A DC/DC converter with high efficiency over a wide load range is necessary for many low voltage applications, such as battery supplied systems and micro-processor power supplies-Voltage Regulator Module (VRM), In order to improve the efficiency of low voltage converters, synchronous rectifier technology is widely used. The disadvantage of this technology is tow efficiency at light load. This paper proposes a new technology, which utilizes the duty cycle signal, to improve light load efficiency with simple implementation, Since current sensors are not required, high density and high efficiency can be achieved that makes the whole circuit suitable for integration, In the paper, two application examples are given, Experimental results verified that the proposed control schemas significantly improve the efficiency of synchronous rectifier buck converters at light load.

Future generation microprocessors are predicted to exhibit heavier loads and faster transients. Conventional voltage regulator modules (VRM) need a large amount of output filter capacitors to meet future requirements and a huge number of decoupling capacitors, mainly due to the presence of parasitic inductance between the VRM and the microprocessor. In this paper, a new active damp concept is presented. By charging some auxiliary capacitors at higher voltage, it is possible to store the amount of charge required by the processor during the step up transient; this extra charge can be locally delivered to the processor in a single shot manner, bypassing the slower VRM. In the same way, this circuit can sink the excess of charge that has to be removed during the step down transient. By using this transient suppressor circuit, a conventional VRM can still provide adequate steady state regulation, while the size of decoupling and filter capacitors can be significantly reduced. Experimental results prove the validity of the concept.

A DC/DC converter with high efficiency over very wide load range is necessary for many low voltage applications, such as battery supplied systems and microprocessor power supplies-voltage regulator module (VRM). In order to improve the efficiency of low-voltage power converters, synchronous rectifier technology is widely used. The disadvantage of this technology is low efficiency at light load. This paper proposes a new technology that can improve light load efficiency with very simple implementation. Since current sensors are not required, high density and high efficiency can be achieved that makes the whole circuit suitable for integration. In the paper, two application examples are given. Experimental results verified that this technology significantly improves synchronous rectifier buck converters light load efficiency