It offers a very high communication bandwidth which enables a much faster transient load response. FluxLink enables feedback information to cross an isolation barrier without the use of any magnetic materials. The heart of the switch is a secondary-side controller for synchronous rectification and an improved isolation barrier called FluxLink. The IC incorporates the primary FET, the primary-side controller. The InnoSwitch IC product line combines primary, secondary and feedback circuits in a single off-line flyback switcher. Recently, the company has introduced higher voltage regulators and improved coupling techniques. The BCD manufacturing process, however, would impose limitations on the size of the on-chip MOSFETs, and the currents it would conduct.
DIGITAL ISOLATOR APPLICATION NOTES OFFLINE
The company helped define a market for miniature AC-DC offline switches, suitable for AC adaptors and battery chargers.
DIGITAL ISOLATOR APPLICATION NOTES DRIVERS
Power Integrations has demonstrated a mastery over switch mode power supplies using ICs with built-in MOSFET drivers and capacitive feedback isolation and control. The newdf, fast switching technologies need a gate-driver with a Common Mode Transient Immunity (CMTI) of at least 120 kV/µs to support typical designs with a 600 V high voltage rail. The entire isolation portfolio supports isolation voltages up to 5 kV. These mixed-signal IC solutions promote high isolation and high voltage expertise to enhance power system performance, flexibility and reliability while reducing system size and cost. Silicon Labs portfolio includes CMOS digital isolators, isolated gate drivers, isolated current sensors, isolated system products and Power over Ethernet (PoE) products. An isolation barrier can offer protection from transients but ― in addition to very high voltage protection ― it must respond fast. In the power supply scenario, a 600 V rail can produce a 120 kV/µs transient (600 V / 5 ns = 120 V/ns or 120 kV/µs). Switching times in the state-of-the-art systems being designed today with GaN power switches are typically about 5ns, or about 10x – 20x faster than conventional systems. Faster switching can enable higher switching transients. While these advantages are highly desirable, there is a risk involved. This loop can be broken by electrically isolating the gate drivers for the power switches. But it also sets up a dangerous feedback loop. MOSFET switches in the feedback loop regulate ― from the secondary to the primary side ― the tempo of the pulsed DC. In switch-mode power supplies, MOSFET switches drive high current pulses across a transformer. Thus, higher switching speeds underwrite power densities. It also enables designers to shrink the size of ancillary components (capacitors and inductors) even as they conduct higher currents. It is possible increase the efficiency of the pulse stream by elevating its frequency. The frequency of the power pulses also effects the efficiency of the power transfer. They include newer technologies like Gallium-Nitride (GaN) or Silicon-Carbide (SiC). These new power switches are faster than silicon-based MOSFETs. According to literature from Silicon Laboratories, the pulses are generated by MOSFET transistor switches ― and the speed with which the pulses can be streamed will affect the power density of the power supply. Here, high current AC (or pulsed DC) at one frequency, is converted to pulsed DC at another (higher) frequency. Shrinking the size while increasing the power density (in terms of watts per cubic centimeter) has become the mantra (the overwhelming design goal) of switching power supply design. How isolation helps with high-speed switching power supplies. But digital isolators, with their ability to pass MBits/s of data (rather than kHz), are encroaching on optocouplers traditional turf. Optical isolators remain popular in AC-to-DC converters for their high degree of isolation and low costs. There is a growing need to pass control data, from one side of the interface to the other, while keeping your receivers (like USB or RS-232 ports) electrically isolated from the power path. The role of isolation barriers has expanded dramatically from telephone line modems: Applications for digital isolators now include industrial and medical equipment, whose armatures and probes run on high voltages. Though isolators (particularly optocouplers) are considered a commodity in some circles, they are expected to perform the same way as other power-handling devices: They need to demonstrate ever great power and precision in smaller, less costly packaging.
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