TWI811035B - Switched capacitor voltage converter circuit and switched capacitor voltage conversion method - Google Patents

Abstract

The present invention provides a switched capacitor voltage converter circuit for converting a first voltage to a second voltage, including: a switched capacitor converter and a control circuit; wherein the switched capacitor converter includes at least two capacitors, plural switches and at least one inductor. In a mode transition period when the switched capacitor converter switches from a present conversion mode to a next conversion mode, at least two forward switches of the plural switches operates in an unidirectional conduction mode. Each of the forward switches has a current channel with a forward conduction toward the second voltage in the unidirectional conduction mode.

Description

Switched capacitor voltage conversion circuit and switched capacitor voltage conversion method

The present invention relates to a switched capacitor voltage conversion circuit, in particular to a switched capacitor voltage conversion circuit and a switched capacitor voltage conversion method capable of reducing inrush current during mode switching.

FIG. 1 shows a conventional resonant switched capacitor voltage converter 10 . This conventional resonant switched capacitor voltage converter 10 can provide high efficiency operation when its switches are operated at the resonant frequency and switched in a flexible switching state with zero current switching/zero voltage switching. However, the conventional resonant switched capacitor voltage converter 10 only has a fixed 2-to-1 conversion ratio of the input voltage Vin to the output voltage Vout.

In view of this, the present invention proposes an innovative switched capacitor voltage conversion circuit aimed at the shortcomings of the above-mentioned prior art.

In one aspect, the present invention provides a switched capacitor voltage conversion circuit for converting a first voltage into a second voltage, the switched capacitor voltage conversion circuit includes: a switched capacitor converter coupled to the first voltage Between a voltage and the second voltage; and a control circuit, used for determining, according to a voltage conversion ratio, that the switched capacitor converter operates in a conversion mode having the voltage conversion ratio, and generating a control signal according to the conversion mode to control the switched capacitor converter to convert the first voltage into the second voltage; wherein the switched capacitor converter includes: at least two capacitors; a plurality of switches coupled to the at least two capacitors; and at least one inductor; wherein , the control signal includes a charge operation signal and at least one discharge operation signal to control the switching of the plurality of switches to convert the first voltage to the second voltage; wherein, in a charging procedure of the conversion mode, by The switching of the plurality of switches is controlled by the charging operation signal, so that at least one of the capacitors and the corresponding inductance are connected in series between the first voltage and the second voltage to form a charging path and resonant operation; wherein, in the conversion In at least one discharge procedure of the mode, the switching of the plurality of switches is controlled by the discharge operation signal, so that the capacitor and the corresponding inductance are connected in series between the second voltage and a DC potential, and multiple discharges are formed simultaneously or alternately path and resonant operation; wherein, in the conversion mode, the charging procedure and the at least one discharging procedure are repeatedly interleaved with each other to convert the first voltage to the second voltage; wherein, in the conversion mode, the The charging operation signal and the at least one discharging operation signal are respectively switched to a conduction level for a period of conduction, and the plurality of conduction periods do not overlap each other, so that the charging process and the at least one discharging process do not overlap each other; wherein, When the control circuit switches the current conversion mode to a mode switching period between the next conversion mode, the control signal is changed into a mode switching control signal, which includes a mode switching charging signal, at least one mode switching discharging signal and A unidirectional communication signal; wherein the unidirectional communication signal is used to control at least two forward switches in the plurality of switches, operating in a unidirectional conduction mode, wherein in the unidirectional conduction mode, each of the forward switches has a direction toward The second voltage is forward-conducting a current channel; wherein, the mode-switching charging signal and the mode-switching discharging signal control switching of other switches except the at least two forward switches operating in the unidirectional conduction mode, and convert the first voltage into the second voltage.

