Isolated gate drivers step up noise immunity in power electronics
Based on Silicon Labs’ digital isolation technology, the ISOdriver family claims the highest noise immunity of any gate driver on the market; its common mode transient immunity (CMTI) suits the drivers for fast-switching and potentially noisy power supply systems.
To maximise power per volume (W/mm³) 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 gallium nitride (GaN) and silicon carbide (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 gate drivers offer noise immunity of 200 kV/µsec and latch-up immunity 400 kV/µsec – twice the immunity rating of any other gate driver available. This 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, and increases system efficiency.
The gate drivers feature an EN (active high enable) pin instead of the typical DIS (active low) pin, under-voltage lockout (UVLO) fault protection, a de-glitch feature for filtering noisy inputs and highly precise dead time (DT pin) programmability. Using this DT feature, developers can precisely control the “dead time” between two switching drivers to optimise power system efficiency and safety.
Built with Silicon Labs’ capacitive-coupled isolation technology, the Si827x gate drivers offer very low electromagnetic interference (EMI) emissions, long lifetimes, fast and accurate timing specs, and a wide temperature range of -40 to +125 °C.
In narrow-body SOIC and compact 5 x 5 mm LGA packages prices are from $1.19 (10,000). The Si8273ISO-KIT, Si8274ISO-KIT and Si8275ISO-KIT evaluation kits are priced at $29.00.
Silicon Labs; www.silabs.com/ISOdriver
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