Transformer assembly for implantable cardiac stimulation device

Abstract

The transformer assembly is coupled between a power supply and a pulse delivery circuit of the implantable cardiac stimulation device for charging a pair of defibrillation capacitors for delivering defibrillation pulses. The power transformer assembly is formed from a printed circuit board (PCB) having a set of transformer coil turns embedded therein and a transformer core mounted adjacent to the windings of the PCB. By embedding the coil of the transformer within the PCB, the transformer may be more easily integrated with other components of the stimulation device so that the overall size of the stimulation device may be reduced. Moreover, the use of a PCB helps avoid reliability problems that might otherwise occur in the fabrication, assembly and operation of the device. In one specific configuration described herein, the transformer assembly includes a primary and two secondary transformers. The primary transformer is used as a flyback transformer for charging the pair of defibrillation capacitors. The two secondary transformers are used to provide voltage for selectively switching on a set of transistors formed in an H-bridge configuration so as to apply charge stored in the capacitors in biphasic pulse waveform to the heart. The coils of the primary and secondary transformers are all embedded within a single PCB. In another configuration, only the coil of the primary transformer is embedded within the PCB. The coils of the two secondary transformers are affixed to the surface of the PCB.