In another viewpoint, the present invention provides a switched capacitor voltage conversion method for converting a first voltage of a switched capacitor converter into a second voltage. The switched capacitor converter includes at least two capacitors, a plurality of switches, and At least one inductor, the switched capacitor voltage conversion method includes: according to a voltage conversion ratio, determining that the switched capacitor converter operates in a conversion mode with the voltage conversion ratio, and generating a control signal according to the conversion mode to control the Switching the plurality of switches in the switching capacitor converter to convert the first voltage to the second voltage, wherein the control signal includes a charging operation signal and at least one discharging operation signal; in a charging process of the switching mode, The switching of the plurality of switches is controlled by the charging operation signal, so that at least one capacitor and the corresponding inductor are connected in series between the first voltage and the second voltage to form a charging path and operate in resonance; in the conversion mode In at least one discharge procedure, the switching of the plurality of switches is controlled by the discharge operation signal, so that the capacitor and the corresponding inductance are connected in series between the second voltage and a DC potential, and multiple discharge paths are formed simultaneously or alternately and resonant operation; in the switching mode, the charging process and the at least one discharging process are repeatedly interleaved with each other to convert the first voltage to the second voltage; in the switching mode, the charging operation signal and the At least one discharge operation signal is respectively switched to a conduction level for a period of conduction, and the plurality of conduction periods do not overlap with each other, so that the charging process and the at least one discharging process do not overlap each other; During a mode switching period between switching to the next conversion mode, the control signal is changed to a mode switching control signal, which includes a mode switching charging signal, at least one mode switching discharging signal and a unidirectional communication signal; The conduction signal controls at least two forward switches in the plurality of switches to operate in a unidirectional conduction mode, wherein in the unidirectional conduction mode, each of the forward switches has a forward conduction current toward the second voltage channel; and switch the charging signal and the discharging signal in the mode, control the switching of the other switches except the at least two forward switches operating in the unidirectional conduction mode, and convert the first voltage into the second Second voltage.

In one embodiment, the at least two forward switches operating in the unidirectional conduction mode are constantly conducting, or are always non-conducting but have internally connected diodes forwardly facing the second voltage.

In one embodiment, during the mode switching period, the duty cycle of the mode switching charging signal and/or the mode switching discharging signal is correspondingly lower than the previous duty cycle of the charging operation signal and/or the discharging operation signal, And the duty cycle of the mode-switching charging signal and/or the mode-switching discharging signal is gradually increased from a preset value, so as to gradually increase or decrease the corresponding capacitor cross-voltage during the mode switching period.

In one embodiment, the control circuit includes: a duty ratio determining circuit, which is used to compare a gradually rising voltage of a gradually rising node with a periodic waveform signal to generate a duty ratio signal; a duty ratio distribution circuit , used to respectively generate the mode switching charging signal and the at least one mode switching discharging signal according to the duty ratio signal; and a gradually rising voltage generating circuit coupled with the duty ratio determining circuit for switching the mode During this period, the gradually rising voltage of the gradually rising node is generated; wherein the gradually rising voltage of the gradually rising node is gradually increased during the mode switching period, so that the duty of the mode switching charging signal and the at least one mode switching discharging signal The ratio corresponding to gradually rises.

In one embodiment, the switched capacitor converter includes a series-parallel switched capacitor converter.

In one embodiment, the DC potential is ground potential.

In one embodiment, the control circuit includes: a current sensing circuit for sensing the current flowing through the at least one inductor to generate at least one current sensing signal; and a control signal generating circuit connected with the current sensing The measuring circuit is coupled to generate the control signal according to the current sensing signal.

In one embodiment, the control circuit further includes a voltage sensing circuit for sensing the second voltage to generate a voltage sensing signal.

In one embodiment, during the mode switching period, the control circuit lowers the duty cycle of the mode switching charging signal and/or the mode switching discharging signal to a preset value, so as to limit an inductor current flowing through the inductor .

In one embodiment, the conversion mode includes a first conversion mode and a second conversion mode, when the control circuit lowers the duty cycle of the mode switching charging signal and/or the mode switching discharging signal to the preset After the value, the control circuit gradually increases the duty ratio of the mode-switching charging signal and/or the mode-switching discharging signal until a switching cycle of the mode-switching charging signal and/or the mode-switching discharging signal and the switching capacitor The converter corresponds to a resonant frequency of the first conversion mode or the second conversion mode.

In one embodiment, the conversion mode includes a first conversion mode and a second conversion mode, during the mode switching, when the second voltage reaches a preset voltage of the second conversion mode or the first conversion mode During a predetermined period of time, the at least two forward switches having the internally connected diodes forward towards the second voltage among the plurality of switches are controlled by the charge operation signal and/or the discharge operation signal.

In one embodiment, the switched capacitor voltage conversion circuit has a bidirectional conversion function.

The advantage of the present invention is that the present invention can reduce the inrush current generated during the mode switching period by reducing the duty cycle to a preset value and gradually increasing the duty cycle to allow the inductor current to freewheel during the mode switching period, and can provide More operating modes with different voltage conversion ratios can limit the switching current during mode switching without stopping or resetting the switched capacitor converter during mode switching.

In the following detailed description by means of specific embodiments, it will be easier to understand the purpose, technical content, characteristics and effects of the present invention.

