High Voltage Regulator for Non-Volatile Memory
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Solution Overview
Problem
Conventional high voltage regulators for flash memory devices suffer from overdischarge and overshooting of program voltage due to different sensing and discharge nodes, and mismatch between low and high voltage comparators, which are critical issues for accurate programming and verification in multi-level cell flash memories.
Innovation Solution
A high voltage regulator design that senses and discharges the program voltage at the same node, using a dual regulating unit system with division circuits and shared comparators to manage voltage levels in both up and down intervals, ensuring accurate regulation and preventing overdischarge and overshooting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different nodes are used for sensing and discharging program voltage, then the conventional high voltage regulator can operate, but response difference causes overdischarge and overshooting
Solution Approach 1:
The patent merges the sensing node and discharge node into a single common node. The program voltage is sensed at the output node through a buffer, and the same output node is used for discharging the program voltage. This eliminates the response time difference between sensing and discharging operations, preventing overdischarge and overshooting issues.
2Use of energy by moving object
If large resistance value resistors are used to reduce active current, then power consumption decreases, but response difference between nodes increases
Solution Approach 1:
The patent introduces a buffer circuit as an intermediary between the high voltage regulator core and the output node. The buffer provides high input impedance to minimize loading effects on the regulator while providing low output impedance for fast voltage transitions. This allows the use of appropriate resistance values without excessive response delay, while still maintaining low active current through the buffer's efficient design.
3Measurement precision
If different comparators are used for detecting low and high voltage, then voltage levels can be detected, but comparator mismatch causes malfunction
Solution Approach 1:
The patent uses a single comparator circuit that serves multiple functions. The same comparator is used to detect both the low voltage threshold (for enabling the regulator) and the high voltage threshold (for disabling the regulator). This eliminates comparator mismatch issues while maintaining accurate voltage detection through the buffer's isolation and the comparator's precise reference voltage comparisons.
Data Source
AI summary
A high voltage regulator may include a first regulating unit, a second regulating unit, and an output node. The first regulating unit regulates the program voltage in a voltage-level-up interval of a program voltage of a memory cell. The second regulating unit regulates the program voltage in a voltage-level-down interval of the program voltage. The output node outputs the regulated program voltage.