Systems and methods for reducing power consumption in an implantable medical device

1. A medical device for providing an electrical stimulation therapy for a patient, the medical device comprising:

telemetry circuitry configured to receive programming instructions via telecommunications conducted with an electronic programmer;

stimulation circuitry configured to provide, in response to the received programming instructions, a plurality of electrical pulses to be delivered to the patient as a part, of the electrical stimulation therapy, wherein the stimulation circuitry contains a microcontroller configured to generate the electrical pulses, wherein each electrical pulse includes a primary phase, an interphase after the primary phase, and a passive recovery phase after the primary phase, and wherein consecutive electrical pulses are separated by a standby period, the microcontroller being further configured to:

operate in an active mode during at least one of: the primary phase and the interphase;

operate in a power-conservation mode during the passive recovery phase and during a substantial majority of the standby period, the microcontroller consuming substantially less power when operating in the power-conservation mode than in the active mode; and

power supply circuitry configured to provide electrical power to the telemetry circuitry and the stimulation circuitry.

2. The medical device of claim 1 , wherein the power-conservation mode is one of a plurality of available power-conservation modes in which the microcontroller can be operated.

3. The medical device of claim 1 , wherein:

the microcontroller contains a microcontroller core and a direct memory access (DMA) unit that is separate from the microcontroller core and consumes substantially less power than the microcontroller core;

the microcontroller core is turned on when the microcontroller operates in the active mode and is turned off when the microcontroller operates in the power-conservation mode; and

the DMA unit remains turned on when the microcontroller operates in the power-conservation mode.

4. The medical device of claim 3 , wherein:

the microcontroller contains a system clock that is running at a first frequency;

the stimulation circuitry further comprises an oscillator that is external to the microcontroller, the oscillator running at a second frequency that is substantially lower than the first frequency;

the microcontroller is driven by the system clock when operating in the active mode; and

the DMA unit is driven by the oscillator when the microcontroller operates in the power-conservation mode.

5. The medical device of claim 4 , wherein when operating in the power-conservation mode, the microcontroller is configured to be woken up by an interrupt signal immediately before a subsequent electrical pulse needs to be generated, such that the microcontroller operates in the active mode after being woken up, wherein the interrupt signal is generated by a timer clocked by the oscillator.

6. The medical device of claim 1 , wherein:

the power supply circuitry comprises:

an inductive charging mechanism configured to receive an inductive energy;

a charging circuit configured to convert the inductive energy into a direct current (DC) signal;

a battery charged by the charging circuit to provide a first DC voltage;

a voltage down-converter that down-converts the first DC voltage to a second DC voltage smaller than the first DC voltage, the second DC voltage being a voltage supply for at least the microcontroller; and

a voltage up-converter that up-converts the first DC voltage to a third DC voltage that is greater than the first DC voltage, the third voltage being a voltage supply for the stimulation circuitry; and

the stimulation circuitry further comprises:

a stimulation driver that amplifies the electrical pulses generated by the microcontroller; and

an array of multiplexers coupled between the stimulation driver and an external lead that includes a plurality of electrodes configured to deliver the electrical stimulation therapy to the patient.

7. The medical device of claim 6 , further comprising a switch coupled between the voltage up-converter and the stimulation driver, wherein the switch is configured to disconnect the stimulation driver from the voltage up-converter during the standby period in between consecutive electrical pulses.

8. The medical device of claim 6 , wherein, for each pulse:

the voltage up-converter and the array of multiplexers are enabled before the primary phase and disabled during the interphase.

9. A medical system for providing an electrical stimulation therapy for a patient, the medical system comprising:

an electronic programmer configured to generate stimulation programming instructions for an implantable pulse generator (IPG); and

the IPG, wherein the IPG comprises:

telemetry circuitry configured to receive the programming instructions via telecommunications conducted with the electronic programmer;

stimulation circuitry configured to provide, in response to the received programming instructions, a plurality of electrical pulses to be delivered to the patient as a part of the electrical stimulation therapy, wherein the stimulation circuitry contains a microcontroller configured to generate the electrical pulses, wherein each electrical pulse includes a primary phase, an interphase after the primary phase, and a passive recovery phase after the primary phase, and wherein consecutive electrical pulses are separated by a standby period, the microcontroller being further configured to:

operate in an active mode during at least one of: the primary phase and the interphase;

operate in a power-conservation mode during the passive recovery phase and during a substantial majority of the standby period, the microcontroller consuming substantially less power when operating in the power-conservation mode than in the active mode; and

power supply circuitry configured to provide electrical power to the telemetry circuitry and the stimulation circuitry.

