High efficiency regulated charge pump
Described herein are systems and methods for creating high efficiency regulated charge pumps. In an exemplary embodiment, a Dickson charge pump is combined with a low voltage amplifier to create an effective class G amplifier with high voltage outputs that achieves very high power efficiency. The charge pump capacitors are alternately driven by either the charge pump circuit or a low voltage amplifier which uses negative feedback from one or more high voltage outputs to give closed loop regulation.
1. A method of operating a regulated charge pump circuit, wherein the regulated charge pump circuit comprises
a clocked charge pump connected to one or more pump capacitors with two terminals each,
an amplifier having an output,
a feedback network,
switches connecting one or more terminals of the pump capacitors to clock phases driven by alternating bi-level signals,
switches connecting the output of the amplifier to said one or more terminals of the pump capacitors,
the method comprising:
performing charge pump operations, wherein
a charge pump operation switches or drives one or more pump capacitor terminals, and
switches connecting the output of the amplifier to said one or more terminals of the pump capacitors are open; and
between charge pump operations, performing voltage regulating operations wherein:
switches connecting one or more terminals of the pump capacitors to clock phases are open,
at least one of the switches connecting the output of the amplifier to said one or more terminals of the pump capacitors is closed, whereby
the amplifier drives a terminal of at least one pump capacitor, and
the feedback network connects to the another terminal of a pump capacitor to create a desired output voltage with the feedback network providing negative feedback from the output voltage to the amplifier.
2. The method of claim 1 wherein the clocked charge pump is a Dickson charge pump.
3. The method of claim 1 wherein the amplifier has lower output voltage range than the desired output voltage.
4. The method of claim 1 , wherein:
during charge pump operations, each charge pump operation transfers charge among the pump capacitors and a power source; and
between charge pump operations, the amplifier is connected to the pump capacitors to drive an output voltage using at least one pump capacitor in series with the amplifier.
5. A regulating charge pump circuit, comprising:
a clocked charge pump connected to one or more pump capacitors with two terminals each,
an amplifier having an output,
switches connecting one or more terminals of the pump capacitors to clock phases,
switches connecting the output of the amplifier to said one or more terminals of the pump capacitors,
a feedback network connected to the amplifier to provide negative feedback from the output terminal to the amplifier.
6. The regulating charge pump circuit of claim 5 , wherein the charge pump is a Dickson charge pump.
7. The regulating charge pump circuit of claim 5 , wherein the amplifier is a low voltage amplifier with insufficient output voltage range to directly drive the output terminal to the desired voltage.
8. The regulating charge pump circuit of claim 6 , wherein the feedback network is comprised of switched capacitors.
9. The regulating charge pump circuit of any one of claims 5 to 8 , further comprising
an output switch, and
an output terminal connected to a stabilizing capacitor,
wherein the output switch connects the output terminal and the stabilizing capacitor to one terminal of a pump capacitor.