IP Library › Granted Patent US 11,380,408
Granted Patent B2
US 11,380,408 · App. 17/247,087 · Granted Jul 5, 2022

Selective overdrive of supply voltage to primary switch for programming memory cells

Inventor: Michele Piccardi (Cupertino, CA)
Assignee: Micron Technology, Inc.
G11C16/30G11C16/10G11C16/0483
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Quick Facts
Patent No.
US 11,380,408
App. No.
17/247,087
Granted
Jul 5, 2022
Kind
B2
Abstract

A circuit includes a linear regulator operatively coupled with a memory array, the linear regulator including a primary switch to generate a regulated voltage usable to program memory cells of the memory array. A first digital-to-analog converter (DAC) includes an output coupled with the linear regulator. A pump regulator is operatively coupled with a charge pump, where the charge pump is to provide a supply voltage to the linear regulator. A second DAC includes an output coupled with the pump regulator. Control logic, operatively coupled with the first DAC and the second DAC, is to perform operations including: causing a first digital input value to be provided to the first DAC to selectively smooth noise on the supply voltage; and causing a second digital input value to be provided the second DAC to selectively adjust the supply voltage based on a programmable offset value.

Claims (66)

1. A circuit comprising:

a linear regulator operatively coupled with a memory array, the linear regulator comprising a primary switch to generate a regulated voltage usable to program memory cells of the memory array;

a first digital-to-analog converter (DAC) having an output coupled with the linear regulator;

a pump regulator operatively coupled with a charge pump, wherein the charge pump is to provide a supply voltage to the linear regulator;

a second DAC having an output coupled with the pump regulator; and

control logic, operatively coupled with the first DAC and the second DAC, the control logic to perform operations comprising:

causing a first digital input value to be provided to the first DAC to selectively smooth noise on the supply voltage; and

causing a second digital input value to be provided to the second DAC to selectively adjust the supply voltage based on a programmable offset value.

2. The circuit of claim 1 , further comprising an adder to combine the first digital input value with the programmable offset value to generate the second digital input value.

3. The circuit of claim 1 , wherein the pump regulator comprises:

a comparator to drive the charge pump, the comparator to receive, as inputs, a feedback voltage from the charge pump and a reference voltage from the second DAC;

one or more diodes coupled with the charge pump and the linear regulator; and

a voltage divider coupled between the one or more diodes and ground, wherein an output of the voltage divider is the feedback voltage.

4. The circuit of claim 1 , wherein the primary switch is a transistor, and wherein the linear regulator further comprises:

an operational amplifier to drive a gate of the transistor, the operational amplifier to receive, as inputs, a feedback voltage from a source of the transistor and a reference voltage from the first DAC that is programmed with a target program voltage; and

a voltage divider coupled between the source of the transistor and ground, wherein an output of the voltage divider is the feedback voltage.

5. The circuit of claim 4 , wherein the primary switch is an n-type complementary metal oxide semiconductor (NMOS) transistor having a gate coupled with an output of the operational amplifier.

6. The circuit of claim 1 , wherein the operations further comprise encoding, within the programmable offset value, one of:

a correction for a body effect mismatch between a string driver replica transistor coupled with the charge pump and a string driver transistor; or

a temperature coefficient value that compensates for a temperature of the memory array.

7. The circuit of claim 1 , wherein the operations further comprise encoding, within the programmable offset value, a lengthened pulse to cause the charge pump to drive the supply voltage higher to boost performance of programming to the memory cells.

8. The circuit of claim 1 , wherein the operations further comprise encoding, within the programmable offset value, one of:

a step function of pulse counts that iteratively causes the charge pump to increase the supply voltage;

a linear function of pulse counts that linearly causes the charge pump to increase the supply voltage;

a selective function of pulse counts that selectively causes the charge pump to increase the supply voltage depending on a pulse count value; or

a combination thereof.

