Techniques for charging a battery within an implantable component (implant) of an implantable medical device system. A multi-loop external charging device includes a plurality of coil/loop antennas that are each configured to emit a magnetic field that is received by an implantable coil of the implantable component. At least one characteristic (e.g., phases, amplitudes, etc.) of the emitted magnetic fields are varied relative to one another over time.

When it has been determined according to a voltage detected by a voltage detecting unit 31 that a voltage detection line 23 between a focused-on battery 21 and the voltage detecting unit 31 has been broken, operations of each of switches 22 are controlled to separate a battery module 2 that includes the voltage detection line 23 from a power supply apparatus 1. When it has been determined according to the voltage detected by the voltage detecting unit 31 that the focused-on battery 21 has been overcharged or overdischarged, power input to, or output from, every battery module 2 is limited.

An onboard charging system for charging from a power source may include an energy storage system. A connector may be configured to couple the onboard charging system with the power source. A charging circuit may be electrically connected between the connector and the energy storage system. A converter may be electrically connected in the charging circuit between the connector and the energy storage system. A rectifier may be electrically connected in the charging circuit between the connector and the converter. Output of an inductive receiver may be electrically connected with the charging circuit between the connector and the converter. The converter may control the delivery of voltage and current to the energy storage system from the power source and from the inductive receiver.

An adaptive constant current-constant voltage (CC-CV) transition circuit comprises an amplifier, a series-pass device with current sense, a feedback network and a constant current controller to provide a stable and smooth transition between a constant voltage mode and a constant current mode, and vice versa. A voltage regulator loop comprises an amplifier, an optional buffer, a series-pass device with current sense and a feedback network which provides a feedback voltage to the amplifier. A current regulation loop comprises the amplifier, the optional buffer, the series-pass device, the feedback network and a constant current controller comprising a trans-impedence amplifier and a transconductance comparator which generate a current signal to a pseudo-constant bias (PCB) and a voltage signal to the adaptive compensation network (ACN) of the amplifier.

Circuitry useable to protect and reliably charge a rechargeable battery, even from a zero-volt state, is disclosed, and is particularly useful when employed in an implantable medical device. The circuit includes two charging paths, a first path for trickle charging the battery at a relatively low current when the battery voltage is below a threshold, and a second path for charging the battery at relatively higher currents that the battery voltage is above a certain threshold. A passive diode is used in the first trickle-charging path which allows trickle charging even when the battery voltage is too low for reliable gating, while a gateable switch (preferably a PMOS transistor) is used in the second higher-current charging path when the voltage is higher and the switch can therefore be gated more reliably. A second diode between the two paths ensures no leakage to the substrate through the gateable switch during trickle charging. The load couples to the battery through the switch, and preferably through a second switch specifically used for decoupling the load.