Monolithic pacemaker utilizing I.sup.2 L circuitry

A pacemaker for generating and delivering pacing signals adapted for pacing a patient's heart, having an oscillator for generating timing signals for controlling the rate of delivery of said pacing signals, and having output circuit means connected to said oscillator for generating said pacing signals from said timing signals, and electrode connection means for connecting said pacing signals to said patient's heart, characterized by said oscillator comprising a current source for delivering a rate control current, a pair of multiple collector transistors in current mirror configuration, each of said transistors being connected to receive said rate current so as to control the current output from the collectors of each, a charging circuit having first and second charging paths, charge path means for alternately connecting a first set of collectors from said transistors to charge said charging circuit in said first path and for connecting a second set of collectors from said pair of transistors to charge said charging circuit in said second path so that said charging circuit charges alternately in one direction and then the other, and means for developing said timing signals as a function of said alternating charging.

A pacemaker adapted for delivering pacing signals to a human patient, having a stimulus circuit for generating pacing signals, an output circuit for delivering said pacing signals, a control circuit for controlling at least one parameter of said pacing signals, and means for receiving an external signal, characterized by said circuits comprising first and second groups of I.sup.2 L gates, said pacemaker further comprising an injector current circuit having a first injector rail connected to said first group to provide injector current to the I.sup.2 L gates of said first group and at least a second normally deenergized injector rail connected to said second group to provide injector current to the I.sup.2 L gates of said second group when it is energized, and means for energizing said second injector rail upon receipt of an external signal.

A pacemaker adapted for use in a human patient, having means for delivering pacing pulses, characterized by having means for controlling the rate of said pacing pulses, said rate controlling means comprising (a) a current source having a series combination of an I.sup.2 L gate and linear transistor and an injector current circuit means connected to said I.sup.2 L gate for controlling the current of said current source, and (b) means for utilizing said current source to control said pacing pulse rate.

A pacemaker adapted for use with a human patient, having a plurality of operating parameters, characterized by comprising a plurality of current sources, each having an I.sup.2 L gate with a feedback loop from output to input, and each having at least another output collector connected to a linear transistor, and means for controlling said parameters with respective different ones of said current sources.

A pacemaker having means for generating pacing pulses at its output, said pacemaker further having means for receiving an externally generated programming signal, characterized by having means responsive to receipt of said programming signal for generating at said output a sole marker pulse of a predetermined form, said marker pulse being in addition to said pacing pulses.