LINEAR, POLYNOMIAL AND EXPONENTIAL RAMP GENERATORS WITH AUTOMATIC SLOPE ADJUSTMENT

A novel method for an automatic slope adjustment of ramp generators is presented. The method has been verified by functional chip implementa tions of both a linear and an exponential ramp generator in a 2 mum st andard CMOS process. Applying start and stop voltages to the ramp gene rator, the ramp will automatically adjust itself, and the time for a c omplete ramp is set by the pulse length of a clock signal. Such a ramp generator needs no trimming, and is insensitive to component values a nd ratios. Ramp forms that are functions of a linear ramp are obtainab le, such as linear, exponential, and polynomial increasing ramp shapes .