The diagrams in the present invention are all schematic and mainly intended to show the coupling relationship between various circuits and the relationship between various signal waveforms. As for the circuits, signal waveforms and frequencies, they are not drawn to scale.

FIG. 2A is a schematic circuit diagram showing a switched capacitor voltage conversion circuit according to an embodiment of the present invention. As shown in FIG. 2A , the switched capacitor voltage conversion circuit 20 is used to convert the first voltage V1 into the second voltage V2 or convert the second voltage V2 into the first voltage V1 . The switched capacitor voltage conversion circuit 20 includes a control circuit 201 and a switched capacitor converter 202 . The switched capacitor converter 202 is coupled between the first voltage V1 and the second voltage V2. The control circuit 201 is used to determine the switched capacitor converter 202 to operate in a conversion mode with the voltage conversion ratio according to the voltage conversion ratio, and generate a control signal to control the switched capacitor converter 202 to convert the first voltage V1 into a second voltage V2 or transform the second voltage V2 into the first voltage V1. Wherein, the aforementioned voltage conversion ratio is the ratio of the first voltage V1 to the second voltage V2.

In this embodiment, the control signal includes a charging operation signal GA and at least one discharging operation signal GB, and the switching of the plurality of switches Q1~Q7 is controlled by the charging operation signal GA or the discharging operation signal GB, so that the switched capacitor converter 202 operates at the first One conversion mode (simultaneous discharge), the first conversion mode (alternate discharge) or the second conversion mode. In this embodiment, the switched capacitor converter 202 operates in the first conversion mode (simultaneous discharge), that is, the ratio of the first voltage V1 to the second voltage V2 is 3:1, and the discharge path is connected in parallel and in the discharge process discharge at the same time. The switched capacitor converter 202 includes at least two capacitors C1 and C2 , a plurality of switches Q1 - Q7 and at least one inductor L. The plurality of switches Q1-Q7 are coupled to at least two capacitors C1 and C2.

In the charging process of the first conversion mode (simultaneous discharge), the switching of the switches Q1, Q2 and Q3 is controlled by the charging operation signal GA, so that at least two capacitors C1 and C2 and the corresponding inductance L are connected in series between the first voltage V1 and the second voltage. Between the two voltages V2 to form a charging path and resonant operation. In at least one discharge process of the first conversion mode (simultaneous discharge), the switching of the switches Q4~Q7 is controlled by the discharge operation signal GB, so that at least two capacitors C1 and C2 and the corresponding inductance L are connected in series with the second voltage V2 and the corresponding inductor L respectively. Between the DC potential (in this embodiment, the DC potential is the ground potential), and "simultaneously" forms a plurality of discharge paths and operates in resonance. In the first conversion mode (simultaneous discharge), the charging process and at least one discharging process are repeatedly interleaved with each other to convert the first voltage V1 to the second voltage V2 or convert the second voltage V2 to the first voltage V1. In the first conversion mode (simultaneous discharge), the charge operation signal GA and at least one discharge operation signal GB are each switched to a conduction level for a period of conduction, and the plurality of conduction periods do not overlap with each other, so that the charging process is consistent with at least one conduction period. The discharge programs do not overlap each other.

FIG. 2B is a schematic diagram showing signal waveforms of related signals of a switched capacitor voltage conversion circuit according to an embodiment of the present invention. The second voltage V2 , the inductor current IL, the capacitor current IC1 , the charge operation signal GA and the discharge operation signal GB are shown in FIG. 2B . As shown in FIG. 2B, in the first conversion mode (simultaneous discharge), the charge operation signal GA and at least one discharge operation signal GB are respectively switched to a conduction level for a period of conduction, and the conduction periods of the plurality of periods do not overlap with each other, so that The charging program and at least one discharging program are not overlapped with each other.

FIG. 2C is a block diagram showing a control circuit of a switched capacitor voltage conversion circuit according to an embodiment of the present invention. Please refer to FIG. 2C and FIG. 2A at the same time, the control circuit 201 includes a current sensing circuit 2011 , a control signal generating circuit 2012 and a voltage sensing circuit 2013 . The current sensing circuit 2011 is used to sense the current flowing through at least one inductor L to generate at least one current sensing signal Cd, and the control signal generating circuit 2012 is coupled to the current sensing circuit 2011 for according to the current sensing signal Cd generates control signals such as a charge operation signal GA and a discharge operation signal GB. The voltage sensing circuit 2013 is used for sensing the second voltage V2 to generate a voltage sensing signal Vd. It should be noted that the control circuit 201 can also determine the charging operation signal GA and the discharging operation signal GB only according to the voltage conversion ratio between the first voltage V1 and the second voltage V2, and control the switched capacitor converter 202 in an open-loop manner. Instead of the embodiment shown in FIG. 2C , control signals such as the charge operation signal GA and the discharge operation signal GB are generated according to the current sensing signal Cd to control the switched capacitor converter 202 in a closed-loop feedback manner.

