Optically controlled MEMS switch and method of using the same
View Patent ↗The present embodiments are directed towards the optical control of switching an electrical assembly. For example, in an embodiment, an electrical package is provided. The electrical package generally includes a micro electromechanical systems (MEMS) device configured to interface with an electrical assembly, the MEMS device being operable to vary the electrical assembly between a first electrical state and a second electrical state, a MEMS device driver in communication with the MEMS device and being operable to produce high voltage switching logic from an electrical signal, and an optical detector in communication with the MEMS device driver and configured to produce the electrical signal from an optical signal produced by a light source in response to an applied current-based electrical control signal.
1. A magnetic resonance imaging (MRI) system, comprising:
a transmitting coil configured to transmit RF energy into a subject of interest;
a receiving coil capable of being switched between at least a first state, in which the receiving coil can resonate in response to RF signals generated within the subject of interest, and a second state, in which the receiving coil is unable to resonate in response to RF energy produced by the transmitting coil;
a switch configured to vary the receiving coil between the first and second states in response to a logic signal, wherein the switch comprises a micro electromechanical systems (MEMS) switch;
a MEMS device driver configured to produce the logic signal in response to an electrical signal;
an opto-isolator in communication with the MEMS device driver and configured to produce the electrical signal from an optical signal produced by a light source in response to a current-based control signal, such that the light source produces a light beam which is transmitted to a photodetector;
wherein the MEMS device driver is connected to the photodetector and in communication with the MEMS switch to produce high voltage switching logic from the electrical signal.
2. The system of claim 1 , wherein the MEMS device driver is positioned in proximity to the photodetector, which results in a reduced probability of electromagnetic interference (EMI) coupling with the connection between the MEMS device driver and the photodetector.
3. The system of claim 1 , wherein the MEMS switch is configured to reversibly create a disconnect in the resonant loop to vary the receiving coil between the first state and the second state.
4. The system of claim 1 , wherein the current-based control signal provided to opto-isolator has a current of between about 5 milliamps (ma) and 20 ma.
5. The system of claim 1 , wherein the MEMS device driver and the opto-isolator are disposed between about 1 mm and 20 mm from each other.
6. The system of claim 1 , wherein the opto-isolator comprises the light source and the photodetector, and the photodetector is in communication with the device driver, the photodetector being operable to produce the electrical signal at between about 1 nanoamp (nA) and 5 nA of current at a voltage of between about 50 volts (V) and 150 V.
7. The system of claim 1 , wherein opto-isolator, the MEMS device driver, and the MEMS switch are integrated into an electrical package that is configured to interface with the receiving coil.
8. The system of claim 1 , wherein the MEMS device driver comprises metal oxide semiconductor field effect transistor (MOSFET) totem pole drivers configured to produce the logic signal.
9. The system of claim 8 , comprising control circuitry configured to send the current-based control signal to the opto-isolator to cause the MEMS switch to vary the receiving coil from the first state to the second state when the transmitting coil is transmitting RF energy, and to vary the receiving coil from the second state to the first state when the transmitting coil is not transmitting RF energy.