A Reliability and Efficiency Optimization System for Hard-Switching DC/DC Converters

The Large Hadron Collider experiments at CERN will use power distribution schemes relying on integrated buck DCIDC converters. Due to the radiation-hardness requirements, the devices used for the development of such converters will have a voltage rating which is close to the converters’ input voltage. The voltage spikes generated during the hard-switching operation can affect the reliability of such low-voltage MOSFETs. A fixed and sufficiently small gate driver current for the high-side switch could be used to guarantee the reliable operation even in the worst-case conditions in terms of input voltage, output current, temperature and process variations. Nevertheless, this would result in a suboptimal efficiency in all the other working conditions. This work presents an integrated system than monitors in real-time the voltage stress, and adjusts the gate driver current to achieve maximum efficiency in all conditions, while ensuring compliance with the reliability specifications. A buck converter including the voltage peak detector and an adjustable gate driver current has been designed in a 130 nm technology, demonstrating the functionality of the voltage stress monitoring system.