FIG. 3A is a schematic circuit diagram showing a switched capacitor voltage conversion circuit according to another embodiment of the present invention. In this embodiment, the switched capacitor converter 202 operates in the first switching mode (discharging in turn). The difference between this embodiment and the embodiment of FIG. 2A is that in this embodiment, in at least one discharge procedure of the first conversion mode (discharging in turn), the switches Q4 and Q5 and the switches Q6 and Q6 are respectively controlled by the discharge operation signals GB and GC. The switching of Q7 makes at least two capacitors C1 and C2 and the corresponding inductance L connected in series between the second voltage V2 and the DC potential (in this embodiment, the DC potential is the ground potential), and "take turns" to form multiple discharge paths and resonant operation.

FIG. 3B is a schematic diagram showing signal waveforms of related signals of a switched capacitor voltage conversion circuit according to an embodiment of the present invention. The second voltage V2, the inductor current IL, the capacitor current IC1, the charge operation signal GA, the discharge operation signal GB, and the discharge operation signal GC are shown in FIG. 3B. As shown in FIG. 3B, in the first switching mode (discharging in turn), the charging operation signal GA, the discharging operation signal GB, and the discharging operation signal GC are respectively switched to a conduction level for a period of conduction, and the conduction periods of the plurality of periods are different from each other. overlapping, so that the charging procedure and at least one discharging procedure do not overlap with each other.

FIG. 4A is a schematic circuit diagram showing a switched capacitor voltage conversion circuit according to yet another embodiment of the present invention. The embodiment of FIG. 4A is similar to the embodiment of FIG. 2A. The difference is that in this embodiment, the switch Q6 is always on, and the switches Q3 and Q7 are always off, so that the switched capacitor converter 202 operates in the second conversion mode. That is, the voltage conversion ratio between the first voltage V1 and the second voltage V2 is 2:1. In the charging process of the second conversion mode, the switching of the switches Q1 and Q2 is controlled by the charging operation signal GA, so that at least one capacitor C1 and the corresponding inductor L are connected in series between the first voltage V1 and the second voltage V2 to form a charging path and resonant operation. In at least one discharge process of the second conversion mode, the switching of the switches Q4 and Q5 is controlled by the discharge operation signal GB, so that at least one capacitor C1 and the corresponding inductance L are connected in series between the second voltage V2 and the DC potential to form a discharge path and resonant operation.

FIG. 4B is a schematic diagram showing signal waveforms of related signals of a switched capacitor voltage conversion circuit according to an embodiment of the present invention. The second voltage V2 , the inductor current IL, the capacitor current IC1 , the charge operation signal GA and the discharge operation signal GB are shown in FIG. 4B . As shown in FIG. 4B , in the second conversion mode, the charge operation signal GA and the discharge operation signal GB are respectively switched to a conduction level for a period of conduction, and the conduction periods of the plurality of periods do not overlap with each other, so that the charging process is compatible with at least one The discharge programs do not overlap each other.

FIG. 5A shows a list of switch states during mode switching of a switched capacitor voltage conversion circuit according to an embodiment of the present invention. Referring to the left side of FIG. 5A, when the control circuit 201 switches the current conversion mode, such as the second conversion mode, to the next conversion mode, such as the first conversion mode (discharge in turn), the control signal is changed to The mode switching control signal includes the mode switching charging signal GA', the mode switching discharging signals GB' and GC', and the one-way communication signal GD'. Among them, the unidirectional communication signal GD' is used to control the forward switches Q2, Q3, Q5, and Q7 among the complex switches Q1~Q7, and operate in the unidirectional conduction mode. In the unidirectional conduction mode, the forward switches Q2, Q3, and Q5 , each switch in Q7 has a forward-conducting current channel toward the second voltage V2, as shown by the dotted arrows in FIG. 4A and FIG. 3A. Among them, the mode switching charging signal GA' and the mode switching discharging signals GB' and GC' control the switching of other switches Q1, Q4, Q6 except the forward switches Q2, Q3, Q5, Q7 operating in the unidirectional conduction mode, And convert the first voltage V1 into the second voltage V2.

