Abstract: A multi-level photovoltaic cell comprises a substrate layer and a plurality of photovoltaic cells positioned above the substrate layer. Each photovoltaic cell has a top contact layer and a bottom contact layer connected in series such that the top contact layer of the first photovoltaic cell is connected to the bottom contact layer of a next photovoltaic cell until the last photovoltaic cell is connected. A different voltage is output between the substrate layer and the top contact layer of each photovoltaic cell. Another multi-level photovoltaic cell comprises a substrate layer and a plurality of photovoltaic cells stacked vertically above the substrate layer. Each photovoltaic cell comprises an active layer separated from the next photovoltaic cell by an etch stop layer until a last photovoltaic cell is reached. A different voltage is output between the substrate layer and the active layer of each photovoltaic cell.

Abstract: A true random number generator includes a latch circuit, a noise circuit coupled to the latch circuit and an equalization circuit coupled to the inputs of the latch circuit, the equalization circuit being configured to maintain the latch circuit in a balanced state and to allow the latch circuit to resolve from a metastable state based on a timing control. A method of generating a random number output includes maintaining a latch circuit in a balanced state by turning on an equalization circuit coupled to the inputs of the latch circuit, coupling at least one noise source to the latch circuit, allowing the latch circuit to resolve from a metastable state by turning off the equalization circuit and repeatedly turning the equalization circuit on and off based on a timing control.

Abstract: A true random number generator includes a latch circuit, a noise circuit coupled to the latch circuit and an equalization circuit coupled to the inputs of the latch circuit, the equalization circuit being configured to maintain the latch circuit in a balanced state and to allow the latch circuit to resolve from a metastable state based on a timing control. A method of generating a random number output includes maintaining a latch circuit in a balanced state by turning on an equalization circuit coupled to the inputs of the latch circuit, coupling at least one noise source to the latch circuit, allowing the latch circuit to resolve from a metastable state by turning off the equalization circuit and repeatedly turning the equalization circuit on and off based on a timing control.

Abstract: A memory having a delayed write-back to the array of data corresponding to a previously opened page allows delays associated with write-back operations to be avoided. After an initial activation opens a first page and the read/write operations for that page are complete, write-back of the open page to the array of memory cells is delayed until after completion of a subsequent activate operation that opens a new page. Techniques to force a write-back in the absence of another activate operation are also disclosed.

Abstract: A memory having a delayed write-back to the array of data corresponding to a previously opened page allows delays associated with write-back operations to be avoided. After an initial activation opens a first page and the read/write operations for that page are complete, write-back of the open page to the array of memory cells is delayed until after completion of a subsequent activate operation that opens a new page. Techniques to force a write-back in the absence of another activate operation are also disclosed.

Abstract: A multi-level photovoltaic cell comprises a substrate layer and a plurality of photovoltaic cells positioned above the substrate layer. Each photovoltaic cell has a top contact layer and a bottom contact layer connected in series such that the top contact layer of the first photovoltaic cell is connected to the bottom contact layer of a next photovoltaic cell until the last photovoltaic cell is connected. A different voltage is output between the substrate layer and the top contact layer of each photovoltaic cell. Another multi-level photovoltaic cell comprises a substrate layer and a plurality of photovoltaic cells stacked vertically above the substrate layer. Each photovoltaic cell comprises an active layer separated from the next photovoltaic cell by an etch stop layer until a last photovoltaic cell is reached. A different voltage is output between the substrate layer and the active layer of each photovoltaic cell.

Abstract: Precharging circuits and techniques are presented for use with magnetic memory devices in order to speed up access to the memory cells for reading and writing. Including precharging in the sense amplifiers used to access the memory cells enables self-referenced read operations to be completed more quickly than is possible without precharging. Similarly, precharging can also be used in conjunction with write-back operations in order to allow the data state stored by magnetic tunnel junctions included in the memory cells to be changed more rapidly.

Abstract: In some examples, a memory device may be configured to use shared read circuitry to sample a voltage drop across both a bit cell and a resistive circuit in order to perform a comparison that produces an output corresponding to the bit stored in the bit cell. The shared read circuitry can include a shared sense amplifier as well as shared N-MOS and P-MOS followers used to apply read voltages across the bit cell and resistive circuit.

Abstract: In some examples, a memory device may be configured to use shared read circuitry to sample a voltage drop across both a bit cell and a resistive circuit in order to perform a comparison that produces an output corresponding to the bit stored in the bit cell. The shared read circuitry can include a shared sense amplifier as well as shared N-MOS and P-MOS followers used to apply read voltages across the bit cell and resistive circuit.

Abstract: A technique for detecting tampering attempts directed at a memory device includes setting each of a plurality of detection memory cells to an initial predetermined state, where corresponding portions of the plurality of detection memory cells are included in each of the arrays of data storage memory cells on the memory device. A plurality of corresponding reference bits on the memory device permanently store information representative of the initial predetermined state of each of the detection memory elements. When a tamper detection check is performed, a comparison between the reference bits and the current state of the detection memory cells is used to determine whether any of the detection memory cells have changed state from their initial predetermined states. Based on the comparison, a tamper detect indication is flagged if a threshold level of change is determined.

