Low power single-ended voltage amplifier with adjustable gain and offset for silicon micro displays

Abstract

A liquid crystal pixel driving technique is described that uses a voltage amplifier employing operational transconductance amplifiers and current mirrors to increase LC (Liquid Crystal)-based micro display contrast fidelity and lower production costs. The voltage amplifier has a current follower coupled between a voltage-to-current converter and a voltage buffer. The voltage amplifier employs operational transconductance amplifiers and at least one current mirror to achieve a fixed output swing of an output voltage from the voltage buffer based upon an input swing of a single-ended input voltage to the voltage-to-current converter. A marginal change in the output voltage from the voltage buffer is substantially linear and proportional to a marginal change in the input voltage input to the voltage-to-current converter. For one embodiment of the voltage amplifier, gain and voltage offset of the output voltage can be adjusted by changing the values of two resistors. For one embodiment of the voltage amplifier, the voltage-to-current converter and the current follower together use two operational transconductance amplifiers and two current mirrors. For an alternative embodiment of the voltage amplifier, the voltage-to-current converter and the current follower together use three operational transconductance amplifiers and a current mirror. Overall, the voltage amplifier can provide a 3 dB bandwidth which is independent of the gain. Moreover, power dissipation of the AC signal path is independent of the gain.

Dependencies are inferred from the claim text.