Flyback regulator eliminates opto-coupler
Suitable for automotive, industrial, medical and military applications, the LT8304/-1 monolithic flyback regulators have been announced by Linear Technolgy. The H-grade regulators have guaranteed operation for junction temperatures up to 150 degree C.
By sampling the isolated output voltage directly from the primary-side flyback waveform, the part requires no opto-coupler or third winding for regulation. Input voltage is 3.0 to 100V with a 2A/150V integrated DMOS power switch to deliver up to 24W output. The LT8304-1 version is tailored for high output voltages up to 1kV.
The regulators operate in boundary mode, which is a variable frequency current mode control switching scheme, typically resulting in better than ± five per cent output voltage regulation over the full line, load and temperature range. Boundary mode enables the use of a smaller transformer compared to equivalent continuous conduction mode designs. According to the company, 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 solution for isolated power delivery.
Additional features include output short-circuit protection, 116microA no load operating quiescent current, accurate enable and under-voltage lockout with hysteresis, internal soft-start and loop compensation, along with output diode temperature compensation.
Operating temperature range is -40 to 150 degree C junction temperature range. The regulators are available in a small thermally enhanced SO-8 package.