Abstract: A memory device is configured to identify a set of bit cells to be changed from a first state to a second state. In some examples, the memory device may apply a first voltage to the set of bit cells to change a least a first portion of the set of bit cells to the second state. In some cases, the memory device may also identify a second portion of the bit cells that remained in the first state following the application of the first voltage. In these cases, the memory device may apply a second voltage having a greater magnitude, duration, or both to the second portion of the set of bit cells in order to set the second portion of bit cells to the second state.

Abstract: In some examples, a memory device may be configured to read or write multiple bit cells as part of the same operation. In some cases, the tunnel junctions forming the bit cells may be arranged to utilize shared read/write circuitry. For instance, the tunnel junctions may be arranged such that both tunnel junctions may be written using the same write voltages. In some cases, the bit cells may be configured such that each bit cell is driven to the same state, while in other cases, select bit cells may be driven high, while others are driven low.

Abstract: In some examples, a memory device may be configured to read or write multiple bit cells as part of the same operation. In some cases, the tunnel junctions forming the bit cells may be arranged to utilize shared read/write circuitry. For instance, the tunnel junctions may be arranged such that both tunnel junctions may be written using the same write voltages. In some cases, the bit cells may be configured such that each bit cell is driven to the same state, while in other cases, select bit cells may be driven high, while others are driven low.

Abstract: In some examples, a memory device may be configured to utilize differential bit cells formed from two or more tunnel junctions. In some cases, the tunnel junctions forming the differential bit cell may be arranged to utilize shared read circuitry to reduce device mismatch. For instance, the read operations associated with both tunnel junction may be time multiplexed such that the same preamplifier circuitry may sense voltages representative of the tunnel junctions.

Abstract: In some examples, a memory device may be configured to read or write multiple bit cells as part of the same operation. In some cases, the tunnel junctions forming the bit cells may be arranged to utilize shared read/write circuitry. For instance, the tunnel junctions may be arranged such that both tunnel junctions may be written using the same write voltages. In some cases, the bit cells may be configured such that each bit cell is driven to the same state, while in other cases, select bit cells may be driven high, while others are driven low.

Abstract: In some examples, a memory device may be configured to read or write multiple bit cells as part of the same operation. In some cases, the tunnel junctions forming the bit cells may be arranged to utilize shared read/write circuitry. For instance, the tunnel junctions may be arranged such that both tunnel junctions may be written using the same write voltages. In some cases, the bit cells may be configured such that each bit cell is driven to the same state, while in other cases, select bit cells may be driven high, while others are driven low.

Abstract: In some examples, a memory device may be configured to utilize differential bit cells formed from two or more tunnel junctions. In some cases, the tunnel junctions forming the differential bit cell may be arranged to utilize shared read circuitry to reduce device mismatch. For instance, the read operations associated with both tunnel junction may be time multiplexed such that the same preamplifier circuitry may sense voltages representative of the tunnel junctions.

Abstract: A technique for detecting tampering attempts directed at a memory device includes setting each of a plurality of detection memory cells to an initial predetermined state, where corresponding portions of the plurality of detection memory cells are included in each of the arrays of data storage memory cells on the memory device. A plurality of corresponding reference bits on the memory device permanently store information representative of the initial predetermined state of each of the detection memory elements. When a tamper detection check is performed, a comparison between the reference bits and the current state of the detection memory cells is used to determine whether any of the detection memory cells have changed state from their initial predetermined states. Based on the comparison, a tamper detect indication is flagged if a threshold level of change is determined.

Abstract: A technique for detecting tampering attempts directed at a memory device includes setting each of a plurality of detection memory cells to an initial predetermined state, where corresponding portions of the plurality of detection memory cells are included in each of the arrays of data storage memory cells on the memory device. A plurality of corresponding reference bits on the memory device permanently store information representative of the initial predetermined state of each of the detection memory elements. When a tamper detection check is performed, a comparison between the reference bits and the current state of the detection memory cells is used to determine whether any of the detection memory cells have changed state from their initial predetermined states. Based on the comparison, a tamper detect indication is flagged if a threshold level of change is determined.

Abstract: Circuitry and a method provide self-referenced sensing of a resistive memory cell by using its characteristic of resistance variation with applied voltage in one state versus a relatively constant resistance regardless of the applied voltage in its opposite state. Based on an initial bias state with equalized resistances, a current comparison at a second bias state between a mock bit line and a bit line is used to determine the state of the memory cell, since a significant difference in current implies that the memory cell state has a significant voltage coefficient of resistance. An offset current applied to the mock bit line optionally may be used to provide symmetry and greater sensing margin.