Programmable I/O Circuit With Dynamic Reference Voltage Selection
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Solution Overview
Problem
Conventional input/output circuits are limited in programmability, unable to dynamically adjust voltage levels for input and output signals, and lack the ability to independently control signal paths without CPU intervention, restricting their versatility in communicating with external devices.
Innovation Solution
A programmable input/output circuit that includes adjustable output and input buffers with user-selectable reference voltages, enabling dynamic control of signal paths and voltage levels, allowing for multiple selectable output and input levels, and the ability to drive signals at various voltages without CPU intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional CMOS input/output circuits are used with fixed voltage levels, then the circuit structure is simple, but the adaptability to different voltage levels is poor
Solution Approach 1:
The patent implements dynamic voltage level selection by making the reference voltage configurable through multiple selectable levels (e.g., Vref, Vref/2, Vref/4). The circuit transitions from a fixed reference voltage to a dynamically selectable one, allowing the I/O circuit to adapt to different external device voltage requirements without changing the physical circuit structure.
Solution Approach 2:
The patent changes the electrical parameter (reference voltage level) to achieve adaptability. By providing multiple reference voltage options (full strength, half strength, quarter strength), the circuit can match different voltage levels required by external devices, resolving the contradiction between simplicity and adaptability.
2Adaptability or versatility
If conventional I/O circuits with fixed output levels are used, then the manufacturing process is simple, but the versatility in signal driving is limited
Solution Approach 1:
The patent makes the I/O circuit universal by enabling it to drive signals at multiple voltage levels (full strength, half strength, quarter strength) using the same physical circuit structure. This multi-functionality allows a single I/O circuit to interface with various external devices having different voltage requirements, achieving versatility without complicating the manufacturing process.
3Productivity
If conventional I/O circuits require CPU intervention for path management, then the control logic is simple, but the productivity is reduced due to CPU overhead
Solution Approach 1:
The patent implements self-service by enabling the I/O circuit to autonomously manage its own signal paths and voltage level selections without requiring CPU intervention. The circuit includes built-in control logic that can independently configure reference voltage levels and manage input/output paths, freeing the CPU from these routine management tasks and improving overall system productivity.
Solution Approach 2:
The patent performs preliminary configuration of voltage levels and signal paths through programmable settings that are established before operation. This allows the circuit to be pre-configured for specific voltage level requirements, and then operates autonomously without needing real-time CPU intervention during signal transmission.
Data Source
AI summary
A programmable input/output (I/O) circuit includes an output buffer coupled between an output signal and an I/O pad and an input comparator coupled between an input signal and the I/O pad. The input comparator includes a first input coupled to the I/O pad. A multiplexor receives a select signal for selecting a first reference voltage from the plurality of reference voltages at a first time and for dynamically selecting a second reference voltage from the plurality of reference voltages at a second time.