Design Of Low Power And High Performance LCD Driver

The increasing trends of information exchanging have brought great prosperity to the display family. Among different kinds of displays, LCD has shown itself an excellent application by virtue of no electromagnetic radiations, high display quality, digital interface and high reliability.A 128 pattern(32 × 4),memory mapping, and multi-function LCD driver is presented. Its S/W configuration feature makes it suitable for multiple LCD applications including LCD modules and display subsystems. Only three or four lines are required for the interface between the host controller and this LCD driver.Based on the property of liquid crystal with a large parasitic capacitance and resulting in a great time constant during charge and discharge, a novel bias circuit using dynamic resistors is proposed in this paper. The output driving circuits would only drive for tens of microseconds at the point that driving voltages change, till pixel voltages reach the levels they are supposed to.Then leaving the LC distributing capacitance itself to keep the voltage level, the bias circuit and thus output driving circuits come into an Off state, the bias circuits is of high impedance and hence consumes no power. Based on the different loads in practice, the pulse width and the frequency of the control signal can be lifted.The proposed scheme has been experimented in this 32×4 LCD diver. It's found out that the power dissipation in the biasing circuitry part could be reduced by about sixty-six times to more than one hundred and thirty times. In addition, if choosing an appropriate frequency for the control signal, it will provide a much better image than a traditional one does.The new bias circuit scheme presented in this paper not only possesses the strong suits of integration facility and the ability to provide multiple bias voltage levels, which are hard for that by means of capacitance, but also reduces the power dissipation by tens of times and even up to hundred times. The bias circuit using dynamic resistors possesses a large applying foreground.