High Voltage Switch Circuit Triple Well Transistor Discharge

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Solution Overview

Problem

Semiconductor memory devices, particularly nonvolatile flash memory, face challenges in rapidly discharging high voltages after operations, leading to potential malfunctions in unselected memory blocks due to lingering operating voltages.

Innovation Solution

A high voltage switch circuit incorporating a triple well transistor is used to rapidly discharge high voltages to the internal power voltage level, preventing voltage leakage to unselected memory blocks and ensuring efficient operation transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high voltage is supplied to block decoder for memory block operation, then memory block operation is enabled, but high voltage remains lingering after operation completion causing malfunction in unselected memory blocks

Engineering Contradiction:

Improvememory block operation reliabilityVSAvoidvoltage leakage to unselected memory blocks

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the high voltage discharge function from the general power management system by introducing a dedicated discharge circuit with a discharge transistor. This separate discharge path quickly removes residual high voltage from the block decoder after operation completion, preventing voltage leakage to unselected memory blocks and eliminating the harmful effect without interfering with normal operation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements preliminary action by preparing the discharge circuit in advance and activating it immediately after memory block operation completion. The discharge transistor is configured to rapidly discharge high voltage as a preliminary protective measure before any potential interference can affect unselected memory blocks, ensuring reliable operation transitions.

Inventive Principle:

Principle #10Preliminary action

2Object-affected harmful factors

If discharge circuit is added to rapidly discharge high voltage, then voltage leakage is prevented, but circuit complexity increases

Engineering Contradiction:

Improvevoltage interference to unselected blocksVSAvoidhigh voltage switch circuit complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent introduces a discharge transistor as an intermediary element between the block decoder and ground. This intermediary component specifically targets and neutralizes the harmful high voltage without requiring complex control logic or additional circuitry, achieving voltage discharge with minimal increase in overall circuit complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11735275B2High voltage switch circuit and semiconductor memory device having the same

Publication Date: 2023.08.22 SK HYNIX INC

AI summary

A high voltage switch circuit and a semiconductor memory device having the same are provided. The high voltage switch circuit includes a switching circuit for outputting a high voltage by transmitting one of a plurality of pump voltages to an output node; and a discharge circuit connected between the output node and a terminal of an internal power voltage, the discharge circuit discharging the high voltage to a level of the internal power voltage. The discharge circuit includes a triple well transistor.