Texas Instruments High-Speed PWM Controller, Part #UC3825ADWTRG4 | Switching Controller | DEX features: • Improved versions of the UC3823/UC3825 PWMs • Compatible with voltage-mode or current-mode control methods • Practical operation at switching frequencies to 1 MHz • 50-ns propagation delay to output • High-current dual totem pole outputs (2-A peak) • Trimmed oscillator discharge current • Low 100-μA startup current • Pulse-by-pulse current limiting comparator • Latched overcurrent comparator with full cycle restart

The UC3823A and UC3823B and the UC3825A and UC3825B family of PWM controllers are improved versions of the standard UC3823 and UC3825 family. Performance enhancements have been made to several of the circuit blocks. Error amplifier gain bandwidth product is 12 MHz, while input offset voltage is 2 mV. Current limit threshold is assured to a tolerance of 5%. Oscillator discharge current is specified at 10 mA for accurate dead time control. Frequency accuracy is improved to 6%. Startup supply current, typically 100 μA, is ideal for off-line applications. The output drivers are redesigned to actively sink current during UVLO at no expense to the startup current specification. In addition each output is capable of 2-A peak currents during transitions.

Functional improvements have also been implemented in this family. The UC3825 shutdown comparator is now a high-speed overcurrent comparator with a threshold of 1.2 V. The overcurrent comparator sets a latch that ensures full discharge of the soft-start capacitor before allowing a restart. While the fault latch is set, the outputs are in the low state. In the event of continuous faults, the soft-start capacitor is fully charged before discharge to insure that the fault frequency does not exceed the designed soft start period. The UC3825 CLOCK pin has become CLK/LEB. This pin combines the functions of clock output and leading edge blanking adjustment and has been buffered for easier interfacing.

TEX:UC3825ADWTRG4 

UC3825ADWTRG4