Load Detection Circuit for Power Supply Safety

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Solution Overview

Problem

Existing load detecting devices fail to accurately determine whether a load is connected or detached from a power supply device, particularly in scenarios where foreign materials are inserted, leading to potential overheating and fire risks.

Innovation Solution

A load detecting device that utilizes a no-load condition detector, a circuit with transistors and a clock generator to sense voltage waveforms, and a detachment detector to identify the connection or detachment based on predetermined gradients, ensuring accurate detection and preventing overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a power supply device supplies power through a port that accepts foreign materials, then the device can operate with various loads, but foreign materials may be inserted in place of loads causing overheating and fire risks

Engineering Contradiction:

Improvecompatibility with various loadsVSAvoidoverheating and fire risk

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by detecting the load connection state before power supply occurs. The detection circuit checks whether a load is properly connected to the USB port before enabling power delivery, preventing foreign objects from receiving power and causing overheating or fire hazards.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary detection circuit between the power supply device and the load. This intermediary circuit monitors the electrical characteristics (such as resistance or current draw) to determine whether a valid load is connected, acting as a mediator that prevents direct power delivery to foreign objects while maintaining compatibility with legitimate loads.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the power supply device detects load connection status, then it can prevent overheating, but existing detection methods fail to accurately distinguish between loads and foreign materials

Engineering Contradiction:

Improveaccuracy of load detectionVSAvoidability to distinguish load from foreign object

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by monitoring multiple electrical parameters (such as resistance, current, voltage drop) rather than relying on a single measurement. By analyzing changes in these parameters when the port is connected or disconnected, the system can accurately distinguish between legitimate loads and foreign objects, improving both detection reliability and measurement precision.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10700592B2Load detecting device

Publication Date: 2020.06.30 SEMICON COMPONENTS IND LLC

AI summary

A load detecting device for detecting whether a load is connected to a power supply device includes a no-load condition detector configured to detect a no-load condition using a sensing voltage having a frequency variant with a switching frequency of the power supply device, a circuit configured to acquire a signal having a waveform differing according to a connection or detachment between the load and the power supply device after the no-load condition is detected by the no-load condition detector, and a detachment detector configured to detect whether the load is detached by sensing the signal acquired by the circuit.