Method and apparatus for powering circuitry with on-chip solar cells within a common substrate

• US 7,098,394 B2
• Filed: 03/21/2003
• Issued: 08/29/2006
• Est. Priority Date: 05/15/2001
• Status: Expired due to Term

• Current Assignee: PharmaSeq, Inc.
• Original Assignee: PharmaSeq, Inc.
• Inventors: Armer, John, Senko, Thomas Richard
• Primary Examiner(s): DIAMOND, ALAN D
• Application Number:
  US10/393,586
• Publication Number:
  US 20030172968A1
• Time in Patent Office: 1,257 Days
• Field of Search: 136/244, 136/245, 136/249, 136/255, 136/293, 257/184, 257/197, 257/187, 257/431, 257/443, 257/461, 257/462, 257/465, 435/4, 435/6, 438/7, 438/6, 438/80
• US Class Current: 136/244
• CPC Class Codes: H01L 27/142 Energy conversion devices photovoltaic modules or arrays of single photovoltaic cells comprising bypass diodes integrated or directly associated with the devices H01L31/0443; photovoltaic modules composed of a plurality of thin film solar cells deposited on the same substrate H01L31/046
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y10S 136/293 Circuits

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.

Claims

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*V_T 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 V_T corresponds to the voltage drop across the base-emitter junction of said bipolar junction transistor.

2. The power supply of claim 1, wherein the common substrate is a P-type substrate and the bipolar junction transistor is a PNP bipolar junction transistor.

3. The power supply of claim 1, wherein the common substrate is a N-type substrate and the bipolar junction transistor is a NPN bipolar junction transistor.

4. The power supply of claim 1, wherein the second photodiode is a first PN diode having a first terminal electrically connected to the common substrate;

wherein, upon illumination, the power supply generates the first potential difference between an emitter of the bipolar junction transistor and a second electrode of the first PN diode; and

wherein V_T also corresponds to the threshold voltage of the first PN diode.

5. The power supply of claim 4, wherein the logic circuit is associated with a photo-activated transponder, and the power supply also powers an antenna associated with the photo-activated transponder, further comprising:

a third photodiode having at least one electrode in electrical contact with the common substrate;

wherein, upon illumination, the power supply generates a second potential difference across the third photodiode, and the second potential difference is used to power the antenna.

6. The power supply of claim 5, wherein the third photodiode is a second PN diode having a first electrode in electrical contact with the common substrate and a second opposite electrode in electrical contact with the antenna.

7. A method for powering a logic circuit, comprising the steps of:

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*V_T; 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 V_T corresponds to the voltage drop across the base-emitter junction of said bipolar junction transistor.

8. The method of claim 7, wherein the common substrate is a P-type substrate and the bipolar junction transistor is a PNP bipolar junction transistor.

9. The method of claim 7, wherein the common substrate is a N-type substrate and the bipolar junction transistor is a NPN bipolar junction transistor.

10. The method of claim 7, wherein the second photodiode is a first PN diode having a first terminal electrically connected to the common substrate;

wherein in response to said illuminating, the first potential difference is generated between an emitter of the bipolar junction transistor and a second electrode of the first PN diode; and

wherein V_T also corresponds to the threshold voltage of the first PN diode.

11. The method of claim 10, wherein the logic circuit is associated with a photo-activated transponder, further comprising the steps of:

providing a third photodiode having at least one electrode in electrical contact with the common substrate;

illuminating the third photodiode;

in response to said illuminating the third photodiode, generating a second potential difference across the third photodiode; and

powering an antenna associated with the photo-activated transponder using the second potential difference.

12. The method of claim 11, wherein the third photodiode is a second PN diode having a first electrode in electrical contact with the common substrate and a second opposite electrode in electrical contact with the antenna.