Regulate output voltage without an optocoupler

A drive signal for secondary-side synchronous rectification improves efficiency, while a programmable volt-second clamp provides a safeguard for transformer reset. This prevents saturation and protects the MOSFET, as well as optimising the transformer and MOSFET in order to reduce solution size. With a programmable 100-500kHz operating switching frequency, the controller can be synchronised to an external clock. This allows it to be used with a wide range of output inductor values and transformer sizes.

In open loop applications, the LT8310 computes the duty cycle required to create a constant output voltage, simplifying the design. If the optocoupler path breaks open in a closed loop application, the LT8310 limits maximum output voltage. The primary-side synchronous forward controller also features programmable overcurrent protection, adjustable input undervoltage, overvoltage lockout and built-in thermal shutdown.

The LT8310 is supplied in a TSSOP-20 with several pins removed for high voltage spacing. It is available in E- and I-grade versions operating over a temperature range from -40 to +125°C, an H-grade version operating over a temperature range from -40 to +150°C and an MP-grade version which operates over a temperature range from -55 to +150°C.