摘要:
A multimode charge pump circuit has a single charge pump that is responsive to a set of clock signals. The set of clock signals is provided in a first mode with a variable frequency according to a first function of the supply potential and temperature, and in a second mode with a variable frequency according to a second function of the supply potential and temperature. Circuitry configures all of the plurality of stages in series during the first mode in order to produce a higher voltage output, and configures a subset of the plurality of stages in series, while disabling the other stages, during the second mode in order to produce a lower voltage output. A precharge circuit is provided that operates as a supply node in the second mode, and as a precharge/clamp in the first mode.
摘要:
The present invention provides a novel method in altering the sequence of multi-level-cell programming in a multi-bit-cell of a nitride trapping memory cell that reduces or eliminates voltage threshold shifts between program steps while avoiding the suppression in the duration of a read window caused by a complementary bit disturbance. In a first embodiment, the present invention programs the multi-level cell in a multi-bit-cell having four bits in the following order: programming a third program level (level3), programming a first program level (level1) and a second program level (level2) to level 1, and programming the second program level from the first program level. In a second embodiment, the present invention programs the multi-level cell in the multi-bit-cell having four bits in the following order: programming a third program level (level3), programming a second program level (level2), and programming a first program level (level1).
摘要:
A virtual ground nitride read-only memory array has a matrix of nitride read-only memory cells in which during an erase operation the non-erasing side of nitride read-only memory cells are connected to a common node for enhancing the erase uniformity of the nitride read-only memory array. If an operation requests erasing on the left side of nitride read-only memory cells, a positive voltage is supplied from an internal power supply to the left side for each of the nitride read-only memory cells, and the right side for each of the nitride read-only memory cells is discharged to a common node. The voltage level of the common mode is selected to be sufficiently high in order to prevent from punch through while at the same time sufficiently low to maintain the lateral electric field for erase operation to function optimally.
摘要:
A negative charge-pump circuit for flash memory includes a well, a pass-gate transistor, a well bias circuit and a negative voltage recovery circuit. The pass-gate transistor has a source, a drain and a gate. The well bias circuit controls the well to remain one of zero biased and reverse biased. The negative voltage recovery circuit is coupled to a negative recovery voltage and coupled to the pass-gate transistor to selectively provide the negative recovery voltage to the pass-gate transistor when the charge-pump circuit is disabled.
摘要:
A virtual ground NROM array has a matrix of NROM cells in which during an erase operation the non-erasing side of NROM cells are connected to a common node for enhancing the erase uniformity of the NROM array. If an operation requests erasing on the left side of NROM cells, a positive voltage is supplied from an internal power supply to the left side for each of the NROM cells, and the right side for each of the NROM cells is discharged to a common node. If an operation requests erasing the right side of NROM cells, a positive voltage is supplied from the internal power supply to the right side for each of the NROM cells, and the right side for each of the NROM cells is connected to the common node. The voltage level of the common mode is selected to be sufficiently high in order to prevent from punch through while at the same time sufficiently low to maintain the lateral electric field for erase operation to function optimally. In an alternative embodiment, non-erasing sides of NROM cells in the NROM array are connected to a current source during an erase operation for enhancing the erase uniformity of the NROM array. If an operation requests erasing the left side of NROM cells, a positive voltage is supplied from an internal power supply to the left side for each of the NROM cells, and the right side for each of the NROM cells is discharged to a current source. If an operation requests erasing the right side of NROM cells, a positive voltage is supplied from the internal power supply to the right side for each of the NROM cells, and the right side for each of the NROM cells is connected to the current source.
摘要:
A locking device, which mounts a user key (the first key) and a manager key (the second key) separatedly, places a first lock and a second lock unitedly in an outer cylinder. The first lock is opened or rotated by the first key. After the first lock is open, the first key cannot be pulled out of the locking device. If the second lock is open by the second key, the first key can be pulled out together with the second key.