The mode switching charging signal GA' and the mode switching discharging signals GB' and GC' are similar to the charging operation signal GA and the discharging operation signal GB and GC. In the charging process during the mode switching period, the switching of the switch Q1 is controlled by the mode switching charging signal GA', and the current channel of the switch Q2 and the switch Q3 is forward-conducted toward the second voltage V2, so that the capacitors C1 and C2 are connected to the corresponding The inductor L is connected in series between the first voltage V1 and the second voltage V2 to form a charging path but does not necessarily operate in resonance. In at least one discharge process during the mode switching period, the switching of the switches Q4 and Q6 is controlled by the mode switching discharge signals GB' and GC', and the current channel of the switch Q5 and the switch Q7 is forward-conducted toward the second voltage V2, so that The capacitors C1 and C2 and the corresponding inductors L are respectively connected in series between the second voltage V2 and the DC potential (in this embodiment, the DC potential is the ground potential) to form a plurality of discharge paths in turn but not necessarily resonant operation. During the mode switching period (discharging in turn), the charging procedure during the mode switching period and at least one discharging procedure during the mode switching period are repeatedly interleaved with each other, so as to convert the first voltage V1 into the second voltage V2 . During the mode switching period (discharging in turn), the mode switching charging signal GA' and at least one mode switching discharging signal GB' and GC' are respectively switched to a conduction level for a conduction period, and the plurality of conduction periods do not overlap with each other, so that The charging procedure during the mode switching and at least one discharging procedure during the mode switching are not overlapped with each other.

Please continue to refer to FIG. 5A. For example, among the plurality of switches Q1-Q7, there are at least two forward switches (such as but not limited to switches Q2, Q3, Q5, Q7) connected to the diodes in the forward direction of the second voltage V2. It is operated in a unidirectional conduction mode, and among the plurality of switches Q1~Q7, there are at least two forward switches (such as but not limited to switches Q1, Q4, Q6) except for at least two forward switches that have diodes connected in the forward direction of the second voltage V2. It is controlled by the mode switching charging signal GA' and the mode switching discharging signals GB' and GC'. In the unidirectional conduction mode, there are at least two forward switches such as but not limited to switches Q2 , Q3 , Q5 , Q7 , with diodes connected in the forward direction toward the second voltage V2 . During mode switching, the switches Q2 , Q3 , Q5 , and Q7 are always on, or are always off but have internally connected diodes in the forward direction of the second voltage V2 .

The mode switching charging signal GA' and the mode switching discharging signal GB' and GC' operate the switches Q1, Q4, and Q6 in a manner similar to that of the charging operation signal GA and the discharging operation signal GB controlling the switching of the plurality of switches Q1~Q7.

Please refer to the right side of FIG. 5A , when the control circuit 201 switches the current conversion mode, such as the first conversion mode (rotating discharge), to the next conversion mode, such as the mode switching between the second conversion modes, the control signal is changed to The mode switching control signal includes the mode switching charging signal GA', the mode switching discharging signals GB' and GC', and the one-way communication signal GD'. Among them, the unidirectional communication signal GD' is used to control the forward switches Q2, Q3, Q5, and Q7 among the complex switches Q1~Q7, and operate in the unidirectional conduction mode. In the unidirectional conduction mode, the forward switches Q2, Q3, and Q5 Each of the switches in Q7 has a forward-conducting current channel toward the second voltage V2. Among them, the mode switching charging signal GA' and the mode switching discharging signal GB' control the switching of other switches Q1, Q4, and Q6 except the forward switches Q2, Q3, Q5, and Q7 operating in the unidirectional conduction mode (mode switching charging The signal GA' controls the switches Q1 and Q6, and the mode switching discharge signal GB' controls the switch Q4) to convert the first voltage V1 into the second voltage V2.

In one embodiment, during the mode switching period, the control circuit 201 can control the duty cycle of the mode switching charging signal GA' and/or the mode switching discharging signals GB' and GC', correspondingly lower than the previous charging operation signal GA and/or Or the duty cycle of the discharge operation signal GB and GC, and the duty cycle of the mode switching charging signal GA' and/or the mode switching discharge signal GB' and GC' gradually increases from the default value, so that during the mode switching period, the corresponding The capacitance cross voltage of the capacitors C1 and/or C2 gradually increases or decreases, and limits the change speed of the inductor current IL flowing through the inductor L. In one embodiment, after the control circuit 201 controls the duty cycle of the mode switching charging signal GA' and/or the mode switching discharging signals GB' and GC' to a preset value, the control circuit 201 switches the mode switching charging signal GA' and The duty ratio of/or the mode switching discharge signal GB' gradually increases until the switching cycle of the mode switching charging signal GA' and/or the mode switching discharging signals GB' and GC' is between the switching mode of the next switching capacitor converter 202 operation. corresponding to the resonant frequency. In one embodiment, after the switched capacitor converter 202 switches from the first conversion mode to the second conversion mode or from the second conversion mode to the first conversion mode, when the second voltage V2 reaches the second conversion mode or the first conversion mode When the preset voltage of the conversion mode is for a preset period, there are at least two forward switches (for example, not limited to switches Q2, Q3, Q5, Q7) that are connected to the second voltage V2 in the forward direction of the second voltage V2. ) is controlled by the charging operation signal GA and/or the discharging operation signal GB.

