MOSFET Gate Breakdown Screening with Voltage Clamp Protection
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Solution Overview
Problem
Existing methods for inspecting the breakdown voltage between the gate and source of a MOSFET in semiconductor circuit devices are inadequate, particularly in ensuring accurate screening of defective products and protecting pre-driver circuits from surge voltages.
Innovation Solution
A semiconductor circuit device configuration that includes a driver circuit with a high-side transistor, a pre-driver circuit, a first pad coupled to the transistor's source, a second pad coupled to the pre-driver's power supply node, and a voltage clamp circuit, allowing for a screening test by setting different inspection voltages between the gate and source and measuring current flow through the first pad.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-driver circuit is added to protect the MOSFET gate, then the MOSFET gate is protected from surge voltages, but the complexity of the circuit increases and the breakdown voltage screening becomes more difficult
Solution Approach 1:
The circuit is divided into separate functional blocks: the pre-driver circuit (with its own power supply node) and the MOSFET driver circuit. This segmentation allows independent testing of the MOSFET breakdown voltage by applying voltage between the first pad (source) and second pad (pre-driver power supply node), while the pre-driver circuit remains protected but electrically isolated during the screening process.
2Measurement precision
If separate pads are used for gate driving and ESD protection, then individual inspection is enabled, but the number of pads and wiring increases
Solution Approach 1:
The first pad serves multiple functions: it is used for normal operation (connecting to MOSFET source) and for breakdown voltage screening (applying inspection voltage). Similarly, the second pad serves dual purposes as both a power supply connection for the pre-driver and a test point for applying gate voltage during inspection. This multi-functionality reduces the need for additional dedicated test pads.
3Measurement precision
If breakdown voltage screening is performed with high voltage between gate and source, then defective MOSFETs are detected, but the pre-driver circuit may be damaged by surge voltage
Solution Approach 1:
The voltage clamp circuit acts as an intermediary protective element between the pre-driver circuit and the high-voltage screening process. During breakdown voltage testing, the clamp circuit limits any voltage spikes that could reach the pre-driver, allowing high-voltage testing between the first and second pads while protecting the pre-driver from damage.
Solution Approach 2:
The voltage clamp circuit is pre-configured in the circuit design to provide protective clamping action before any potential surge voltage can damage the pre-driver circuit. This beforehand protection enables safe performance of high-voltage breakdown screening without risking pre-driver damage.
Data Source
AI summary
A semiconductor circuit device includes a driver circuit, a pre-driver circuit, a first pad, first wiring, a second pad, second wiring, and a voltage clamp circuit. The driver circuit includes a high-side first transistor. The pre-driver circuit includes a first pre-driver that drives a gate of the first transistor. The first wiring couples the first pad to a source of the first transistor. The second wiring couples the second pad to a power supply node of the first pre-driver. The voltage clamp circuit clamps a voltage between power supplies of the first pre-driver.