ELECTRONIC DIMMER CONTROL FOR VACUUM FLUORESCENT DISPLAY DEVICES

摘要

Apparatus and method for setting the pulse width modulation duty cycle that drives a vacuum fluorescent display device in response to changes in the setting of a dimmer control rheostat by establishing a constant window of acceptable voltage references that are changed when the setting of the dimmer control rheostat is changed, and by sequentially stepping through a set of discrete voltages whenever the setting of the dimmer control rheostat is changed until one of the discrete voltages is found to lie within the window of reference voltages. A dimmer signal is sent to a display driver circuit that corresponds to the selected discrete voltage lying within the reference window and determines the duty cycle and consequent brightness level for the display device. .