STMicroelectronics L99MH94/L99MH92 Half-Bridge Pre-Drivers
STMicroelectronics L99MH94/L99MH92 Quad and Dual Half-Bridge Pre-Drivers are dedicated to controlling up to eight N-channel MOSFETs. It is intended for DC motor control applications such as automotive power seat control or other applications. A 24-bit serial peripheral interface (SPI) is used to configure and control the eight half-bridges. SPI status registers provide high-level diagnostic information, including supply-voltage monitoring, charge-pump voltage monitoring, temperature warnings, and overtemperature shutdown.
Each gate driver independently monitors its external MOSFET's drain-source voltage for fault conditions. The L99MH94/L99H92 support indirect current measurement on external MOSFETs, enabling cost savings and lower system complexity by eliminating the need for shunt resistors. A more efficient gate-current control of the external MOSFETs, called "three-stage gate current", reduces electromagnetic interference (EMI) and optimizes it.
Protection features (drain-source monitoring for short-circuit detection, overtemperature warning and shutdown, timeout watchdog for MCU control, detailed off-state diagnostics via SPI) ensure ASIL-B compliance with ISO 26262. The STMicroelectronics L99MH94 is housed in VFQFN48L and VFQFN32L packages with an exposed pad; the L99MH92 is housed in a VFQFN32L package with an exposed pad. These packages have wettable flanks for easy visual inspection of the solder joint.
Features
- AEC-Q100 qualified
- ISO26262 compliant, covering ASIL-B safety integrity level
- Quad (L99MH94) and dual (L99MH92) half-bridge, or dual (L99MH94) and single (L99MH92) H-Bridge, pre-driver
- Independent channel driver up to 4x (L99MH94) and 2x (L99MH92) high-side or 4x (L99MH94) and 2x (L99MH92) low-side
- Driving logic permits any H-bridge configuration, pairing different half-bridges, using the internal gate drivers (GHx/SHx/GLx can be associated with any GHy/SHy/GLy)
- Support logic level and standard level MOSFETs
- Control of reverse battery protection MOSFET
- Fully configurable half-bridge driver in case of fault occurrence
- Generator mode for power trunk/tailgate applications
- Supporting indirect current measurement of external MOSFETs
- Adaptive MOSFET gate control
- Three-step gate control of external HS/LS
- Improved electromagnetic emission
- Programmable gate current up to 120mA
- Reduced switching losses in PWM mode
- SPI configurable overvoltage threshold
- Vds monitoring
- Low IQ (1.05μA) in reset mode
- High-side and low-side are capable of protection and diagnosis
- Two external diodes control - needed for assisting calibration of indirect current measurement, can be used for steady temperature monitoring
- Drain-source monitoring for short circuit detection
- Overtemperature warning and shutdown
- Timeout watchdog for MCU control
- Detailed off-state diagnostic (open load, short circuit to battery or short circuit to GND) via SPI
- Three PWM inputs
- High-side and low-side PWM capable
- Active freewheeling
- Up to 50kHz PWM frequency
- Out-of-frame serial peripheral interface (SPI), 24-bit
- QFN package with wettable flanks
- Green product (RoHS-compliant)
Applications
- Seat control
- Steering column and gas pedal adjustment
- Sunroofs, sliding doors, window lifts, seat-belt pre-tensioners, cargo covers, and washer pumps
- Engine vibrations compensation systems
- Power lift gates
- Central door locks
L99MH2 Block Diagram
L99MH94 Block Diagram
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