Temperature-Compensated Internal Voltage Generator for Semiconductor Memory
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Solution Overview
Problem
Conventional back bias voltage detecting units in semiconductor memory devices fail to precisely detect changes in back bias voltage due to temperature fluctuations, maintaining a constant voltage level despite temperature changes.
Innovation Solution
An internal voltage generator is designed with a reference voltage generator that produces a voltage inversely proportional to temperature changes, and an internal voltage detecting unit that outputs a pumping control signal with identical temperature characteristics, enabling precise detection and adjustment of internal voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional back bias voltage detecting unit is used, then the circuit structure is simple, but the voltage detection precision deteriorates due to temperature fluctuations
Solution Approach 1:
The patent introduces a reference voltage that changes with temperature to compensate for temperature-induced variations in the back bias voltage detection. By using a temperature-dependent reference voltage, the detecting unit can accurately detect the back bias voltage across different temperature conditions, resolving the contradiction between detection precision and circuit simplicity.
Solution Approach 2:
The patent introduces a reference voltage generator as an intermediary component that provides a temperature-compensated reference level for comparison. This intermediary reference voltage acts as a mediator between the temperature environment and the detection process, enabling precise detection without requiring complex temperature sensing and compensation circuits.
2Reliability
If the back bias voltage is kept constant, then the circuit operation is simplified, but the write recovery time margin decreases at high temperatures
Solution Approach 1:
The patent implements a feedback mechanism where the detecting unit continuously monitors the back bias voltage and generates a control signal to adjust the voltage pumping unit. This feedback loop ensures that the back bias voltage is dynamically adjusted to maintain adequate write recovery time margins across different temperature conditions, improving reliability while keeping the control mechanism relatively simple.
Solution Approach 2:
The patent transitions from a static constant back bias voltage to a dynamic voltage that can be adjusted based on temperature conditions. The back bias voltage pumping unit is controlled to provide different voltage levels as needed, allowing the system to adapt to temperature changes and maintain optimal write recovery time margins without requiring complex external control circuits.
3Measurement precision
If a temperature-compensated reference voltage is introduced, then the detection accuracy improves, but the device complexity increases
Solution Approach 1:
The reference voltage generator is designed to serve multiple functions: it provides a stable reference voltage for detection, compensates for temperature variations, and enables accurate back bias voltage detection across different operating conditions. By making this single component multi-functional, the patent achieves temperature compensation without proportionally increasing overall device complexity.
Data Source
AI summary
An internal voltage generator of a semiconductor memory device generates an internal voltage sensitive to a change in a temperature. The internal voltage generator includes a reference voltage generator, an internal voltage detecting unit and an internal voltage pumping unit. The reference voltage generator generates a reference voltage which is inversely proportional to the change in the temperature. The internal voltage detecting unit detects a difference between the reference voltage and the internal voltage to output a pumping control signal according to a detecting result, wherein the pumping control signal has an identical temperature characteristic as the reference voltage. The internal voltage pumping unit generates the internal voltage by a pumping operation in response to the pumping control signal.