USB Type-C Receiver High Voltage Protection Circuit
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Solution Overview
Problem
Current protection circuits against high voltages on USB Type-C devices are either too expensive, bulky, or omitted in low-cost products, compromising reliability and compliance with the USB 3.1 PD standard.
Innovation Solution
A compact and inexpensive resistive pull-down circuit configured as a voltage divider, with specific resistor values, provides protection against high voltages while maintaining the required pull-down function, using two resistive voltage divider bridges between channel configuration pins and ground, ensuring the voltage is limited and measurable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high voltage transistors are connected between channel configuration pins and detection stages to limit voltage to about 2.7V, then protection against high voltages is achieved, but the device becomes expensive and bulky
Solution Approach 1:
The patent merges the voltage protection function with the pull-down circuit function by using a single resistive module to perform both tasks. The resistive module limits high voltages to safe levels while simultaneously providing the required pull-down resistance, eliminating the need for separate protection transistors and reducing overall device complexity and cost
Solution Approach 2:
The resistive module is designed to serve multiple functions: it acts as both a voltage divider for protection and a pull-down circuit for connection detection. This multi-functional approach allows a single component to replace what would traditionally require multiple separate components, addressing the contradiction between protection reliability and device simplicity
2Ease of manufacture
If protection circuits are omitted in low-cost products, then cost is reduced, but reliability and compliance with USB 3.1 PD standard are compromised
Solution Approach 1:
The patent employs inexpensive resistive elements that can be easily manufactured and integrated into low-cost USB devices. These simple resistive components provide adequate protection without the need for expensive transistors, making protection feasible even in budget-friendly products while maintaining reliability and standard compliance
Solution Approach 2:
The invention changes the approach from using active transistor-based protection to passive resistive protection. By selecting appropriate resistance values for the resistive module, the circuit achieves both cost-effectiveness and adequate voltage limiting performance, enabling protection in low-cost products without compromising reliability
3Ease of operation
If a resistive pull-down circuit with nominal value of 5100 ohms is implemented, then connection detection is enabled, but protection against high voltages is not provided
Solution Approach 1:
The patent combines the pull-down circuit functionality with voltage protection by configuring the resistive module as a voltage divider. The same resistive elements that provide the required 5100 ohm pull-down resistance also limit high voltages to safe levels, enabling both connection detection and protection with a single circuit configuration
Solution Approach 2:
The resistive module serves dual purposes: it provides the necessary pull-down resistance for connection detection while simultaneously acting as a voltage divider to protect against high voltages. This multi-functional design ensures that connection detection operates correctly while high voltage protection is also achieved
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 solution effectively limits high voltages to safe levels, meets USB standard requirements, and allows for precise voltage measurement using available analog-to-digital converters, enhancing the reliability and compliance of USB Type-C devices.
Implementation Method 1
The protection stage includes a resistive module coupled between the channel configuration input and the ground terminal and configured to form both a voltage divider and the resistive pull down circuit
Implementation Method 2
The USB 3.1 standard also recommends that the receiver be equipped on the channel configuration pins with a resistive pull-down circuit (pull-down resistor)
Data Source
Figure 1~2
AI summary
USB Type C receiver device, comprising a port (30) having a channel configuration input, a ground pin, a resistive pull-down circuit coupled between the channel configuration input and the ground pin, and a high-voltage protection stage on the channel configuration input, wherein the protection stage comprises a resistive module (31) coupled between the channel configuration input (CC1, CC2) and the ground terminal (GND) and configured to form both a voltage divider and the resistive pull-down circuit.