Communications Power

100V Synchronous Forward Controller needs no Opto-Coupler

Linear Technology Corporation announces the LT8310, a primary-side synchronous forward controller. The LT8310 operates over an input voltage range of 6V to 100V, is targeted for power levels up to 200W and provides a drive signal for secondary-side synchronous rectification to improve efficiency. Output voltage regulation of ±8% can be attained without the use of an opto-coupler. When an opto-coupler is used, ±1.5% regulation can be realized. A programmable volt-second clamp provides a safeguard for transformer reset that prevents saturation and protects the MOSFET. This function optimizes the transformer and MOSFET, reducing solution size.

The LT8310 computes the duty cycle required to create a constant VOUT in open loop applications, thereby simplifying the design. In closed loop applications, the LT8310 limits maximum VOUT if the opto-coupler path breaks open. Additional features include programmable overcurrent protection, adjustable input undervoltage, overvoltage lockout and built-in thermal shutdown. The LT8310 has a programmable 100kHz to 500kHz operating switching frequency and can be synchronized to an external clock, enabling the use of a wide range of output inductor values and transformer sizes.

The LT8310 is available in a TSSOP-20 package with several pins removed for high-voltage spacing. The LT8310 E- and I-grade versions operate from a -40 to 125 degrees C junction temperature. The LT8310 H grade is guaranteed to operate from a -40 to 150 degrees C operating junction temperature. The LT8310 MP grade is guaranteed to operate from -55 to 150 degrees C operating junction temperature. The 1,000-piece price starts at $2.99 each.

Linear Technology Corporation
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