Internal Voltage Compensation Circuit for Multi-Voltage Power-Up
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Solution Overview
Problem
Conventional high voltage compensation circuits in semiconductor memory devices fail to properly adjust the level of internal voltages when faced with multiple external voltages of different types during the power up section, leading to potential latch up issues due to insufficient voltage pumping.
Innovation Solution
An internal voltage compensation circuit that includes a power up signal generator, a select signal generator, and a voltage compensation unit, which compares the levels of multiple external voltages and electrically connects the high voltage VPP to the external voltage with the highest level, using PMOS and NMOS transistors to manage the connection based on the comparison signals, thereby preventing latch up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the high voltage VPP is electrically connected to a single external voltage in a power up section, then the pumping operation can be performed, but the level of high voltage VPP becomes lower than other external voltages causing latch up
Solution Approach 1:
The patent implements dynamic selection of the external voltage source for high voltage VPP pumping. The select signal generator dynamically determines which external voltage (first or second) has the higher level at any given time and routes the pumping operation to that voltage source. This dynamic adaptation ensures that the high voltage VPP level never falls below any externally applied voltage, preventing latch up while handling multiple voltage sources effectively.
2Reliability
If the high voltage VPP is pumped independently without connection to external voltage, then the pumping operation is stable, but the level of high voltage VPP cannot be compensated during power up section
Solution Approach 1:
The patent applies preliminary action by electrically connecting the high voltage VPP to the selected external voltage source during the power up section before independent pumping begins. This initial connection ensures that the high voltage VPP starts at an appropriate level relative to external voltages, preventing latch up conditions. After this preliminary compensation phase, the system transitions to stable independent pumping operation.
Data Source
AI summary
An internal voltage compensation circuit is provided which includes a power up signal generator configured to generate a power up signal, a select signal generator configured to compare a level of a first external voltage with a level of a second external voltage to generate first and second select signals, wherein the second select signal is generated in response to the power up signal, and a voltage compensation unit configured to electrically connect an internal voltage to the first external voltage or the second external voltage in response to the first and second select signals.