Average current mode controlled energy storage in a defibrillator
View Patent ↗Techniques are described for charging an energy storage device, such as the high-voltage energy storage capacitors of an external defibrillation device, using an average current mode control technique. By controlling the average current in a transformer, energy may be stored rapidly and at controlled energy levels.
1. A method for charging an energy storage device associated with a defibrillator, the method comprising:
applying current to a primary coil in a flyback transformer;
sensing an average current through the flyback transformer;
controlling the applied current to cause the average current to follow a reference current; and
transferring energy from the flyback transformer to the energy storage device.
2. The method of claim 1 , wherein controlling the applied current to cause the average current to follow a reference current comprises:
determining the difference between the average current and a reference current; and
controlling the applied current as a function of the difference.
3. The method of claim 2 , wherein controlling the applied current to cause the average current to follow a reference current further comprises:
generating an error signal as a function of the difference;
comparing the error signal to a time-varying clock signal;
generating a modulation signal as a function of the comparison; and
controlling the applied current with the modulation signal.
4. The method of claim 1 , wherein transferring energy to the energy storage device comprises charging a capacitor.
5. The method of claim 4 , further comprising adjusting the reference current as a function of the voltage across the capacitor.
6. The method of claim 1 , further comprising supplying the applied current from a voltage source.
7. The method of claim 6 , further comprising adjusting the reference current as a function of the voltage across the voltage source.
8. The method of claim 1 , wherein sensing an average current through a flyback transformer comprises:
sensing the current through the primary coil of the transformer; and
sensing the current through a secondary coil of the transformer.
9. The method of claim 8 , wherein sensing an average current through a flyback transformer further comprises summing the current through the primary coil and the current through the secondary coil.