Dual mode cardiac pacer power source

Claim 2

In a cardiac pacer, a redundant power supply operative to provide first and second states of voltage output and comprising: power output terminals; first and second electrical power sources; selectively actuable means having first and second states and providing serial connection of said first and second sources to said power output terminals in said first state; means for providing parallel redundant connection of said sources to said power output terminals when said selectively actuable means is in said second state.

Claim 3

The cardiac pacer redundant power supply of claim 1 further having means responsive to said second state for isolating one of said sources if that source is in a failed condition.

Claim 4

The cardiac pacer redundant power supply of claim 1 further including means for by-passing open circuits in failed sources thereby to provide an operative series connection in said first state despite open circuit failure of said first or second source.

Claim 5

A cardiac pacer having the redundant power supply of claim 1 and including: demand cardiac stimulation pulse providing means receiving power from said output terminals; and means responsive to said first state of said selectively actuable means for causing said pulse providing means to operate in a continuous mode.

Claim 6

A cardiac pacer having the redundant power supply of claim 1 and including: means receiving operating power from said output terminals for providing demand generation of artificial cardiac pulses with an interval between pulses and further having first means to reinitiate the interval between artificial pulses after each artificial pulse and seconD means to reinitiate the interval to the next artificial pulse in response to natural heartbeats; said first and second means including means operative to reinitiate substantially equal intervals whereby power supply conditions can be monitored in said first state in the demand mode of said providing means whenever an artificial pulse is generated.

Claim 7

A cardiac pacer having the redundant power supply of claim 1 and including: means receiving operating power from said output terminals for providing demand generation of cardiac pulses with pulse timing representative of voltage applied to said terminals; and externally actuable means for causing said pulse providing means to operate in a continuous mode.

Claim 8

A cardiac pacer having the redundant power supply of claim 1 and further including: means receiving operating power from said output terminals for generating cardiac pulses; and means responsive to said first state of said selectively actuable means for diminishing the energy supplied by pulses of said pulse generating means thereby to reduce the increase in power consumption from said power supply in an elevated voltage output condition resulting from said first state.

Claim 9

A cardiac pacer having the redundant power supply of claim 1 and including: pulse generating means receiving operating power from said output terminals and responsive in pulse timing to the voltage of said power supply; and means for regulating said pulse timing against load variations.

Claim 10

The cardiac pacer redundant power supply of claim 1 further including means for providing different combinations of power supply voltage outputs in said first and second states corresponding to predetermined normal and failed conditions of said first and second sources.

Claim 11

A redundant power supply for cardiac pacer electronics operative to provide first and second output characteristics and comprising: first and second electrical sources; current switching means selectively operative to open or close a circuit; first and second terminals for connecting said power supply to said pacer electronics; means for interconnecting said first and second sources and said switch to provide a series connection of said first and second sources to said terminals in response to said switching means being in a closed circuit state; first and second controllable semiconductor switches; means for providing a bias current to said first switch from at least one of said sources; means for providing a bias current to said second switch from at least one of said sources; means for connecting said first source to said terminals for supplying operating current to said pacer electronics through said first semiconductor switch in response to said switching means being in an open circuit condition; means operative in association with said first and second semiconductor switches to inhibit conduction thereof in response to said switching means being in said closed circuit condition.

Claim 12

A redundant power supply for cardiac pacer electronics operative to provide first and second output characteristics and comprising: first and second electrical sources; current switching means selectively operative to open or close a circuit; first and second terminals for connecting said power supply to said pacer electronics; means for interconnecting said first and second sources and said switch to provide a series connection of said first and second sources to said terminals in response to said switching means being in a closed circuit state; first and second controllable semiconductor switches; means for providing a bias current to said first switch from at least one of said sources; means for providing a bias current to said second switch from at least one of said sources; means for connecting said first source to said terminals for supplying operating current to said pacer electronics through said first semiconductor switch in response to said switching means being in an open circuit condition; means operative in association with said first and second semiconductor switches to inhibit conduction thereof in response to said switching means being in said closed circuit condition.

Claim 13

A redundant power supply for cardiac pacer electronics operative to provide first and second output characteristics and comprising: first and second sets of batteries; a selectively actuable switch for providing open and closed circuit conditions; first and second terminals for providing operating power; means for interconnecting said switch and said first and second sets of batteries to serially connect said batteries to said terminals in response to said switch being in said closed circuit condition; first and second transistors, each having an emitter-base junction and an emitter-collector junction; means for biasing the emitter-base junction of said first transistor with current from said first battery set; means for connecting opposite terminals of said first battery set respectively directly to said second terminal and to said first terminal through the emitter-collector circuit of said first transistor; means for biasing the emitter-base junction of said second transistor with current from said second battery set; means for connecting opposite terminals of said second battery set respectively directly to said first terminal and to said second terminal through the emitter-collector circuit of said second transistor; said first and second transistors thereby blocking emitter-collector conduction in response to said switch being in said closed circuit condition and enabling emitter-collector conduction in response to said switch being in an open condition and further in response to said first and second batteries being of substantially equivalent voltage output.

Claim 14

A redundant power supply for cardiac pacer electronics operative to provide first and second output characteristics and comprising: first and second sets of batteries; a selectively actuable switch for providing open and closed circuit conditions; first and second terminals for providing operating power; means for interconnecting said switch and said first and second sets of batteries to serially connect said batteries to said terminals in response to said switch being in said closed circuit condition; first and second transistors, each having an emitter-base junction and an emitter-collector junction; means for biasing the emitter-base junction of said first transistor with current from said first battery set; means for connecting opposite terminals of said first battery set respectively directly to said second terminal and to said first terminal through the emitter-collector circuit of said first transistor; means for biasing the emitter-base junction of said second transistor with current from said second battery set; means for connecting opposite terminals of said second battery set respectively directly to said first terminal and to said second terminal through the emitter-collector circuit of said second transistor; said first and second transistors thereby blocking emitter-collector conduction in response to said switch being in said closed circuit condition and enabling emitter-collector conduction in response to said switch being in an open condition and further in response to said first and second batteries being of substantially equivalent voltage output.

Claim 15

The cardiac pacer redundant power supply of claim 11 further including a diode connected across each battery in said battery sets to provide conduction by-passing a battery in the event of open circuit failure thereof and to provide a shunt for reverse polarization of a battery.

Claim 16

A cardiac pacer having the redundant power supply of claim 11 and further including: means receiving operating power from said terminals for generating an artificial heart stimulating pulse; and means for reducing the energy in said pulse in response to said switch being in said closed circuit condition.

Claim 17

A cardiac pacer having the redundant power source of claim 11 and further including: means receiving operating power from said terminals for generating artificial heart stimulating pulses with an interval between pulses and pulse width which varies in response to the voltage applied to said terminals of said pacer electronics; the timing of artificial pulses generated by said pulse generating means thereby providing an indication of the voltage supplied to said pacer electronics when said switch is in said open and closed conditions thereby to indicate the conditions of said first and second battery sets.

Claim 18

The cardiac pacer of claim 14 further including: means for providing demand operation of said generating means; and means actuable in said first state to provide an inhibition of said demand operation providing means thereby to cause said pulse generating means to provide continuously generated pulses at a rate reflecting the voltage supplied to the terminals of said pacer electronics.