Technology company STMicroelectronics has introduced the L99H92 automotive gate driver which provides an SPI port for programming and diagnostics, a charge pump, protective features and two extra current-sense amplifiers for system monitoring.
Featuring two high-side and two low-side drivers, the L99H92 can control a single H-bridge powering one bidirectional DC motor or two half bridges for two unidirectional motors. Common applications for this driver include electric sunroofs, window lifts, powered trunks, sliding doors and seat-belt pre-tensioners.
The built-in charge pump provides stable operation of the high-side drivers even as the vehicle battery voltage fluctuates, which the company says enables the outputs to function reliably with a supply voltage as low as 5.41V.
The charge-pump output can be accessed externally to control a metal–oxide–semiconductor field-effect transistor (MOSFET) for reverse-battery protection.
The gate-driving current is programmed through the SPI port, allowing slew-rate control to minimize electromagnetic emissions and thermal dissipation. This feature is designed to eliminate the need for up to four external discrete components per MOSFET, typically required for slew-rate setting with conventional drivers. With a maximum drive current of 170mA, designers can have the flexibility to use the driver with various external MOSFETs, including high-power devices with large gate capacitance.
STMicroelectronics says the L99H92 is designed for reliability and safety, through numerous features for system protection and diagnostics.
It includes overcurrent protection with a programmable threshold, cross-conduction protection with programmable dead time and additional safeguards such as overtemperature early warning and shutdown, overvoltage and undervoltage protection, and open-load and output short-circuit detection in off-state diagnostic mode.
A fail-safe input can instantly turn off all MOSFETs, and a dedicated diagnostic pin provides immediate fault warning without the need for periodic SPI transfers.
