Sense amplifier having capacitively coupled input for offset compensation
First Claim
1. A sense amplifier circuit for reading one of a plurality of memory cells that are coupled to a bit line, the circuit comprising:
- a supply terminal;
a reference memory cell;
a comparator having first and second input terminals and having an output terminal that provides a read signal;
a first load device having a first terminal coupled to said supply terminal and having a second terminal coupled to said bit line;
a second load device having a first terminal coupled to said supply terminal and having a second terminal coupled to said reference memory cell and to said second input terminal of said comparator;
a first capacitive component having a first terminal coupled to said second terminal of said first load device and having a second terminal coupled to said first input terminal of said comparator; and
a first switch having a control terminal, a first terminal coupled to said supply terminal, and a second terminal coupled to said second terminal of said first capacitive component, said first switch operable to allow an offset-compensation charging current to flow through said first capacitive component to said bit line.
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Accused Products
Abstract
A sense amplifier circuit for a semiconductor memory device comprises a first current/voltage converter for convening a current of a memory cell to be read into a voltage signal, a second current/voltage converter for converting a reference current into a reference voltage signal, and a voltage comparator for comparing the voltage signal with the reference voltage signal. The sense amplifier circuit comprises a capacitive decoupler for decoupling the voltage signal from the comparator, and circuitry for providing the capacitive decoupler with an electric charge suitable for compensating an offset voltage introduced in the voltage signal by an offset current superimposed on the current of the memory cell to be read.
60 Citations
18 Claims
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1. A sense amplifier circuit for reading one of a plurality of memory cells that are coupled to a bit line, the circuit comprising:
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a supply terminal; a reference memory cell; a comparator having first and second input terminals and having an output terminal that provides a read signal; a first load device having a first terminal coupled to said supply terminal and having a second terminal coupled to said bit line; a second load device having a first terminal coupled to said supply terminal and having a second terminal coupled to said reference memory cell and to said second input terminal of said comparator; a first capacitive component having a first terminal coupled to said second terminal of said first load device and having a second terminal coupled to said first input terminal of said comparator; and a first switch having a control terminal, a first terminal coupled to said supply terminal, and a second terminal coupled to said second terminal of said first capacitive component, said first switch operable to allow an offset-compensation charging current to flow through said first capacitive component to said bit line. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for reading data stored in a memory cell of a plurality of memory cells that are coupled to a bit line, the method comprising:
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before reading said memory cell, storing an offset-compensation signal that compensates for an offset signal on said bit line; while reading said memory cell, combining said stored offset-compensation signal with a signal on said bit line to obtain a read signal from said memory cell; and comparing said read signal with a reference signal to generate a data signal that identifies said data stored in said memory cell. - View Dependent Claims (9, 10)
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- 11. Sense amplifier circuit for a semiconductor memory device, comprising first current/voltage conversion means for converting a current of a memory cell to be read into a voltage signal, second current voltage/conversion means for converting a reference current into a reference voltage signal, and voltage comparator means for comparing said voltage signal with said reference voltage signal, characterized in that said sense amplifier circuit comprises capacitive decoupling means for decoupling said voltage signal from said comparator means, and means for providing said capacitive decoupling means with an electric charge suitable for compensating an offset voltage introduced in said voltage signal by an offset current superimposed on the current of the memory cell to be read.
Specification