Single Pin Power Controller for USB Over-Current Detection

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Solution Overview

Problem

Existing USB power control systems require two separate pins on an integrated circuit (IC) package to manage power enable and over-current sense functions, leading to increased pin count and potential cost, as well as the need for an external resistor.

Innovation Solution

Combining the power enable and over-current sense functions onto a single pin of the IC package, allowing the power enable output signal to also serve as the over-current sense input, thereby reducing the pin count and eliminating the need for an external resistor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two separate pins are used for power enable and over-current sense functions, then reliable power control and over-current detection are achieved, but pin count increases and cost increases

Engineering Contradiction:

Improvepower control and over-current detectionVSAvoidpin count

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the power enable output signal and over-current sense input signal onto a single pin of the IC package. The power controller uses the same pin to both drive the power enable signal to the power switch and to sense the over-current condition, thereby reducing pin count while maintaining functional reliability through careful signal differentiation within the controller logic.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single pin serves multiple functions: it acts as both an output pin for the power enable signal and an input pin for the over-current sense signal. This multi-functionality allows the IC package to reduce pin count while maintaining complete power control and protection capabilities.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If two separate pins are used for power enable and over-current sense functions, then reliable power control is achieved, but IC package size increases

Engineering Contradiction:

Improvepower controlVSAvoidIC package size

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

By merging the power enable and over-current sense functions onto a single pin, the patent reduces the number of external connections required, thereby reducing the overall IC package size while maintaining reliable power control functionality.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If two separate pins and an external resistor are used, then over-current detection is achieved, but component count and cost increase

Engineering Contradiction:

Improveover-current detectionVSAvoidcomponent count

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent eliminates the need for an external resistor by integrating the over-current sensing functionality directly within the IC package using the same pin that provides the power enable signal. This integration reduces component count and simplifies manufacturing while maintaining over-current detection capability.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS8321700B2Using a single terminal for a power enable output signal and detecting an over-current condition

Publication Date: 2012.11.27 MICROCHIP TECHNOLOGY INC

AI summary

A power controller for a peripheral bus interface. A peripheral bus power controller includes a first terminal, a second terminal coupled to receive an power enable input signal from a host controller, and a third terminal coupled to provide an over-current output signal indicative of an over-current condition to the host controller. The peripheral bus power controller further includes an enable circuit configured to assert a power enable output signal on the first terminal responsive to receiving the power enable input signal and a first buffer configured to provide the over-current output signal to the host controller responsive to the power controller detecting the over-current condition on the first terminal.