
Isolated gate drivers target industrial inverters and motor drives
The Si828x ISOdriver family provides industrial-grade isolation of 5 kVrms along with an optional DC-DC converter, fast desaturation detection, propogation delays of less than 55ns and high noise and transient immunity.
The family is aimed at industrial motor drives, solar inverters, high-voltage power converters, uninterruptable power supplies, and heating, ventilation and air conditioning (HVAC) compressor control. Many of these systems are expected to last more than 25 years while operating in harsh environments. Isolators can be first points of failure and lifetime-limiting devices in these systems and traditional optocoupler-based isolators have significant limitations in temperature range, noise immunity and product lifetime. The CMOS Si828x gate drivers can operate over a full industrial temperature range and meet stringent UL, VDE, CQC and CSA standards.
The Si828x family combines robust isolation, advanced gate driver technology and fast over-current monitoring in a single, cost-effective device designed to protect costly IGBT switches. High-power inverter and power converter systems typically use IGBTs for the switching element, and over-current conditions can destroy IGBTs, compromise system-critical functions, jeopardize product safety and diminish reliability.
The key feature is a 4 A gate driver coupled with desaturation detection to monitor the IGBT for over-current. In that event, the Si828x driver initiates a controlled shutdown of the switch while updating the controller with the fault status, protecting the IGBT and the system. Additional integrated features include split outputs, a Miller clamp to prevent parasitic gate turn-on, and driver power state and fault feedback to the controller.
The Si828x family includes driver versions with an integrated isolated DC-DC converter which helps developers simplify the layout, reduce component count and board size and ease the complexity of creating and managing multiple power domains. A single power bus can be routed across the system, eliminating complex spacing concerns. Localizing power supplies to each driver reduces inductance, minimizes noise and removes transients.
“Today’s power inverters and converters for industrial and green energy designs require state-of-the-art signal isolation technology with superior timing characteristics, lower emissions and higher reliability,” said Ross Sabolcik, Vice President of power products at Silicon Labs. “Silicon Labs’ new Si828x ISOdriver family provides the ultimate gate driver solution for these applications by helping developers achieve higher system efficiency and noise immunity, minimize design complexity, and enhance system safety and product lifetimes.”
Silicon Labs offers three evaluation kits to help developers evaluate Si828x ISOdriver performance and key features. The Si8285_86-KIT demonstrates the basic Si828x driver functionality while the Si8281-KIT demonstrates the driver with an integrated dc-dc converter and the Si8284-KIT demonstrates the driver with full-featured dc-dc converter capable of using higher supply voltages.
Samples and production quantities of the Si828x isolated gate drivers are available now in a variety of compact wide-body SOIC packages. Pricing in 10,000-unit quantities begins at $1.59 for base driver products and $2.87 for devices with an integrated dc-dc converter. The Si8285_86-KIT, Si8281-KIT and Si8284-KIT evaluation kits are priced at $19.00 each (USD MSRP).
