Current-Sense Amplifier With Low-Offset Adjustment and Method of Low-Offset Adjustment Thereof

• US 20120294090A1
• Filed: 05/16/2011
• Published: 11/22/2012
• Est. Priority Date: 05/16/2011
• Status: Active Grant

• Current Assignee: National Tsing Hua University
• Original Assignee: National Tsing Hua University
• Inventors: Chang, Meng-Fan, Lin, Yu-Fan, Shen, Shin-Jang, Chih, Yu-Der
• Granted Patent: US 8,320,211 B1
• Time in Patent Office: Days
• US Class Current: 365/185.21
• CPC Class Codes: G11C 16/06 Auxiliary circuits, e.g. for writing into memory
• CPC Class Codes: G11C 16/26 Sensing or reading circuits; Data output circuits
• CPC Class Codes: G11C 7/06 Sense amplifiers; Associated circuits , e.g. timing or triggering circuits

Abstract

A current-sense amplifier with low-offset adjustment and a low-offset adjustment method thereof are disclosed. The current-sense amplifier includes a sensing unit, an equalizing unit and a bias compensation unit. The sensing unit includes a sense amplifier, a latch circuit, a first precharged bit line, and a second precharged bit line. The equalizing unit is electrically connected to the first and the second precharged bit line for regulating a voltage of the first precharged bit line and a voltage of the second precharged bit line to the same electric potential. The bias compensation unit is electrically connected to the sense amplifier for compensating an input offset voltage of the current-sense amplifier.

Claims

1. A current-sense amplifier with low-offset adjustment, comprising:

a sensing unit including a sense amplifier, a latch circuit, a first precharged bit line, and a second precharged bit line;

an equalizing unit being electrically connected to the first precharged bit line and the second precharged bit line for regulating voltages of the first and the second precharged bit line to a same electric potential; and

a bias compensation unit being electrically connected to the sense amplifier for compensating an input offset voltage of the sense amplifier.

2. The current-sense amplifier with low-offset adjustment as claimed in claim 1, wherein the equalizing unit further includes a first transistor;

the first transistor being coupled at a drain to the first precharged bit line, and at a source to the second precharged bit line;

whereby when the first transistor is turned on, the equalizing unit regulates voltages of the first and the second precharged bit line to the same electric potential.

3. The current-sense amplifier with low-offset adjustment as claimed in claim 1, wherein the sense amplifier further includes a first output and a second output for outputting a first sensing signal and a second sensing signal, respectively.

4. The current-sense amplifier with low-offset adjustment as claimed in claim 1, wherein the bias compensation unit further includes a first and a second compensation circuit being electrically connected to the first and the second output, respectively.

5. The current-sense amplifier with low-offset adjustment as claimed in claim 4, wherein the first compensation circuit further includes:

a first voltage source supplying a first compensation voltage; and

a first transmission gate being coupled at an end to the first voltage source and at another end to the first output;

whereby when the first transmission gate is turned on, the first transmission gate outputs the first compensation voltage to the first output; and

wherein the second compensation circuit further includes;

a second voltage source for supplying a second compensation voltage; and

a second transmission gate being coupled at an end to the second voltage source and at another end to the second output;

whereby when the second transmission gate is turned on, the second transmission gate outputs the second compensation voltage to the second output.

6. The current-sense amplifier with low-offset adjustment as claimed in claim 5, wherein the first voltage source and the second voltage source respectively supply a stable voltage to compensate the input offset voltage of the sense amplifier.

7. The current-sense amplifier with low-offset adjustment as claimed in claim 4, wherein the first compensation circuit and the second compensation circuit are further electrically connected to the latch circuit, and the latch circuit includes a second transistor and a third transistor;

the second transistor being coupled at a gate to a drain of the third transistor and the second compensation circuit for receiving the second compensation voltage output by the second compensation circuit; and

the second transistor being further coupled at the gate to the second output for receiving the second sensing signal output by the sense amplifier; and

the third transistor being coupled at a gate to a drain of the second transistor and the first compensation circuit for receiving the first compensation voltage output by the first compensation circuit; and

the third transistor being further coupled at the gate to the first output for receiving the first sensing signal output by the sense amplifier.

8. The current-sense amplifier with low-offset adjustment as claimed in claim 7, wherein the voltage output by the first compensation circuit and the voltage output by the second compensation circuit are smaller than a first threshold voltage of the third transistor and a second threshold voltage of the second transistor, respectively.

9. A low-offset adjustment method for compensating an offset voltage of a current-sense amplifier;

the current-sense amplifier including a sensing unit, an equalizing unit and a bias compensation unit; and

the sensing unit including a sense amplifier, a latch circuit, a first precharged bit line and a second precharged bit line;

the method comprising the following steps;

regulating a voltage of the first precharged bit line and a voltage of the second precharged bit line to a same electric potential by the equalizing unit; and

outputting a compensation voltage to the sense amplifier to compensate an input offset voltage of the sense amplifier by the bias compensation unit.

10. The low-offset adjustment method as claimed in claim 9, further comprising the following step:

regulating the voltage of the first precharged bit line and the voltage of the second precharged bit line to the same electric potential by the equalizing unit when a first transistor of the equalizing unit is turned on.

11. The low-offset adjustment method as claimed in claim 9, further comprising the following step:

respectively outputting a first compensation voltage and a second compensation voltage by a first compensation circuit and a second compensation circuit of the bias compensation unit, for compensating the input offset voltage of the sense amplifier.

12. The low-offset adjustment method as claimed in claim 11, further comprising the following steps:

outputting the first compensation voltage to the sense amplifier by the first compensation circuit for compensating the input offset voltage of the sense amplifier when a first transmission gate of the first compensation circuit is turned on; and

outputting the second compensation voltage to the sense amplifier by the second compensation circuit for compensating the input offset voltage of the sense amplifier when a second transmission gate of the second compensation circuit is turned on.

13. The low-offset adjustment method as claimed in claim 12, wherein the first and the second compensation voltage are stable voltages for compensating the input offset voltage of the sense amplifier.

14. The low-offset adjustment method as claimed in claim 11, further comprising the following steps:

receiving a first sensing signal output by the sense amplifier and the first compensation voltage output by the first compensation circuit by the third transistor when a third transistor of the latch circuit is turned on;

temporarily storing the first sensing signal in the latch circuit;

receiving a second sensing signal output by the sense amplifier and the second compensation voltage output by the second compensation circuit by the second transistor when a second transistor of the latch circuit is turned on; and

temporarily storing the second sensing signal in the latch circuit.

15. The low-offset adjustment method as claimed in claim 14, wherein the voltage output by the first compensation circuit and the voltage output by the second compensation circuit are smaller than a first threshold voltage of the third transistor and a second threshold voltage of the second transistor, respectively.