Cascaded step-up converter and charge pump for efficient compliance voltage generation in an implantable stimulator device
First Claim
1. A method for boosting a battery voltage to a compliance voltage in an implantable medical device, comprising:
- boosting a battery voltage to an intermediate voltage using at least a first boosting stage;
if a compliance voltage is higher than a threshold voltage, boosting the intermediate voltage to the compliance voltage using at least a second boosting stage, else using the intermediate voltage as the compliance voltage; and
using the compliance voltage to drive a current through an electrode of the implantable medical device for stimulating a patient'"'"'s tissue.
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Accused Products
Abstract
Disclosed herein are circuits and methods for generating a compliance voltage from a battery voltage in an implantable stimulator device. In one embodiment, the battery voltage is boosted to form the compliance voltage for driving the current sources (DACs) that provide therapeutic current to the electrodes on the device. Such improved boosting circuitry is preferably cascaded and comprises two stages. The first stage is preferably a step-up converter, which is used to generate an intermediate voltage from the battery voltage. The second stage is preferably a charge pump, which is used to generate the compliance voltage from the intermediate voltage. By splitting the boosting into stages, power efficiency during generation of high voltages is improved compared to the use of step-up converters and resolution in setting the compliance voltage is improved compared to the use of charge pumps alone. Moreover, depending on the compliance voltage to be produced by the boosting circuitry, the various stages can be selectively activated.
107 Citations
29 Claims
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1. A method for boosting a battery voltage to a compliance voltage in an implantable medical device, comprising:
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boosting a battery voltage to an intermediate voltage using at least a first boosting stage; if a compliance voltage is higher than a threshold voltage, boosting the intermediate voltage to the compliance voltage using at least a second boosting stage, else using the intermediate voltage as the compliance voltage; and using the compliance voltage to drive a current through an electrode of the implantable medical device for stimulating a patient'"'"'s tissue. - View Dependent Claims (2, 3, 4)
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5. A method for boosting a battery voltage to a compliance voltage in an implantable medical device, the device comprising a battery voltage coupled to at least a first boosting stage for producing a first voltage, and the first voltage coupled to at least a second boosting stage for producing a compliance voltage, comprising:
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using the compliance voltage to drive a current through an electrode of the implantable medical device for stimulating a patient'"'"'s tissue; assessing the magnitude of the compliance voltage; depending on the magnitude of the compliance voltage, generating control signals; and selectively activating none, some, or all of the boosting stages in accordance with the control signals, wherein failure to activate a boosting stage comprises bypassing that boosting stage. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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13. Circuitry for an implantable medical device, comprising:
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a battery having a battery voltage; a step-up converter, wherein the step-up converter receives the battery voltage at its input and is selectable to produce an intermediate voltage higher than the battery voltage at its output; a charge pump, wherein the charge pump receives the intermediate voltage at its input and is selectable to produce a compliance voltage higher than the intermediate voltage at its output; control logic for selectively activating the step-up converter and for selectively activating the charge pump in accordance with a magnitude of the compliance voltage; and a current source powered by the compliance voltage, configured to provide a predetermined current through an electrode of the implantable medical device for stimulating a patient'"'"'s tissue. - View Dependent Claims (14, 15)
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16. Circuitry for an implantable medical device, comprising:
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a battery having a battery voltage; a first boosting stage, wherein first boosting stage receives the battery voltage at its input and is configured to produce a first output voltage higher than the battery voltage; a first multiplexer for selecting either the first output voltage or the battery voltage as an intermediate voltage; a second boosting stage, wherein the second boosting stage receives the intermediate voltage at its input and is configured to produce a second output voltage higher than the intermediate voltage; and a second multiplexer for selecting either the second output voltage or the intermediate voltage as a compliance voltage, wherein the compliance voltage provides the power for providing a current through an electrode of the implantable medical device for stimulating a patient'"'"'s tissue. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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23. Circuitry for an implantable medical device, comprising:
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a battery having a battery voltage; a first boosting stage, wherein first boosting stage receives the battery voltage at its input and is configured to produce an intermediate voltage; a second boosting stage, wherein the second boosting stage receives the intermediate voltage at its input and is configured to produce an output voltage higher than the intermediate voltage; and a multiplexer for selecting in accordance with a control signal either the output voltage or the intermediate voltage as an actual compliance voltage, wherein the actual compliance voltage provides the power for providing a current through an electrode of the implantable medical device for stimulating a patient'"'"'s tissue. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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Specification