Electrosurgical medical device with power modulation

Abstract

An electrosurgical ablation device provides pulse width modulated DC power to a heating segment in a catheter for use in providing treatment. In some embodiments the DC power to be modulated is sourced from an AC/DC power converter coupled to a source of AC power. In some embodiments the DC power to be modulated is sourced from a battery. In some embodiments the device switchably selects for modulation DC power sourced from either the AC/DC power converter or the battery, for example based on availability of power from the AC/DC power converter.

What is claimed is: 
     
         1 . A direct current (DC) powered an electrosurgical ablation device, comprising:
 a catheter including a heating segment;   modulation circuitry configured to modulate DC power provided to the heating segment; and   at least one DC power source for providing the DC power to the modulation circuitry.   
     
     
         2 . The device of  claim 1 , wherein the modulation is pulse width modulation (PWM). 
     
     
         3 . The device of  claim 1 , wherein the modulation circuitry includes pulse width modulation (PWM) driver circuitry and a switch. 
     
     
         4 . The device of  claim 1 , wherein the at least one DC power source comprises two DC power sources. 
     
     
         5 . The device of  claim 4  wherein a first of the two DC power sources comprises an AC/DC power converter and a second of the two DC power sources comprises a battery. 
     
     
         6 . The device of  claim 5 , further comprising a switch to switchably provide power from either the AC/DC converter or the battery to the PWM circuitry for provision to the heating segment. 
     
     
         7 . The device of  claim 5 , wherein the AC/DC converter and the battery are coupled in parallel to the PWM circuitry. 
     
     
         8 . The device of  claim 5 , further comprising a DC/DC power converter coupled between the AC/DC power converter and the PWM circuitry. 
     
     
         9 . The device of  claim 1 , wherein the heating segment comprises a resistive coil. 
     
     
         10 . The device of  claim 9 , wherein the resistive coil is housed in a plastic cover. 
     
     
         11 . The device of  claim 2 , wherein a frequency of the PWM is in a range of 1 kHz to 50 kHz, inclusive. 
     
     
         12 . A method of operating an electrosurgical ablation device, comprising:
 providing direct current (DC) power;   modulating the DC power using pulse width modulation (PWM); and   applying the modulated DC power to a heating element in a catheter.   
     
     
         13 . The method of  claim 12 , wherein modulating the DC power using PWM comprises providing the DC power to a switch, and opening and closing the switch using a PWM driver signal. 
     
     
         14 . The method of  claim 13 , wherein a frequency of the PWM is in the range of 1 kHz to 50 kHz, inclusive. 
     
     
         15 . The method of  claim 12 , wherein providing DC power comprises selectably providing DC power from an AC/DC power converter or from a battery. 
     
     
         16 . The method of  claim 15 , wherein selection of provision of DC power from the AC/DC power converter or from the battery is based on availability of AC power to the AC/DC power converter. 
     
     
         17 . The method of  claim 16 , wherein selection of DC power from the AC/DC power converter or from the battery may be performed during application of power to the heating element. 
     
     
         18 . An electrosurgical ablation device, comprising:
 an AC/DC power converter;   a battery;   a catheter including a resistive coil; and   power switching circuitry for switching provision of power to the resistive coil from power sourced from the AC/DC power converter to power sourced from the battery based on a cessation of availability of DC power from the AC/DC power converter.   
     
     
         19 . The device of  claim 18 , further comprising pulse width modulation (PWM) circuitry for modulating power provided to the resistive coil.