Voltage regulators, amplifiers, memory devices and methods

Patent metadata

Field	Value
Publication number	US-9306518-B2
Application number	US-201414287381-A
Country	US
Kind code	B2
Filing date	May 27, 2014
Priority date	Mar 29, 2010
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

Circuits, devices and methods are provided, such as an amplifier (e.g., a voltage regulator) that includes a feedback circuit that supplies negative feedback through a feedback path. One such feedback path includes a capacitance coupled in series with a “one-way” isolation circuit through which a feedback signal is coupled. The “one-way” isolation circuit my allow the feedback signal to be coupled from a “downstream” node, such as an output node, to an “upstream” node, such as a node at which an error signal is generated to provide negative feedback. However, the “one-way” isolation circuit may substantially prevent variations in the voltage at the upstream node from being coupled to the capacitance in the isolation circuit. As a result, the voltage at the upstream node may quickly change since charging and discharging of the capacitance responsive to voltage variations at the upstream node may be avoided.

First claim

What is claimed is:

1. An apparatus, comprising:
a feedback path coupled between a downstream node of an amplifying circuit and an upstream node of the amplifying circuit; and
an isolation circuit included in the feedback path and configured to isolate variations in the upstream node from the downstream node.

2. The apparatus of claim 1 , wherein the isolation circuit is configured to provide one-way isolation between the upstream and downstream nodes of the amplifying circuit.

3. The apparatus of claim 2 , wherein the one-way isolation allows for variations at the downstream node to be provided to the upstream node while isolating variations at the upstream node from the downstream node.

4. The apparatus of claim 2 , wherein the one-way isolation allows for high-frequency variations at the downstream node to be provided to the upstream node while isolating voltage variations at the upstream node from the downstream node.

5. The apparatus of claim 1 , wherein the isolation circuit is selectively enabled to provide high-frequency negative feedback from the downstream node to the upstream node of the amplifying circuit.

6. The apparatus of claim 1 , wherein the isolation circuit includes a charge maintenance circuit configured to maintain a charge on a capacitor in the feedback path to reduce capacitor charging and discharging time when the isolation circuit is selectively enabled and disabled.

7. The apparatus of claim 1 , further comprising a stabilizing circuit coupled to the downstream node of the amplifying circuit and ground, and configured to prevent oscillation developing in the amplifying circuit by reducing positive high-frequency feedback in the amplifying circuit.

8. A method, comprising:
adjusting an output voltage of an amplifier circuit based at least in part on a feedback signal; and
isolating a downstream node of a feedback path of the amplifier circuit from signals provided at an upstream node of the feedback path.

9. The method of claim 8 , further comprising selectively providing high-frequency negative feedback in the amplifier circuit from the downstream node to the upstream node.

10. The method of claim 9 , wherein selectively providing high-frequency negative feedback in the amplifier circuit from the downstream node to the upstream node comprises:
enabling the high-frequency negative feedback in the amplifier circuit responsive to an enable signal indicating an active state; and
disabling the high-frequency negative feedback in the amplifier circuit responsive to the enable signal indicating an inactive state.

11. The method of claim 10 , further comprising charging or discharging a capacitor included in the high-frequency feedback path while the feedback path is disabled.

12. The method of claim 8 , further comprising regulating a magnitude of the output voltage based at least in part on the feedback signal.

13. The method of claim 8 , further comprising providing an output voltage using the amplifier circuit based at least in part on a reference voltage.

14. A circuit, comprising:
an amplifier circuit to provide an output voltage based, at least in part, on a feedback signal; and
a feedback path to provide the feedback signal, the feedback path configured to isolate an upstream node of the feedback path from a downstream node of the feedback path, wherein the isolation is in one direction.

15. The circuit of claim 14 , wherein the isolation in one direction isolates voltage changes at the upstream node from the downstream node while providing high-frequency feedback from the downstream node to the upstream node.

16. The circuit of claim 14 , further comprising a compensation circuit in the feedback path, the compensation circuit configured to provide high-frequency negative feedback to reduce oscillations in the amplifier circuit.

17. The circuit of claim 16 , wherein the compensation circuit comprises a capacitive element.

18. The circuit of claim 14 , wherein the feedback path comprises an isolation circuit configured to selectively isolate the upstream node of the feedback path from the downstream node of the feedback path responsive to an enable signal, wherein the feedback path provides high-frequency feedback when the isolation circuit is enabled.

19. The circuit of claim 18 , wherein the feedback path does not provide high-frequency feedback when the isolation circuit is disabled.

20. The circuit of claim 19 , wherein a compensation capacitor included in the feedback path is charged while the isolation circuit is disabled.

Assignees

• Micron Technology Inc

Inventors

• Pan Dong

Classifications

• G11C5/147

  Voltage reference generators, voltage or current regulators; Internally lowered supply levels; Compensation for voltage drops (G11C5/141 takes precedence) · CPC title

• H03F2003/45008

  Electricity · mapped topic

• G11C7/065

  Differential amplifiers of latching type · CPC title

• G11C7/12

  Bit line control circuits, e.g. drivers, boosters, pull-up circuits, pull-down circuits, precharging circuits, equalising circuits, for bit lines · CPC title

• H03F2203/45264

  the dif amp comprising frequency or phase stabilisation means · CPC title