Internal Voltage Detection Circuit for Semiconductor Memory
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Solution Overview
Problem
Conventional bulk bias voltage generators in semiconductor devices face operation errors at extreme temperatures due to inadequate voltage level detection, leading to inconsistent data retention and writing times.
Innovation Solution
An internal voltage detection circuit comprising multiple voltage detection units and a signal generation unit that combines detection signals to maintain a stable bulk bias voltage across varying temperatures, preventing operation errors by adjusting the charge pumping operation accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single voltage detection method (normal or modulation detector) is used, then the circuit structure is simple, but operation errors occur at extreme temperatures
Solution Approach 1:
The voltage detection circuit is divided into multiple independent detection units: a normal detector for constant voltage level detection and a modulation detector for temperature-dependent voltage level detection. Each detector operates independently and covers different temperature ranges, ensuring reliable operation across the entire temperature spectrum while maintaining reasonable circuit complexity.
2Device complexity
If only constant voltage level detection is used, then the detection circuit is simple, but data retention time decreases at high temperatures
Solution Approach 1:
The detection system dynamically adapts to temperature changes by switching between constant voltage level detection (normal detector) and temperature-dependent voltage level detection (modulation detector). At high temperatures, the modulation detector adjusts the bulk bias voltage level to maintain optimal data retention time, while at low temperatures, the normal detector maintains stable operation.
3Duration of action of moving object
If only temperature-dependent voltage level detection is used, then data retention is improved at high temperatures, but writing time increases at low temperatures
Solution Approach 1:
The system changes the detection parameter (voltage level reference) based on temperature conditions. The modulation detector uses temperature-dependent voltage levels to optimize data retention at high temperatures, while the normal detector uses constant voltage levels to minimize writing time at low temperatures. The selection between detectors is based on temperature-dependent parameter changes.
4Reliability
If multiple voltage detection units are used, then operation reliability at extreme temperatures is improved, but the circuit complexity increases
Solution Approach 1:
The system uses feedback mechanisms where the output of each detector feeds into a selection logic that determines which detector's output is active. The modulation detector's temperature-dependent output and the normal detector's constant output are combined through feedback-controlled switching, achieving high reliability across temperature ranges while managing circuit complexity through systematic feedback architecture.
Data Source
AI summary
An internal voltage generator for use in a semiconductor memory device includes a first voltage detection unit, a second voltage detection unit, a detection signal generation unit, and an internal voltage generation unit. The first voltage detection unit detects a voltage level of an internal voltage changing linearly depending on a temperature variation to output a first detection signal. The second voltage detection unit detects the voltage level having a constant value without concerning the temperature variation to output a second detection signal. The detection signal output unit combines the first and the second detection signal to generate a combined detection signal for detecting the voltage level linearly varying according to the temperature variation in a first range of temperature and detecting the voltage level having the constant value in a second range of temperature.