High-voltage gate driver with 6kV galvanic isolation

2nd November 2020

Alex Lynn

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Recently released by STMicroelectronics, the STGAP2HS is a compact, high-voltage gate driver for applications that require up to 6kV galvanic isolation between the gate-driving channel and the low-voltage control and interface circuitry.

The 1,200V device can sink and source up to four amp output current to simplify the design and enhance the reliability of mid- and high-power convertors, power supplies, and inverters in home appliances and industrial equipment such as factory automation, fans, induction heaters, welders, and UPSes.

Fabricated using ST’s BCD6s technology, the device has dual input pins that give designers control over signal polarity and provides interlocking protection in hardware to prevent cross conduction if the controller malfunctions. The inputs are compatible with CMOS/TTL logic down to 3.3V, offering easy interfacing with control devices.

Matched propagation delays between the low-voltage and high-voltage sections prevent cycle distortion, minimise energy losses, and allow high-frequency operation. Common-Mode Transient Immunity (CMTI) is ±100V/ns across the full temperature range of -40 to +125°C.

The STGAP2HS is available in two different configurations. One has separate output pins that allow independent optimisation of turn-on and turn-off times using a dedicated gate resistor. The second configuration features a single output pin and Miller-clamp function that prevents gate spikes during fast commutations in half-bridge topologies.

Each configuration lets designers use N-channel MOSFETs in both the high-side and low-side bridge circuitry and thus lower the bill of materials for external components.

In addition to over-temperature protection, the STGAP2HS integrates dedicated UVLO protection and thermal-shutdown protection on both the low-voltage section and the high-voltage driving channel. This enhances reliability by preventing the power switches from operating in low-efficiency or dangerous conditions.

Input-to-output propagation delay of less than 75ns permits accurate pulse-width modulation (PWM) control and a standby mode helps designers reduce system power consumption.

Housed in a wide-body SO-8W package that ensures creepage within a space-efficient footprint, the STGAP2HS is available now priced at $1.34 in quantities of 1,000 units.