Voltage multiplier and relative operating method

A method of operating a voltage multiplier that includes a charging section provided with first and second charge transfer capacitors and first and second parasitic capacitances respectively placed between respective first terminals of the charge transfer capacitors and a reference voltage, said method comprising:

• applying an input voltage to said charging section;
• producing at an output terminal an output voltage that is a multiple of the input voltage by applying phase opposition signals in phase opposition to the first terminals of said charge transfer capacitors;
• transferring charge from one parasitic capacitor to the other;
• and
• isolating the charging section from the output terminal while transferring charge from one parasitic capacitor to the other, wherein:
• producing the output voltage comprises successive phases of charge transfer from the first or from the second capacitor in alternate periods of pumping time;
• the transferring charge step is actuated in periods of transition time comprised between two successive periods of pumping time;
• and
• the isolating step includes isolating said charging section from said input voltage, from the phase opposition signals, and from the output terminal during said periods of transition time, said isolating beginning previous to transferring the charge from one parasitic capacitor to the other.

A voltage multiplier, comprising:

• an input terminal that receives an input voltage;
• an output terminal at which an output voltage is produced that is a multiple of the input voltage;
• a charging section coupled between the input and output terminals and structured to produce the output voltage, the charging section including:
• a first charge transfer capacitor having a first terminal, coupled to a first control signal, and a second terminal;
• a second charge transfer capacitor having a first terminal, coupled with a second signal in phase opposition to the first signal, and a second terminal;
• a first transfer switch, coupled between the second terminal of the first charge transfer capacitor and an intermediate node, and structured to transfer charge from the first charge transfer capacitor to the output terminal during a first pumping phase;
• a second transfer switch, coupled between the second terminal of the second charge transfer capacitor and the intermediate node, and structured to transfer charge from the second charge transfer capacitor to the output terminal during a second pumping phase;
• and a first switch structured to transfer charge from the charging section and the output terminal during the first and second pumping phases and disconnect the output terminal from the intermediate node during a transition period between the first and second pumping phases.

A voltage multiplier for receiving a constant input voltage, said multiplier comprising:

• means for generating first and second signals in phase opposition between each other;
• a charging section structured to operate over a repeatable sequence of a respective pumping period and a respective transition period and that includes:
• a first charge transfer capacitor having a first terminal, coupled to the first signal, and a second terminal;
• a second charge transfer capacitor having a first terminal, coupled with the second signal, and a second terminal;
• a first parasitic capacitance placed between the first terminal of the first charge transfer capacitor and a reference voltage;
• and
• a second parasitic capacitance placed between the first terminal of the second charge transfer capacitor and the reference voltage, said charging section being coupled with said input voltage and being suitable for producing an output a multiple voltage that is a multiple of the input voltage;
• output means receiving said multiple voltage and being suitable for supplying a substantially constant output voltage which is multiple of the input voltage;
• means for connecting said parasitic capacitances to carry out a charge transfer from one parasitic capacitance to the other during transition periods;
• and
• isolation means for isolating the charging section from the output means during transition periods while charge is transferred from one parasitic capacitance to the other, wherein:
• the charging section comprises further means connected to the second terminals of the first and second charge transfer capacitors and suitable for permitting a charge transfer from the first or from the second charge transfer capacitor towards said output means in alternate pumping periods;
• said means for connecting said parasitic capacitances including switch means connected between said parasitic capacitances;
• said multiplier comprising means suitable for closing said switch means during a respective transition period occurring between two successive pumping periods;
• and
• said further means comprise a four transistor bridge circuit, that includes two inverters connected together in a loop to form a flip-flop, the two inverters having respective control terminals respectively connected to the second terminals of said charge transfer capacitors, said two inverters having first and second supply terminals coupled respectively to said input voltage and to said output means.

