Programmable current source
AssigneeAdvanced Micro Devices, Inc.
InventorsShane C. Hollmer, Joseph G. Pawletko
Life of this patent
Estimating the term…
Abstract
A programmable reference current source used with a memory array during test and user modes to program or erase verify. The reference current source is programmable so that optimal reference currents can be determined during test mode. A value representing the optimal reference current is stored so that the reference current source provides the determined reference current during user mode.
Claims31
A programmable current source that provides current to a bit line coupled to a memory cell, the current source comprising:
- a source of a reference current value;
- a reference current source that provides a reference current specified by the reference current value;
- and
- a storage device, wherein the reference current value is selectively stored into the storage device.
A programmable current source that provides current to a bit line coupled to a memory cell, the current source comprising:
- a source of a reference current value;
- and
- a reference current source that provides a reference current specified by the reference current value, wherein the reference current value comprises N bits and wherein the reference current source comprises N current sources, each current source controlled by one of the N bits, and wherein each of the N current sources contribute to the reference current.
A programmable current source that provides current to a bit line coupled to a memory cell, the current source comprising:
- a source of a reference current value;
- a reference current source that provides a reference current specified by the reference current value, and
- wherein:
- the bit line includes a line transistor and wherein the reference current source includes a source transistor;
- the line transistor and source transistor are similar;
- and
- the reference current source provides a voltage to the source transistor thereby to match a current from the source transistor with a current from the line transistor.
A programmable current source that provides current to a bit line coupled to a memory cell, the current source comprising:
- a source of a reference current value;
- a reference current source that provides a reference current specified by the reference current value, wherein the reference current source comprises:
- a source transistor, having a first, second, and third terminals, wherein the second and third terminals of the source transistor are coupled together;
- M transistors, each having a first, second, and third terminals, wherein:
- the third terminals of each of the M transistors are coupled together;
- the second terminals of each of the M transistors are coupled together and are coupled to the first terminal of the source transistor;
- the size of a jth transistor is half the size of a (j−1)th transistor, where j=0 to M;
- each of the first terminals of the M transistors are coupled to a distinct switch;
- and
- the reference current value controls which of the M transistors are turned on.
A method of providing an adjustable reference current to a bit line coupled to a memory cell, the method comprising:
- providing a reference current value, wherein the act of providing further comprises selecting among at least two reference current values depending on a mode of operation;
- and
- outputting a reference current to the bit line, wherein the reference current is specified by the reference current value.
A method of providing an adjustable reference current to a bit line coupled to a memory cell, the method comprising:
- providing a reference current value, wherein the reference current value comprises a N bits;
- and
- outputting a reference current to the bit line, wherein the reference current is specified by the reference current value, wherein the act of outputting comprises the acts of:
- associating N current streams with each of the N bits;
- and
- selectively providing the current streams depending on the state of the
- combing the provided current streams thereby to provide the reference current.
A programmable current source that provides current to a bit line coupled to a memory cell, the current source comprising:
- a storage device storing a reference current value;
- and
- a reference current source that provides a reference current specified by the reference current value.
Dependencies are inferred from the claim text.