Voltage boost circuit

Patent metadata

Field	Value
Publication number	US-10127970-B2
Application number	US-201715465045-A
Country	US
Kind code	B2
Filing date	Mar 21, 2017
Priority date	Jul 10, 2014
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

A voltage boost circuit for eDram using thin oxide field effect transistors (FETs) is disclosed. The voltage boost circuit includes a boost capacitor which is precharged with a precharge voltage in a precharge stage and which provides a boosted supply voltage to a thin oxide FET during a pump phase. The voltage boost circuit further include a drive capacitor which provides a turn on voltage to the thin oxide FET so that the boosted supply voltage can pass to an output node in the pump phase.

First claim

What is claimed:

1. A method comprising:
precharging a boost capacitor with a precharge voltage in a precharge stage;
providing a boosted supply voltage to a thin oxide FET by the boost capacitor during a pump phase; and
providing a turn on voltage to the thin oxide FET by a drive capacitor so that the boosted supply voltage can pass to an output node in the pump phase.

2. The method of claim 1 , wherein the boosted supply voltage is approximately 2× of a supply voltage.

3. The method of claim 1 , wherein the boosted supply voltage is below a reliability limit of the thin oxide FET.

4. The method of claim 1 , wherein a voltage difference between a source and a drain of the thin oxide FET is below a reliability limit of the thin oxide FET.

5. The method of claim 1 , wherein the thin oxide FET is turned off during the pump phase.

6. The method claim 1 , further comprising:
precharging the drive capacitor with the precharge voltage by a drive-cap precharge circuit during the precharge stage; and
turning on a transistor by a low signal received from a transfer control circuit in order to charge the drive capacitor with the precharge voltage.

7. The method of claim 6 , wherein the precharge voltage is provided to a node of the thin oxide FET during the pump phase by opening a plurality of transistors coupled to the thin oxide FET.

8. The method of claim 1 , further comprising supplying a first terminal of the boost capacitor with the precharge voltage and turning on a second transistor to provide GND to a second terminal of the boost capacitor.

9. The method of claim 8 , further comprising turning on a third transistor which, in the pump phase, to add a supply voltage to the boost capacitor to obtain the boosted supply voltage.

10. The method of claim 1 , further comprising tailoring a current during the precharge phase and pump phase with a bias generator to provide a functional transfer of signal XL 1 to a drive-cap precharge circuit, wherein the bias generator provides a signal to the transistor of the drive-cap precharge circuit to turn it on.

11. A voltage boost circuit, comprising:
a boost capacitor which is precharged with a precharge voltage and provides a boosted supply voltage to a thin oxide FET during a pump phase; and
a drive capacitor which provides a turn on voltage to the thin oxide FET.

12. The voltage boost circuit of claim 11 , wherein the boosted supply voltage is approximately 2× of a supply voltage.

13. The voltage boost circuit of claim 11 , further comprising a first transistor which supplies a first terminal of the boost capacitor with the precharge voltage and a second transistor which is turned on to provide GND to a second terminal of the boost capacitor.

14. The voltage boost circuit of claim 13 , further comprising a third transistor which, in the pump phase, is turned on to add a supply voltage to the boost capacitor to obtain the boosted supply voltage.

15. The voltage boost circuit of claim 14 , wherein, in the pump phase, the first transistor and the second transistor are turned off and the thin oxide FET is turned on by the voltage from the drive capacitor which is less than the boosted supply voltage.

16. The voltage boost circuit of claim 15 , wherein the voltage from the drive capacitor is equal to the precharge voltage, and the precharge voltage subtracted from the boosted supply voltage is below a reliability limit of the thin oxide FET.

17. The voltage boost circuit of claim 11 , further comprising a drive-cap precharge circuit which comprises the drive capacitor and a transistor which is controlled by a transfer control circuit, wherein:
the drive-cap precharge circuit precharges the drive capacitor with the precharge voltage during a precharge phase; and
the transistor is turned on by a low signal received from the transfer control circuit in order to charge the drive capacitor with the precharge voltage.

18. The voltage boost circuit of claim 17 , wherein the precharge voltage is provided to a node of the thin oxide FET during the pump phase by opening a plurality of transistors coupled to the thin oxide FET.

19. The voltage boost circuit of claim 18 , further comprising a bias generator which tailors a current during the precharge phase and pump phase to provide a functional transfer of signal XL 1 to the drive-cap precharge circuit.

20. The voltage boost circuit of claim 11 , wherein the boost capacitor and the drive capacitor have a precharge voltage provided in a precharge phase, and, in the pump phase, a power supply voltage is added to the precharge voltage of the boost capacitor to obtain a boosted output voltage passed across the thin oxide FET to an output node when the thin oxide FET is turned on by the precharge voltage of the drive capacitor applied at a gate node of the thin oxide FET.

Assignees

• IBM

Inventors

• Fifield John A
• Pontius Dale E

Classifications

• H02M3/07 Primary

  using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps} · CPC title

• H02M3/158

  including plural semiconductor devices as final control devices for a single load · CPC title

• G11C11/4085 Primary

  Word line control circuits, e.g. word line drivers, - boosters, - pull-up, - pull-down, - precharge · CPC title

• G11C11/4074

  Power supply or voltage generation circuits, e.g. bias voltage generators, substrate voltage generators, back-up power, power control circuits · CPC title

• H05K999/99

  Electricity · mapped topic