A Loop Control Design to Achieve Boundary Conduction Mode in DC-DC Power Converter for Maximizing Efficiency

In this paper, a loop control design for different DC-DC power converter operating in Boundary Conduction Mode is studied. The loop control circuit including a pulse frequency modulator allows the converter to adapt its switching frequency to load variations to maximize efficiency. Cadence simulation results using practical switch and circuit component models show that a buck converter employing the loop control circuit achieves a peak efficiency of 97.7% that is ~4 % higher than that of the conventional ones. The full loop control offers an increasing of efficiency at high load from 1 to 3% for a 4-to-l Dickson converter comparing to the same converter with only a PWM closed-loop with fixed dead-time.