9. A memory device comprising:

a memory array comprising memory cells;

a linear regulator operatively coupled with the memory array, the linear regulator comprising a primary switch to generate a regulated voltage usable to program the memory cells;

a first digital-to-analog converter (DAC) having an output coupled with the linear regulator;

a comparator having an output that is coupled to a charge pump, the charge pump to provide a supply voltage to the linear regulator;

a second DAC having an output coupled with the comparator; and

control logic, operatively coupled with the first DAC and the second DAC, the control logic to perform operations comprising:

causing a first digital input value to be provided to the first DAC to selectively smooth noise on the supply voltage; and

causing a second digital input value to be provided to the second DAC to selectively adjust the supply voltage based on a programmable offset value.

10. The memory device of claim 9 , further comprising an adder to combine the first digital input value with the programmable offset value to generate the second digital input value.

11. The memory device of claim 9 , further comprising a pump regulator comprising:

the comparator, which is to receive, as inputs, a feedback voltage from the charge pump and a reference voltage from the second DAC;

one or more diodes coupled with the charge pump and the linear regulator; and

a voltage divider coupled between the one or more diodes and ground, wherein an output of the voltage divider is the feedback voltage.

12. The memory device of claim 9 , wherein the primary switch is a transistor, and wherein the linear regulator further comprises:

an operational amplifier to drive a gate of the transistor, the operational amplifier to receive, as inputs, a feedback voltage from a source of the transistor and a reference voltage from the first DAC that is programmed with a target program voltage; and

a voltage divider coupled between the source of the transistor and ground, wherein an output of the voltage divider is the feedback voltage.

13. The memory device of claim 9 , wherein the operations further comprise encoding, within the programmable offset value, one of:

a correction for a body effect mismatch between a string driver replica transistor coupled with the charge pump and a string driver transistor; or

a temperature coefficient value that compensates for a temperature of the memory array.

14. The memory device of claim 9 , wherein the operations further comprise encoding a lengthened pulse within the programmable offset value to cause the charge pump to drive the supply voltage higher to reduce time to program the memory cells.

15. The memory device of claim 9 , wherein the operations further comprise encoding, within the programmable offset value, one of:

a step function of pulse counts that iteratively causes the charge pump to increase the supply voltage;

a linear function of pulse counts that linearly causes the charge pump to increase the supply voltage; or

a selective function of pulse counts that selectively causes the charge pump to increase the supply voltage depending on a pulse count value.

16. A memory device comprising:

a memory array comprising memory cells;

a linear regulator operatively coupled with the memory array, the linear regulator comprising:

a transistor to generate a regulated voltage to program the memory array; and

an operational amplifier to drive a gate of the transistor, the operational amplifier to receive, as inputs, a feedback voltage from a source of the transistor and a reference voltage;

a first digital-to-analog converter (DAC) having an output coupled with the linear regulator and to supply the reference voltage;

a charge pump to provide a supply voltage to the linear regulator; and

control logic, operatively coupled with the first DAC, the control logic to perform operations comprising causing a first digital input value to be provided to the first DAC to selectively smooth noise on the supply voltage.

17. The memory device of claim 16 , wherein the output of the first DAC is programmed with a target program voltage, further comprising a voltage divider coupled between the source of the transistor and ground, wherein an output of the voltage divider is the feedback voltage.

18. The memory device of claim 16 , further comprising a pump regulator operatively coupled with the charge pump, the pump regulator comprising:

a comparator to drive the charge pump, the comparator to receive, as inputs, a feedback voltage from the charge pump and a second reference voltage from a second DAC;

one or more diodes coupled with the charge pump and the linear regulator; and

a voltage divider coupled between the one or more diodes and ground, wherein an output of the voltage divider is the feedback voltage.

19. The memory device of claim 18 , further comprising the second DAC having an output coupled with the pump regulator, wherein the operations performed by the control logic further comprise causing a second digital input value to be provided to the second DAC to selectively adjust the supply voltage based on a programmable offset value.

20. The memory device of claim 19 , further comprising an adder to combine the first digital input value with the programmable offset value to generate the second digital input value.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Nov 30, 2020
From: PICCARDI, MICHELE
To: MICRON TECHNOLOGY, INC.
Reel/Frame 054491/0095 →
Continuity (1)
Related Publication 20220172789A1 · Jun 2, 2022