In one embodiment, during the mode switching period, the control circuit 201 can control the duty cycle of the mode switching charging signal GA' and/or the mode switching discharging signals GB' and GC' to a preset value and gradually increase, so as to operate multiple switches Among Q1~Q7, at least two forward switches (such as but not limited to switches Q2, Q3, Q5, Q7) with diodes connected in the forward direction towards the second voltage V2 are always conducting, or are always non-conducting but have a direction towards the second voltage V2. When the second voltage V2 is connected to the diode in the forward direction, the inductor current IL flowing through the corresponding inductor L will continue to flow through at least one forward-conducting current channel, so that the inductor current IL flowing toward the second voltage V2 is at a state. In one embodiment, the above state is that the inductor current IL flowing toward the second voltage V2 is a non-resonant current. In a preferred embodiment, the above state is that the inductor current IL flowing toward the second voltage V2 is a linear ramp current.

For example, please refer to FIG. 5A and FIGS. 3A and 4A at the same time. During the mode switching period, the control circuit 201 controls the duty cycle of the mode switching charging signal GA' and/or the mode switching discharging signals GB' and GC' to a preset value. And gradually increase, so that when at least two forward switches (such as but not limited to switches Q2, Q3, Q5, Q7) with diodes connected in the forward direction of the second voltage V2 in the plurality of switches Q1~Q7 are not turned on, One end of the corresponding inductance L is connected to a direct current potential through at least two forward switches (such as forward switches Q3 and Q7 and/or forward switches Q2 and Q5) connected to the body diode, so that The inductor current IL flowing toward the second voltage V2 is a linear ramp current.

In an alternative embodiment, during the mode switching period, the control circuit 201 controls the duty cycle of the mode switching charging signal GA' and/or the mode switching discharging signals GB' and GC' to a preset value and gradually increases, so as to When the switches Q1~Q7 have at least two forward switches (such as but not limited to the forward switches Q2, Q3, Q5, Q7) with diodes connected in the forward direction toward the second voltage V2, when the corresponding inductance L One end is turned on at a DC potential through at least two forward switches (for example, forward switches Q3 and Q7 and/or forward switches Q2 and Q5) that are constantly turned on, so that the inductor current IL flowing toward the second voltage V2 is a linear slope current.

FIG. 5B is a schematic diagram showing a control circuit in a switched capacitor voltage conversion circuit according to an embodiment of the present invention. This embodiment shows a more specific exemplary embodiment of the control circuit 201, but the control circuit 201 of the present invention can also be implemented with other structures. As shown in FIG. 5B , in one embodiment, the control circuit 201 includes a duty ratio determination circuit 2011 , a duty ratio distribution circuit 2012 and a gradual voltage generation circuit 2013 . The duty ratio determination circuit 2011 is used to compare the ramp-up voltage Va generated by the ramp-up voltage generating circuit 2013 at the ramp-up node between the current source CS2 and the capacitor Ca with the periodic waveform signal Vramp to generate a duty ratio signal Vd. The periodic waveform signal Vramp is, for example but not limited to, a triangular wave as shown in FIG. 5C . The duty ratio distribution circuit 2012 is used to generate the mode switching charging signal GA' and the mode switching discharging signals GB' and GC' respectively according to the duty ratio signal Vd. In one embodiment, as shown in FIG. 5B , the duty ratio determining circuit 2011 includes a comparator and a logic AND gate, and the duty ratio distribution circuit 2012 includes a flip-flop and a logic AND gate. The ramp-up voltage generating circuit 2013 includes a current source CS2, a capacitor Ca and a reset switch S2.

