Jindrich Windels

Comparative study on the effects of PVT variations between a novel all-MOS current reference and alternative CMOS solutions

Sensitivity to supply voltage, temperature and process variations of a number of current reference topologies and a novel circuit is compared in ON Semi I3T80 technology. The novel current reference shows the lowest process dependency, while supply and temperature dependency remain acceptably low.

Monolithic integration of an active asynchronous voltage clamp with a 12V/3A full bridge synchronous rectifier

In transformer isolated converters, a large voltage overshoot is present on the secondary side switching nodes at every switch transition. As is well known in the design of monolithically integrated high voltage circuits, the peak voltage stress in a circuit is the paramount parameter for an efficient implementation of smart-power circuits. A voltage clamping circuit that minimizes the voltage stress in the circuit is crucial for an efficient monolithic implementation of a synchronous rectifier in a smart-power technology. This paper presents a smart-power implementation of an asynchronous active clamping circuit on the same IC as a 12V/3A synchronous rectifier for a full bridge phase shifted dc-dc converter. The asynchronous clamping circuit minimizes the number and size of required external components to provide the voltage clamping, and optimizes the efficiency of the synchronous rectifier by accurately controlling the clamping operation.

Automatic load-based MOSFET segmentation for switching DC-DC converters

This paper proposes an automated approach for the optimization of the number of active segments in switching DC-DC converters with a segmented power stage. The drain-source voltage of the active power MOSFET segments is used to estimate the load current, and an automated segment controller activates an optimized number of segments. Using this approach automatically balances the switching loss and the conduction loss in the converter over the load range. The proposed concept is implemented in a prototype discrete 500 kHz boost converter, which confirms the optimized efficiency over the load range. Potential applications include high power discrete converters, where multiple power MOSFETs in parallel are already used and monolithically integrated converters, where the power MOSFET segments, drivers and control circuits are integrated on a single ASIC.