High-Voltage Logic Circuits Using Split Voltage Signal Stages
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Solution Overview
Problem
Existing digital logic circuits face challenges in handling digital input and output signals with larger voltage ranges, as they often require MOS transistors with breakdown voltages that match or exceed the signal voltages, limiting their applicability and reliability.
Innovation Solution
The implementation of high voltage logic circuits using MOS transistors with breakdown voltages smaller than the signal range, which split the full voltage range into two reduced ranges, allowing for efficient handling and processing of digital signals through a multi-stage design involving input, second, and output stages with self-biasing configurations and inverters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If MOS transistors are designed to handle the voltage range of digital input and output signals, then the circuit can process signals with larger voltage ranges, but the transistor breakdown voltage must match or exceed the signal voltage, limiting component selection and increasing device complexity
Solution Approach 1:
The patent divides the voltage handling function into two separate stages: a first circuit stage that processes signals within a first voltage range, and a second circuit stage that processes signals within a second voltage range. This segmentation allows each stage to use transistors with breakdown voltages matched to their specific voltage ranges, rather than requiring all transistors to handle the full signal voltage range, thereby reducing device complexity while maintaining adaptability.
Solution Approach 2:
The patent introduces an intermediate voltage conversion stage that converts between the first voltage range and the second voltage range. This intermediary stage acts as a bridge, allowing the system to handle larger overall voltage ranges by chaining multiple stages with different voltage ranges, while each individual stage uses transistors with appropriate breakdown voltages for its specific range.
2Reliability
If MOS transistors with breakdown voltages matching the signal voltage are used, then reliable operation is achieved, but the circuit cannot handle signals with voltage ranges larger than the transistor breakdown voltage
Solution Approach 1:
By segmenting the voltage handling into multiple stages, each stage maintains reliable operation with transistors whose breakdown voltages match their specific voltage ranges, while the overall system achieves the ability to handle larger voltage ranges through the cascaded stages.
Solution Approach 2:
The patent changes the voltage range parameter between stages by using voltage conversion circuits that transform signals from one voltage range to another. This allows the system to process signals with voltage ranges larger than any single transistor's breakdown voltage, while each transistor operates within its safe voltage limits, maintaining reliability.
3Device complexity
If a single-stage circuit design is used, then the circuit structure is simple, but it requires transistors with breakdown voltages that exceed the full signal voltage range, increasing manufacturing difficulty and cost
Solution Approach 1:
The patent segments the circuit into multiple stages with different voltage ranges, which increases the number of components but allows each component to be manufactured with standard breakdown voltage specifications, thereby improving ease of manufacture despite increased structural complexity.
Solution Approach 2:
By changing the voltage range parameter between stages through voltage conversion, the patent allows each stage to use transistors with standard breakdown voltages that are easier to manufacture, rather than requiring a single stage with transistors having extremely high breakdown voltages that would be difficult and expensive to manufacture.
Data Source
AI summary
High voltage logic circuits that can handle digital input and output signals having a larger voltage range are described. In an exemplary design, a high voltage logic circuit includes an input stage, a second stage, and an output stage. The input stage receives at least one input signal and provides (i) at least one first intermediate signal having a first voltage range and (ii) at least one second intermediate signal having a second voltage range. The second stage receives and processes the first and second intermediate signals based on a logic function and provides (i) a first drive signal having the first voltage range and (ii) a second drive signal having the second voltage range. The output stage receives the first and second drive signals and provides an output signal having a third voltage range, which may be larger than each of the first and second voltage ranges.