Practical Implementation of a High-Frequency Current Sensing Technique for VRM

Inductor current tracking in high-frequency DC/DC converters is not effortless, especially when high current and low voltages loads are demanded. This paper proposes a simple technique to obtain a good resolution in the inductor current measurement obtaining an equivalent voltage image which can be used for a high-frequency PWM controller. This strategy of measurements is generic and it has been validated by simulations. Our experimental results are obtained with very low output voltages and several loads between 10mA to high currents covering the needs of portable and embedded VRM applications.