Sensing circuit and method for phase-change memory

Abstract

A sensing circuit for a phase change memory comprises a first storage capacitor and a reference capacitor, a storage memory element and a reference memory element, a storage discharge switch and a reference discharge switch, and a judgment device. The first ends of the storage capacitor and the reference capacitor are both coupled with a pre-charged voltage via a first switch, the first ends of the storage memory element and the reference memory element are respectively coupled with the first ends of the storage capacitor and the reference capacitor via a second switch, the storage discharge switch and the reference discharge switch are respectively coupled with the first ends of the storage memory element and the reference memory element, and the judgment device is coupled with the first ends of the storage memory element and the reference memory element and provides an output as the read result of the storage state of the storage memory element.

Description

technical field [0001] The invention relates to a phase-change memory, in particular to a sensing / reading circuit of the phase-change memory. Background technique [0002] figure 1 It is a sensing circuit diagram of a traditional phase-change memory, in figure 1 In, a current I R Flowing through a phase-change memory unit 115, since the resistance value of the phase-change memory unit 115 varies with its storage state, the current I R The voltage drop generated at both ends of the phase-change memory unit 115 is also different, and the voltage is sent to a comparator 130 and compared with a reference voltage V REF By comparison, the storage state of the phase-change memory unit 115 can be judged. Generally speaking, the comparator 130 is an analog circuit, which can distinguish subtle differences through design. However, due to the resistance and capacitance load on the bit line It delays the charging time to convert the current to voltage, so the reading speed is slower...

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Problems solved by technology

[0002] figure 1 It is a sensing circuit diagram of a traditional phase-change memory, in figure 1 In, a current I R Flowing through a phase-change memory unit 115, since the resistance value of the phase-change memory unit 115 varies with its storage state, the current I R The voltage drop generated at both ends of the phase-change memory unit 115 is also different, and the voltage is sent to a comparator 130 and compared with a reference voltage V REF By comparison, the storage state of the phase-change memory unit 115 can be judged. Generally speaking, the comparator 130 is an analog circuit, which can distinguish subtle differences through design. However, due to the resistance and capacitance load on the bit line Delays the charging time to convert current to voltage, so the reading speed is slower

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