1. Field of the Invention
This invention relates to method and apparatus for injecting charge in a circuit.
2. Description of the Related Art
A number of applications, notably in-pixel analog-to-digital conversion based on sigma-delta techniques, require a circuit that can precisely inject a very small amount of charge onto a node. The injected charge must be low noise, repeatable, controllable, reproducible from cell to cell, and insensitive to the node voltage. Furthermore, the circuit must be compact and low power. The present invention satisfies this need.