Sense amplifier for MLC flash memory and BL quick-charging circuit

Abstract

The invention discloses a sense amplifier for an MLC (multi-level cell) flash memory and a BL (bit line) quick-charging circuit. The BL quick-charging circuit applicable to the sense amplifier of the MLC flash memory comprises a ZNMOS transistor Z3 connected in parallel with an impeder, wherein the gate of the ZNMOS transistor Z3 is connected with the output terminal of an inverting amplifier. By using the ZNMOS transistor to bypass the high impedance of the impeder in the establishment process, the sense amplifier can accelerate the charging process of the BL; and meanwhile, the sense amplifier can prevent the voltage of the voltage output terminal SAIN from being drawn close to the voltage of the BL after adding the NMOS transistor of the quick-charging circuit, i.e., the sense amplifier can respectively stabilize the voltages of the BL and the SAIN terminal to a balanced state in one-step level establishment, thus reducing the overall time for charging the BL and improving the overall performance of the sense amplifier.

Description

technical field [0001] The present invention relates to the technical field of the memory of integrated circuit, relate in particular to a kind of sense amplifier (Senseamplifier) ​​used for MLC flash memory (MLC Flash Memory, multi-level cell flash memory), and a kind of bit line (BL) in the sense amplifier fast charging circuit. Background technique [0002] A semiconductor memory (Memory) is generally composed of word line (WL) rows and bit line (BL) columns. The intersection of each row and column is a memory cell (cell), and the memory cell is composed of a transistor and a capacitor. The data in the memory cell depends on the charge stored in the capacitor, and the switching of the transistor controls the access of the data. When the word line is selected and the transistor is turned on, the charge stored in the capacitor changes the BL voltage through charge sharing. Existing Flash memories may include SLC Flash Memory (Single-Level Cell, single-level cell flash mem...

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Problems solved by technology

However, in this circuit, when the power supply voltage VCC range is relatively large, especially when the VCC is low, since the ZNMOS transistor Z2 is fully turned on, the impedance of the ZNMOS transistor Z2 is very small; and the ZNMOS transistor Z1 is a large impedance device; therefore, Although this charging circuit can quickly charge the voltage of BL to a position close to equilibrium, but at the same time, the voltage of the SAIN terminal is pulled to be very close to the voltage of BL

In this case, it takes time to establish the stability of the SAIN terminal voltage after charging BL, so the overall settling time is still slow, resulting in a decrease in overall performance

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