Bipolar voltage level shifter

Abstract

Most of the advanced CCD sensors require bipolar clocks with large voltage swings. Hence there is a need of voltage level shifter to translate TTL/CMOS compatible levels to bipolar voltage swings (up to 20V). The CMOS drivers have advantages of low power and high input impedance but its main challenge is to attain negative voltage swing. Hence different topologies have been studied to implement the bipolar CMOS voltage level shifter design to guarantee a wide bipolar voltage conversion range with limited static power and total energy consumption. This circuit is implemented in a high voltage CMOS process. Design simulations have been carried out for TTL/CMOS input signals and output is verified for operational frequencies up to 20MHz and voltage swings up to 20V for all process-voltage-temperature variations. Designed level shifter provides output with rise /fall time less than 2ns. This paper discusses the designed circuit and detailed simulation results.