Method and apparatus for powering circuitry with on-chip solar cells within a common substrate
First Claim
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1. A power supply for powering a logic circuit, comprising:
- at least first and second photodiodes connected in series and integrated on a common substrate, said first photodiode having a first terminal and a second terminal, said second photodiode having a first terminal and a second terminal, wherein said first terminal of said first photodiode and said first terminal of said second photodiode are in electrical contact with the common substrate;
wherein, upon illumination, the power supply generates a first potential difference between the second electrode of the first photodiode and the second electrode of the second photodiode, wherein the first potential difference is equal to 2*VT and is used to power the logic circuit; and
wherein the first photodiode is a bipolar junction transistor having a collector that is shorted to a base;
the collector and the base of the bipolar junction transistor are electrically connected to the common substrate, and VT corresponds to the voltage drop across the base-emitter junction of said bipolar junction transistor.
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Abstract
A system and method for providing power to a light-powered transponder. In order to create a sufficient voltage differential, two different photovoltaic elements are used. The photovoltaic elements generate voltages of different polarities. Because the photovoltaic elements are used independently to generate voltages with different polarities, the present system can achieve a desired voltage differential despite the inherent difficulties presented by the use of a standard CMOS process.
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Citations
12 Claims
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1. A power supply for powering a logic circuit, comprising:
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at least first and second photodiodes connected in series and integrated on a common substrate, said first photodiode having a first terminal and a second terminal, said second photodiode having a first terminal and a second terminal, wherein said first terminal of said first photodiode and said first terminal of said second photodiode are in electrical contact with the common substrate; wherein, upon illumination, the power supply generates a first potential difference between the second electrode of the first photodiode and the second electrode of the second photodiode, wherein the first potential difference is equal to 2*VT and is used to power the logic circuit; and wherein the first photodiode is a bipolar junction transistor having a collector that is shorted to a base;
the collector and the base of the bipolar junction transistor are electrically connected to the common substrate, and VT corresponds to the voltage drop across the base-emitter junction of said bipolar junction transistor. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for powering a logic circuit, comprising the steps of:
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providing at least first and second photodiodes connected in series and integrated on a common substrate, said first photodiode having a first terminal and a second terminal, said second photodiode having a first terminal and a second terminal, wherein said first terminal of said first photodiode and said first terminal of said second photodiode are in electrical contact with the common substrate; illuminating the at least first and second photodiodes; in response to said illuminating, generating a first potential difference between the second electrode of the first photodiode and the second electrode of the second photodiode, wherein the first potential difference is equal to 2*VT; and powering the logic circuit using the first potential difference; wherein the first photodiode is a bipolar junction transistor having a collector that is shorted to a base;
the collector and the base of the bipolar junction transistor are electrically connected to the common substrate, and VT corresponds to the voltage drop across the base-emitter junction of said bipolar junction transistor. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification