Single-Polarity Power Supply Bootstrapped Comparator for GaN Smart Power Technology

A high-performance bootstrapped comparator operating with a single-polarity power supply is demonstrated for the development of GaN smart power ICs. The comparator features monolithically integrated enhancement-mode (E-mode) and depletion mode (D-mode) AlGaN/GaN HEMTs. The tail current source uses E-mode HEMT, enabling single-polarity power supply. The input stage could be either E-mode or D-mode HEMTs to cover a wide voltage range (from 0 to 6 V), while the bootstrapped loads are implemented with D-mode HEMTs. At room temperature, the comparator delivers a voltage gain as high as 132 V/V and a unity-gain bandwidth of 270 MHz. The comparator is also capable of operating at 250 °C with temperature-compensated bias.