Switch Drive Circuit Preventing Accidental Turn-On
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Solution Overview
Problem
Existing drive circuits for switches face high loss and accidental turning from OFF to ON states due to reverse transfer capacitors, which supply electric charge to the control terminal, causing unintended activation.
Innovation Solution
A drive circuit configuration that includes a discharge path with a capacitor, an AC suppressor, and a DC voltage generator, where the AC suppressor regulates electric current to prevent accidental ON states by maintaining a negative voltage on the control terminal and reducing loss by suppressing AC components during charge and discharge processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a buffer amplifier is used to maintain negative voltage on the control terminal, then the switch can be prevented from accidentally turning ON, but high loss occurs in the buffer amplifier
Solution Approach 1:
The circuit is divided into separate functional blocks: a discharge path with capacitor for voltage maintenance, an AC suppressor for noise filtering, and a DC voltage generator for regulated voltage supply. This segmentation allows each component to perform its specific function efficiently without the energy loss associated with using a buffer amplifier for all functions.
Solution Approach 2:
A capacitor is introduced as an intermediary element in the discharge path to store and maintain the negative voltage on the control terminal. This capacitor acts as a mediator that maintains voltage without requiring continuous energy input, thereby eliminating the need for a power-consuming buffer amplifier.
2Reliability
If the control terminal potential is maintained at negative potential, then accidental turn-ON is prevented, but the circuit complexity increases
Solution Approach 1:
The AC suppressor is extracted as a separate component from the main discharge path. This allows the AC suppression function to be implemented independently using simple passive components (resistors and capacitors) rather than requiring complex active circuitry, thus maintaining reliability while minimizing added complexity.
Solution Approach 2:
The discharge path circuit serves multiple functions simultaneously: it maintains the negative voltage on the control terminal, provides AC suppression through the coupled suppressor circuit, and regulates voltage through the DC voltage generator. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby limiting the increase in overall circuit complexity.
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
Effectively reduces loss in the drive circuit while preventing accidental switching from OFF to ON states by regulating the potential difference across the control and second terminals, ensuring reliable operation.
Implementation Method 1
The capacitor is provided in the discharge path and has a high-potential terminal connected to the second terminal side and a low-potential terminal connected to the control terminal side
Implementation Method 2
These switches have a reverse transfer capacitor formed between the first terminal and the control terminal. Therefore, in the OFF state, electric charge may be supplied to the control terminal via the reverse transfer capacitor
Data Source
AI summary
A drive circuit drives a switch that has first and second terminals and a control terminal. The drive circuit includes a discharge path, a capacitor, an AC suppressor and a DC voltage generator. The discharge path connects the control terminal and the second terminal. The capacitor has a high-potential terminal connected to the second terminal side and a low-potential terminal connected to the control terminal side. The AC suppressor has a first end connected to a part of the discharge path between the high-potential terminal the second terminal. The DC voltage generator has a connection terminal connected to a second end of the AC suppressor. The DC voltage generator regulates electric current flowing between the connection terminal and the AC suppressor so as to keep the potential of the part of the discharge path between the high-potential terminal and the second terminal higher than the potential of the low-potential terminal.