Driver for MEMS device
A driver for electrically causing a MEMS device to change shape or position includes an amplifier having a first feedback loop and a second feedback loop. The first feedback loop stabilizes output voltage and the second feedback loop reduces current changes through the MEMS device to zero.
1 . A driver for electrically causing a MEMS device to change shape or position, said driver comprising:
an amplifier having a first feedback loop and a second feedback loop;
wherein said first feedback loop stabilizes output voltage and said second feedback loop stabilizes current through a MEMS device.
2 . The driver as set forth in claim 1 wherein said amplifier exhibits gain, a, and said first feedback loop includes a voltage divider that divides an applied voltage by approximately α.
3 . The driver as set forth in claim 2 wherein the applied voltage is the output voltage, V, of said amplifier and the voltage V/α is coupled back to an input of said amplifier.
4 . The driver as set forth in claim 1 and further including:
a digital to analog converter coupled to an input of said amplifier, wherein data applied to said digital to analog converter causes a change in the output voltage of said amplifier and a change in position of a MEMS device coupled to said driver.
5 . The driver as set forth in claim 4 wherein said digital to analog converter is a ten-bit converter.
6 . The driver as set forth in claim 4 and further including:
a serial interface coupled to said converter.
7 . A driver for electrically causing a MEMS device to change shape or position, said driver comprising:
an amplifier having a first input and a first output;
a digital to analog converter having an output coupled to said first input, thereby controlling the nominal output voltage of said amplifier;
a first impedance and a second impedance connected in series and having a junction coupled to a second input of said amplifier;
a third impedance coupling said MEMS device to said junction.
8 . The driver as set forth in claim 7 wherein said third impedance includes a capacitor.
9 . The driver as set forth in claim 7 wherein said third impedance includes a resistor.
10 . The driver as set forth in claim 7 wherein said first impedance includes a capacitor and said second impedance includes a capacitor.
11 . The driver as set forth in claim 7 wherein said digital to analog converter is a ten-bit digital to analog converter.
12 . The driver as set forth in claim 7 and further including:
a serial interface coupled to said digital to analog converter.