Mono-polarity switchable PCMO resistor trimmer
View Patent ↗Using programmable resistance material for a matching resistor, a resistor trimming circuit is designed to reversibly trim a matching resistor to match a reference resistor. The programmable resistance materials such as metal-amorphous silicon metal materials, phase change materials or perovskite materials are typically used in resistive memory devices and have the ability to change the resistance reversibly and repeatable with applied electrical pulses. The present invention reversible resistor trimming circuit comprises a resistance bridge network of a matching resistor and a reference resistor to provide inputs to a comparator circuit which generates a comparing signal indicative of the resistance difference. This comparing signal can be used to control a feedback circuit to provide appropriate electrical pulses to the matching resistor to modify the resistance of the matching resistor to match that of the reference resistor.
1. A circuit for reversible trimming of a matching resistor to a reference resistor wherein a material of the matching resistor comprises a programmable resistance material with a mono-polarity switchable property, the circuit comprising
a resistor bridge network including the reference resistor and the matching resistor, wherein the resistor bridge network
compares the resistance values of the reference resistor and the matching resistor and
generates a comparing signal indicative of the difference between the reference resistor and the matching resistor; and
a pulse feedback circuit coupled to the resistor bridge network and providing a mono-polarity electrical pulse signal corresponding to the comparing signal to modify the resistance of the matching resistor toward that of the reference resistor.
2. A circuit as in claim 1 wherein the programmable resistance material is selected from the group of materials consisting of a metal-amorphous silicon-metal material, a phase change material and a thin film perovskite material.
3. A circuit as in claim 1 wherein the mono-polarity switchable property of the programmable resistance material is such that the same polarity of the mono-polarity electrical pulse signal is used to increase and to decrease the resistance of the programmable resistance material.
4. A circuit as in claim 1 wherein the mono-polarity electrical pulse signal has a high amplitude and a short duration to change the resistance of the matching resistor in one way, and a lower amplitude and a longer duration to change the resistance of the matching resistor in another way.
5. A circuit for reversible trimming of a matching resistor to a reference resistor wherein a material of the matching resistor comprises a programmable resistance material with a mono-polarity switchable property, the circuit comprising
a resistor bridge network including the reference resistor and the matching resistor, wherein the resistor bridge network
compares the resistance values of the reference resistor and the matching resistor and
generates a comparing signal indicative of the difference between the reference resistor and the matching resistor;
an input transmission gate coupled to the resistor bridge network;
an output transmission gate coupled to the resistor bridge network; and
a pulse feedback circuit for providing a mono-polarity electrical pulse signal to reversibly modify the resistance of the matching resistor toward that of the reference resistor, the feedback circuit receiving a signal input from the input transmission gate and transmitting the mono-polarity electrical pulse signal to the output transmission gate; wherein the transmission gates provide signal isolation between the resistor bridge network and the pulse feedback circuit.
6. A circuit as in claim 5 wherein the timing of the transmission gates is mutually exclusive.
7. A circuit as in claim 6 wherein the mutually exclusive timing of the transmission gates is such that
the input transmission gate is pulsed open after the closing of the output transmission gate for the resistor bridge network to transmit the comparing signal; and
the output transmission gate is pulsed open after the closing of the input transmission gate to propagate the mono-polarity electrical pulse signal to the resistor bridge network.
8. A circuit as in claim 5 wherein the resistor network includes the reference resistor, the matching resistor and two resistors having equal resistances.
9. A circuit as in claim 5 further comprising a differential amplifier to amplify the comparing signal from the resistor bridge network.
10. A circuit as in claim 5 wherein each of the transmission gates is a single transistor.
11. A circuit as in claim 5 wherein the comparing signal input to the input transmission gate and the mono-polarity electrical pulse signal input to the output transmission gate are repetitive.
12. A circuit as in claim 5 wherein the mono-polarity switchable property of the programmable resistance material is such that the same polarity of the mono-polarity electrical pulse signal is used in increasing and decreasing the resistance of the programmable resistance material.
13. A circuit as in claim 5 wherein the mono-polarity electrical pulse signal has a high amplitude to change the resistance of the matching resistor in one way, and a lower amplitude to change the resistance of the matching resistor in other way.
14. A circuit as in claim 13 wherein the high amplitude is between 4 V to 10 V, and the lower amplitude is between 2 V to 6 V.
15. A circuit as in claim 5 wherein the pulse feedback circuit includes two different supply voltages which are adjustable to provide resistance trimming voltages.
