Level Shifter Voltage Sequencing to Prevent Reverse Leakage
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Solution Overview
Problem
Current semiconductor devices face challenges in preventing leakage current due to the generation of internal voltages during power-up and standby modes, which can lead to reverse voltage and subsequent leakage currents.
Innovation Solution
A level shifter is designed to generate a first internal voltage using an external voltage in power-up mode and a second internal voltage using the first internal voltage, while in standby mode, the second internal voltage is generated directly from the external voltage, thereby preventing reverse voltage and leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the level shifter generates both first internal voltage and second internal voltage using the external voltage simultaneously in power-up mode, then the voltage conversion function is achieved, but reverse voltage occurs causing leakage current
Solution Approach 1:
The level shifter generates the first internal voltage using the external voltage before generating the second internal voltage. This preliminary action ensures that the first internal voltage is already available and stable before the second internal voltage generation begins, preventing reverse voltage occurrence and subsequent leakage current while maintaining a controlled voltage generation sequence
Solution Approach 2:
The voltage generation process is segmented into distinct phases: first generating the first internal voltage from the external voltage, then generating the second internal voltage from the first internal voltage. This segmentation separates the voltage generation into sequential steps rather than simultaneous generation, preventing reverse voltage conditions
2Reliability
If the level shifter uses a simple voltage generation method, then the device structure is simple, but leakage current cannot be effectively prevented
Solution Approach 1:
The level shifter performs preliminary voltage generation by creating the first internal voltage before the second internal voltage. This preliminary action ensures proper voltage sequencing without requiring complex active control circuits, achieving leakage current prevention through inherent voltage generation timing while maintaining reasonable energy consumption
Solution Approach 2:
The first internal voltage acts as an intermediary between the external voltage and the second internal voltage. This intermediary voltage serves as a stable reference and power source for generating the second internal voltage, preventing reverse voltage conditions and leakage current while using a straightforward voltage conversion approach
Data Source
AI summary
A semiconductor device includes a memory cell array including a plurality of memory blocks, a control logic, a level shifter configured to generate a first internal voltage and a second internal voltage lower than the first internal voltage using a received external voltage on the basis of a control signal from the control logic, and a row decoder configured to provide the first and second internal voltages generated by the level shifter to the memory cell array. The level shifter generates the first internal voltage using the external voltage, generates the second internal voltage using the generated first internal voltage in a power-up mode of the semiconductor device, and generates the second internal voltage using the external voltage in a standby mode of the semiconductor device.