The LM5025 PWM controller contains all of the features necessary to implement power
converters using the active clamp and reset technique. The device can be configured to control
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 and 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 specified
(for P-channel switch applications) or a specified 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 1 MHz and total PWM and current sense propagation delays less than 100
The LM5025 includes a high-voltage start-up regulator that operates over a wide input
13 V to 90 V. Additional features include: line undervoltage lockout (UVLO), soft-start,
oscillator UP and DOWN sync capability, precision reference and thermal shutdown.