USB Overvoltage Protection Switch With Mode-Dependent Resistance
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Solution Overview
Problem
USB devices are vulnerable to damage from overvoltage due to conductive foreign materials or electrical shorts, leading to potential communication failures and excessive power consumption.
Innovation Solution
A circuit with an overvoltage protection (OVP) switch and a switch controller that interrupts power when an overvoltage is detected, with different on-resistances for normal and low-power modes to minimize signal distortion and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the OVP switch has low on-resistance to minimize signal distortion, then signal integrity is improved, but power consumption increases
Solution Approach 1:
The OVP switch dynamically adjusts its on-resistance based on the operational mode (normal mode vs. low-power mode). In normal mode, the switch maintains low on-resistance to ensure signal integrity. In low-power mode, the switch increases its on-resistance to reduce power consumption, accepting some signal distortion as a trade-off for energy savings.
2Measurement precision
If the OVP switch maintains low on-resistance during low-power mode, then signal integrity is preserved, but power consumption is not reduced
Solution Approach 1:
The patent changes the resistance parameter of the OVP switch based on the operational mode. A switch controller receives a mode signal indicating whether the USB device is in normal mode or low-power mode, and accordingly adjusts the OVP switch resistance to either first resistance (low) or second resistance (high), optimizing the balance between signal integrity and power consumption.
Data Source
AI summary
A circuit to protect an overvoltage in a universal serial bus (USB) device include an overvoltage protection (OVP) switch connected to a pin of a USB receptacle and a switch controller to turn off the OVP switch when an overvoltage is detected such that power between the pin and the USB device is interrupted. The switch controller supplies a control signal to the OVP switch such that the OVP switch has a first on-resistance when the USB device is operating in a normal mode and no overvoltage is detected, and has a second on-resistance, higher than the first on-resistance, when the USB device is operating in a low-power mode and no overvoltage is detected.