Resonance mems mirror control system
AssigneeSTMicroelectronics S.r.l.
InventorSason SOURANI
Life of this patent
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Abstract
A method for controlling operation of a MEMS mirror includes steps for: generating activation pulses for operating the MEMS mirror and generating a window activation signal for current detection, with the window activation signal overlapping with an end of an activation pulse. The method also includes detecting current through a stator or a rotor of the MEMS mirror during the window activation signal and terminating a current activation pulse and the window activation signal in response to detecting a change in the direction of the current through the stator or the rotor of the MEMS mirror during the window activation signal.
Claims24
A control circuit for controlling operation of a resonance MEMS mirror, comprising:
- a circuit configured to generate a first set of activation pulses for operating the resonance MEMS mirror and to generate a window activation signal for detection of a current through one of a stator or a rotor of the resonance MEMS mirror, wherein the window activation signal overlaps an end of an activation pulse of the first set of activation pulses, wherein the first set of activation pulses includes a first primary pulse applied to a first portion of the resonance MEMS mirror and a second primary pulse applied to a second portion of the resonance MEMS mirror and wherein the first primary pulse commences when an angle of the resonance MEMS mirror is at its greatest positive value and terminates at an angle of maximum capacitance for the first portion of the resonance MEMS mirror, and wherein the second primary pulse commences when the angle of the resonance MEMS mirror is at its greatest negative value and terminates at an angle of maximum capacitance for the second portion of the resonance MEMS mirror;
- and
- a detection circuit configured to detect current through the stator or rotor of the resonance MEMS mirror during the window activation signal and to generate a reset signal in response to detecting a change in direction of the current;
- wherein the circuitry is further configured to terminate an activation pulse of the first set of activation pulses and the window activation signal in response to receiving the reset signal from the detection circuit.
A method for controlling operation of a resonance MEMS mirror, the method comprising:
- generating a first set of activation pulses for operating the resonance MEMS mirror, wherein generating the first set of activation pulses includes applying a first primary pulse to a first portion of the resonance MEMS mirror and applying a second primary pulse to a second portion of the resonance MEMS mirror, wherein the first primary pulse commences when an angle of the resonance MEMS mirror is at its greatest positive value and terminates at an angle of maximum capacitance for the first portion of the resonance MEMS mirror, and wherein the second primary pulse commences when the angle of the resonance MEMS mirror is at its greatest negative value and terminates at an angle of maximum capacitance for the second portion of the resonance MEMS mirror;
- generating a window activation signal for current detection, the window activation signal overlapping with an end of an activation pulse of the first set of activation pulses;
- detecting current at one of a stator or a rotor of the resonance MEMS mirror during the window activation signal;
- and
- terminating the activation pulse of the first set of activation pulses and the window activation signal in response to detecting a change in the direction of the current through the stator or the rotor of the resonance MEMS mirror during the window activation signal.
A method for controlling operation of a MEMS mirror, comprising:
- generating activation pulses for operating the MEMS mirror;
- generating a window activation signal for current detection, the window activation signal overlapping with an end of an activation pulse;
- detecting current through a stator or a rotor of the MEMS mirror during the window activation signal;
- and
- terminating a current activation pulse and the window activation signal in response to detecting a change in the direction of the current through the stator or the rotor of the MEMS mirror during the window activation signal.
A control circuit for controlling operation of a MEMS mirror, comprising:
- a comparator having a first input coupled to a rotor of the MEMS mirror, a second input coupled to a reference voltage, and an output;
- a logic circuit having a first input coupled to the output of the comparator, a second input, and an output;
- a timing circuit having an input coupled to the output of the logic circuit, a window activation signal output coupled to the second input of the logic circuit, and an activation signal output;
- and
- an amplifier having an input coupled to the activation signal output of the timing circuit and an output coupled to a stator of the MEMS mirror.
Dependencies are inferred from the claim text.