The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 25, 1997
Filed:
Jun. 07, 1995
Xintao Wang, Lake Jackson, TX (US);
Mohammed Zafar Munshi, Missouri City, TX (US);
Sulzer Intermedics Inc., Angleton, TX (US);
Abstract
An improved transcutaneous energy transmission device is disclosed for charging rechargeable batteries in an implanted medical device. A current with a sinusoidal waveform is applied to a resonant circuit comprising a primary coil and a capacitor. Current is induced in a secondary coil attached to the implanted medical device. Two solid state switches are used to generate the sinusoidal waveform by alternately switching on and off input voltage to the resonant circuit. The sinusoidal waveform reduces eddy current effects in the implanted device which detrimentally increases the temperature of the implanted device. The present invention charges the batteries using a charging protocol that reduces charging current as the charge level in the battery increases. The controller preferably is constructed as a pulse width modulation device with a variable duty cycle to control the current level applied to the primary coil. An alignment indicator also is provided to insure proper alignment between the energy transmission device and the implanted medical device.