High Current Half Bridge with Over-Current Shutdown

This high-current half-bridge driver board is designed as a flexible, open-design platform that can be configured to meet a wide range of voltage, current, and switching-frequency requirements. The board includes an adjustable overcurrent protection circuit, allowing users to set the desired current limit by selecting an appropriate shunt resistor value and adjusting the onboard threshold trimmer.

An onboard current-sense shunt resistor is provided for over-current detection. Users can select the shunt resistor value according to the required current threshold. Gate resistors and optional gate-drive diodes can also be customized to optimize switching performance for specific PWM frequencies and load characteristics.

Features

• Load supply voltage up to 90 VDC (limited by installed DC bus capacitor ratings)
• Gate driver supply voltage: 15 V nominal (10 V to 20 V operating range)
• High dV/dt immunity: ±50 V/ns over the full temperature range
• 4 A source/sink gate drive capability
• Fast switching performance: 15 ns rise/fall time with 1 nF load
• Compatible with 3 V and 5 V TTL/CMOS logic inputs with hysteresis
• Integrated bootstrap diode
• Smart shutdown function
• Adjustable dead time via R9
• Adjustable overcurrent protection
• Interlock function to prevent shoot-through
• Comprehensive fault protection
• On Board LED for Logic Power
• Open-design architecture for easy customization and experimentation
• 4 x 4 mmPCB Mounting Holes
• PCB Dimensions 57.15 x 46.51 mm

Applications

• DC motor drives
• BLDC and PMSM motor control
• High-power PWM switching applications
• Half-bridge and full-bridge inverter systems
• Power electronics development and prototyping
• Industrial and robotics control systems

Open Design and Customization

• Default MOSFET: FDB075N15A (150 V, 130 A, 7.5 mΩ RDS (on))
• Shunt resistor value can be selected to set the desired overcurrent threshold.
• Default current-sense threshold: 0.108 V
• With the default 0.04 Ω shunt resistor (R15), the sense voltage reaches approximately 0.2 V at 5 A.
• PR2 trimmer potentiometer allows adjustment of the overcurrent shutdown threshold. (Adjustable Range 0 to 0.238V)
• Gate resistors can be selected according to the required switching frequency, PWM characteristics, and EMI considerations.

L6491 Description

It is a single-chip half-bridge gate driver for N-channel power MOSFETs or IGBTs, with a 4 A sink and source current capability. The high-side (floating) section is designed to stand a voltage rail up to 600 V. The logic inputs are CMOS/TTL compatible down to 3.3 V for easy interfacing a microcontroller or DSP. An integrated comparator is available for fast overcurrent protection, and is also suited for other functions such overtemperature, etc. An integrated comparator is available for fast protection against over-current, over-temperature, etc.

Connections

• CN1: Pin 1 = Load Supply 12-90V DC, Pin 2 = GND
• CN2: Pin 1,2 = VCC 15V DC, Pin 3.4 = GND
• CN3: Pin 1 = GND, Pin 2 = Output/Load
• CN4: Pin 1 = VP/5V DC, Pin 2 = GND, Pin 3 = Low Side PWM Input, Pin 4 = Shutdown, Pin 5 = High Side PWM Input, Pin 6 = GND
• D3: Power LED Logic

Schematic

Parts List

Connections

Gerber View

Photos

L6491 Datasheet