Internal Voltage Generator With Segmented Reference Voltages
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Solution Overview
Problem
Conventional internal voltage generators for semiconductor memory devices produce unstable core voltages due to the use of a single constant reference voltage, leading to unnecessary charge/discharge operations and voltage level instability.
Innovation Solution
An internal voltage generator that includes a reference voltage generator producing both a supply reference voltage and a discharge reference voltage, with the discharge reference voltage being higher than the supply reference voltage to account for the response speed delay of the core voltage discharger, ensuring stable core voltage generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single constant reference voltage is used for both core voltage supply and discharge control, then the circuit structure is simple, but the core voltage becomes unstable and unnecessary charge/discharge operations occur
Solution Approach 1:
The single reference voltage generator is segmented into two independent reference voltage generators: a first reference voltage generator for controlling the core voltage supplier and a second reference voltage generator for controlling the core voltage discharger. This segmentation allows each generator to be optimized for its specific function, preventing the instability caused by using a single constant reference voltage for both supply and discharge operations.
2Device complexity
If a single reference voltage is used for both core voltage supplier and discharger, then the device complexity is reduced, but response speed and voltage level stability deteriorate due to response speed delay
Solution Approach 1:
The reference voltage control is segmented into two independent generators that can operate simultaneously and independently, allowing the core voltage supplier and discharger to respond without the delay inherent in sequential single-reference control.
Solution Approach 2:
The first reference voltage generator prepares the reference voltage for the core voltage supplier in advance, while the second reference voltage generator simultaneously prepares the reference voltage for the core voltage discharger. This preliminary preparation of both reference voltages eliminates the response speed delay that would occur if a single reference voltage had to be sequentially adjusted.
3Device complexity
If a single constant reference voltage is used, then the circuit configuration is simplified, but unnecessary charge/discharge operations occur causing voltage instability
Solution Approach 1:
The reference voltage generation is segmented into two independent generators, each optimized for its specific control function. This prevents the voltage instability caused by a single constant reference voltage that cannot simultaneously satisfy both supply and discharge requirements.
Solution Approach 2:
Each reference voltage generator is designed with local quality optimized for its specific function: the first generator provides appropriate reference characteristics for the core voltage supplier, while the second generator provides appropriate reference characteristics for the core voltage discharger. This localized optimization prevents unnecessary charge/discharge operations.
Data Source
AI summary
An internal voltage generator for a semiconductor memory device is provided. The internal voltage generator includes a first reference voltage generator for generating a first reference voltage, a second reference voltage generator for generating a second reference voltage, a core voltage generator for raising a core voltage based on the first reference voltage, and a core voltage discharger for discharging the core voltage depending on the second reference voltage.