Current sensing in two-dimensional area sensors

A method performed at an analog front end of a two-dimensional current sensing system, the method comprising:

• converting a received current signal to a voltage signal by a low noise amplifier;
• directing a voltage signal to an in-phase (I) mixer;
• converting the voltage signal into an I current signal;
• generating by the I-mixer a differential current;
• outputting from the I mixer the differential current to an I multiplexer;
• generating a current stream, the current stream representative of the differential current from a starting time to an ending time, wherein the I multiplexer generates a current stream for each of a plurality of input differential currents;
• summing each current stream to form a summed differential current;
• integrating the summed differential current;
• and
• directing the summed differential current to an analog to digital converter.

A system comprising:

• a two dimensional array of sensor elements, each element comprising a first face and a second face,
• a first set of metal wires connected to the first face of each sensor element of the array of sensor elements;
• a second set of metal wires connected to the bottom face of each sensor element the array sensor elements, the first set of metal wires oriented substantially orthogonal to the second set of metal wires;
• a receiver circuit comprising a first set of inputs, each input of the first set of inputs connected to one of the first set of metal wires;
• the receive circuit comprising:
• a first number of low noise amplifier circuits (LNA), each LNA connected one of the first set of inputs, and each LNA connected on an output side to an input of a pair of mixer circuits, the receiver circuit comprising a number of mixer pairs equal to the first number of LNAs, each mixer pair driven by a clock and a quadrature version of the clock, the output of each mixer of the mixer pair are In-phase (I) and Quadrature-phase (Q) down-converted signals of the output of the LNA;
• a plurality of integrator circuits, each integrator circuit comprising an input from I-outputs of multiple mixer-pairs, each integrator configured to add signals coming from one or more I-outputs and is configured to integrate the resultant sum over a time-period;
• a number of integrators each with input from Q-outputs of multiple mixer-pairs, each integrator configured to add signals coming from one or more such Q-outputs and integrate the resultant sum over a time-period;
• and
• a plurality of analog to digital converters, the final integrated values in the integrators are digitized and transferred to digital signal processing for further processing.