Current sensing multiple output current stimulators

摘要

A multiple output current stimulator circuit with fast turn on time is described. At least one pair of input side and output side transistors is arranged in a current mirror connected to a supply transistor by cascode coupling. The output side transistor supplies stimulation current to an electrode in contact with tissue. An operational amplifier connected to a reference voltage and to the output side transistor drives the supply transistor to maintain the voltage at the output side transistor equal to the reference voltage. The at least one pair of transistors includes multiple pairs of transistors whose output side transistors drive respective electrodes with stimulation currents. The stimulator determines the initiation and duration of stimulation current pulses supplied to each electrode. At circuit activation, large currents are generated which discharge capacitances in the output side transistors causing rapid output side transistor turn on.

主权项

1. A multiple output current stimulator circuit comprising:
a reference voltage source to provide a reference voltage; a plurality of input side transistors; a plurality of output side transistors current mirror coupled to respective ones of the input side transistors, the output side transistors coupled together to provide a common sensing voltage, each one of the output side transistors having a current output terminal for providing a respective output current; a supply transistor switchably coupled in cascode arrangement between each input side transistor and a predetermined voltage port; a differential amplifier comprising: a first input coupled to the reference voltage; a second input coupled to the common sensing voltage; and an output arranged to drive the supply transistor as a function of the difference between the reference voltage and the common sensing voltage; and a switching control circuit configured to selectively activate each one of the input side transistors so as to cause the corresponding current mirrored output side transistor to provide a respective output current in accordance with the corresponding input side transistor current.