New 5 kV Isolated Gate Drivers Help Meet Today's Green Energy Standards
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Isolated gate drivers are critical building blocks within the power delivery stages of many systems. The new Si823x and Si822x ISOdrivers from Silicon Labs are single chip, isolated gate drivers based on the company’s highly regarded and patented RF isolation technology. This technology, now introduced as a single chip solution, gives you exactly the value you’ve been looking for: reduced BOM costs, higher system reliability and increased energy efficiency – critical to meeting today’s “green” energy standards. Certified up to 5 kVrms, ISOdrivers are suitable for universal powered (120/220 Vac) and safety critical industrial systems. Supporting gate drive voltages up to 24 V, these 0.5 and 4.0 A peak output current devices drive MOSFET and IGBT power stages in a wide variety of applications. A choice of compact packages, high performance and robust reliability make ISOdrivers an ideal choice for system designers.
ISOdrivers are targeted at manufacturers of a broad array of systems and applications which fundamentally require two critical electronic functions:
Galvanic isolation
On-chip, 5 kV isolators provide DC level shifting for the high-side driver; as a result, ISOdrivers can drive external switches with common mode voltages up to 1 kV. Isolation also helps protect humans and/or the equipment itself from damage or loss of life. Isolation is required to comply with international safety standards such as VDE (German Association for Electrical, Electronic and Information Technologies). Typical isolation ratings range from 1 to 5 kVrms and above.
Driving a power switch
Power switches, such as MOSFETs and IGBTs, have very high gate capacitance which requires a driver with fast rise and fall times and a high peak driver current. Depending on the end product, the drive stage (“gate driver”) typically drives multiple external switches that ultimately must deliver power in the application, ranging from hundreds of milliwatts (plasma display panels) to hundreds of Watts (switching power supplies) or even several kilowatts (industrial motors).
Representative systems which must provide isolation and also drive a power stage are switch mode ac-dc and isolated dc-dc power supplies, UPS, test and measurement equipment, robotic assemblies, industrial automation and drives, solar inverters, motor controls, PDPs, and electronic lighting ballasts.
ISOdrivers are fundamental building blocks in the power delivery stages of many systems. Some of the most common examples include switch mode ac-dc and dc-dc power supplies and UPS. Many other products require an isolated gate driver such as test and measurement and fitness equipment. The included diagram highlights a typical consumer treadmill application where Si823x ISOdrivers and Si84xx isolators interface to a C8051 MCU from Silicon Labs. The parts control the overall system or to isolate and drive the motors’ power stage. The Si84xx isolators provide isolated communications between the heart rate sensor and user display.