# US 10,312,802 B2 · Charge pump circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,312,802 B2 - Document ID: US10312802B2 - Status: Granted - Kind: B2 - Application number: 15/628,021 - Filed: 2017-06-20 - Published: 2017-10-05 - Granted: 2019-06-04 - Earliest claimed: 2010-12-27 - Assignees: Cirrus Logic, Inc. - Applicants: Cirrus Logic International Semiconductor Ltd. - Inventors: John P. Lesso; Peter J. Frith; John L. Pennock - Web page: https://patentgrep.com/patent/US10312802B2 ## CPC - H02M 3/07: using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps} - H03G 3/30: in amplifiers having semiconductor devices - H02M 3/071: {adapted to generate a negative voltage output from a positive voltage source} - H02M 3/072: {adapted to generate an output voltage whose value is lower than the input voltage} - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) - H03G: CONTROL OF AMPLIFICATION ## Abstract A bipolar output charge pump circuit having a network of switching paths for selectively connecting an input node and a reference node for connection to an input voltage, a first pair of output nodes, two pairs of flying capacitor nodes, and a controller for controlling the switching of the network of switching paths. The controller is operable to control the network of switching paths when in use with two flying capacitors connected to the two pairs of flying capacitor nodes, to provide a first mode and a second mode when in use with two flying capacitors connected to the flying capacitor nodes, wherein at least the first mode corresponds to a bipolar output voltage of +/−3 VV, +/−VV/5 or +/−VV/6. ## Claims ### Claim 1 A charge pump circuit operable to output a bipolar output voltage, comprising: an input node and a reference node for connection to an input voltage; a first output node and a second output node arranged to output the bipolar output voltage; two pairs of flying capacitor nodes; a network of switching paths for interconnecting said nodes; and a controller operable in at least a first mode to control the network of switching paths, when in use with two flying capacitors connected to the flying capacitor nodes and with first and second reservoir capacitors connected to the first and second output nodes respectively, to repeatedly charge the first and second reservoir capacitors to provide a first bipolar output voltage, wherein the first bipolar output voltage comprises one of +/−3*VV, +/−2*VV, +/−VV/3, +/−VV/4, +/−VV/5 or +/−VV/6 where VV is the input voltage; and wherein the controller is configured such that, in the first mode, a frequency of charging of the first and second reservoir capacitors is variable. ### Claim 2 (depends on 1) The charge pump circuit as claimed in claim 1, wherein the controller is configured to receive at least one feedback signal from at least one of the first and second output nodes and to vary the frequency of charging of the first and second reservoir capacitors based on said at least one feedback signal. ### Claim 3 (depends on 2) The charge pump circuit as claimed in claim 2, wherein the controller comprises at least one comparator for comparing the at least one feedback signal with at least one reference voltage. ### Claim 4 (depends on 3) The charge pump circuit as claimed in claim 3, wherein the at least one reference voltage is independent of the input voltage. ### Claim 5 (depends on 3) The charge pump circuit as claimed in claim 3, wherein the controller comprises a sequencer for controlling the network of switching paths in a sequence of switch states and the controller is configured to stop and start the sequencer based on an output of said at least one comparator. ### Claim 6 (depends on 3) The charge pump circuit as claimed in claim 3, wherein the controller is configured to receive first and second feedback signals from the first and second output nodes respectively and the controller comprises first and second comparators for comparing the first and second feedback signals with respective reference voltages. ### Claim 7 (depends on 6) The charge pump circuit as claimed in claim 6, wherein the controller comprises a sequencer for controlling the network of switching paths in a sequence of switch states and the controller is configured to modify the sequence of switch states so as to vary relatively frequency of charging of the first and second reservoir capacitors based on outputs of said first and second comparators. ### Claim 8 (depends on 7) The charge pump circuit as claimed in claim 7, wherein the controller is configured to modify the sequence of switch states by omitting and/or replacing one or more switch states in a cycle of switch states. ### Claim 9 (depends on 3) The charge pump circuit as claimed in claim 3, wherein the controller comprises a sequencer for controlling the network of switching paths in a sequence of switch states, wherein the sequencer has an input for a first clock signal for controlling timing of the switch states and wherein the controller is configured to vary a clock frequency of the first clock signal based on an