Logic Level Shifter With Gate Voltage Limiting
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Solution Overview
Problem
Existing logic level shifters face limitations in effectively translating logic input signals with different potential levels, leading to inefficiencies and potential damage to transistors due to improper control voltage management.
Innovation Solution
The proposed solution involves a logic level shifting device comprising first and second transistors connected in series, with a first voltage generator providing a DC voltage to set a high limit for the control voltage of the first transistor, and a second voltage generator, controlled by a representative value of the first voltage, providing a similar DC voltage for the second transistor, thereby ensuring proper control voltage management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If logic level shifters are used to translate logic input signals with different potential levels, then signal translation capability is improved, but transistor damage risk increases due to improper control voltage management
Solution Approach 1:
The patent introduces voltage generators as intermediary components that generate control voltages for the transistors. These voltage generators act as mediators between the input signal and the transistor control terminals, ensuring that control voltages remain within safe thresholds. The voltage generators prevent direct application of potentially damaging voltages to the transistor gates by providing buffered, limited control voltages instead.
Solution Approach 2:
The patent changes the voltage parameters by introducing voltage generators that output control voltages with predefined maximum values. The first voltage generator limits the control voltage of the first transistor to a first maximum value, and the second voltage generator limits the control voltage of the second transistor to a second maximum value. This parameter control ensures that transistors operate within safe voltage ranges while still enabling level shifting functionality.
2Reliability
If control voltage limits are imposed on transistors, then transistor safety is improved, but circuit complexity increases due to additional voltage generators
Solution Approach 1:
The voltage generators serve multiple functions: they generate control voltages for transistor switching, limit maximum control voltages to prevent damage, and provide reference voltages for level translation. By making the voltage generators multi-functional, the patent reduces the need for separate protective components, thereby limiting the increase in circuit complexity while maintaining transistor safety.
Solution Approach 2:
The voltage generators perform preliminary action by pre-establishing safe operating voltage ranges before the transistors are activated. The control voltages are generated and limited in advance through the voltage generators, ensuring that transistors are always controlled within safe thresholds from the moment they are switched on, without requiring additional protective circuits.
3Reliability
If voltage generators are added to limit control voltages, then transistor protection is improved, but power consumption increases
Solution Approach 1:
The voltage generators provide partial action by only generating control voltages when needed for transistor switching, rather than continuously driving the transistors. The voltage generators output controlled voltages that are sufficient to achieve the required level translation and transistor control, without excessive voltage or power application. This partial action approach limits power consumption while maintaining transistor protection.
Data Source
AI summary
An output potential level among two first levels is delivered according to an input level among two second levels. The output potential level is delivered at a first node connecting together first and second transistors electrically in series between two second nodes of application of the first levels. A first DC voltage defining a high limit for the control voltage of the first transistor is delivered by a first voltage generator powered by one of the second nodes. A second DC voltage defining a high limit for the control voltage of the second transistor is delivered by a second voltage generator controlled by a value representative of the first voltage and powered between the second nodes.