NAND Flash Drive Circuit Pre-Pulse Calibration
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Solution Overview
Problem
Conventional methods for reducing signal delay in electronic devices with linear wiring, such as semiconductor memory and flat panel displays, require costly and time-consuming calibration processes due to manufacturing variations in parasitic resistance and capacitance, leading to increased test costs and times.
Innovation Solution
A drive circuit that generates a drive voltage with a pre-pulse of predetermined amplitude, applied to the wiring portion, and a control unit that detects the voltage value at a predetermined position to set the time width of the pre-pulse, allowing for automatic calibration and reduced test time and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If pre-emphasis is used to shorten signal delay time in wiring portions, then the speed of electronic devices is improved, but manufacturing variations in parasitic resistance and capacitance require costly and time-consuming calibration for each product
Solution Approach 1:
The drive circuit automatically adjusts the pre-emphasis time width by detecting the voltage at a predetermined position during normal operation, eliminating the need for external calibration equipment and manual adjustment for each product. The circuit self-calibrates by monitoring its own output and adjusting the pre-pulse duration accordingly.
Solution Approach 2:
The control unit detects the voltage value at a predetermined position of the wiring portion and uses this feedback information to adjust the time width of the pre-pulse. This closed-loop feedback mechanism enables automatic optimization of the pre-emphasis parameters without requiring external calibration equipment.
2Speed
If pre-emphasis is used to shorten signal delay time in wiring portions, then the speed of electronic devices is improved, but the test cost for calibration process increases
Solution Approach 1:
The drive circuit performs self-calibration using only its internal components (voltage application unit, control unit with detection capability), eliminating the need for expensive external calibration equipment and reducing test costs while maintaining optimal signal propagation speed.
Solution Approach 2:
The internal voltage detection and feedback control mechanism enables the circuit to automatically optimize its pre-emphasis parameters during normal operation, replacing expensive external calibration processes with inexpensive internal self-adjustment.
3Reliability
If pre-emphasis is used to compensate for parasitic resistance and capacitance effects, then signal integrity is improved, but the device complexity increases due to additional calibration requirements
Solution Approach 1:
The calibration function is integrated into the drive circuit itself using only two functional units (voltage application and voltage detection), avoiding the need for separate calibration equipment or complex external systems while maintaining signal integrity.
Solution Approach 2:
The calibration functionality is merged with the normal drive operation by using the same voltage application and detection circuits for both calibration and operational purposes, eliminating the need for separate calibration hardware and reducing overall system complexity.
Data Source
AI summary
A NAND flash memory according to an embodiment includes a memory array, a detection circuit, and a drive circuit. The drive circuit is a circuit for driving a plurality of linearly arranged memory cells through a linear word line connected to the plurality of memory cells. The drive circuit has a function of generating a drive voltage in which a pre-pulse having a predetermined amplitude value is set at a timing corresponding to rising of a voltage signal, which rises stepwise by a voltage value, and applying the drive voltage to the word line and a function of detecting a voltage value at a predetermined position of the word line and setting a time width of the pre-pulse according to the detected voltage value.