Single Level Shifter for Bipolar Voltage Output With Lower Silicon Area
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Solution Overview
Problem
Existing level shifters typically require separate designs for positive and negative target voltages, leading to increased silicon area costs in semiconductor circuits.
Innovation Solution
A single level shifter design that outputs both positive and negative target voltages, utilizing a mid voltage output circuit, feedback circuit, pull-up and pull-down voltage control circuits, and a combination of P-channel and N-channel transistors to achieve this functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate level shifters are used for positive and negative target voltages, then voltage conversion reliability is improved, but silicon area cost increases
Solution Approach 1:
The patent combines separate positive and negative level shifter circuits into a single integrated level shifter that can simultaneously handle both positive and negative voltage conversions. This merging reduces the total silicon area while maintaining the reliability of voltage conversion by preserving the functional separation internally through different transistor pairs (first and second transistor pairs for positive voltage, third and fourth transistor pairs for negative voltage).
Solution Approach 2:
The level shifter circuit is designed with multi-functionality to perform both positive and negative voltage level shifting operations using a unified structure. The circuit accepts a single input voltage and can generate multiple output voltages (positive and negative) through controlled switching of transistor pairs, eliminating the need for separate dedicated circuits for each voltage type.
2Area of stationary object
If a single level shifter outputs both positive and negative voltages, then silicon area cost is reduced, but device complexity increases
Solution Approach 1:
The single level shifter is segmented into distinct functional modules: first and second transistor pairs for positive voltage output, third and fourth transistor pairs for negative voltage output, along with separate control circuits for each polarity. This segmentation allows the complex functionality to be organized into manageable, independent units that can be controlled separately, reducing the overall device complexity while maintaining compact integration.
Data Source
AI summary
A level shifter includes a mid voltage output circuit configured to output a mid voltage based on an input voltage swinging between a first voltage level and a second voltage level, a feedback circuit configured to output a feedback voltage and an output voltage that swings between a positive target voltage level and a negative target voltage level based on a positive target voltage, a negative target voltage and the mid voltage, a pull-up voltage control circuit configured to output a first voltage or the positive target voltage to the mid voltage output circuit based on the feedback voltage, and a pull-down voltage control circuit configured to output at least one of a second voltage or the negative target voltage to the mid voltage output circuit based on the feedback voltage.