Switched capacitor defibrillation circuit

Abstract

A defibrillator circuit for generating a rectangular waveform across a patient from capacitively stored energy and employing a plurality of capacitors initially chargeable to a common voltage and thereafter sequentially switchable into parallel relation with one another so as to raise the voltage supplied to an H-bridge circuit from a point of decay back to said common voltage.

1 . A device for providing electrical cardiac treatment, the device comprising: 
 first capacitor means for storing and discharging electrical energy;    second capacitor means for storing and discharging electrical energy; and    a first switch coupled to the first capacitor means and second capacitor means such that:    when the first switch is in a first state, the second capacitor means is isolated from the first capacitor means; and    when the first switch is in a second state, the second capacitor means is connected in parallel to the first capacitor means.    
   
   
       2 . The device of  claim 1 , further comprising an H-bridge output circuit for delivering energy from the capacitor means to a receiver for receiving the proximal end of a lead electrode assembly.  
   
   
       3 . The device of  claim 2 , further comprising a control circuit coupled to the switch and the H-bridge, the control circuit adapted to provide control signals causing the H-bridge to send a biphasic waveform to the lead, the control circuit further adapted to cause the switch to be: 
 in the first state for a first portion of the first phase of the biphasic waveform; and    in the second state for a second portion of the first phase of the biphasic waveform.    
   
   
       4 . The device of  claim 3 , wherein the control circuit is also adapted to cause the switch to be in the second state during the second phase of the biphasic waveform.  
   
   
       5 . The device of  claim 1 , wherein the capacitor means are housed in a canister and the device is adapted to provide the electric signal between an electrode disposed on the canister and a receiver for receiving the proximal end of a lead electrode assembly.  
   
   
       6 . The device of  claim 1 , wherein the capacitor means are housed in a canister and the device is adapted to provide the electric signal between two electrodes disposed on a lead electrode assembly secured to the canister.  
   
   
       7 . A device for providing electrical cardiac treatment, the device comprising: 
 a plurality of separate energy storage devices each characterized by a degrading discharge curve;    at least one switch coupled to the plurality of energy storage devices such that:    when a switch is in a first state it causes a first energy storage device to be isolated from a second energy storage device; and    when the switch is in a second state it causes the first energy storage device to be connected in parallel to the second energy storage device; and    a control circuit coupled to the at least one switch and adapted to enable the first energy storage device to be sequentially coupled in parallel to additional energy storage devices.    
   
   
       8 . The device of  claim 7 , wherein the at least one energy storage device includes at least one capacitor.  
   
   
       9 . The device of  claim 7 , further comprising an H-bridge output circuit for delivering energy from the at least one energy storage device to a receiver for receiving the proximal end of a lead electrode assembly.  
   
   
       10 . The device of  claim 9 , wherein the control circuit is coupled to the H-bridge and is adapted to provide control signals causing the H-bridge to send a biphasic waveform to receiver for the lead electrode assembly.  
   
   
       11 . The device of  claim 10 , wherein the control circuit is also adapted to cause the at least one switch to sequentially place each of the plurality of energy storage devices in parallel during the second phase of the biphasic waveform.  
   
   
       12 . The device of  claim 7 , wherein the at least one energy storage device is housed in a canister and the electric signal is provided between the canister and a receiver for receiving the proximal end of a lead electrode assembly.  
   
   
       13 . The device of  claim 7 , wherein the device is adapted to provide the electric signal between two electrodes disposed on a lead electrode assembly.  
   
   
       14 . A device for providing electrical cardiac treatment, the device comprising: 
 a first capacitor;    means for selectively coupling the first capacitor to a lead electrode assembly;    a second capacitor; and    a first switch coupled to the first and second capacitors such that, when the means for selectively coupling the first capacitor to the lead is enabled to couple the first capacitor to the lead:    when the switch is in a first state, the second capacitor is isolated from the first capacitor; and    when the switch is in a second state, the second capacitor is connected in parallel to the first capacitor.    
   
   
       15 . The device of  claim 14 , wherein the means for selectively coupling includes an H-bridge circuit.  
   
   
       16 . The device of  claim 14 , further comprising a control circuit coupled to the switch and the means for selectively coupling, the control circuit adapted to provide control signals causing the means for selectively coupling to provide a biphasic waveform to the lead, the control circuit further adapted to cause the switch to be: 
 in the first state for a first portion of the first phase of the biphasic waveform; and    in the second state for a second portion of the first phase of the biphasic waveform.    
   
   
       17 . The device of  claim 16 , wherein the control circuit is also adapted to cause the switch to be in the second state during the second phase of the biphasic waveform.  
   
   
       18 . The device of  claim 14 , further comprising a canister.  
   
   
       19 . The device of  claim 18 , wherein the capacitors are housed in the canister and the device is adapted to selectively provide an electric stimulus between the lead electrode assembly and an electrode disposed on the canister.  
   
   
       20 . The device of  claim 18 , wherein the device is adapted to provide the electric signal between two electrodes disposed on the lead electrode assembly.