Microcontroller I/O Voltage Selection for Built-In Level Shifting
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Solution Overview
Problem
The development of microcontroller products is hindered by the complexity and time-consuming nature of creating level shifting circuitry to operate in different voltage domains, which requires converting signals between various supply voltages.
Innovation Solution
An integrated circuit device with a microcontroller that includes input/output circuitry capable of selecting between multiple supply voltages, featuring a switching unit that couples the I/O voltage supply with internal or external voltages, and optionally includes a buffer amplifier and multiplexer to manage these voltage levels, thereby eliminating the need for external level shifting circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If external level shifting circuitry is used to convert signals between different voltage domains, then signal compatibility between different voltage domains is achieved, but device complexity and development time increase
Solution Approach 1:
The patent integrates level shifting functionality directly into the microcontroller's I/O circuitry by merging the voltage selection logic with the existing I/O ports. The I/O circuitry is configured to sense and apply multiple supply voltages (VDD and VDD_EXT) through integrated switching circuitry, eliminating the need for separate external level shifting components while maintaining signal compatibility across different voltage domains.
Solution Approach 2:
The I/O circuitry is designed with multi-functionality to operate with multiple supply voltages. The circuit can selectively switch between VDD and VDD_EXT based on configuration, allowing the same I/O ports to function across different voltage domains without requiring dedicated level shifting circuitry for each voltage domain.
2Adaptability or versatility
If external level shifting circuitry is used to convert signals between different voltage domains, then signal compatibility between different voltage domains is achieved, but development time increases
Solution Approach 1:
The level shifting capability is built into the microcontroller during manufacturing, with the I/O circuitry pre-configured to sense and switch between multiple voltage domains. This preliminary integration eliminates the need for developers to design and implement external level shifting circuitry, significantly reducing development time while maintaining adaptability across voltage domains.
3Reliability
If the microcontroller operates with a fixed supply voltage, then internal circuit stability is maintained, but flexibility in interfacing with external circuits at different voltage levels is reduced
Solution Approach 1:
The I/O circuitry incorporates dynamic voltage selection capability, allowing the microcontroller to adapt its operating voltage based on external requirements. The circuit can sense external voltage levels and switch between VDD and VDD_EXT supplies, enabling flexible interfacing with external circuits at different voltage levels while maintaining internal stability through controlled voltage transitions and protection circuitry.
Data Source
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AI summary
An integrated circuit including a processor configured to operate off a supply voltage being applied at one of a plurality of external pins; and internal input/output circuitry configured to select between the supply voltage and at least one other supply voltage being applied at another of the plurality of external pins.