Configurable I/O Protection Circuit for Tolerant Pad Switching
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Solution Overview
Problem
Existing input-output circuits in electronic chips lack flexibility, as they are either non-tolerant, restricting voltage range, or tolerant, which may not be suitable for all applications, and cannot be modified post-manufacturing.
Innovation Solution
A device comprising three MOS transistors (P-type and two N-type) connected in series, controlled by a digital signal, which can switch between a diode and an open circuit, allowing for configurable pad functionality between tolerant and non-tolerant modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-tolerant pads with protection diodes are used, then protection against current injections is improved, but the range of admissible input voltages is restricted
Solution Approach 1:
The pad configuration is made dynamic through a control signal that can switch between tolerant and non-tolerant modes. The third transistor acts as a switch controlled by a digital signal, allowing the circuit to adapt its protection characteristics in real-time based on operational requirements, rather than being fixed during manufacturing.
Solution Approach 2:
The invention changes the electrical parameters of the pad by controlling the state of the third transistor. When the transistor is activated, it modifies the voltage distribution across the circuit, effectively changing the pad's tolerance characteristics and allowing switching between different voltage ranges and protection modes.
2Adaptability or versatility
If tolerant pads are used, then the range of admissible input voltages is widened, but protection against current injections may be degraded for certain applications
Solution Approach 1:
The circuit dynamically adjusts its protection level by controlling the third transistor with a digital signal. When high voltage tolerance is needed, the transistor remains off; when protection is prioritized, the transistor activates to provide current injection protection, allowing the same pad to serve different functional requirements.
3Ease of manufacture
If the pad type is fixed during manufacturing, then production simplicity is maintained, but flexibility of existing input-output circuits is reduced
Solution Approach 1:
The invention makes all pads universal by incorporating the three-transistor configuration that can operate in both tolerant and non-tolerant modes. This single circuit design replaces the need for different pad types, allowing the same physical structure to adapt to different application requirements through digital control signals.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration provides greater flexibility by enabling the chip to handle a wider range of input voltages, protecting against overvoltages while maintaining signal integrity, and preventing involuntary re-powering.
Implementation Method 1
a first P-type MOS transistor; a second N-type MOS transistor, connected to the first transistor; and a third N-type MOS transistor, connected to the second transistor
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The present description relates to a device comprising, in series (71): a first P-type MOS transistor (73); a second N-type MOS transistor (75), connected to the first transistor (71); and a third transistor (77), connected to the second transistor (75), said third transistor (77) being controlled by a digital signal, in which the gate (733) of the first transistor (73) and the gate (753) of the second transistor (75) are interconnected and intended to receive a power supply potential (VDD) from a chip.