  A low-power, compact device for performing measurements in electrical systems
with isolated voltage domains is proposed. Isolated measurements are required
in numerous applications. For instance, a measurement of the bus voltage for a
system with a high supply voltage and lower isolated local voltage level may be
needed for system health monitoring and control. Such a requirement may
necessitate the use of isolation amplifiers to provide voltage telemetry for
the local system. Isolation amplifiers require dual galvanically isolated
supplies and use magnetic, capacitive, or optical barriers between primary and
secondary sides. Producing this supplemental voltage requires an extra voltage
converter, which consumes power and generates electromagnetic interference
which must, in turn, be filtered. Complex designs incorporating feedback are
needed to achieve linear response. The proposed Analog Isolated Multilevel
Quantizer (AIMQ) addresses these issues by monitoring the primary-side signal
and communicating the results to the secondary side using a novel scheme
involving Zener diodes, optocouplers, transistors, one-hot coding, and discrete
outputs. The result is a low power isolated transducer that can in principle be
extended to an arbitrary bit depth.
