High voltage monolithic flyback regulator simplifies design of isolated DC-DC converter

Linear Technology offer the LT8315, a high voltage monolithic flyback regulator that simplifies the design of an isolated DC-DC converter. By sampling the reflected isolated output voltage across the third winding on the power transformer, the part requires no opto-isolator or LT1431 for regulation. The device operates over an 18V to 560V input voltage range, has a 0.3A/630V integrated power switch and delivers up to 15W of output power, ideal for electric vehicles and battery stacks, as well as off line, automotive, industrial and medical applications. Several off-the-shelf transformers identified in the data sheet can be used for numerous applications. The device operates in quasi-resonant boundary mode, which is a variable frequency current mode control switching scheme, resulting in better than ±1% load and line regulation. Boundary mode enables the use of a smaller transformer compared to equivalent continuous conduction mode designs. The high level of integration and the use of low ripple Burst Mode operation result in a simple to use, low component count and high efficiency application solution for isolated power delivery. Additional features include output short-circuit protection, 70µA no load operating quiescent current, accurate enable and undervoltage lockout with hysteresis, along with output diode temperature compensation. The device is available in a TSSOP-20 package with four pins removed for high voltage spacing. Extended and industrial versions operate over a junction temperature range of -40C to 125C. A high temperature automotive grade operates from -40C to 150C.