Double Gate Terminal Circuit for Power Switch Diagnostics
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Solution Overview
Problem
Existing semiconductor switching circuitry in high voltage and high current applications, such as electric or hybrid vehicles, faces challenges in ensuring proper operation and safety due to potential floating control terminals and impedance issues in the signal chains, which can lead to inefficiencies and hazards.
Innovation Solution
The implementation of a circuitry with double gate terminals, where a driver signal chain connects to a first gate terminal and a separate diagnostic signal chain connects to a second gate terminal, ensuring the entire signal chain is functioning properly and preventing floating control terminals through the use of resistors and separate conductive pathways.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single gate terminal is used for controlling the power switch, then the device complexity is reduced, but the reliability is compromised due to potential floating control terminals and inability to verify signal chain functionality
Solution Approach 1:
The gate terminal is segmented into two separate terminals: a first gate terminal for receiving the driver signal and a second gate terminal for diagnostic purposes. This segmentation allows independent verification of the signal chain through the second terminal while maintaining the primary control function through the first terminal, thereby improving reliability without significantly increasing overall device complexity
Solution Approach 2:
The second gate terminal acts as an intermediary for diagnostic signal chains, allowing verification of signal integrity and detection of floating conditions without interfering with the primary control signal path. This intermediary terminal enables reliability verification while keeping the main control path simple
2Power
If parallel power switches are used to distribute current, then the current handling capability is improved, but the risk of floating control terminals and signal chain failures increases
Solution Approach 1:
The second gate terminal provides feedback capability by allowing a diagnostic signal chain to verify the state of the control terminal. This feedback mechanism detects floating conditions and signal chain failures in parallel switches, ensuring that current distribution remains reliable even as power handling capability increases
Solution Approach 2:
The diagnostic signal chain connected to the second gate terminal performs preliminary verification of signal chain integrity before the power switches are activated. This preliminary action prevents floating control terminal issues from developing into failures during high-current operation
Data Source
AI summary
Circuitry to control and monitor solid state power switches. The circuitry may be configured to measure the signal at a control terminal for the power switch to ensure the power switch is in the desired state, e.g., switched ON and conducting current or switched OFF and blocking current. In some examples the circuitry may also be configured to avoid a floating control terminal. The circuit of this disclosure may have at least two connections to the control terminal, e.g., to a gate terminal for a metal oxide semiconductor field effect transistor (MOSFET) or insulated gate bipolar junction transistor (IGBT). In this manner the circuit of this disclosure may ensure the entire signal chain to the control terminal is functioning properly.