A Novel Low Delay High-Voltage Level Shifter with Transient Performance Insensitive to Parasitic Capacitance and Transfer Voltage Level

Abstract

In this paper, a new high-voltage level shifter (HVLS) structure is proposed, which has a significantly improved transient response over existing structures. To overcome signal transfer delay of the conventional HVLS caused by parasitic capacitance due to high-voltage MOSFETs, this structure employs a novel circuit module "inverse Schmitt trigger" to drive the pull-up transistors of conventional HVLS. As a result, the "Miller Plateau" caused by parasitic capacitance can be minimized. Hence, the overall transfer delay of the structure is significantly reduced. The simulation results based on SPECTRE and 0.5μm high-voltage CMOS process show that compared to other currently available structures whose transfer delays are several nanoseconds on average, the proposed structure is able to provide a nanosecond transfer delay without using large boost capacitors which are impractical to be integrated or using complex logic units which decrease reliability of circuit. Also, the typical transfer delay of the proposed structure is a constant 1.3ns, which is irrelevant to parasitic capacitance and insensitive to transfer voltage level.