Buck Converters Reach 96% Light-Load Efficiency Levels
By integrating a light-load efficiency improvement algorithm, Diodes Inc. was able to push the efficiency of its AP6550 and AP6540 synchronous dc-dc converters up to 96%. Subsequently, they deliver continuous load currents of 4 and 5 A, respectively. Current-mode control produces a fast transient response and simple loop stabilization, leading to dependable line and load regulation in distributed point-of-load power-management applications. Their fixed switching frequencies of 500 and 750 kHz helps shrink the size of external inductive and capacitive components. The 500-kHz, 4-A AP65402 and 5-A AP65502 feature an adjustable 0.925- to 16-V output voltage range, while the 750-kHz AP65403 and AP65503 range from 2.5 to 16 V. The converters’ 4.75- to 17-V operating voltage range suits 5- and 12-V bus system design. All devices tolerate a transient peak voltage of up to 7 A. Protection includes thermal shutdown, undervoltage lockout, overvoltage, and current-limit. A capacitor-programmed soft-start controls inrush current and output-voltage overshoot. Packaging is an exposed-pad SO-8EP; pinouts are identical throughout the product family.
