Circuits, architectures, apparatuses, systems, algorithms, and methods for memory with multiple power supplies and/or multiple low power modes

• US 9,218,856 B2
• Filed: 11/12/2013
• Issued: 12/22/2015
• Est. Priority Date: 09/09/2009
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell World Trade Limited (Marvell Technology Group Limited)
• Inventors: Lee, Winston, Kim, Ha Soo
• Primary Examiner(s): King, Douglas
• Application Number:
  US14/077,634
• Publication Number:
  US 20140071782A1
• Time in Patent Office: 770 Days
• Field of Search: 365/226, 365/227, 365/229, 365/230.06
• US Class Current: 1/1
• CPC Class Codes: G11C 5/14 Power supply arrangements , e.g. power down, chip selection or deselection, layout of wirings or power grids, or multiple supply levels
• CPC Class Codes: G11C 7/02 with means for avoiding parasitic signals
• CPC Class Codes: G11C 8/08 Word line control circuits, e.g. drivers, boosters, pull-up circuits, pull-down circuits, precharging circuits, for word lines

Abstract

Circuits, architectures, a system and methods for memories with multiple power supplies and/or multiple low power modes. The circuit generally includes peripheral circuitry operating at a first voltage, a memory array operating at a second voltage, and translation circuitry configured to receive an input from the peripheral circuitry at the first voltage and provide an output to the memory array at the second voltage, the translation circuitry further configured to prevent leakage during a standard operating mode of the memory. The method generally includes operating peripheral circuitry at a first voltage from a first power rail, operating a memory array at the first voltage or a second voltage, the memory array being coupled to a second power rail, coupling the first and second power rails during standard operating mode when the memory array operates at the first voltage, otherwise not coupling the first and second power rails, and reducing leakage in the memory array during a leakage reduction mode by reducing a voltage differential between a ground plane in the memory array and the second power rail.

Claims

1. A memory comprising:

a memory array having a memory array ground terminal at a memory array ground potential, wherein the memory array is configured to function in a higher power mode and a lower power mode;

a supply ground terminal located external to the memory array, wherein the supply ground terminal is at a supply ground potential;

a voltage bias source connected from the memory array ground terminal to the supply ground terminal to raise the memory array ground potential above the supply ground potential by a voltage differential;

a switching device connected in parallel with the voltage bias source, wherein the switching device is configured to (i) conduct during the higher power mode and thereby bypass the voltage bias source to reduce the voltage differential and (ii) refrain from conducting during the lower power mode and thereby not bypass the voltage differential device and not reduce the voltage differential;

a power supply configured to provide a supply voltage at a higher level to power the memory array; and

a processor configured to

control the switching device to, in the higher power mode, conduct and thereby bypass the voltage bias source without the voltage bias source being deactivated and without the voltage bias source being disconnected from the memory array ground terminal and without the voltage bias source being disconnected from the supply ground terminal;

in at least one period of the lower power mode, control the power supply to lower the supply voltage to a lower level, wherein the lower level is sufficiently high for the memory array to function to retain data; and

in another period of the lower power mode, control the power supply to keep the supply voltage at the higher level.

2. The memory of claim 1, wherein the reducing of the voltage differential includes reducing the voltage differential to substantially zero.

3. The memory of claim 1 wherein the voltage differential device comprises a fixed voltage source.

4. The memory of claim 1, wherein the voltage bias source includes a diode, and the voltage differential is a forward voltage threshold of the diode.

5. The memory of claim 1, wherein the voltage bias source comprises diodes connected in series and simultaneously contributing respective diode forward biases to the voltage differential.

6. The memory of claim 1, wherein the voltage bias source comprises diodes connected in parallel and simultaneously contributing respective diode forward biases to the voltage differential.

7. A method performed by an electronic circuit that (i) includes a supply ground plane at a supply ground potential and that (ii) further includes a memory array having a memory array ground plane at a memory array ground potential and that (iii) is configured to operate in a higher power mode and in a lower power mode, the method comprising:

providing, by a power supply, a supply voltage at a higher level to power the memory array;

providing a voltage bias source connected from the supply ground plane to the memory array ground plane to raise the memory ground potential above the supply ground potential by a voltage differential;

providing a switching device connected in parallel with the voltage bias source;

lowering the voltage differential in the higher power mode by the switching device conducting and thereby bypassing the voltage bias source, without the voltage bias source being deactivated and without the voltage bias source being disconnected from the supply ground plane and without the voltage bias source being disconnected from the memory array ground plane;

raising the voltage differential in the lower power mode by a processor controlling the switch device to refrain from conducting and thereby not bypassing the voltage bias source;

during at least one period of the lower power mode, the processor controlling the power supply to lower the supply voltage to a lower level, wherein the lower level is sufficiently high for the memory array to function to retain data; and

in another period of the lower power mode, the processor controlling the power supply to keep the supply voltage at the higher level.

8. The method of claim 7, wherein the lowering of the voltage differential includes lowering the voltage differential to substantially zero.

9. The method of claim 7 wherein the voltage differential device comprises a fixed voltage source.

10. The method of claim 7, wherein the voltage bias source includes a diode, and wherein the voltage differential is a forward voltage threshold of the diode.

11. The method of claim 7, wherein the voltage bias source comprises diodes connected in series and simultaneously contributing respective diode forward biases to the voltage differential.

12. The method of claim 7, the voltage bias source comprises diodes connected in parallel and simultaneously contributing respective diode forward biases to the voltage differential.