Charge recovery driver for MEMS mirror with reduced number of tank capacitors

A charge recovery driver for a pair of loads, comprising:

• a tank capacitor having first and second terminals;
• first and second output nodes coupled to the pair of loads;
• a first switch circuit configured to selectively couple the second terminal of the tank capacitor to the first and/or second output nodes;
• a second switch circuit configured to selectively couple the first and second output nodes to one another;
• a third switch circuit configured to selectively couple the first terminal of the tank capacitor to the first and/or second output nodes;
• a fourth switch circuit configured to selectively couple the first output node between a supply voltage and/or ground;
• a fifth switch circuit configured to selectively couple the second output node between the supply voltage and/or ground;
• and
• control circuitry configured to:
• a) cause the fourth switch circuit to couple the first output node to ground and to cause the fifth switch circuit to couple the second output node to the supply voltage during an initial phase;
• b) cause the third switch circuit to couple the first terminal of the tank capacitor to the second output node and the first switch circuit to couple the second terminal of the tank capacitor to the first output node during a first phase;
• c) cause the second switch circuit to couple the first and second output nodes to one another during a second phase;
• d) cause the third switch circuit couple the first terminal of the tank capacitor to the first output node and the first switch circuit to couple the second terminal of the tank capacitor to the second output node during a third phase;
• e) cause the fourth switch circuit to couple the first output node to the supply voltage and the fifth switch circuit to couple the second output node to ground during a fourth phase;
• and
• perform d), c), b), and a).

A charge recovery driver for a pair of loads, comprising:

• a first tank capacitor having first and second terminals;
• a second tank capacitor having first and second terminals;
• first and second output nodes coupled to the pair of loads;
• a first switch circuit configured to selectively couple the second terminal of the first tank capacitor to the first and/or second output nodes;
• a second switch circuit configured to selectively couple the second terminal of the second tank capacitor to the first and/or second output nodes;
• a third switch circuit configured to selectively couple the first and second output nodes to one another;
• a fourth switch circuit configured to selectively couple the first terminal of the second tank capacitor to the first and/or second output nodes;
• a fifth switch circuit configured to selectively couple the first terminal of the first tank capacitor to the first and/or second output nodes;
• a sixth switch circuit configured to selectively couple the first output node between a supply voltage and/or ground;
• a seventh switch circuit configured to selectively couple the second output node between the supply voltage and/or ground;
• and
• control circuitry configured to:
• a) cause the sixth switch circuit to couple the first output node to ground and cause the seventh switch circuit to couple the second output node to the supply voltage during an initial phase;
• b) cause the first switch circuit to couple the second terminal of the first tank capacitor to the first output node and the fifth switch circuit to couple the first terminal of the first tank capacitor to the second output node during a first phase;
• c) cause the second switch circuit to couple the second terminal of the second tank capacitor to the first output node and the fourth switch circuit to couple the first terminal of the second tank capacitor to the second output node during a second phase;
• d) cause the third switch circuit to couple the first and second output nodes to one another during a third phase;
• e) cause the fourth switch circuit to couple the first terminal of the second tank capacitor to the first output node and the second switch circuit to couple the second terminal of the second tank capacitor to the second output node during a fourth phase;
• f) cause the fifth switch circuit to couple the first terminal of the first tank capacitor to the first output node and the first switch circuit to couple the second terminal of the first tank capacitor to the second output node during a fifth phase;
• g) cause the sixth switch circuit to couple the first output node to the supply voltage and the seventh switch circuit to couple the second output node to ground during a sixth phase;
• and
• perform f), e), d), c), b), and a).

A charge recovery driver for a pair of loads, comprising:

• a tank capacitor having first and second terminals;
• first and second output nodes coupled to the pair of loads;
• a first switch circuit configured to selectively couple the second terminal of the tank capacitor to a first output node and/or a second output node;
• a second switch circuit configured to selectively couple the first and second output nodes to one another;
• a third switch circuit configured to selectively couple the first terminal of the tank capacitor to the first output node and/or the second output node;
• a fourth switch circuit configured to selectively couple the second terminal of the tank capacitor to ground;
• a fifth switch circuit configured to selectively couple the first terminal of the tank capacitor to a supply voltage;
• a sixth switch circuit configured to selectively couple the first output node between the supply voltage and/or ground;
• a seventh switch circuit configured to selectively couple the second output node between the supply voltage and/or ground;
• and
• control circuitry configured to:
• a) cause the sixth switch circuit to couple the first output node to ground and cause the seventh switch circuit to couple the second output node to the supply voltage during an initial phase;
• b) cause the first switch circuit to couple the second terminal of the tank capacitor to the first output node and the third switch circuit to couple the first terminal of the tank capacitor to the second output node during a first phase;
• c) cause the first switch circuit to couple the second terminal of the tank capacitor to the first output node and the fifth switch circuit to couple the first terminal of the tank capacitor to the supply voltage during a second phase, while allowing the second output node to float;
• d) cause the third switch circuit to couple the first terminal of the tank capacitor to the second output node and the fourth switch circuit to couple the second terminal of the tank capacitor to ground during a third phase, while allowing the first output node to float;
• e) cause the second switch circuit to couple the first and second output nodes to one another during a fourth phase;
• f) cause the third switch circuit to couple the first terminal of the tank capacitor to the first output node and the fourth switch circuit to couple the second terminal of the tank capacitor to ground during a fifth phase, while allowing the second output node to float;
• g) cause the first switch circuit to couple the second terminal of the tank capacitor to the second output node and the fifth switch circuit to couple the first terminal of the tank capacitor to the supply voltage during a sixth phase, while allowing the first output node to float;
• h) cause the first switch circuit to couple the second terminal of the tank capacitor to the second output node and the third switch circuit to couple the first terminal of the tank capacitor to the first output node during a seventh phase;
• i) cause the sixth switch circuit to couple the first output node to the supply voltage and cause the seventh switch circuit to couple the second output node to ground;
• and
• perform h), g), f), e), d), c), b), and a).

A method of operating charge recovery driver, the method comprising:

• a) coupling a first output node to ground and coupling a second output node to a supply voltage, while leaving first and second terminals of at least one tank capacitor floating during an initial phase;
• b) causing charge transfer from the second output node to the at least one tank capacitor, and from the at least one tank capacitor to the first output node, by coupling the first terminal of the at least one tank capacitor to the second output node and by coupling the second terminal of the at least one tank capacitor to the first output node during a first intermediate phase;
• c) causing charge equalization between the first and second output nodes by coupling the first and second output nodes to one another, while leaving the first and second terminals of the at least one tank capacitor floating during a second intermediate phase;
• d) causing charge transfer from the second output node to the at least one tank capacitor, and from the at least one tank capacitor to the first output node, by coupling the second terminal of the at least one tank capacitor to the second output node and by coupling the first terminal of the at least one tank capacitor to the first output node during a third intermediate phase;
• e) coupling the first output node to the supply voltage and coupling the second output node to ground, while leaving first and second terminals of at least one tank capacitor floating during a final phase;
• and
• perform d), c), b), and a).