Internal Voltage Generation Circuit Segmentation for Semiconductor Memory
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Solution Overview
Problem
Semiconductor memory devices face challenges in efficiently generating internal voltages such as core voltage, high voltage, and back-bias voltage, as existing charge pump circuits are complex and may not effectively manage voltage levels during operations like read and write operations.
Innovation Solution
An internal voltage generation circuit comprising a drive controller and an initialization unit, where the drive controller detects internal voltage levels and generates drive signals in response to reference signals, and the initialization unit synchronizes these signals with command signals to initialize and terminate the drive signals during predetermined periods, ensuring stable voltage generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If charge pump circuits are used to generate high voltage VPP and back-bias voltage VBB, then the required voltage levels can be achieved, but the circuit complexity increases
Solution Approach 1:
The voltage generation function is segmented into two independent parts: a drive signal generator that produces the drive signal PU, and a charge pump circuit that generates voltages based on this drive signal. This segmentation allows the drive signal generator to be optimized independently for reliability while managing complexity through functional separation.
Solution Approach 2:
The drive signal generator performs preliminary action by generating and stabilizing the drive signal PU before the charge pump circuit operates. The initialization unit pre-charges or pre-discharges the drive signal to predetermined levels in advance, ensuring the charge pump circuit receives a stable control signal, which improves voltage generation reliability without adding complexity to the charge pump itself.
2Speed
If the drive signal is continuously updated, then the internal voltage can respond to operations, but excessive voltage boosting may occur
Solution Approach 1:
The update of the drive signal PU is made periodic rather than continuous. The initialization unit updates the drive signal only at specific periods determined by the command signal, creating a rhythmic update pattern. This periodic action ensures the internal voltage responds to operations at appropriate intervals while preventing excessive voltage boosting that would occur with continuous updates.
Solution Approach 2:
The initialization unit monitors the internal command signal and uses it as feedback to control when the drive signal PU should be updated. This feedback mechanism ensures updates occur only when necessary (synchronized with commands) and prevents unnecessary updates that could cause excessive voltage boosting, while still maintaining responsive voltage generation during active operations.
3Stability of the object's composition
If initialization is performed for every command signal, then voltage stability is maintained, but time is lost during frequent updates
Solution Approach 1:
Initialization is performed periodically based on the command signal timing rather than continuously. The initialization unit synchronizes drive signal updates with command signal edges, creating a periodic initialization pattern that maintains stability at critical moments while minimizing unnecessary initialization operations that would waste time during normal operation.
Solution Approach 2:
The initialization unit applies partial initialization action by only updating the drive signal when commanded, rather than continuously initializing. This selective initialization approach maintains sufficient voltage stability for reliable operation while reducing the total time spent on initialization, thereby minimizing time loss during frequent command sequences.
Data Source
AI summary
Internal voltage generation circuits are provided. The internal voltage generation circuit includes a drive controller and an initialization unit. The drive controller detects a level of an internal voltage signal in response to a reference voltage signal to generate a drive signal and drives the internal voltage signal in response to the drive signal. The initialization unit initializes the drive signal in synchronization with an internal command signal and terminates an initialization of the drive signal during a predetermined period.