Quad-array diode-less RF-to-DC rectifying charge-pump converter for energy harvesting
First Claim
1. A RF-to-DC converter comprising:
- a first Radio-Frequency (RF) input and a second RF input that receive a RF signal from an antenna;
a buffer circuit for generating a first buffered RF signal and a second buffered RF signal from the first and second RF input, and for generating a first control signal and a second control signal;
wherein the first control signal and the second control signal alternately indicate a pre-charge phase and a pumping phase;
a first array of capacitors having bottom plates receiving the second buffered RF signal;
a second array of capacitors having bottom plates receiving the first buffered RF signal;
a first bank of L-switches, each L-switch coupled between an input capacitor in the second array of capacitors and an output capacitor in the first array of capacitors;
a third array of capacitors having bottom plates receiving the first buffered RF signal;
a fourth array of capacitors having bottom plates receiving the second buffered RF signal;
a second bank of L-switches, each L-switch in the second bank coupled between an input capacitor in the fourth array of capacitors and an output capacitor in the third array of capacitors;
wherein each L-switch comprises;
a pre-charge transistor that charges the input capacitor during the pre-charge phase;
a stage-transfer transistor that transfers charge from the input capacitor to the output capacitor during the pumping phase;
wherein the first control signal and the second control signal are connected to the first bank of L-switches and to the second bank of L-switches to cause the first bank of L-switches to operate in the pre-charge phase when the second bank of L-switches operate in the pumping phase,whereby the first bank and the second bank operate in opposite phases.
1 Assignment
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Accused Products
Abstract
A RF-to-DC converter charges a battery or powers a circuit from the energy of received radio waves. The RF energy received is very small for far-field applications, so the converter is highly sensitive. Four capacitor arrays are arranged in two banks. Buffered RF signals pump bottom plates of the capacitors. A series of L-switches in each bank connect between the two capacitor arrays in that bank. Each L switch has a pre-charge switch that charges that stage'"'"'s input capacitor, and a stage-transfer switch that shares charge from the input capacitor to an output capacitor for that stage. Switches in the two banks alternately pre-charge and pump, with the left bank pumping while the right bank pre-charges. Switches are transistors with substrates tied to their sources or actively driven by substrate control signals. One bank may use n-channel transistors with the other bank uses p-channel transistors. Gate voltages may be boosted.
13 Citations
20 Claims
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1. A RF-to-DC converter comprising:
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a first Radio-Frequency (RF) input and a second RF input that receive a RF signal from an antenna; a buffer circuit for generating a first buffered RF signal and a second buffered RF signal from the first and second RF input, and for generating a first control signal and a second control signal; wherein the first control signal and the second control signal alternately indicate a pre-charge phase and a pumping phase; a first array of capacitors having bottom plates receiving the second buffered RF signal; a second array of capacitors having bottom plates receiving the first buffered RF signal; a first bank of L-switches, each L-switch coupled between an input capacitor in the second array of capacitors and an output capacitor in the first array of capacitors; a third array of capacitors having bottom plates receiving the first buffered RF signal; a fourth array of capacitors having bottom plates receiving the second buffered RF signal; a second bank of L-switches, each L-switch in the second bank coupled between an input capacitor in the fourth array of capacitors and an output capacitor in the third array of capacitors; wherein each L-switch comprises; a pre-charge transistor that charges the input capacitor during the pre-charge phase; a stage-transfer transistor that transfers charge from the input capacitor to the output capacitor during the pumping phase; wherein the first control signal and the second control signal are connected to the first bank of L-switches and to the second bank of L-switches to cause the first bank of L-switches to operate in the pre-charge phase when the second bank of L-switches operate in the pumping phase, whereby the first bank and the second bank operate in opposite phases. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An energy harvesting circuit comprising:
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a first plurality of L-switches, each L-switch in the first plurality of L-switches comprising; a first pre-charge transistor with a channel coupled between a stage input capacitor and a stage input node; a first stage-transfer transistor with a channel coupled between the stage input capacitor and a stage output; a second plurality of L-switches, each L-switch in the second plurality of L-switches comprising; a second pre-charge transistor with a channel coupled between a stage input capacitor and a stage input node; a second stage-transfer transistor with a channel coupled between the stage input capacitor and a stage output; a control circuit, receiving an input from an antenna, and generating a first buffered input and a second buffered input, the control circuit also generating a first control signal and a second control signal having a same period as the input from the antenna, wherein the first control signal and the second control signal are non-overlapping alternating signals; a first array of capacitors each coupled to the second buffered input, the first array of capacitors each also being connected to the stage output of a first stage-transfer transistor of an L-switch in the first plurality of L-switches and to the stage input node of the first pre-charge transistor, wherein a stage output node or a prior L-switch in the first plurality of L-switches connects to a stage input node of a next L-switch in the first plurality of L-switches; a second array of capacitors each coupled to the first buffered input, the second array of capacitors each also being the stage input capacitor that connects to a first stage-transfer transistor of an L-switch in the first plurality of L-switches; a third array of capacitors each coupled to the first buffered input, the third array of capacitors each also being connected to the stage output of a second stage-transfer transistor of an L-switch in the second plurality of L-switches and to the stage input node of the second pre-charge transistor, wherein a stage output node or a prior L-switch in the second plurality of L-switches connects to a stage input node of a next L-switch in the second plurality of L-switches; a fourth array of capacitors each coupled to the second buffered input, the fourth array of capacitors each also being the stage input capacitor that connects to a second stage-transfer transistor of an L-switch in the second plurality of L-switches; and a power line for powering a circuit or for charging a battery; wherein the stage output of a last L-switch in the first plurality of L-switches drives the power line; wherein the stage output of a last L-switch in the second plurality of L-switches also drives the power line. - View Dependent Claims (15, 16, 17, 18)
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19. A RF-to-DC energy harvester comprising:
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an antenna for receiving a Radio-Frequency (RF) signal; a buffer circuit connected to the antenna to generate a positive buffered RF signal and a negative buffered RF signal, and a first control signal and a second control signal; a first array of capacitors having bottom plates receiving the negative buffered RF signal; a second array of capacitors having bottom plates receiving the positive buffered RF signal; a first bank of L-switches, each L-switch coupled between an input capacitor in the second array of capacitors and an output capacitor in the first array of capacitors; a third array of capacitors having bottom plates receiving the positive buffered RF signal; a fourth array of capacitors having bottom plates receiving the negative buffered RF signal; a second bank of L-switches, each L-switch in the second bank coupled between an input capacitor in the fourth array of capacitors and an output capacitor in the third array of capacitors; wherein each L-switch comprises; pre-charge transistor means for charging the input capacitor; stage-transfer transistor means for transferring charge from the input capacitor to the output capacitor; first control phase means, in the buffer circuit, for generating the first control signal and the second control signal to activate in the first bank of L-switches the stage-transfer transistor means to conduct and to de-activate the pre-charge transistor means to isolate and not conduct in the first bank of L-switches, and at a same time in the second bank of L-switches activating the pre-charge transistor means to conduct and to de-activate the stage-transfer transistor means to isolate and not conduct; and second control phase means, in the buffer circuit, for generating the first control signal and the second control signal to activate in the first bank of L-switches the pre-charge transistor means to conduct and to de-activate the stage-transfer transistor means to isolate and not conduct in the first bank of L-switches, and at a same time in the second bank of L-switches activating the stage-transfer transistor means to conduct and to de-activate the pre-charge transistor means to isolate and not conduct; wherein the first control signal and the second control signal are connected to the first bank of L-switches and to the second bank of L-switches. - View Dependent Claims (20)
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Specification