Galvanic-Isolated Gate Driver Controls and Protects SiC or Si Power TransistorsAugust 02, 2018 by Paul Shepard
With 26V maximum gate-drive output voltage and optional separate turn-on/turn-off outputs or integrated active Miller clamp, STMicroelectronics' STGAP2S single-channel galvanic isolated gate driver can control silicon-carbide (SiC) or silicon MOSFETs and IGBTs across a range of switching topologies.
The STGAP2SCM has a dedicated active Miller clamp pin that provides a convenient solution to prevent unwanted transistor turn-on in half-bridge configurations. Connecting the MOSFET gate to this pin clamps the voltage to isolated ground at turn off, until the next genuine turn-on signal.
The STGAP2SM with separate turn-on and turn-off outputs helps optimize switching transitions using two external gate resistors.
All STGAP2S gate drivers have 4A rail-to-rail outputs for crisp, efficient switching, even with high-power inverters. Input-to-output propagation delay is within 80ns for precise pwm control at the high switching frequencies suited to SiC devices. High dV/dt common-mode transient immunity prevents energy-sapping spurious switching.
With 1700V galvanic isolation also built-in, these devices can simplify the bill of materials for consumer or industrial motor drives, 600V or 1200V inverters, dc-dc converters, battery chargers, welders, induction heaters, uninterruptible power supplies (UPS), and power-factor correction (PFC) controllers.
Extensive integrated protection features include Under-Voltage Lockout (UVLO) to protect the power switch if the supply voltage falls too low.
In addition, over-temperature protection is provided, as well as hardware interlocking to prevent high-side/low-side cross conduction in half-bridge circuits.
There is also a standby mode, which keeps the output in a safe state while saving power.
Designers can also take advantage of the EVALSTGAP2SCM evaluation board, which provides a fast and easy way to kick-start design.
The device is available in two different configurations:
Summary of key features:
- 1700V single channel gate driver
- Driver current capability: 4A sink / source at 25°C
- dV/dt transient immunity ± 100V/ns
- Overall input-output propagation delay: 80ns
- Separate sink and source for easy gate driving configuration
- 4A Miller clamp dedicated pin
- UVLO function
- Gate driving voltage up to 26V
- 3V, 5V TTL/CMOS inputs with hysteresis
- Temperature shutdown protection
- Standby function
The STGAP2SCM, available now, and STGAP2SM, available in Q4 2018, are housed in the compact, industry-standard SO-8 power package, priced from $1.49 for orders of 1000 pieces.