Current Sense Circuit Powered by MOSFET Gate Drive

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Solution Overview

Problem

Existing power transistor circuits require a high voltage supply rail for operation, which complicates packaging and limits their use in environments where such a rail is not readily available.

Innovation Solution

A circuit design that incorporates a power transistor and a sense transistor, where the current sense circuit is powered by a fluctuating control signal from the control drive terminal, eliminating the need for a fixed high voltage supply rail and simplifying packaging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed high voltage supply rail is used to power the current sense circuit, then the circuit can operate reliably, but the packaging becomes more complex and additional terminals are required

Engineering Contradiction:

Improvecurrent sense circuit operationVSAvoidpackaging complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The control drive terminal is designed to serve dual functions: it provides control signals to the power transistor and simultaneously provides power to the current sense circuit. This multi-functionality eliminates the need for a separate high voltage supply terminal, reducing packaging complexity while maintaining reliable operation of the current sense circuit

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the control signal path and the power supply path into a single control drive terminal. By combining these two functions into one terminal, the circuit reduces the number of required terminals and simplifies the overall packaging structure

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If a fixed high voltage supply rail is used, then the current sense circuit can operate independently, but the circuit cannot be used where high voltage supply is not readily available

Engineering Contradiction:

Improvecircuit applicabilityVSAvoidsupply rail requirement

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The control drive terminal performs multiple functions including providing control signals and powering the current sense circuit. This design makes the circuit adaptable to environments where a separate high voltage supply rail is not available, as the control terminal itself serves as the power source

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The current sense circuit draws power from the control drive terminal that is already present in the system, eliminating the need for external high voltage supply infrastructure. The circuit uses existing resources (the control drive signal) to power itself, enhancing its versatility

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS12424920B2Circuit with power transistor and current sense that uses control drive as power source

Publication Date: 2025.09.23 GAN SYST INC

AI summary

A circuit that includes a power transistor and at least one sense transistor and that uses the control drive terminal to not only control the power transistor and the sense transistor, but also to provide power to a current sense circuit. The control nodes of the power transistor and sense transistor are connected, and the input nodes of the power transistor and the sense transistor are also connected. The current sense circuit is connected to the sense transistor control node and is configured to detect current passing through the sense transistor. The current sense circuit is also connected to the control drive terminal and is configured to draw power from the control drive terminal when a high control signal is present on the control drive terminal. Accordingly, the current sense circuit does not require an independent fixed high voltage supply in order to operate.