During the mode switching period, the current source CS2 of the ramp-up voltage generation circuit 2013 charges the capacitor Ca, so that the ramp-up voltage Va on the ramp-up node gradually rises, and the duty ratio determination circuit 2011 compares the ramp-up voltage Va with the periodic waveform signal Vramp , the duty ratio of the duty ratio signal Vd will gradually increase, and then the duty ratios of the mode switching charging signal GA' and the mode switching discharging signals GB' and GC' will also gradually increase, so that the first voltage V1 is converted to the second When the second voltage V2 or the second voltage V2 is converted into the first voltage V1, the surge current is reduced.

In one embodiment, when the gradually rising voltage Va rises beyond the maximum value of the periodic waveform signal Vramp, the duty ratio distribution circuit 2012 generates the mode switching charging signal GA' and the mode switching discharging signal GB' according to the duty ratio signal Vd. With GC', it can directly enter the first conversion mode (discharge in turn) or the second conversion mode. Of course, after entering the first conversion mode (discharging alternately) or the second conversion mode, the duty ratio distribution circuit 2012 can also be turned off, and other circuits generate the charging operation signal GA and at least one discharging operation signal GB. In addition, the ramp-up voltage generating circuit 2013 can turn on the reset switch S2 at an appropriate time point (for example, before the start of the next mode switching period) according to the reset signal Srst to discharge the capacitor Ca to reset the ramp-up voltage Va.

5C is a schematic diagram showing signal waveforms of related signals of a control circuit of a switched capacitive voltage conversion circuit during mode switching according to an embodiment of the present invention. The ramp-up voltage Va of the ramp-up node, the periodic waveform signal Vramp, the clock signal CLK, the duty cycle signal Vd, the mode switching charging signal GA' and the mode switching discharging signal GB' are shown in FIG. 5C. As shown in FIG. 5C , the ramp-up voltage Va of the ramp-up node increases gradually during the mode switching period. As shown in FIG. 5C , during the mode switching period, the time lengths of the plurality of conduction periods t1˜t4 are gradually increased. Therefore, in one embodiment, the duty cycle is gradually increased from a preset value to 50%.

FIG. 5D is a schematic diagram showing signal waveforms of related signals of a switched capacitor voltage conversion circuit according to an embodiment of the present invention. FIG. 5E is a partial enlarged view of signals related to switching from the second conversion mode to the first conversion mode (alternating discharge) in FIG. 5D during the mode switching period. FIG. 5F is a partial enlarged view of switching from the first conversion mode (alternating discharge) to the second conversion mode in FIG. 5D . The second voltage V2, the second current I2, the inductor current IL, the capacitor voltage VC1, and the capacitor voltage VC2 are shown in FIGS. 5D, 5E and 5F. It can be seen from FIGS. 5D , 5E and 5F that the switched capacitor voltage conversion circuit can further reduce the inrush current by gradually increasing the duration of the conduction period during the mode switching period.

FIG. 6A shows a list of switch states during mode switching of a switched capacitor voltage conversion circuit according to another embodiment of the present invention. Referring to the left side of FIG. 6A, when the control circuit 201 switches the current conversion mode, such as the second conversion mode, to the next conversion mode, such as the first conversion mode (simultaneous discharge), the control signal changes to the mode The switching control signal includes a mode switching charging signal GA', a mode switching discharging signal GB' and a one-way communication signal GD'. Among them, the unidirectional communication signal GD' is used to control the forward switches Q2, Q3, Q5, and Q7 among the complex switches Q1~Q7, and operate in the unidirectional conduction mode. In the unidirectional conduction mode, the forward switches Q2, Q3, and Q5 Each of the switches in Q7 has a forward-conducting current channel toward the second voltage V2. Among them, the mode switching charging signal GA' and the mode switching discharging signal GB' control the switching of other switches Q1, Q4, Q6 except the forward switches Q2, Q3, Q5, Q7 operating in the unidirectional conduction mode, and the second A voltage V1 is converted into a second voltage V2.

Please continue to refer to FIG. 6A, for example, among the plurality of switches Q1~Q7, there are at least two forward switches (such as but not limited to switches Q2, Q3, Q5, Q7) connected to the second voltage V2 with diodes in the forward direction. It is operated in a unidirectional conduction mode, and among the plurality of switches Q1~Q7, there are at least two forward switches (such as but not limited to switches Q1, Q4, Q6) except for at least two forward switches that have diodes connected in the forward direction of the second voltage V2. It is controlled by the mode switching charging signal GA' or the mode switching discharging signal GB'. In the unidirectional conduction mode, at least two forward switches (such as but not limited to switches Q2, Q3, Q5, Q7) with diodes connected in the forward direction toward the second voltage V2 are always conducting, or are always not conducting but The current can flow through the inner connecting diode forwardly toward the second voltage V2.

