STMicroelectronics L99H92 automotive gate driver

The STMicroelectronics L99H92 automotive gate driver provides an SPI port for programming and diagnostics, a charge pump, protective features and two additional current-sense amplifiers for system monitoring.

Containing two high-side and two low-side drivers, the automotive gate driver can control a single H bridge powering one bidirectional DC motor or two half bridges for two unidirectional motors. Typical applications for the driver include electric sunroofs, window lifts, powered trunks, sliding doors and seatbelt pre-tensioners.

The charge pump powers the high-side drivers to maintain correct operation as the vehicle battery voltage fluctuates, enabling the outputs to function with a supply as low as 5.41 V. The charge-pump output is also available at an external pin to control a MOSFET for reverse-battery protection.

The gate-driving current is programmed through the SPI port, allowing slew-rate control to minimise electromagnetic emissions and thermal dissipation. Programming the current saves up to four external discrete components per MOSFET, typically needed for slew-rate setting with conventional drivers. The maximum drive current of 170 mA gives designers flexibility to use the driver with a variety of external MOSFETs, including high-power devices with large gate capacitance.

With many features for system protection and diagnostics, the automotive gate driver is built for safety. There is overcurrent protection with a programmable threshold, detected by monitoring the MOSFET drain current. The device also features cross-conduction protection with a programmable dead time for safety and efficiency. Additional protection includes over-temperature early warning and shutdown, overvoltage and undervoltage protection on analog and digital power supply inputs, and open-load and output short-circuit detection in off-state diagnostic mode.

A fail-safe input can turn off all MOSFETs instantaneously and a dedicated diagnostic pin provides immediate fault warning without waiting for periodic SPI transfers. Two current-sense amplifiers are also integrated for system-status monitoring. Suitable for high-side, low-side and inline sensing, the amplifiers have independently programmable gain, low offset and low thermal drift. They can be independently disabled to reduce current consumption when unused.

The L99H92 is in production now and packaged as a TQFP32 or QFN32 with wettable flanks to facilitate inspection.