Patent ID: 6762737
Filing Date: 2004-07-13
Classification: G09G

Abstract:
A tone display voltage generating device which includes reference voltage generating means for generating tone display voltages of different levels according to the number of bits of display data, and selecting means for selecting a voltage from the tone display voltages of different levels according to the display data so as to output the selected voltage to a tone display element,said tone display voltage generating device comprising: at least one buffer means with a lower output impedance with respect to the reference voltage generating means; switching means for switching a state of connection between an output stage of the reference voltage generating means, the buffer means, and an input stage of the selecting means, so as to select whether to utilize the buffer means or not when outputting the tone display voltages from the reference voltage generating means to the selecting means; and first control means for controlling switching operations of the switching means according to a state of tone display of the tone display element, said at least one buffer means, said switching means, and said first control means being provided between the output stage of the reference voltage generating means and the input stage of the selecting means.