Output stage with switchable constant current modes
First Claim
1. An output circuit for delivering a controllable output pulse to a patient, comprising:
- a pulse generating circuit for generating an output pulse;
control mode means, for controlling said pulse generating circuit to operate in a constant voltage mode during the generation of a first portion of an output pulse and in a constant current mode during the generation of a second portion of the output pulse; and
amplitude control means for controlling the amplitude of the output pulse as it is being delivered and means for delivering said output pulse to the tissue of a patient.
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Accused Products
Abstract
An output circuit is provided for delivering output pulses in either a constant voltage or constant current mode. The output circuit has a simple architecture built around a pair of area-ratioed transistors which operate in a linear range carrying a ratio of currents corresponding to the area ratio. The circuit is mode controlled by a switch network which connects to a constant current source, which constant current source controls the pulse amplitude, either current or voltage. As used in a pacemaker embodiment, the circuit is controllable to control the mode and/or amplitude of the pulse following a cyclical decision to deliver a pulse, and with an amplitude derived from pacemaker data and controllable during delivery of the pulse. The circuit has high speed control which enables amplitude modulation of the pulse, for transmitting encoded data to an external device adapted to receive the data.
66 Citations
27 Claims
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1. An output circuit for delivering a controllable output pulse to a patient, comprising:
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a pulse generating circuit for generating an output pulse; control mode means, for controlling said pulse generating circuit to operate in a constant voltage mode during the generation of a first portion of an output pulse and in a constant current mode during the generation of a second portion of the output pulse; and amplitude control means for controlling the amplitude of the output pulse as it is being delivered and means for delivering said output pulse to the tissue of a patient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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- 9. A medical stimulator having an output circuit for generating stimulus pulses, said output circuit comprising mode means for controlling the delivery of each said stimulus pulses in a constant voltage mode during the generation of a first portion of an output pulse and in a constant current mode during the generation of a second portion of the output pulse, and amplitude control means for controlling the amplitude of each delivered stimulus pulse during the generation and delivery of the pulse and means for delivering the stimulus pulses to a heart of a patient.
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16. A controllable output circuit operable for delivering an output pulse to a patient in either a constant voltage or constant current mode, said circuit comprising:
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a pulse generating circuit having two current-ratioed transistors, each resistor alternatively switchably connected to an input of an operational amplifier mode means for controlling said pulse generating circuit to operate in a selected one of said constant voltage mode during the generation of a first portion of an output pulse and in a constant current mode during the generation of a second portion of the output pulse, the mode means coupled to the pulse generator circuit; amplitude means for controlling the constant voltage or constant current amplitude of a pulse delivered by said pulse generating circuit, the amplitude means coupled to the pulse generator circuit. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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24. Medical apparatus for cyclically generating stimulus pulses for delivery to a patient, comprising:
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a pulse output circuit to generate an output pulse; and mode means operable each cycle for controlling said output circuit to operate in a constant voltage mode for a first portion of a generated output pulse and in a constant current mode for a second portion of the generated output pulse and means for delivering said generated output pulse to a heart of a patient. - View Dependent Claims (25, 26, 27)
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Specification