USB Host Detection Circuit Without Pull-Up Resistors
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Solution Overview
Problem
In multi-interface integrated circuit devices, the floating state of USB pads (D+ and D−) due to the absence of a USB host connection leads to increased power consumption and potential non-functionality, and existing methods using pull-up and pull-down resistors are inefficient in terms of space and power usage.
Innovation Solution
A multi-interface integrated circuit (IC) device employing a plurality of transistors and a level detection block to detect the presence of a USB host connection, where transistors control the voltage levels of D+ and D−, reducing power consumption and eliminating the need for resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pull-up resistors are used to detect USB host presence, then USB host detection is enabled, but power consumption increases and physical space is significantly occupied
Solution Approach 1:
The patent changes the detection parameter from voltage level (using resistors) to current level. The USB host detection is achieved by detecting whether the host can sink current from the D+ or D- lines, rather than measuring voltage drops across resistors. This current-based detection eliminates the need for high-value resistors while maintaining reliable detection capability.
Solution Approach 2:
The patent extracts and eliminates the resistor components from the detection circuit. By using the inherent current-sinking capability of the USB host controller, the design removes the need for external pull-up resistors, thereby reducing both power consumption and physical space requirements while preserving the essential USB host detection function.
2Reliability
If pull-up resistors are used to detect USB host presence, then USB host detection is enabled, but physical space significantly increases
Solution Approach 1:
The patent changes the detection parameter from voltage level (using resistors) to current level. The USB host detection is achieved by detecting whether the host can sink current from the D+ or D- lines, rather than measuring voltage drops across resistors. This current-based detection eliminates the need for high-value resistors while maintaining reliable detection capability.
Solution Approach 2:
The patent extracts and eliminates the resistor components from the detection circuit. By using the inherent current-sinking capability of the USB host controller, the design removes the need for external pull-up resistors, thereby reducing both power consumption and physical space requirements while preserving the essential USB host detection function.
3Adaptability or versatility
If USB pads are left floating when USB host is not connected, then multi-interface IC functionality is maintained, but power consumption increases and device may become non-functional
Solution Approach 1:
The patent implements dynamic control of the USB interface pads through a detection circuit that monitors the electrical state of D+ and D- lines. Based on the detection results, the system dynamically configures the pads - either maintaining them in a high-impedance floating state when no host is present (saving power) or switching to a low-impedance connected state when a host is detected (enabling functionality). This dynamic adaptation resolves the contradiction between maintaining versatility and reducing power consumption.
Solution Approach 2:
The USB interface pads are equipped with self-detection capability through the level detection block that monitors the electrical characteristics of the connected device. The system automatically determines whether a USB host is present and configures itself accordingly, eliminating the need for external control logic or continuous power consumption to maintain interface readiness. The pads serve themselves by detecting and adapting to the connection state.
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 detects the presence of a USB host with low power consumption, reducing the risk of non-functionality and improving CPU processing efficiency by eliminating the need for resistors, thereby optimizing power management and interface detection.
Implementation Method 1
A level detection block samples a level on the D+ or D− lead during a CPU cycle to determine whether a USB host is present.
Implementation Method 2
At least one transistor of the plurality of transistors is in communication with a first terminal and either a first or a second lead of the multi-interface IC
Data Source
AI summary
A multi-interface integrated circuit (IC) comprises a plurality of transistors, and a level detection block. At least one transistor of the plurality of transistors is in communication with a first terminal and either a first or a second lead of the multi-interface IC, and at least one of the plurality of transistors is in communication with the first terminal, a second terminal and either the first or a second lead of the multi-interface IC. The level detection block is in communication with at least one of the plurality of transistors and the first and second leads.