VOLTAGE GENERATOR TO COMPENSATE SENSE AMPLIFIER TRIP POINT OVER TEMPERATURE IN NON-VOLATILE MEMORY
First Claim
1. Circuitry for use in a non-volatile storage system, comprising:
- a current mirror circuit comprising a reference current path and a mirror current path, the reference current path receives a reference current which is mirrored in the minor current path;
a first transistor in the minor current path, the first transistor is matched to a voltage-setting transistor (NHLL) in at least one sense amplifier, and the mirror current path provides a voltage to the voltage-setting transistor, in response to which the voltage-setting transistor sets an initial voltage at a sense node in the at least one sense amplifier at a start of a sensing period;
a resistor connected in series with the current minor circuit; and
a second transistor connected in series with the current minor circuit, the second transistor is matched to a voltage-sensing transistor (NSEN) in the at least one sense amplifier, the voltage-sensing transistor senses a final voltage at the sense node at the end of the sensing period.
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Accused Products
Abstract
In a non-volatile memory system, a voltage generator provides a voltage to a gate of a voltage-setting transistor which is used in a sense circuit to set an initial voltage at a sense node. At the end of a sense period, a final voltage of the sense node is compared to a trip point, which is the threshold voltage of a voltage-sensing transistor. To account for temperature variations and manufacturing process variations, the voltage generator includes a transistor which is matched to the voltage-setting transistor, and a transistor which is matched to the voltage-sensing transistor. As a result, a voltage swing between the initial voltage and the trip point is constant, even as the initial voltage and trip point vary. In a particular implementation, the voltage generator uses a cascode current mirror circuit, and receives a reference current from a band gap voltage circuit.
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Citations
20 Claims
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1. Circuitry for use in a non-volatile storage system, comprising:
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a current mirror circuit comprising a reference current path and a mirror current path, the reference current path receives a reference current which is mirrored in the minor current path; a first transistor in the minor current path, the first transistor is matched to a voltage-setting transistor (NHLL) in at least one sense amplifier, and the mirror current path provides a voltage to the voltage-setting transistor, in response to which the voltage-setting transistor sets an initial voltage at a sense node in the at least one sense amplifier at a start of a sensing period; a resistor connected in series with the current minor circuit; and a second transistor connected in series with the current minor circuit, the second transistor is matched to a voltage-sensing transistor (NSEN) in the at least one sense amplifier, the voltage-sensing transistor senses a final voltage at the sense node at the end of the sensing period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. Circuitry for use in a non-volatile storage system, comprising:
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a plurality of sense amplifiers, each sense amplifier is associated with at least one non-volatile storage element, each sense amplifier comprise a sense node, a voltage-setting transistor and a voltage-sensing transistor; and a voltage generator, the voltage generator provides a common voltage to each voltage-setting transistor, each voltage-setting transistor sets an initial voltage at its sense node at a start of a sensing period, based on the common voltage, and each voltage-sensing transistor senses a final voltage at the sense node at the end of the sensing period, the voltage generator comprises first and second transistors connected in series, the first transistor is matched to the voltage-setting transistors, the second transistor is matched to the voltage-sensing transistors, the common voltage is provided at a drain or source of the first transistor, and the common voltage varies with temperature based on temperature coefficients of the first and second transistors. - View Dependent Claims (13, 14, 15, 16)
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17. A method for operating a non-volatile storage system, comprising:
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providing a reference current, the reference current exhibits a variation with temperature based on a temperature coefficient, and the variation is offset, at least in part; providing a voltage based on the reference current, the voltage exhibits a variation with temperature based on temperature coefficients of first and second transistors, the first transistor is matched to a voltage-setting transistor in a sense amplifier, and the second transistor is matched to a voltage-sensing transistor in the sense amplifier; and coupling the voltage to the voltage-setting transistor. - View Dependent Claims (18, 19, 20)
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Specification