DC-DC switched capacitor voltage converter with series and parallel switched capacitors during discharge

A switched capacitor voltage converter to convert a DC voltage source level to a DC load voltage level, comprising:

• a plurality of capacitors that includes m+n capacitors, wherein m and n are integers and m+n is greater than eight;
• a load voltage monitor circuit configured to identify the DC load voltage level;
• a switch controller responsive to the identified DC load voltage level;
• and
• an array of switches responsive to the switch controller, configured to alternately switch the plurality of capacitors between at least one first phase configuration and a second phase configuration that is selectable from among multiple second phase configurations;
• wherein in the at least one first phase configuration, the plurality of capacitors are coupled in series with each other and in parallel with a source voltage, each capacitor having a first plate and a second plate, a capacitor coupled at a first end of the series having its first plate coupled to the source voltage, a capacitor at a second end of the series having its second plate coupled to ground, each capacitor in between the capacitors at the first and second ends of the series having its first plate coupled to a second plate of a capacitor adjacent to it in the series;
• wherein in the selectable second phase configuration, the plurality of capacitors have their second plates coupled to a load, a first set of capacitors having n capacitors from the plurality of capacitors are coupled in parallel with each other and in series with the load, and a second set of capacitors from the plurality of capacitors having m capacitors coupled in parallel with the load and having their first plates coupled to ground;
• wherein the switch controller is configured to select the selectable second phase configuration based at least in part upon the identified DC load voltage level;
• and
• wherein the switch controller is configured to cause the array of switches to alternately couple the plurality of capacitors in the at least one first phase configuration and the selected second phase configuration.

A switched capacitor voltage converter to convert a DC voltage source level to a DC load voltage level, comprising:

• multiple capacitors;
• a load voltage monitor circuit configured to identify the DC load voltage level;
• a switch controller responsive to the identified DC load voltage level;
• and
• an array of switches responsive to the switch controller, configured to alternately switch the multiple capacitors between at least one first phase configuration and a second phase configuration that is selectable from among multiple second phase configurations, each corresponding to a different gain;
• wherein in the at least one first phase configuration, the multiple capacitors are coupled in series with each other and in parallel with a source voltage, each capacitor having a first plate and a second plate, a capacitor coupled at a first end of the series having its first plate coupled to the source voltage, a capacitor coupled at a second end of the series having its second plate coupled to ground, each capacitor in between the capacitors at the first and second ends of the series having its first plate coupled to a second plate of a capacitor adjacent to it in the series;
• and
• wherein in the selectable second phase configuration, the multiple capacitors have their second plates coupled to a load, a first set of capacitors having a first number of the multiple capacitors coupled in parallel with each other and in series with the load, and a second set of capacitors from the multiple capacitors having a second number of the multiple capacitors coupled in parallel with the load and having their first plates coupled to ground;
• wherein the switch controller is configured to select a gain based at least in part upon the identified DC load voltage level;
• and
• wherein the switch controller is configured to cause the array of switches to alternately couple the multiple capacitors in the at least one first phase configuration and a second phase configuration that corresponds to the selected gain.

A method to configure switched multiple capacitors to convert a DC voltage source level to a DC load voltage level, comprising:

• alternately switching a plurality of capacitors that includes m+n capacitors, wherein m and n are integers and m+n is greater than eight, between a first phase configuration and a second phase configuration;
• wherein in the first phase configuration, the plurality of capacitors are coupled in series with each other and in parallel with a source voltage, each capacitor having a first plate and a second plate, a capacitor coupled at a first end of the series having its first plate coupled to the source voltage, a capacitor coupled at a second end of the series having its second plate coupled to ground, each capacitor in between the capacitors at the first and second ends of the series having its first plate coupled to a second plate of a capacitor adjacent to it in the series;
• and
• wherein in the second phase configuration, the plurality of capacitors have their second plates coupled to a load, a first set of capacitors having n capacitors from the plurality of capacitors are coupled in parallel with each other and in series with the load and have their first plates coupled to the source voltage, and a second set of capacitors having m capacitors coupled in parallel with the load and having their first plates coupled to ground.

A method to configure switched multiple capacitors to convert a DC voltage source level to a DC load voltage level, comprising:

• monitoring the DC load voltage level to identify a current DC voltage load level;
• selecting a gain in response to the identified current DC voltage level;
• and
• alternately switching the multiple capacitors between at least one first phase configuration and a second phase configuration that corresponds to the selected gain selected from among multiple second phase configurations, each corresponding to a different gain;
• wherein in the at least one first phase configuration, the multiple capacitors are coupled in series with each other and in parallel with a source voltage, each capacitor having a first plate and a second plate, a capacitor coupled at a second end of the series having its first plate coupled to the source voltage, a capacitor coupled at a second end of the series having its second plate coupled to ground, each capacitor in between the capacitors at the first and second ends of the series having its first plate coupled to a second plate of a capacitor adjacent to it in the series;
• and
• wherein in the selectable second phase configuration, the multiple capacitors have their second plates coupled to a load, a first set of capacitors having a first number of the multiple capacitors coupled in parallel with each other and in series with the load, and a second number of capacitors having a second number of the multiple capacitors coupled in parallel with the load and having their first plates coupled to ground.