LM5025

LM5025 Active Clamp Voltage Mode PWM Controller March 2004 LM5025 Active Clamp Voltage Mode PWM Controller General Description The LM5025 PWM controller contains all of the features necessary to implement power converters utilizing the Active Clamp / Reset technique. The device can be configured to control either a P-Channel clamp switch or an N-Channel clamp switch. With the active clamp technique, higher efficiencies and greater power densities can be realized compared to conventional catch winding or RDC clamp / reset techniques. Two control outputs are provided, the main power switch control (OUT_A) and the active clamp switch control (OUT_B). The active clamp output can be configured for either a guaranteed overlap time (for P-Channel switch applications) or a guaranteed deadtime (for N_Channel applications). The two internal compound gate drivers parallel both MOS and Bipolar devices, providing superior gate drive characteristics. This controller is designed for high-speed operation including an oscillator frequency range up to 1MHz and total PWM and current sense propagation delays less than 100ns. The LM5025 includes a high-voltage start-up regulator that operates over a wide input range of 13V to 90V. Additional features include: Line Under Voltage Lockout (UVLO), softstart, oscillator UP/DOWN sync capability, precision reference and thermal shutdown. Features n Internal Start-up Bias Regulator n 3A Compound Main Gate Driver n Programmable Line Under-Voltage Locko...