A method for generating an adaptive reference current for a non-volatile memory (NVM)

Abstract

The invention discloses a method for generating adaptive reference current of a non-volatile memory. An NVM adaptive reference current generation circuit includes an NVM memory cell and a control circuit based on the NVM memory cell. The circuit for generating NVM adaptive reference current also includes an NVM redundant memory cell and a control circuit based on the NVM redundant memory cell. Thecircuit for generating NVM adaptive reference current also includes a current comparison circuit. The invention relates to the non-volatile memory adaptive reference current generation method, whichhas a compact structure, reduces the dependence of the storage unit on the process, and has higher stability because the reference current generated by the redundant unit also undergoes the same change under the condition of changing the working environment.

Description

technical field [0001] The invention relates to the technical field related to integrated circuits, in particular to a method for generating a non-volatile memory NVM self-adaptive reference current. Background technique [0002] With the application requirements of product intelligence, the development of SoC chips is increasingly inseparable. For System on Chip (SoC) applications, it integrates many functional blocks into a single integrated circuit. The most commonly used system-on-chip includes a microprocessor or microcontroller, static random access memory (SRAM) modules, non-volatile memory (such as OTP, MTP, FLASH, EEPROM modules, etc.) modules and various special function logic modules . The patent of the present invention aims to improve the stability of the non-volatile memory module; the design of the traditional non-volatile memory module usually needs to be supported by a high-stability production process. For example, there are still many integrated circuit m...

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Problems solved by technology

[0007] However, since the injection number of hot electrons is closely related to external conditions, it is known that it is related to temperature, voltage difference, and writing time, so it is difficult to accurately calculate the injection number of hot electrons with an accurate formula , but the amount of hot electrons injected determines the conduction state of the MOS tube, and the reading of the NVM memory cell is to judge whether there is written data according to the change of the conduction state of the MOS, and the change of the conduction state depends on the The above description can be judged to be an inaccurate value. The current common solution in the market is to make a high-precision constant current source externally, such as figure 1 Use bandgap to generate a constant current source that has nothing to do with temperature and voltage. Use this constant current source as a reference current to compare with the current read by NVM. When it is greater than the set constant current value, it is considered to have been changed. If the read current value is less than the constant current value, it is considered that it has not changed. The simple schematic diagram is as follows figure 2 ; However, due to the deviation of different processes and different temperatures and voltages, it is difficult to achieve a reference current that is truly irrelevant to the outside world, and even if it is really possible to achieve a reference current source that is completely irrelevant, but due to the OTP readout The circuit will also change accordingly with changes in external voltage and temperature conditions, so the current method is only suitable for empirical reference and the output generated under certain conditions is in line with the requirements

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