output of said at least one comparator. ### Claim 10 (depends on 3) The charge pump circuit as claimed in claim 3, wherein the at least one feedback signal comprises a differential signal from said first and second output nodes and said comparator comprises a differential comparator. ### Claim 11 (depends on 1) The charge pump circuit as claimed in claim 1, wherein the controller is configured to receive an indication of voltage drop of at least one the first and second reservoir capacitors and to vary the frequency of charging of the first and second reservoir capacitors based on said indication of voltage droop. ### Claim 12 (depends on 1) The charge pump circuit as claimed in claim 1, wherein the controller is configured to independently vary the frequency of charging of the first and second output capacitors. ### Claim 13 (depends on 1) The charge pump circuit as claimed in claim 1, wherein the controller is further operable in a second mode to provide a second bipolar output voltage which is different to the first bipolar output voltage. ### Claim 14 (depends on 13) The charge pump circuit as claimed in claim 13, wherein the controller is configured such that, in the second mode, a frequency of charging of the first and second reservoir capacitors is variable. ### Claim 15 (depends on 14) The charge pump circuit as claimed in claim 14, wherein the controller is configured to receive at least one feedback signal from at least one of the first and second output nodes and to vary the frequency of charging of the first and second reservoir capacitors based on said at least one feedback signal, wherein the controller comprises at least one comparator for comparing the at least one feedback signal with at least a first reference voltage in the first mode and at least a second different reference voltage in the second mode. ### Claim 16 (depends on 1) An audio output chain comprising the charge pump circuit as claimed in claim 1 and an audio amplifier, wherein the charge pump circuit is arranged to output said first bipolar output voltage as a supply voltage for the audio amplifier. ### Claim 17 (depends on 16) The audio output chain as claimed in claim 16, wherein the controller is configured to receive at least one feedback signal from at least one of the first and second output nodes and to vary the frequency of charging of the first and second reservoir capacitors based on said at least one feedback signal, wherein the controller comprises at least one comparator for comparing the at least one feedback signal with at least one reference voltage and the controller is configured to vary the at least one reference voltage based on an indication of a signal level of an audio signal input to said audio amplifier. ### Claim 18 (depends on 1) An electronic device comprising the charge pump circuit as claimed in claim 1. ### Claim 19 A charge pump circuit operable to output a bipolar output voltage, comprising: an input node for connection to an input voltage; a first output node and a second output node for outputting the bipolar output voltage; two pairs of flying capacitor nodes; a network of switching paths for interconnecting said nodes; and a controller operable, when in use with two flying capacitors connected to the flying capacitor nodes and with first and second reservoir capacitors connected to the first and second output nodes respectively, in at least a first mode to control the network of switching paths to repeatedly cycle between a plurality of switch states; wherein said plurality of switch states of switch states includes at least one switch state for charging the first reservoir capacitor and at least one switch state for charging the second reservoir capacitor, and wherein said plurality of switch states is selected to provide a first bipolar output voltage that comprises one of +/−3*VV, +/−2*VV, +/−VV/3, +/−VV/4, +/−VV/5 or +/−VV/6 where VV is the input voltage; and wherein the controller is configured such that the rate of occurrence of said switch states for charging the first or second reservoir capacitors is variable. ### Claim 20 A charge pump circuit comprising: an input node for connection to an input voltage; first and second output nodes for outputting an bipolar output voltage; two pairs of flying capacitor nodes; a network of switching paths for interconnecting said nodes; and a controller operable, in use with two flying capacitors connected to the flying capacitor nodes and with first and second reservoir capacitors connected to the first and second output nodes respectively, in at least a first mode to control the network of switching paths in a plurality of switch states to provide a first bipolar output voltage that comprises one of +/−3*VV, +/−2*VV, +/−VV/3, +/−VV/4, +/−VV/5 or +/−VV/6 where VV is the input voltage; wherein the controller is configured to control said switch states based on an indication of voltage droop of said first and second reservoir capacitors to vary a rate of occurrence of a switch state for recharging at least one of said first and second reservoir capacitors.