I/O Device Blocking Feedback Signals Using Voltage Tying
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In RF ICs, unwanted feedback signals occur due to parasitic capacitors on the board, degrading output signal quality during transmission, as the transmitter and receiver share a common signal path, leading to interference.
Innovation Solution
The implementation of an input/output device with a bonding pad, a signal transport circuit, and a blocking unit that ties the bonding pad to a predetermined voltage level when an enable signal is de-asserted, effectively blocking signal transport and preventing feedback signals from interfering with the signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the transmitter and receiver share a common signal path on the board, then device complexity is reduced, but feedback signals interfere with signal transmission quality
Solution Approach 1:
The blocking unit is activated before the transmitter operates to preemptively prevent feedback signals from reaching the receiver. By tying the bonding pad to a predetermined voltage level in advance, the system eliminates the interference path before harmful feedback can occur, resolving the contradiction between shared signal paths and signal quality.
Solution Approach 2:
The blocking unit acts as an intermediary element between the bonding pad and the receiver input. When activated, it introduces a high-impedance state that mediates the signal path, allowing the transmitter and receiver to share the same physical path while preventing harmful feedback through the intermediary blocking mechanism.
2Object-affected harmful factors
If a blocking unit is added to prevent feedback signals, then signal transmission quality is improved, but device complexity increases
Solution Approach 1:
The blocking unit is merged with the existing I/O device structure, sharing the bonding pad and control logic with the signal transport circuit. This integration allows the blocking function to be added without proportionally increasing overall device complexity, as the blocking unit utilizes existing structural elements and control mechanisms.
Solution Approach 2:
The blocking unit operates periodically based on the operational state of the transmitter and receiver. It activates only when needed to block feedback during transmission phases and remains inactive during reception phases, allowing the system to maintain simple average complexity while providing protection when required.
3Object-affected harmful factors
If the blocking unit ties the bonding pad to a predetermined voltage level, then signal transport is blocked effectively, but signal transport capability is reduced when blocking is active
Solution Approach 1:
The blocking unit dynamically changes its impedance state based on operational requirements. When the enable signal is asserted, the blocking unit transitions to a high-impedance state that allows normal signal transport. When the enable signal is de-asserted, it transitions to a low-impedance state that ties the bonding pad to the predetermined voltage level and blocks feedback. This dynamic switching resolves the contradiction by providing both blocking and transport capabilities at different times.
Solution Approach 2:
The system temporarily discards signal transport capability when blocking is required to prevent feedback interference. After the blocking period, the signal transport capability is recovered by re-asserting the enable signal and transitioning the blocking unit back to high-impedance state. This temporary discarding and subsequent recovery allows the system to prioritize feedback prevention when necessary while maintaining full transport functionality when safe.
Data Source
AI summary
An input/output device comprises a bonding pad, a signal transport circuit, and a blocking unit. The signal transport circuit has a first terminal connected to the bonding pad and a second terminal connected to a core circuit of an IC product. The signal transport circuit is capable of transporting a signal either from the bonding pad to the core circuit or from the core circuit to the bonding pad. The blocking unit has a control terminal and is coupled between the bonding pad and the signal transport circuit. The control terminal is coupled to receive an enable signal. The blocking unit ties the bonding pad to a predetermined voltage level when the enable signal is de-asserted, thereby blocking the signal transport provided by the signal transport circuit. The blocking unit unties the bonding pad from the predetermined voltage level when the enable signal is asserted.