High efficiency, low power IC step-down controller for ultra-low power applications

Nowadays the evolution of Smart Technology has led to an increasing need for efficient power management systems, especially for low power and wearable applications. In such architectures, in order to minimize power consumption and achieve higher efficiency, switching regulators for power management are almost mandatory. When dealing with ultra-low power applications (average load current of hundreds of µA), the main source of losses is the control system itself, so the main challenge is to minimize the steady-current consumption for the entire control system and adapt it with load conditions.In this paper a novel control architecture principle that maximizes efficiency is proposed, and the whole system and its sub-parts are described in detail. Its main feature is an extremely low bias current (tens of nA), with an operating power consumption that is frequency-dependent; whilst high-side switch on-time is kept almost constant, system frequency is adapted with load requirements, obtaining thus a controller consumption that is proportional with load demands.