A Monolithic GaN Driver With Power-Rail Charging Saturation Bootstrap Technique Achieving Enhanced Slew Rate and Gate Rise/Fall Time Ratio of 1.28

A monolithic gallium nitride (GaN) driver with power-rail charging saturation bootstrap (PCSB) technique is proposed in this article. The proposed driver features an internal PCSB driver to significantly improve the gate slew rate of GaN power switch through the combined action of embedded cross-coupled charge pump (ECCP) and $3V_{\mathrm {DD}}$ biasing stage. Transmission speed enhancement and shoot-through current elimination are also realized in the PCSB driver. Moreover, an integrated GaN overcurrent protection (OCP) circuit with a high-speed high-precision (H ² ) GaN comparator is implemented for GaN power switch and realizes high-speed OCP with enhanced accuracy. The proposed driver is fabricated in a GaN-on-SOI process and occupies an active chip area of 4.7 mm². The experimental results show that the deviation of the ratio of gate rise-to-fall time of power GaN (=1.28) from the ratio of the designed static peak sink-to-source current (=1) is as low as 28%, indicating stronger output pull-up capability than prior arts. Benefiting from this, the proposed driver achieves 96% peak efficiency for a 15-W LED driver. The short-circuit protection response time of only 43 ns is realized by the proposed OCP circuit.