Redriver Resistive Termination for Safe Mode Switching
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Solution Overview
Problem
Switching between different operational modes in redrivers can cause abrupt voltage changes at input/output terminals, potentially damaging connected IC chips due to large capacitance values of decoupling capacitors.
Innovation Solution
The redriver includes safe-mode resistive units terminated to a DC termination voltage close to the DC supply voltage, reducing voltage changes during mode switching by using voltage regulators and switches to manage impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a redriver supports multiple operational modes, then the adaptability of the redriver is improved, but switching between modes causes abrupt voltage changes that can damage connected IC chips
Solution Approach 1:
The patent applies preliminary action by proactively managing the decoupling capacitor discharge through controlled resistive paths before mode switching occurs. The redriver actively discharges the capacitor through internal resistors during mode transitions, preventing abrupt voltage changes that would otherwise damage connected IC chips. This anticipatory approach ensures safe mode switching while maintaining the multi-mode operational capability.
2Reliability
If a large capacitance value decoupling capacitor is used to isolate DC levels, then the reliability of IC chip protection is improved, but the voltage change during mode switching increases causing potential damage
Solution Approach 1:
The patent extracts the harmful voltage change component by providing a dedicated discharge path for the decoupling capacitor. The internal resistive elements create a separate energy dissipation route that removes the problematic voltage spike effect from the signal path, allowing the capacitor to maintain its DC isolation function while preventing damage during mode transitions.
Solution Approach 2:
The patent introduces resistive elements as intermediary components between the decoupling capacitor and the signal path. These resistors act as mediators that gradually dissipate the capacitor's stored energy during mode switching, transforming the abrupt voltage change into a controlled, gradual discharge that protects connected IC chips while maintaining effective DC level isolation.
3Reliability
If the redriver actively manages voltage during mode switching, then the protection of IC chips is improved, but the current consumption increases
Solution Approach 1:
The patent applies dynamics by making the resistive discharge path actively controllable rather than static. The redriver dynamically adjusts the discharge path activation based on mode transition requirements, enabling protective action only when needed during mode switching. This dynamic approach provides IC chip protection while minimizing unnecessary current consumption during normal operation.
Data Source
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AI summary
Embodiments of redrivers and resistive units for redrivers are disclosed. In an embodiment, a resistive unit for a redriver includes at least one resistor connected to an input/output terminal of the redriver, at least one switch serially connected to the at least one resistor, and a voltage regulator connected to the at least one switch and configured to generate a termination voltage for the at least one switch. Instead of grounding the at least one resistor, using the voltage regulator can avoid large voltage jump at input/output terminals to keep connected devices safe.