Features

• Wide Input Range: 3V to 25V
• Programmable Volt-Second Clamp
• Output Power Levels from 25W to 500W
• Auxiliary Boost Converter Provides 10V Gate Drive from V_IN as Low as 3V
• Programmable Operating Frequency (100kHz to 500kHz) with One External Resistor
• Programmable Slope Compensation
• Programmable Leading Edge Blanking
• ±2% Internal 1.23V Reference
• Accurate Shutdown Pin Threshold with Programmable Hysteresis
• 60ns Current Sense Delay
• 2.5V Auxiliary Reference Output
• Synchronizable to an External Clock up to 1.5 • f_OSC
• Current Mode Control
• Small 16-Pin SSOP Package

Typical Application

Description

The LT1950 is a wide input range, forward, boost, flyback and SEPIC controller that drives an N-channel power MOSFET with few external components required.

A resistor programmable duty cycle clamp can be used to generate a volt-second clamp for forward converter applications. An internal boost switcher is available for creating a separate supply for the output gate driver, allowing 10V gate drive from input voltages as low as 3V. The LT1950’s operating frequency can be set with an external resistor over a 100kHz to 500kHz range and a SYNC pin allows the part to be synchronized to an external clock. Additional programmability exists for leading edge blanking and slope compensation.

A fast current sense comparator achieves 60ns current sense delay and the error amplifier is a true voltage mode error amplifier, allowing a wide range of compensation networks. An accurate shutdown pin with programmable hysteresis is available for undervoltage lockout and shutdown. The LT1950 is available in a small 16-Pin SSOP package.