Bidirectional I/O Port Hi-Z Feedback for Lower Power
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Programmable logic devices, particularly FPGAs, face significant power wastage due to energy inefficiencies in bidirectional I/O connections, which existing designs fail to adequately address.
Innovation Solution
Implementing a low-power bi-directional I/O arrangement in CMOS devices by asserting a high impedance signal on the output driver to prevent floating of the I/O port, and using a current blocking pair of transistors to reduce power consumption, with alternatives including driving constant logical values or maintaining the last value driven to prevent signal feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bidirectional I/O connections are used in conventional designs, then versatility and adaptability are improved, but power consumption increases due to energy wastage in the bidirectional signaling mechanism
Solution Approach 1:
The patent applies dynamics by making the I/O port configuration changeable and adaptive based on operational needs. The system dynamically switches between bidirectional mode (for versatility) and unidirectional mode with Hi-Z assertion (for power saving), allowing the device to adapt its signaling behavior to minimize power consumption while maintaining bidirectional functionality when required.
Solution Approach 2:
The patent changes the electrical state parameter of the output driver by asserting a high-impedance (Hi-Z) signal. This parameter change transforms the output driver from an active driving state to a high-impedance state, effectively disconnecting it from the I/O port during input operations and reducing power consumption while maintaining bidirectional capability when needed.
2Reliability
If the output driver remains active during bidirectional operations, then signal driving capability is maintained, but unnecessary current flow increases power consumption
Solution Approach 1:
The patent applies preliminary action by asserting the Hi-Z signal on the output driver before it is needed for input operations. This preliminary assertion of high-impedance state prevents unnecessary current flow in advance, reducing power consumption during periods when the I/O port is functioning as an input, while ensuring the output driver can quickly resume driving capability when bidirectional output is required.
3Ease of operation
If conventional bidirectional I/O arrangements are used, then ease of operation is maintained, but device complexity increases due to additional power management requirements
Solution Approach 1:
The patent applies self-service by implementing power management that is automatically controlled by the operational mode of the I/O port. The system self-regulates power consumption by asserting Hi-Z signals based on whether the port is functioning as input or output, eliminating the need for external power management intervention and reducing overall device complexity while maintaining ease of operation.
Data Source
AI summary
An arrangement and method of reducing power in bidirectional I/O ports includes driving an input signal from an I/O port by asserting a high impedance (Hi-Z) signal to an output drive, driving an output signal from the I/O port by refraining from asserting a Hi-Z signal to an output driver, and feeding back the output signal to an input driver when driving the output signal. The method can float the I/O port when the Hi-Z signal is asserted on the output driver or drive the I/O port as an input when the Hi-Z signal is asserted on the output driver. The method can refrain from floating a signal back into the I/O port when driving a signal out by driving a constant logical zero back into the I/O port or driving a constant logical one back or by maintaining a last value driven.