Switching regulator for implantable spinal cord stimulation

An improved power supply for an implantable device, the power supply comprising:

• a battery;
• control circuitry;
• a step-up switching regulator inductor with an input connected to the battery and an output connected to a node Vout;
• a first switch connected between the node Vout and ground, wherein the first switch is controlled by the control circuitry;
• a diode including a cathode side and an anode side, wherein the cathode side is connected to the node Vout, and the anode side is connected to a node Vh;
• a holding capacitor connected between the node Vh and ground;
• a second switch controlled by the control circuitry;
• a first lead;
• a fixed capacitor;
• a node Vcd;
• and
• a variable capacitor;
• wherein the second switch, the first lead, the fixed capacitor, the node Vcd, and the variable capacitor are electrically connected in series between Vh and ground;
• a third switch connected between the first lead and ground, wherein the third switch is controlled by the control circuitry;
• a fourth switch connected between the node Vcd and ground, wherein the fourth switch is controlled by the control circuitry;
• and
• a comparator having a first input connected to the node Vcd, a second input connected to a reference voltage Vref, and a comparator output provided to the control circuitry.

An improved switching regulator for an implantable device, wherein the switching regulator includes a duty cycle, the improvement comprising:

• a capacitor divider;
• a divided voltage between at least two capacitors of the capacitor divider;
• and
• two or more selectable duty cycles wherein the duty cycle is selectable from the two or more selectable duty cycles based on the divided voltage.

A method to efficiently operate a switching regulator, comprising:

• providing a voltage input to a switching inductor;
• providing a switched path from the switching inductor to ground;
• providing a second path from the switching inductor to a storage device;
• measuring the voltage level of the storage device using a capacitor divider;
• and
• controlling the switching regulator based on the voltage level.