초록 ▼

A battery monitoring means for an implantable tissue stimulator in which a signal related to the internal impedance of an implanted battery is telemetered to an external receiving means. More specifically, the implanted battery is loaded by a varible load until current flowing through the battery lo

A battery monitoring means for an implantable tissue stimulator in which a signal related to the internal impedance of an implanted battery is telemetered to an external receiving means. More specifically, the implanted battery is loaded by a varible load until current flowing through the battery lowers its output voltage until it has a predetermined relationship with respect to a reference voltage. The current flowing through the battery to achieve the predetermined relationship is directly related to the internal impedance of the battery. A voltage related to the value of this current is then telemetered to the external receiving means. In a specific embodiment, the variable load is a field effect transistor (FET) connected as a source follower. The impedance of the FET is controlled by the output of an operational amplifier having as inputs the reference voltage and a voltage related to the output voltage of the battery. The monitoring means operates in a closed-loop servo system manner until the two input voltages to the operational amplifier are equal. The other terminal of the battery is connected to a shunting resistor. Thus the voltage drop across the shunting resistor is related to the current drawn from, and the internal impedance of, the battery. This voltage is telemetered to the external receiving means.

대표청구항 ▼

In an implantable tissue stimulator powered by a battery having a positive terminal and a negative terminal, a battery monitoring means comprising: means for drawing a loading current from said battery that results in said battery output voltage having a predetermined relationship with respect to a

In an implantable tissue stimulator powered by a battery having a positive terminal and a negative terminal, a battery monitoring means comprising: means for drawing a loading current from said battery that results in said battery output voltage having a predetermined relationship with respect to a reference voltage; and means for generating a battery monitoring signal related to said loading current, said battery monitoring signal being related to the internal impedance of said battery.