IMPLANTABLE DRUG DELIVERY DEVICE WITH PROGRAMMABLE RATE CAPACITOR CHARGE CONTROL

摘要

An implantable drug delivery device includes a pump motor that is asserted by drive currents from a storage capacitor. A programmable rate charge control delivers charging current from a battery to the storage capacitor based upon a programmable charge rate value, a minimum battery voltage value, sensed charging current, and sensed battery voltage. When sensed battery voltage droops to below a threshold value, the charge control reduces the charging rate value until other electrical loads within the drug device have been serviced and battery voltage is restored. The charge control also monitors capacitor voltage and provides a charge complete signal to a motor control, which then connects the pump motor to the storage capacitor to produce a pump stroke. Efficiency of charging is enhanced by controlling the charging at a programmable substantially constant rate.