Voltage down pump and method of operation

• US 6,486,730 B1
• Filed: 10/23/2000
• Issued: 11/26/2002
• Est. Priority Date: 10/23/2000
• Status: Expired due to Term

• Current Assignee: Oticon A/S (William Demant Fonden)
• Original Assignee: Sonic Innovations Incorporated (William Demant Fonden)
• Inventors: Green, Robert S.
• Primary Examiner(s): Callahan, Timothy P.
• Assistant Examiner(s): ENGLUND, TERRY LEE
• Application Number:
  US09/695,721
• Time in Patent Office: 764 Days
• Field of Search: 327/538, 327/540, 327/541, 327/543, 327/535, 327/536, 327/537
• US Class Current: 327/541
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps

Abstract

A regulated voltage down pump circuit comprises a reference generator circuit receiving a voltage. P channel and N channel device voltage thresholds are measured and compared. A first reference voltage is generated using the largest voltage threshold. A second reference voltage is generated an amount (which may be programmable) above the first reference voltage. The second reference voltage is compared with an output voltage of a pump circuit. When the output voltage is less than the second reference voltage, a clock signal is sent to the pump circuit that generates and pumps up the output voltage to the reference voltage. The pumped voltage at the second reference is then used for logic circuits at reduced power and nearly constant gate delay over voltage, temperature and process variations.

Claims

1. A method for regulating the output voltage of a voltage pump circuit, comprising:

supplying a voltage to a reference generator circuit;

measuring a first threshold voltage of a P channel device within said reference generator circuit;

measuring a second threshold voltage of a N channel device within said reference generator circuit; and

generating a first reference voltage by comparing said first threshold voltage with said second threshold voltage, said first reference voltage being the largest of said first threshold voltage and said second threshold voltage.

2. The method according to claim 1, further comprising setting the output voltage of the voltage pump circuit to a first voltage above said first reference voltage.

3. The method according to claim 2 wherein said first voltage is a fixed programmable value.

4. The method according to claim 1, further comprising:

generating a second reference voltage, wherein said second reference voltage is above said first reference voltage;

comparing said second reference voltage with the output voltage of the voltage pump circuit;

generating a clock signal to the voltage pump circuit whenever the output voltage is less than said second reference voltage; and

pumping up the output voltage when the voltage pump circuit receives said clock signal.

5. The method according to claim 4, further comprising supplying additional current to the output voltage when the output voltage is less than said second reference voltage.

6. The method according to claim 4, further comprising receiving at least one trim bit that selects how much said second reference voltage is above said first reference voltage.

7. An apparatus for regulating the output voltage of a voltage pump circuit, comprising:

means for supplying a voltage to a reference generator circuit;

means for measuring a first threshold voltage of a P channel device within said reference generator circuit;

means for measuring a second threshold voltage of a N channel device within said reference generator circuit; and

means for generating a first reference voltage by comparing said first threshold voltage with said second threshold voltage, said first reference voltage being the largest of said first threshold voltage and said second threshold voltage.

8. The apparatus according to claim 7, further comprising means for setting the output voltage of the voltage pump circuit to a first voltage above said first reference voltage.

9. The apparatus according to claim 8 wherein said first voltage is a fixed programmable value.

10. The apparatus according to claim 7, further comprising:

means for generating a second reference voltage, wherein said second reference voltage is above said first reference voltage;

means for comparing said second reference voltage with the output voltage of the voltage pump circuit;

means for generating a clock signal to the voltage pump circuit whenever the output voltage is less than said second reference voltage; and

means for pumping up the output voltage when the voltage pump circuit receives said clock signal.

11. The method according to claim 10, further comprising means for supplying additional current to the output voltage when the output voltage is less than said second reference voltage.

12. The method according to claim 10, further comprising means for receiving at least one trim bit that selects how much said second reference voltage is above said first reference voltage.

13. A regulated voltage down pump circuit comprising:

a reference generator circuit receiving a voltage; and

a comparator within said reference generator circuit, comparing a first threshold voltage of a P channel device with a second threshold voltage of a N channel device, and generating a first reference voltage, said first reference voltage being the largest of said first threshold voltage and said second threshold voltage.

14. The regulated voltage down pump circuit according to claim 13, further comprising a pump generating a fixed programmable voltage above said first reference voltage as an output of said regulated voltage down pump circuit.

15. The regulated voltage down pump circuit according to claim 13, further comprising:

a voltage setting circuit for generating a second reference voltage, wherein said second reference voltage is above said first reference voltage;

a comparator circuit comparing said second reference voltage with an output voltage of said regulated voltage down pump circuit;

a clock circuit generating a clock signal to at least one pump circuit whenever said output voltage is less than said second reference voltage; and

said at least one pump circuit pumping up the output voltage when said at least one pump circuit receives said clock signal.

16. The regulated voltage down pump circuit according to claim 15, further comprising a shunt backup circuit supplying additional current to the output voltage when the output voltage is less than said second reference voltage.

17. The regulated voltage down pump circuit according to claim 15, wherein said voltage setting circuit receives at least one trim bit that selects how much said second reference voltage is above said first reference voltage.

18. The regulated voltage down pump circuit according to claim 15, further comprising at least a second pump circuit, wherein said pump circuits have different sizes.

19. An apparatus comprising:

one or more digital circuits operable to perform at least one function;

a power source supplying a first fixed voltage; and

at least one pump down circuit having said first fixed voltage supplied thereto, wherein said at least one pump down circuit generates a second fixed voltage to the one or more digital circuits, said second fixed voltage being lower than said first fixed voltage and regulated to a fixed delta above the voltage threshold of the one or more digital circuits, wherein the voltage threshold is the larger of a P type or N type voltage threshold of the one or more digital circuits.

20. The apparatus according to claim 19, wherein said fixed delta is regulated by a voltage setting circuit receiving at least one trim bit that selects how much said second fixed voltage is above the voltage threshold.

21. The apparatus according to claim 19, further comprising at least a second pump down circuit, wherein said pump down circuits have different sizes.

22. An apparatus comprising:

one or more analog circuits operable to perform at least one function;

one or more digital circuits operable to perform at least one function;

means for supplying a first fixed voltage; and

means for generating a second fixed voltage supplied to the one or more analog circuits and to the one or more digital circuits, said second fixed voltage being lower than said first fixed voltage and regulated to a fixed delta above a voltage threshold of the one or more analog circuits and of the one or more digital circuits,

wherein the voltage threshold is the larger of a P type or N type voltage threshold of the one or more digital circuits.

23. The apparatus according to claim 22, wherein said fixed delta is regulated by a voltage setting circuit receiving at least one trim bit that selects how much said second fixed voltage is above the voltage threshold.