16. A circuit as in claim 15 wherein the two different supply voltages are between 4 V to 10 V and between 2 V to 6 V.
17. A circuit as in claim 5 wherein the mono-polarity electrical pulse signal has a short duration to change the resistance of the matching resistor in one way, and a longer duration to change the resistance of the matching resistor in other way.
18. A circuit as in claim 17 wherein the short duration is between 10 ns to 10 μs, and the longer duration is between 1 μs to 1 ms.
19. A circuit as in claim 17 wherein the longer duration is accomplished with a one-bit counter or a higher-bit counter.
20. A circuit as in claim 5 wherein the transmission gates have different gate opening durations and the different gate opening durations of the transmission gates provide the different durations for the mono-polarity electrical pulse signal.
21. A circuit as in claim 5 wherein the pulse feedback circuit comprises two branch circuits and a branch selector circuit to combine the outputs from these two branch circuits, the two branch circuits comprising a first matching resistance branch and a second matching resistance branch, wherein
the first matching resistance branch circuit receives the comparing signal indicating one status of the matching resistance and generates the mono-polarity electrical pulse having high amplitude or short duration or both; and
the second matching resistance branch circuit receives the comparing signal indicating another status of the matching resistance and generates the mono-polarity electrical pulse having low amplitude or long duration or both.
22. A circuit as in claim 21 wherein the branch selector circuit comprises an amplifier.
23. A circuit as in claim 21 wherein the first matching resistance branch circuit comprises a level shifter circuit.
24. A circuit as in claim 21 wherein the second matching resistance branch circuit comprises a level shifter circuit and a one-bit counter or a higher bit counter.
25. A circuit as in claim 5 wherein the programmable resistance material is selected from the group of materials consisting of a metal-amorphous silicon-metal material, a phase change material and a thin film perovskite material.
26. A circuit as in claim 25 wherein the metal-amorphous silicon-metal material comprises boron doped amorphous silicon layer located between two electrodes, one electrode being Cr and the other being V, Co, Ni, Pd, Fe or Mn.
27. A circuit as in claim 25 wherein the phase change material comprises at least one chalcogen and one or more transition metals.
28. A circuit as in claim 25 wherein the thin film perovskite material is selected from a group of materials consisting of colossal magnetoresistive materials and high temperature superconducting materials.
29. A circuit as in claim 25 wherein the thin film perovskite material is selected from the group of perovskite materials consisting of PrCaMnO (PCMO), LaCaMnO (LCMO), LaSrMnO (LSMO), LaBaMnO (LBMO), LaPbMnO (LPMO), NdCaMnO (NCMO), NdSrMnO (NSMO), NdPbMnO (NPMO), LaPrCaMnO (LPCMO), and GdBaCoO (GBCO) and mixtures and combinations thereof.
30. A method of reversible trimming of a matching resistor to a reference resistor wherein a material of the matching resistor comprises a programmable resistance material with a mono-polarity switchable property, the method comprising
comparing the matching resistor to the reference resistor;
generating a comparing signal indicative of the difference between the reference resistor and the matching resistor;
generating a mono-polarity electrical pulse signal from a pulse feedback circuit connected to the matching resistor, the electrical pulse signal corresponded to the comparing signal; and
applying the mono-polarity electrical pulse signal to the matching resistor to modify the resistance of the matching resistor toward that of the reference resistor.
31. A method as in claim 30 wherein the pulse feedback circuit is connected to the matching resistor through input and output transmission gates which provide electrical signal isolation during the period of resistor comparing and resistor modifying.
32. A method as in claim 30 wherein the mono-polarity electrical pulse signal has an amplitude or a duration corresponding to a polarity or an amplitude of the comparing signal from a comparator circuit to reversibly modify the resistance of the matching resistor toward that of the reference resistor.
33. A method as in claim 30 wherein the mono-polarity electrical pulse signal has different pulse duration corresponding to the polarity of the comparing signal.
34. A method as in claim 30 wherein the mono-polarity electrical pulse signal has different pulse amplitudes corresponding to the polarity of the comparing signal.
35. A method as in claim 30 further comprising the repetition of the above steps until the resistances of the matching resistor and the reference resistor are matched.
36. A method as in claim 30 wherein the programmable resistance material is selected from the group of materials consisting of a metal-amorphous silicon-metal material, a phase change material and a thin film perovskite material.