A voltage multiplier, comprising:

• an input terminal that receives an input voltage;
• an output terminal at which an output voltage is produced that is a multiple of the input voltage;
• a charging section coupled between the input and output terminals and structured to produce the output voltage, the charging section including:
• a first charge transfer capacitor having a first terminal, coupled to a first control signal, and a second terminal;
• a second charge transfer capacitor having a first terminal, coupled with a second signal in phase opposition to the first signal, and a second terminal;
• a first parasitic capacitance placed between the first charge transfer capacitor and a reference voltage;
• and
• a second parasitic capacitance placed between the second charge transfer capacitor and the reference voltage, the charging section being;
• a first switch that selectively connects the parasitic capacitances to one another;
• a second switch that selectively connects the charging section and the output terminal;
• a third switch that selectively connects the charging section and the input terminal;
• and
• a controller coupled to the first, second, and third switches and structured to close the first switch and open the second and third switches during a transition period between a first pumping phase when charge is pumped from the first charge transfer capacitor to the output terminal and a second pumping phase when charge is pumped from the second charge transfer capacitor to the output terminal, wherein the controller includes a fourth switch having a control terminal coupled to a control terminal of the second switch, a first conduction terminal coupled to the output terminal, and a second conduction terminal coupled to a control terminal of the third switch.

A voltage multiplier, comprising:

• an input terminal that receives an input voltage;
• an output terminal at which an output voltage is produced that is a multiple of the input voltage;
• a charging section coupled between the input and output terminals and structured to produce the output voltage, the charging section including:
• a first charge transfer capacitor having a first terminal, coupled to a first control signal, and a second terminal;
• a second charge transfer capacitor having a first terminal, coupled with a second signal in phase opposition to the first signal, and a second terminal;
• a first parasitic capacitance placed between the first charge transfer capacitor and a reference voltage;
• and
• a second parasitic capacitance placed between the second charge transfer capacitor and the reference voltage, the charging section being;
• a first switch that selectively connects the parasitic capacitances to one another;
• a second switch that selectively connects the charging section and the output terminal;
• a third switch that selectively connects the charging section and the input terminal;
• and
• a controller coupled to the first, second, and third switches and structured to close the first switch and open the second and third switches during a transition period between a first pumping phase when charge is pumped from the first charge transfer capacitor to the output terminal and a second pumping phase when charge is pumped from the second charge transfer capacitor to the output terminal, wherein the controller includes:
• a first inverter having an input connected to a control terminal of the second switch and an output connected to a control terminal of the third switch;
• and
• a second inverter having an input connected to the control terminal of the third switch and an output connected to a control terminal of the second switch.

A voltage multiplier, comprising:

• an input terminal that receives an input voltage;
• an output terminal at which an output voltage is produced that is a multiple of the input voltage;
• a charging section coupled between the input and output terminals and structured to produce the output voltage and to operate over a repeatable sequence of a respective pumping period and a respective transition period, the charging section including:
• a first charge transfer capacitor having a first terminal, coupled to a first control signal, and a second terminal;
• a second charge transfer capacitor having a first terminal, coupled with a second signal in phase opposition to the first signal, and a second terminal;
• a first parasitic capacitance placed between the first charge transfer capacitor and a reference voltage;
• and
• a second parasitic capacitance placed between the second charge transfer capacitor and the reference voltage, the charging section being;
• a first switch that selectively connects the parasitic capacitances to one another during transition periods and selectively disconnects the parasitic capacitances from one another during pumping periods;
• a second switch that selectively connects the charging section and the output terminal during pumping periods and selectively disconnects the charging section and the output terminal during transition periods;
• a first buffer connected between the first control signal and the first charge transfer capacitor, the first buffer being structured to disconnect the first control signal from the first charge transfer capacitor during transition periods when the first switch is closed to connect the first and second parasitic capacitances to one another;
• and
• a second buffer connected between the second control signal and the second charge transfer capacitor, the second buffer being structured to disconnect the second control signal from the second charge transfer capacitor during transition periods when the first switch is closed to connect the first and second parasitic capacitances to one another.

A voltage multiplier, comprising:

• an input terminal that receives an input voltage;
• an output terminal at which an output voltage is produced that is a multiple of the input voltage;
• a charging section coupled between the input and output terminals and structured to produce the output voltage and to operate over a repeatable sequence of a respective pumping period and a respective transition period, the charging section including:
• a first charge transfer capacitor having a first terminal, coupled to a first control signal, and a second terminal;
• a second charge transfer capacitor having a first terminal, coupled with a second signal in phase opposition to the first signal, and a second terminal;
• and
• first and second inverters connected together in a loop to form a flip-flop, the first and second inverters having respective inputs respectively connected to the second terminals of the charge transfer capacitors, respective first supply terminals coupled to the input terminal, and respective second supply terminals coupled to the output terminal;
• and
• a first switch that selectively connects the charging section and the output terminal during pumping periods and selectively disconnects the charging section and the output terminal during transition periods.