10. The medical system of claim 9 , further comprising: an implantable lead configured to be attached to the IPG, wherein the implantable lead contains a plurality of electrodes configured to deliver the electrical pulses generated by the IPG to a peripheral nerve of the patient.

11. The medical system of claim 9 , wherein:

the power supply circuitry comprises:

an inductive charging mechanism configured to receive an inductive energy;

a charging circuit configured to convert the inductive energy into a direct current (DC) signal;

a battery charged by the charging circuit to provide a first DC voltage;

a voltage down-converter that down-converts the first DC voltage to a second DC voltage smaller than the first DC voltage, the second DC voltage being a voltage supply for at least the microcontroller; and

a voltage up-converter that up-converts the first DC voltage to a third DC voltage that is greater than the first DC voltage, the third voltage being a voltage supply for the stimulation circuitry; and

the stimulation circuitry further comprises:

a stimulation driver that amplifies the electrical pulses generated by the microcontroller; and

an array of multiplexers coupled between the stimulation driver and an external lead that includes a plurality of electrodes configured to deliver the electrical stimulation therapy to the patient.

12. The medical system of claim 11 , further comprising a switch coupled between the voltage up-converter and the stimulation driver, wherein the switch is configured to disconnect the stimulation driver from the voltage up-converter during the standby period in between consecutive electrical pulses.

13. The medical system of claim 11 , wherein, for each pulse:

the voltage up-converter and the array of multiplexers are enabled before the primary phase and disabled during the interphase, and the microcontroller is configured to operate in the power-conservation mode during the passive recovery phase.

14. A method of providing an electrical stimulation therapy for a patient, the method comprising:

receiving programming instructions from an electronic programmer; and

generating, via a microcontroller and in response to the received programming instructions, a plurality of electrical pulses to be delivered to the patient as a part of the electrical stimulation therapy, wherein each electrical pulse includes a primary phase, an interphase after the primary phase, and a passive recovery phase after the primary phase, wherein consecutive electrical pulses are separated by a standby period, and wherein the generating of the electrical pulses comprises:

operating the microcontroller in an active mode during at least one of: the primary phase and the interphase;

operating the microcontroller in a power-conservation mode during the passive recovery phase and during a substantial majority of the standby period; and

wherein the microcontroller consumes substantially less power when operating in the power-conservation mode than in the active mode.

15. The method of claim 14 , wherein:

the microcontroller contains a microcontroller core and a direct memory access (DMA) unit that is separate from the microcontroller core and consumes substantially less power than the microcontroller core;

the operating of the microcontroller comprises:

turning on the microcontroller core in the active mode;

turning off the microcontroller core in the power-conservation mode; and

keeping the DMA unit turned on in the power-conservation mode.

16. The method of claim 15 , wherein:

the microcontroller contains a system clock that is running at a first frequency;

the microcontroller is a part of a stimulation circuitry that further comprises an oscillator that is external to the microcontroller, the oscillator running at a second frequency that is substantially lower than the first frequency;

the operating of the microcontroller comprises driving the microcontroller with the system clock in the active mode; and

driving the DMA unit with the oscillator in the power-conservation mode.

17. The method of claim 16 , further comprising:

generating an interrupt signal with a timer unit that is clocked by the oscillator; and

waking up the microcontroller from the power-conservation mode via the interrupt signal immediately before a subsequent electrical pulse needs to be generated.

18. The method of claim 14 , further comprising:

receiving an inductive energy;

converting the inductive energy into a direct current (DC) signal;

charging a battery with the DC signal, thereby providing a first DC voltage via the battery;

down-converting the first DC voltage to a second DC voltage smaller than the first DC voltage;

providing the second DC voltage as a voltage supply for at least the microcontroller;

up-converting the first DC voltage to a third DC voltage greater than the first DC voltage;

providing the third DC voltage as a voltage supply for a stimulation driver and an array of multiplexers coupled to the stimulation driver;

amplifying, via the stimulation driver, the electrical pulses generated by the microcontroller; and

delivering the amplified electrical pulses to the patient at least in part by configuring the array of multiplexers.

19. The method of claim 18 , further comprising: disconnecting the stimulation driver from the voltage up-converter during the standby period between consecutive electrical pulses.

20. The method of claim 18 , further comprising, for each pulse:

enabling the voltage up-converter and the array of multiplexers before the primary phase;

disabling the voltage up-converter and the array of multiplexers during the interphase; and

operating the microcontroller in the power-conservation mode during the passive recovery phase.