;
a second switch having a control electrode coupled to receive a second charge control signal, wherein the second capacitor selectively receives charge, based on the second charge control signal, from the output node. - View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40)
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41. A charge pump, comprising:
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an output node;
a first capacitor having a first terminal coupled to a first circuit node;
a first switch having a first current electrode coupled to the first circuit node, a control electrode coupled to receive a first switch control signal, and a second current electrode coupled to the output node, wherein the first switch control signal controls charge transfer between the first capacitor and the output node;
a second capacitor having a first terminal coupled to a second circuit node; and
a second switch having a first current electrode coupled to the second circuit node, a control electrode coupled to receive a second switch control signal, and a second current electrode coupled to the output node, wherein the second switch control signal controls charge transfer between the second capacitor and the output node;
a third capacitor having a first terminal coupled to a third circuit node;
a third switch having a first current electrode coupled to the third circuit node, a second current electrode coupled to the output node;
a first delay circuit having an input coupled to receive the first switch control signal and an output coupled to a control electrode of the third switch;
a fourth capacitor having a first terminal coupled to a fourth circuit node;
a fourth switch having a first current electrode coupled to the fourth circuit node, a second current electrode coupled to the output node;
a second delay circuit having an input coupled to receive the second switch control signal and an output coupled to a control electrode of the fourth switch. - View Dependent Claims (42, 43)
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Specification