Multi-Channel LED Driver Circuit for Collective Fault Detection

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Solution Overview

Problem

Conventional technologies face difficulties in determining whether all channels in a multi-channel light emitting device are normal due to the small size of microbump connection pads, making it challenging for a single driver chip to establish proper contact with test probes.

Innovation Solution

A drive device comprising a drive circuit that individually drives channels and a detection circuit that collectively detects abnormalities, electrically and mechanically connected to a light emitting element array via microbumps, allowing the driver chip to assess the normalcy of all channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If microbump connection pads are used to connect VCSEL chip to driver chip, then connection density and integration are improved, but test probe contact capability deteriorates

Engineering Contradiction:

Improveconnection densityVSAvoidtest probe contact capability

Core Design Contradiction:

Quantity of substanceVSDifficulty of detecting and measuring

Solution Approach 1:

The connection interface is segmented into two types: microbump connection pads for electrical connection and test probe contact pads for testing. This segmentation allows each type of pad to be optimized for its specific function without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Test probe contact pads serve as intermediary elements between the driver chip and external test equipment. These pads enable test probes to access and test the driver chip circuits without interfering with the microbump connection functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If microbump connection pads are used for connecting driver chip, then electrical connection is improved, but circuit abnormality detection capability deteriorates

Engineering Contradiction:

Improveelectrical connectionVSAvoidcircuit abnormality detection capability

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The pad structure is segmented into microbump connection pads for reliable electrical connection and separate test probe contact pads for circuit abnormality detection. This allows simultaneous achievement of both connection reliability and detection capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Test probe contact pads are provided in advance to enable preliminary testing and detection of circuit abnormalities before final product deployment, allowing defects to be identified and addressed early in the manufacturing or testing process.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11996673B2Drive device and light emitting device

Publication Date: 2024.05.28 SONY SEMICON SOLUTIONS CORP

AI summary

A drive device according to the present disclosure includes a drive circuit (10) and a detection circuit (20). The drive circuit (10) drives a plurality of channels on an individual basis. The plurality of channels includes a plurality of light emitting elements (5). The detection circuit (20) collectively detects abnormalities of all the channels. Further, the drive device (10) is electrically and mechanically connected, with a plurality of microbumps (4), to a light emitting element array that includes the plurality of light emitting elements (5).