Isolated Switching Element Drive Circuit for High-Voltage Detection
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Solution Overview
Problem
Existing switching element drive circuits face challenges in detecting the high voltage state of semiconductor switching elements due to low voltage detection circuits, leading to increased circuit size and cost when external circuits are added to enhance breakdown voltage.
Innovation Solution
A switching element drive circuit with a primary and secondary circuit isolated by an insulating element, incorporating a high voltage detection circuit on a semiconductor substrate with a pn junction isolation portion, and a controller on the same substrate to control the semiconductor switching element, eliminating the need for external circuits to enhance breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low voltage detection circuit is used to detect the state of a semiconductor switching element, then the circuit size and cost are reduced, but the high voltage state of the semiconductor switching element cannot be detected
Solution Approach 1:
The patent changes the voltage detection parameter by using a voltage division circuit that divides the high voltage to be detected into a lower voltage suitable for the detection circuit. This allows the low voltage detection circuit to detect high voltage states indirectly, resolving the contradiction between detection capability and circuit simplicity.
Solution Approach 2:
The patent introduces a voltage division circuit as an intermediary between the high voltage terminal and the low voltage detection circuit. This intermediary circuit transforms the high voltage signal into a detectable low voltage signal, enabling detection without requiring the detection circuit to directly withstand high voltage.
2Reliability
If an external circuit is added to enhance the breakdown voltage of the detection circuit, then the high voltage state can be detected, but the size and cost of the circuit increase
Solution Approach 1:
The patent merges the voltage division circuit with the detection circuit into a single integrated design. By combining these functions, the patent eliminates the need for separate external enhancement circuits, thereby maintaining detection capability while reducing overall circuit size and avoiding additional components.
Solution Approach 2:
The patent changes the voltage parameter through internal voltage division rather than requiring external circuit enhancement. The voltage division circuit transforms the high voltage detection requirement into a low voltage detection task, eliminating the need for external breakdown voltage enhancement circuits.
3Reliability
If an external circuit is added to enhance the breakdown voltage of the detection circuit, then the high voltage state can be detected, but the cost of the circuit increases
Solution Approach 1:
The patent combines the voltage division and detection functions into a single integrated circuit design, eliminating the need for separate external enhancement components. This integration reduces component count and assembly complexity, thereby lowering manufacturing cost while maintaining the required breakdown voltage capability.
Solution Approach 2:
The voltage division circuit serves as an intermediary that enables high voltage detection using low voltage detection components. This approach avoids the need for expensive high-voltage-rated detection components or external enhancement circuits, reducing overall system cost while maintaining detection reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution allows for direct detection of high voltage states without increasing circuit size or cost, enhancing breakdown voltage and improving CMTI characteristics, while simplifying design and reducing external component reliance.
Implementation Method 1
an insulating element isolating the primary circuit and the secondary circuit from each other in terms of a direct current, and generating a second signal for the second circuit based on a first signal for the primary circuit
Implementation Method 2
a detector provided on a portion of the semiconductor substrate, including a pn junction isolation portion, and configured to detect a voltage of the high voltage terminal
Data Source
AI summary
An object is to provide a technique that eliminates the need for an external circuit for enhancing the breakdown voltage. A switching element drive circuit includes a primary circuit and a secondary circuit, and an insulating element isolating the primary circuit and the secondary circuit from each other in terms of a direct current. The secondary circuit includes a semiconductor substrate, a detector provided on a portion of the semiconductor substrate, including a pn junction isolation portion, and configured to detect a voltage of a high voltage terminal, and a controller provided on a remaining portion of the semiconductor substrate and configured to control a control voltage of a semiconductor switching element based on a second signal and a detection result of the detector.