HV623

The HV623 is a 32-channel driver IC for gray shade display use. It is designed to produce varying output voltages between 3 and 80 volts. This amplitude modulation at the output is facilitated by an external ramp voltage VR. See Theory of Operation for detailed explanation.

This device HV623 consists of a dual 16-bit shift registers, 32 data latches and comparators, and control logic to preform 128 levels of gray shading. There are 7 bits of data inputs. Data is shifted through the shift registers at both edges of the clock, resulting a data transfer rate of twice of the shift clock frequency. When the DIR pin is high, CSI/CSO is the input/output for the chip select pulse. When DIR is low, CSI/CSO is the output/input for the chip select pulse. The DIR = HIGH also allows the HV623 to shift data in the counterclockwise direction when viewed from the top of the package.

When the DIR pin of HV623 is low, data is shifted in the clockwise direction. The output circuitry allows the energy which is stored in the output capacitance to be returned to VPP through the body diode of the output transistor.