Power Integrations - Device simplifies design of industrial supplies for 440VAC line input

Power Integrations has announced a new reference design (DER-479) that demonstrates industry using the company ’s LinkSwitch-4TM series of CV / CC primary-side regulation (PSR) switching ICs and 1200V bipolar junction transistors (BJT). power supply. The design supports 440 VAC line inputs and has three outputs that, when combined, provide high-precision constant-voltage DC power supplies up to 11W. LinkSwitch-4 controllers have adaptive base and emitter switch drive schemes to improve switching performance and efficiency. Advanced switching technology is particularly beneficial in high-voltage applications because it reduces slow-off switching losses and eliminates BJT failures due to secondary breakdown, which improves the reverse bias safe operating area (RBSOA) and system reliability. In addition, the primary-side regulation sensing method of the LinkSwitch-4 controller eliminates expensive and unreliable optocouplers and replaces them in the feedback loop with simple transformer windings. The design uses only 50 mW under no-load conditions while maintaining fast transient response. The 65kHz operating frequency minimizes transformer size, which reduces system cost and PCB size. LinkSwitch-4 devices can also compensate for many factors, including: transformer inductance tolerance; input line voltage changes; cable voltage drops; and external component temperature changes. Silvestro Fimiani, senior product marketing manager at Power Integrations, said: "The development of power supplies for high-voltage systems such as three-phase meters and motor drives is challenging, and in such designs, efficiency, reliability and component count are often affected. The LinkSwitch-4 controller is paired with a 1200V BJT, making the design very simple and extremely reliable. " The company said that DER-479 can be downloaded for free from the Power Integrations website.