Analysis of dead time losses in energy harvesting boost converters for implantable biosensors

Efficiency of an ultra-low power energy harvesting dc-dc converter depends on its losses and the power consumption of the control circuit. Unlike other loss mechanisms, losses related to dead times have not been thoroughly studied. Therefore, in most cases these losses are not adequately suppressed. This paper investigates dead time losses and their impact on the overall system efficiency. Simple expressions for fast estimation of dead time losses are derived. Analysis shows that in many applications where high voltage conversions are required, such as implantable biosensors, the efficiency reduction due to these losses can easily exceed 2%. The analysis is validated using an adaptive dead time circuit which minimizes the associated losses and improves the overall system efficiency according to the calculated values.