Patent ID: 8332168

Claim:
An instrument power controller ( 120 ) for adaptively providing an output voltage V O and an output current I O that together maintain a substantially constant electrical output power P O , the instrument power controller ( 120 ) comprising inputs ( 121 ) for receiving an input power P I , outputs ( 122 ) for providing the substantially constant output power P O to a variable impedance load L, and a communication path ( 126 ) for receiving a load voltage V L from the load L, with the instrument power controller ( 120 ) being characterized by: the instrument power controller ( 120 ) being configured to determine an input voltage V I and an input current I I determine an effective resistance R L , of the load L and set the output voltage V O and the output current I O based on the input voltage V I the input current I I , and the effective resistance R L , with the output voltage V O being substantially independent from the input voltage V I and with the output voltage V O and the output current I O being varied so as to maximize a load power P L being transferred to the variable impedance load L while maintaining the substantially constant electrical output power P O .