US 6,788,567 B2 · Data holding device and data holding method

Abstract

To provide a data holding device and a data holding method with which data can be held even when the power source is interrupted and the held data can be restored accurately, which does not largely increase the circuit area, and which does not require fine timing control. In data restoring operation, a reading signal is applied to the other end 5b of a ferroelectric capacitor 5 with the power source of the data holding device 1 on. An electric charge corresponding to a polarization state stored in the ferroelectric capacitor 5 is thereby discharged to a ferroelectric connecting node 17. At this time, transfer gates 11 and 15 are both off. Thus, the electric charge discharged to the ferroelectric connecting node 17 does not leak through the transfer gates 11 and 15. The potential at the ferroelectric connecting node 17 accurately reflects the discharged electric charge.

Claims22

Dependent claims

A data holding device comprising:

a data holding circuit in which data are held by connecting first and second inverter circuits in a loop at the time of latching data;
and
a nonvolatile memory element which records a nonvolatile state corresponding to data existing in said data holding circuit with one end of the nonvolatile memory element connected to an input node of said first inverter circuit at the time of writing data, and which discharges an electric charge which corresponds to said nonvolatile state recorded in the nonvolatile memory element and which can generate a voltage higher or lower than the threshold voltage of said first inverter circuit at said input node of said first inverter circuit to said input node of said first inverter circuit when said one end is connected to said input node of said first inverter circuit and a reading signal is applied to the other end of the nonvolatile memory element at the time of restoring data,
said data holding circuit having a loop switching gate which is interposed between a nonvolatile memory element connecting node defined as a connecting node between said input node of said first inverter circuit and said one end of said nonvolatile memory element, and an output node of said second inverter circuit, and which is on at the time of latching and writing data, and off in applying said reading signal and on after a lapse of a predetermined period of time at the time of restoring data.

1 more element

A data holding method comprising:

a step of preparing a data holding device having a data holding circuit in which data are held by connecting first and second inverter circuits in a loop at the time of latching data, and a nonvolatile memory element having an end which is connected to an input node of said first inverter circuit at least at the time of writing and restoring data,
said data holding circuit having a loop switching gate interposed between a nonvolatile memory element connecting node defined as a connecting node between said input node of said first inverter circuit and said one end of said nonvolatile memory element, and an output node of said second inverter circuit;
a step of recording a nonvolatile state corresponding to data existing in said data holding circuit in said nonvolatile memory element with said one end of said nonvolatile memory element connected to said input node of said first inverter circuit at the time of writing data;
and
a step of restoring data corresponding to a nonvolatile state recorded in said nonvolatile memory element in said data holding circuit, including the steps of switching off said loop switching gate with the power source of said data holding device on, allowing said nonvolatile memory element to discharge an electric charge which corresponds to said nonvolatile state recorded therein and can generate a voltage higher or lower than the threshold voltage of said first inverter circuit at said input node of said first inverter circuit to said input node of said first inverter circuit by connecting said one end of said nonvolatile memory element to said input node of said first inverter circuit and applying a reading signal to the other end of said nonvolatile memory element, and connecting said first and second inverter circuits in a loop by switching on said loop switching gate after a lapse of a predetermined period of time at the time of restoring data.

2 more elements

A data holding device having a data holding circuit in which data are held by connecting two inverter circuits in a loop, comprising:

a variable resistance element interposed between a memory node of said data holding circuit and a reference potential;
and
a nonvolatile memory element for controlling the resistance value of said variable resistance element,
wherein a state corresponding to data stored in said data holding circuit is recorded in said nonvolatile memory element, and data corresponding to a state recorded in said nonvolatile memory element are restored in said data holding circuit.

1 more element

Dependencies are inferred from the claim text.

Data holding device and data holding method

Life of this patent

Data holding device and data holding method

Life of this patent

Abstract

Claims22