US 6,856,838 B2 · Voltage converter for implantable microstimulator using RF-powering coil

Abstract

A combination, voltage converter circuit for use within an implantable device, such as a microstimulator, uses a coil, instead of capacitors, to provide a voltage step up and step down conversion functions. The output voltage is controlled, or adjusted, through duty-cycle modulation. In accordance with one aspect of the invention, applicable to implantable devices having an existing RF coil through which primary or charging power is provided, the existing RF coil is used in a time-multiplexing scheme to provide both the receipt of the RF signal and the voltage conversion function. This minimizes the number of components needed within the device, and thus allows the device to be packaged in a smaller housing or frees up additional space within an existing housing for other circuit components. In accordance with another aspect of the invention, the voltage up/down converter circuit is controlled by a pulse width modulation (PWM) low power control circuit. Such operation allows high efficiencies over a wide range of output voltages and current loads.

Claims13

Dependent claims

A combination voltage converter circuit for performing multiple operating functions, the combination circuit comprising:

an RF coil (L1′) having a first end (72′), a second end (85), and a tap point (85′);
a diode (D1) connected between the first end (72′) of the RF coil (L1′) and an output node (75′);
a first capacitor (C1) connected between the output node (75′) and ground potential (87);
a first transistor switch (M1′) connected between the second end (85) of the coil (L1′) and a primary power source (VS);
a second transistor switch (M2) connected between the tap point (85) and the primary power source (VS);
a second diode (D2) connected between the tap point (85) and ground potential (87);
a data amplifier (U1) having an input and an output;
a third diode (D3) connected between the first end (72′) of the RF coil (L1′) and the input of the data amplifier (U1);
a third transistor switch (M3) connected between the input of the data amplifier (U1) and ground potential (87);
a tuning capacitor (C3′) having a first side connected to the first end (72′) of the RF coil (L1′) and a second side connected to the tap point (85′) through a fourth transistor switch (M4);
and
a fifth transistor switch (M5) connected between the tap point (85′) and ground potential (87).

9 more elements

A combination voltage converter circuit for performing multiple operating functions, the combination circuit comprising:

a coil having a first end, a second end, and a tap point, wherein the tap point on the coil divides the coil into N1 turns between the tap point and the first end of the coil, and N2 turns between the tap point and the second end of the coil;
and
circuit means, including switches, for implementing operating modes and switching between operating modes of the combination circuit;
wherein the coil is coupled to the circuit means;
wherein the operating modes include four modes;
(i) an energy and data receive mode wherein energy is received inductively through the coil and, concurrently, data is received through the coil;
(ii) a voltage step up conversion mode wherein a voltage step up conversion occurs using the coil;
(iii) a voltage step down conversion mode wherein a voltage step down conversion occurs using the coil;
and (iv) a data transmit mode wherein data is transmitted through the coil;
wherein the switching means comprises first, second, third, fourth and fifth transistor switches, which switches are selectably turned on, turned off, or modulated in various switch combinations to configure the combination circuit to at least one of the four operating modes;
and
wherein the selection of the operating modes is implemented through a time multiplexing scheme.

9 more elements

Dependencies are inferred from the claim text.

Voltage converter for implantable microstimulator using RF-powering coil

Life of this patent

Voltage converter for implantable microstimulator using RF-powering coil

Life of this patent

Abstract

Claims13