Monolithically Integrated Bootstrapped Gate Driver With a 200-V GaN Power Switch

This paper presents the design and experimental measurement of a fully integrated gate driver fabricated together with a 200-V GaN power switch in a GaN-on-SOI technology. The driver exploits 20-V low-voltage enhancement-mode HEMTs (E-HEMTs), Metal-Insulator-Metal (MIM) bootstrap capacitors and two-dimensional electron gas (2DEG) resistors. To overcome the inherent lack of p-channel devices in the GaN technology, the design employs the bootstrapping approach which allows for full turn-on of the 200-V power GaN switch while minimizing static power consumption. Furthermore, the relatively high breakdown voltage (20 V) of the low-power E-HEMTs allows them to withstand the high voltages generated during bootstrapping. Static power consumption is further reduced by minimizing the number of ratioed logic inverters and implementing an anti-cross-conduction network to eliminate cross-conduction switching losses. The design also leverages the third quadrant of the HEMTs’ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$I_{\mathrm{DS}}-V_{\mathrm{DS}}$ </tex-math></inline-formula> characteristic to emulate the diode behavior, potentially reducing external component requirements. Measured performance reveals an average gate driver current consumption ranging from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$370 \mu \mathrm{~A}$ </tex-math></inline-formula> at -40°C to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$150 \mu \mathrm{~A}$ </tex-math></inline-formula> at 150°C. Additionally, the rise and fall times when driving the power switch with 365-m <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega$ </tex-math></inline-formula> on-resistance are respectively 6.5 ns and 3.5 ns at room temperature.