Isolated IGBT gate pre-driver protects EV/HEV inverters

April 29, 2016 // By Graham Prophet
Toshiba Electronics has an opto-isolated IGBT gate pre-driver IC with enhanced protection functions for the in-vehicle inverters of electric and hybrid vehicles. As control and drive functions have different operating voltages, they must be isolated from each other with a device such as a photocoupler.

Toshiba’s TB9150FNG is a high-performance IGBT gate pre-driver IC that can address this issue while providing the necessary protection functionality. The TB9150FNG integrates a photocoupler that secures high-level isolation between control (the primary side) and drive (the secondary side). It also incorporates a highly precise IGBT temperature detection function, a flyback transformer controller and a short circuit detection function (current sense and DESAT2 monitor) that all contribute to system downsizing.


Supplied in an SSOP48 package, the TB9150FNG measures 10.4 x 12.5 x 2.0 mm. Operating temperature range is -40°C to 125°C. Electrical isolation and high-withstand voltage isolation of 2500Vrms (AC, one minute) are achieved by a built-in photocoupler. The IC has a constant current source for a temperature sense diode incorporated in IGBT and the A/D converter, to support precise monitoring of the IGBT’s operating temperature. A flyback transformer control circuit in the primary side supplies power to the secondary side while maintaining isolation. It also has a soft-start function that secures smooth start-up when turning on power to the circuit, avoiding current overload. The power supply, output, current and voltage of the IGBT are all monitored. Information on any detected abnormality is transferred to the main controller via an SPI interface. A dedicated circuit provides protection against any abnormality with the potential to destroy the IC and IGBT. The device is based on AEC-Q100 standards.


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