Gate drivers offer industry's highest noise immunity

1st March 2016
Nat Bowers

Designed for cutting-edge power supply designs and based on Silicon Labs' proven digital isolation technology, Silicon Labs has announced its Si827x ISOdriver family. The family is claimed to provide the highest Common Mode Transient Immunity (CMTI) of any gate driver on the market, making them suited for fast-switching and potentially noisy power supply systems.

Target applications include power supplies for servers, computers and base stations, as well as solar power inverters and microinverters, class D amplifiers, motor controllers and EV/HEV chargers.

An overriding metric for power supply designers is power per volume (W/mm3). To maximise power density, many designers choose faster switching frequencies for their modulation schemes. Power delivery systems use high-power semiconductor switches, such as silicon-based MOSFETs and new GaN and SiC-based MOSFETs, requiring a high-current isolated driver to control the switch. Fast switching improves system efficiencies but also produces higher noise transients that can cause signal loss or permanent damage from latch-up. The Si827x gate drivers protect power systems by offering exceptional immunity to these noise transients caused by high-speed switching.

The Si827x gate drivers offer industry-leading noise immunity (200kV/µs) and latch-up immunity (400kV/µs) - twice the immunity rating of any other gate driver available today. With its high-performance noise immunity, the Si827x family eliminates risks posed by faster switching speeds, preventing modulation loss as well as latch-up, which can be a major safety concern. The Si827x family's very high latch-up specification makes the gate drivers extremely robust, preventing permanent latch-up damage.

The Si827x family offers a choice of single- or dual-isolated drivers with either two independent input controls or a single input for power converter applications. The drivers operate with a wide range of 2.5-5.5V input VDD and a maximum drive supply voltage of 30V. The lower VDDI voltage capability of 2.5V enables developers to design systems with a low-voltage power supply that consumes less power, increases system efficiency and is compatible with low-power MCUs such as Silicon Labs' EFM32 Gecko MCUs.

The Si827x gate drivers feature an EN (active high enable) pin instead of the typical DIS (active low) pin, UVLO fault protection, a de-glitch feature for filtering noisy inputs and highly precise dead time programmability. Using this feature, developers can precisely control the dead time between two switching drivers to optimise power system efficiency and safety.

Ross Sabolcik, Vice President, Power Products, Silicon Labs, commented: "Silicon Labs' new Si827x gate driver family solves real-world customer problems, safely enabling fast switching and low-power 2.5V operation with excellent timing specs. The best-in-class noise immunity of our Si827x gate drivers allows developers to safely design power supply systems with fast-switching MOSFETs or faster GaN and SiC switches, which can significantly improve overall system efficiency while enhancing reliability."

Leveraging Silicon Labs' proprietary capacitive-coupled isolation technology, the Si827x gate drivers offer very low EMI emissions, long lifetimes, fast and accurate timing specs and a wide temperature range from -40 to +125°C.

Samples and production quantities of the Si827x isolated gate drivers are available now in narrow-body SOIC and compact 5x5mm LGA packages. Si827x family pricing in 10,000-unit quantities begins at $1.19.

To simplify application development, Silicon Labs supports the Si827x family with the Si8273ISO-KIT, Si8274ISO-KIT and Si8275ISO-KIT evaluation kits, priced at $29.00 each.

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