High-Side Driver Gate-Stress Testing Without a Dedicated Test Pad
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Solution Overview
Problem
Existing high side driver circuits for buck regulators require a dedicated test pad for gate stress testing, which consumes die area and complicates the design, especially in split power MOS applications.
Innovation Solution
A high side driver circuit design that eliminates the need for a test pad by using a switch between the SBUCK and PHASE nodes, allowing for a gate-stress test mode that measures leakage current without a separate gate-stress pad, and can be adapted for multiple split power MOS transistors with a single switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated test pad is used for gate stress testing, then gate stress testing can be performed, but die area is consumed and design is complicated
Solution Approach 1:
The patent merges the gate stress testing function with the existing driver stage output. The driver stage output is directly coupled to the gate of the power MOS transistor, eliminating the need for a separate test pad. The same driver stage circuitry is used for both normal operation and gate stress testing by controlling the gate voltage through the existing output node.
Solution Approach 2:
The driver stage is designed to serve multiple functions: it provides normal gate drive during operation and also enables gate stress testing when needed. By making the driver stage multi-functional, the patent eliminates the need for dedicated test pad structures while maintaining both operational and testing capabilities.
2Reliability
If a dedicated test pad is used for gate stress testing, then gate stress testing can be performed, but device complexity increases
Solution Approach 1:
The patent combines the gate stress testing functionality into the existing driver stage, merging two separate functions (normal operation and stress testing) into a single integrated circuit structure. This reduces device complexity by eliminating separate test pad connections and associated control circuitry.
Solution Approach 2:
The driver stage is designed as a universal circuit that performs both normal gate driving and gate stress testing functions. This multi-functionality approach reduces overall device complexity by avoiding the need for separate dedicated test structures and their associated complexity.
3Area of stationary object
If a switch is added between SBUCK and PHASE nodes for test mode, then gate stress testing becomes possible without test pad, but circuit complexity increases slightly
Solution Approach 1:
The patent extracts the gate stress testing capability from the external test pad structure and integrates it into the internal driver stage circuitry. By taking out the testing function from the periphery and embedding it in the core driver stage, the patent reduces die area while keeping the added complexity minimal and localized.
Data Source
AI summary
A high side driver circuit includes a driver stage having an input, an output, a first power terminal and a second power terminal, a transistor having a first power terminal, a second power terminal, and a control terminal coupled to the output of the driver stage, and a switch coupled between the second power terminal of the driver stage and the second power terminal of the transistor.