A read circuit of flash memory

Abstract

The invention discloses a read circuit of flash memory. The read circuit comprises a sensitive amplifier, which comprises a first input terminal, a second input terminal, and an output terminal; a switch unit; a plurality of reference units, which are floating gate MOS memory devices; and a control unit, which is used for indicating the switch unit to select one reference unit from the plurality of reference units, and then indicating the switch unit to select other reference units, when the work state of the chosen reference unit satisfies the predetermined conditions. The switch unit is used for connecting the drain electrode of the chosen reference unit to the first input end of the sensitive amplifier. The read circuit is capable of increasing the reliability of a flash memory after many times of reading and writing on the flash memory.

Description

technical field [0001] The invention relates to the field of circuits, in particular to a read circuit of a flash memory. Background technique [0002] With the development of the consumer electronics market, flash memory, as the main memory, has been widely used in mobile phones, digital cameras and other products, and the market scale is constantly expanding. [0003] The flash memory can keep the stored information for a long time without power on, and its read operation is as follows: figure 1 As shown, a certain voltage is applied to the gates of the storage unit (Array Cell) and the reference unit (Ref Cell), the source of the storage unit is grounded, and the drain passes through the resistor R A Connect high level V cc , the source of the reference cell is grounded, and the drain is through resistor R R Connect high level V cc ; Read current I from the drain of the memory cell cell , read current I from the reference cell drain ref , the two are compared with e...

AI Technical Summary

Problems solved by technology

However, the reference cell may be affected by various factors, for example, a disturbance of the power supply may cause a change in the voltage applied to the reference cell, thereby causing a change in the reference cell current

What's more serious is that because the performance of the reference unit itself may change after multiple operations, the designed reference current will drift, resulting in the failure of the memory to work normally and greatly reducing the service life of the memory.

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