Programmable voltage offset circuit

DETAILED DESCRIPTION What is claimed is: 1.
Apparatus for simultaneously producing several offset voltages, comprising: several programmable voltage offset circuits, each comprising: a digital latch memory; coupled to an input of the latch memory, a latch disable circuit for selectively releasing the contents of the latch memory; coupled to an output of the latch memory, a resistor array which outputs a voltage offset; and associated with the resistor array, a programmable nonvolatile memory; wherein desired offset voltages are initially produced by inputting voltage information into the latch memories and subsequently releasing said information to the resistor arrays via the latch disable circuits, while more permanent voltage offsets are subsequently programmed into the nonvolatile memories.
2.
The apparatus of claim 1 further comprising: voltage setting means coupled to each latch memory; and circuit select means coupled to each latch disable circuit for selectively determining which programmable voltage offset circuit will have the contents of its latch memory forwarded to its resistor array.
3.
The apparatus of claim 2 wherein the voltage setting means outputs a binary code to each latch memory, and the circuit select means outputs a binary code to each latch disable circuit.
4.
The apparatus of claim 1 wherein each resistor array comprises several resistors whose values form a binary progression; and each resistor in the array is driven by an inverting buffer amplifier.
5.
The apparatus of claim 1 wherein the several offset voltages are fed to a CCD; all the components recited in claim 1 are fabricated using CMOS technology; and the CCD and all the components recited in claim 1 reside on the same semiconductor chip.
6.
The apparatus of claim 1 further comprising: coupled to each nonvolatile memory: a conductor conveying one bit from the associated latch memory and an avalanche voltage power supply; wherein applying an avalanche voltage to the nonvolatile memory selectively programs the nonvolatile memory, depending upon the status of the bit from the latch memory