GaN Monolithic PWM Generator With Dynamic Offset Compensation

The first fully integrated GaN pulse width modulation (PWM) generator for power conversion applications is presented in this paper. The solution is implemented in a 0.5-mu m technology, avoiding additional pins and external capacitors for sawtooth signal generation while providing high accuracy. Indeed, the large GaN process spreads are addressed through an innovative dynamic offset compensation approach whose clock signal takes advantage of the PWM signal itself. The proposed PWM generator adopts a 6-V power supply and includes a 2(5) digital divider to set the PWM frequency at 500 kHz and the minimum and maximum duty cycles at 6% and 94%, respectively. Experimental results on integrated prototypes validated the correct circuit functionality over the temperature range from -40 degrees C to 120 degrees C. As a main achievement, this work demonstrates effective all-GaN integration of complex mixed analog and digital circuits, thus representing a significant advancement in the approaches to overcome the main limitations of GaN devices and enable fully integrated signal processing implementation.