Defibrillator
Several defibrillators, defibrillator architectures, defibrillator components and methods of operating defibrillators are described. In one aspect, a defibrillator (as for example an automated external defibrillator) that can be powered by a mobile communication device such as a smart cellular phone or a tablet computer is described. Utilizing a phone (or other mobile communication device) as the power supply for an external defibrillator allows the external defibrillator to be smaller and, in some circumstance, removes the need for a battery that stores sufficient energy for shock delivery—which would need to be checked and/or replaced on a regular basis. Additionally, when desired, certain control functionality, computation, data processing, and user instructions can be handled/presented by the mobile communications device thereby further simplifying the defibrillator design and improving the user experience. This architecture takes advantage of the nearly ubiquitous availability of smart phones, tablet computers and other mobile communication devices.
1. A defibrillation unit comprising:
a capacitor unit capable of temporarily storing and discharging sufficient energy to deliver a defibrillation shock to a patient;
a shock delivery circuit for discharging the capacitor unit to deliver the defibrillation shock; and
a flyback converter for charging the capacitor unit, the flyback converter including a transformer and a variable maximum transformer current control circuit that controls a current level at which current to a primary coil in the flyback converter is turned off such that different maximum primary coil current levels may be set during the charging of the capacitor unit, such that the maximum primary coil current level changes during the charging of the capacitor unit.
2. A defibrillation unit as recited in claim 1 further comprising a defibrillation unit controller configured to set and reset the maximum primary coil current level during the charging of the capacitor unit.
3. A defibrillation unit as recited in claim 2 wherein the defibrillation unit controller is configured to periodically adjust the maximum primary coil current level during charging of the capacitor unit based at least in part on a then present measured voltage of the capacitor unit.
4. A defibrillation unit as recited in claim 1 wherein:
the defibrillation unit is an automated external defibrillator suitable for delivering an external defibrillation shock; and
the flyback converter has an input voltage of no more than approximately 5 volts and an output configured to charge the capacitor unit to a voltage suitable for delivering the defibrillation shock.
5. A defibrillation unit as recited in claim 1 configured to be connected to a mobile communication device that serves as a power supply for the flyback converter to facilitate charging of the capacitor unit.
6. A defibrillation unit as recited in claim 5 further comprising a defibrillator controller that sets the maximum primary coil current level based at least in part on a current delivery capability of the connected mobile communication device.
7. A defibrillation unit as recited in claim 1 further comprising a defibrillator housing, wherein the defibrillator housing holds a communication device, the capacitor unit, the shock delivery circuit, a defibrillation unit controller and the flyback converter.
8. A defibrillation unit as recited in claim 1 further comprising:
a current sensor for sensing a current drawn from a power supply;
a transitory electrical energy store arranged to receive electrical energy from the power supply and to supply electrical energy to the flyback converter; and
wherein the variable maximum transformer current control circuit includes a switch and wherein when the switch is turned off electrical current from the power supply charges the transitory electrical energy store and when the switch is turned on electrical current flows to the voltage boosting circuitry from both the power supply and the transitory electrical energy store.
9. A defibrillation unit as recited in claim 8 wherein the transitory electrical energy store includes at least one of (a) an LC circuit, and (b) a plurality of capacitors arranged in parallel.
10. A defibrillation unit as recited in claim 1 wherein:
the defibrillation shock is an external defibrillation shock; and
the flyback converter is arranged to receive a power input having a current of three amps or less and a voltage of five volts or less and to boost a voltage of the input power suitably to charge the capacitor unit to a voltage suitable for delivery of the external defibrillation shock.
11. A defibrillation unit as recited in claim 10 wherein the flyback converter includes a plurality of stages arranged in series, each stage being configured to boost the voltage of the stage's input power.
12. A defibrillation unit as recited in claim 11 wherein the flyback converter stages include:
a first stage having an input voltage of no more than 5 volts and an output voltage of approximately 12 volts; and
a second stage having an input voltage of approximately 12 volts and being configured to charge the capacitor unit to a voltage suitable for delivering the defibrillation shock.
13. A defibrillation unit as recited in claim 10 further comprising a transitory energy store, that serves as a temporary store for electrical energy drawn from a power source during periodic current shut-off intervals of a primary coil of the flyback converter and as a supply of supplemental current to the primary coil during at least portions of periodic current draw intervals of the primary coil.
14. A defibrillation unit as recited in claim 1 wherein:
the defibrillation unit is an automated external defibrillator;
the capacitor unit is capable of temporarily storing and discharging sufficient energy to deliver an external defibrillation shock to a patient; and
the flyback converter unit is arranged to receive a power input having a current of three amps or less and a voltage of five volts or less and to boost a voltage of the input power suitably to charge the capacitor unit to a voltage suitable for delivery of the external defibrillation shock.
15. An automated external defibrillator comprising:
a capacitor unit capable of temporarily storing and discharging sufficient energy to deliver an external defibrillation shock to a patient;
a shock delivery circuit for discharging the capacitor unit to deliver the defibrillation shock; and
a flyback converter for charging the capacitor unit, the flyback converter including a transformer and a variable maximum transformer current control circuit that controls a current level at which current to a primary coil in the flyback converter is turned off such that different maximum primary coil current levels may be set during the charging of the capacitor unit, such that the maximum primary coil current level changes during the charging of the capacitor unit.
16. An automated external defibrillator as recited in claim 15 wherein the capacitor unit is configured to be charged to a voltage in the range of 1400 to 2000 volts and the defibrillation shock has an energy in the range of 120 to 200 joules.
17. An automated external defibrillator as recited in claim 15 further comprising a controller configured to set and reset the maximum primary coil current level during the charging of the capacitor unit based at least in part on a then present measured voltage of the capacitor unit.