Method and apparatus for converting a low dynamic range analog signal to a large dynamic range floating-point digital representation

An analog-to-digital conversion circuit for converting an analog signal to a cumulative digital representation having a dynamic range greater than an input dynamic range of the analog-to-digital conversion circuit, the circuit comprising:

• (a) a first signal generator for generating a first signal having a plurality of levels;
• (b) a comparator having a first input connected to receive the first signal and a second input connected to receive the analog signal;
• (c) a binary signal generator for generating a series of binary signals;
• and
• (d) a latch having a first input coupled to receive an output of the comparator, the latch also having a data input coupled to receive the binary signals, the output of the comparator controlling when the latch provides an output signal corresponding to the binary signals applied to the data input,
• wherein the analog signal is received from a photodetector after the photodetector is exposed to a scene for a total exposure time T;
• wherein the latch provides a first N-bit digital code representing the analog signal at a first sampling time T1>0, and
• wherein the latch provides at least a portion of subsequent N-bit digital codes representing the analog signal_sampled at subsequent sampling times T2>T1, T3>T2, . . . TM<TM−1, and TM<=T.