ST's gapDRIVE integrated gate drivers include on-chip galvanic isolation

November 27, 2014 // By Graham Prophet
The STGAP1S advanced single-channel gate driver from STMicroelectronics, that integrates galvanic isolation with analogue and logic circuitry in the same chip to help simplify driver design while ensuring high noise immunity for safe and reliable power control.

STGAP1S is the first in ST's new generation of gapDRIVE gate drivers, which combine proprietary bipolar-CMOS-DMOS (BCD) process technology with innovations that enable an isolation layer to be grown on-chip to allow even greater system integration. Up to 1500V can be present on the high-voltage rail without interfering with other circuitry, ensuring a level of robustness that makes this new device suitable for use in industrial drives, high-power 600V or 1200V inverters, solar inverters, and uninterruptible power supplies.

With signal-propagation delay of 100 nsec across the isolation layer, the STGAP1S is capable of transmitting high-accuracy PWM signals. The integrated driver stage can sink or source up to 5A, and has a rail-to-rail output that allows negative drive voltages for use with large IGBTs or wide-bandgap power switches, such as silicon-carbide MOSFETs. High common-mode transient immunity, in excess of ±50 V/nsec, allows reliable communication across the isolation layer and safe operation. Separate sink and source outputs enhance design flexibility and help eliminate external components.

The device also has a built-in SPI port, which provides an industry-standard host connection for configuring the control logic and monitoring status on the fly. The STGAP1S is able to provide rich digital diagnostics to the host via this interface, allowing enhanced system protection and reliability.

This intelligent driver also integrates an extensive set of protection features that help maximise reliability in harsh industrial environments. These include an active Miller clamp in the power stage to prevent unwanted transistor turn-on, desaturation detection to protect the power switch under short-circuit conditions, collector-emitter overvoltage protection and output two-level turn-off capability to prevent damaging voltage overshoot, over-temperature protection, Under-Voltage Lockout (UVLO), Over-Voltage Lockout (OVLO), and a dedicated sense pin for over-current detection.

The STGAP1S is packaged as fully integrated and compact SO24W device priced from $3 (1000).

STMicroelectronics; www.st.com/gapdrive-nb