Please refer to the right side of FIG. 6A , when the control circuit 201 switches the current conversion mode, such as the first conversion mode (simultaneous discharge), to the next conversion mode, such as the mode switching period between the second conversion mode, the control signal is changed to The mode switching control signal includes a mode switching charging signal GA', a mode switching discharging signal GB' and a one-way communication signal GD'. Among them, the unidirectional communication signal GD' is used to control the forward switches Q2, Q3, Q5, and Q7 among the complex switches Q1~Q7, and operate in the unidirectional conduction mode. In the unidirectional conduction mode, the forward switches Q2, Q3, and Q5 Each of the switches in Q7 has a forward-conducting current channel toward the second voltage V2. Among them, the mode switching charging signal GA' and the mode switching discharging signal GB' control the switching of other switches Q1, Q4, and Q6 except the forward switches Q2, Q3, Q5, and Q7 operating in the unidirectional conduction mode (mode switching charging The signal GA' controls the switches Q1 and Q6, and the mode switching discharge signal GB' controls the switch Q4) to convert the first voltage V1 into the second voltage V2.

In one embodiment, during the mode switching period, the control circuit 201 can control the duty cycle of the mode switching charging signal GA' and/or the mode switching discharging signals GB' and GC', correspondingly lower than the previous charging operation signal GA and/or Or the duty cycle of the discharge operation signal GB and GC, and the duty cycle of the mode switching charging signal GA' and/or the mode switching discharge signal GB' and GC' gradually increases from the default value, so that during the mode switching period, the corresponding The capacitance cross voltage of the capacitors C1 and/or C2 gradually increases or decreases, and limits the change speed of the inductor current IL flowing through the inductor L. In one embodiment, after the control circuit 201 controls the duty cycle of the mode switching charging signal GA' and/or the mode switching discharging signals GB' and GC' to a preset value, the control circuit 201 switches the mode switching charging signal GA' and The duty ratio of/or the mode switching discharge signal GB' gradually increases until the switching cycle of the mode switching charging signal GA' and/or the mode switching discharging signals GB' and GC' is between the switching mode of the next switching capacitor converter 202 operation. corresponding to the resonant frequency. In one embodiment, after the switched capacitor converter 202 switches from the first conversion mode to the second conversion mode or from the second conversion mode to the first conversion mode, when the second voltage V2 reaches the second conversion mode or the first conversion mode When the preset voltage of the conversion mode is for a preset period, there are at least two forward switches (for example, not limited to switches Q2, Q3, Q5, Q7) that are connected to the second voltage V2 in the forward direction of the second voltage V2. ) is controlled by the charging operation signal GA and/or the discharging operation signal GB.

In one embodiment, during the mode switching period, the control circuit 201 can control the duty cycle of the mode switching charging signal GA' and/or the mode switching discharging signals GB' and GC' to a preset value and gradually increase, so as to operate multiple switches Q1~Q7 have at least two forward switches (such as but not limited to switches Q2, Q3, Q5, Q7) with diodes connected in the forward direction toward the second voltage V2. They are always conducting, or are always not conducting but current can flow. When the diode is forwardly connected to the second voltage V2, the inductance current IL flowing through the corresponding inductance L will continue to flow through at least one forward-conducting current channel, thereby making the inductance flowing towards the second voltage V2 The current IL is in a state. In one embodiment, the above state is that the inductor current IL flowing toward the second voltage V2 is a non-resonant current. In a preferred embodiment, the above state is that the inductor current IL flowing toward the second voltage V2 is a linear ramp current.

For example, please refer to FIG. 6A and FIGS. 2A and 4A at the same time. During the mode switching period, the control circuit 201 controls the duty cycle of the mode switching charging signal GA' and/or the mode switching discharging signals GB' and GC' to a preset value. And gradually increase, so that when at least two forward switches (such as but not limited to switches Q2, Q3, Q5, Q7) with diodes connected in the forward direction of the second voltage V2 in the plurality of switches Q1~Q7 are not turned on, One end of the corresponding inductance L is connected to a direct current potential through at least two forward switches (such as forward switches Q3 and Q7 and/or forward switches Q2 and Q5) connected to the body diode, so that The inductor current IL flowing toward the second voltage V2 is a linear ramp current.

In an alternative embodiment, during the mode switching period, the control circuit 201 controls the duty cycle of the mode switching charging signal GA' and/or the mode switching discharging signals GB' and GC' to a preset value and gradually increases, so as to When the switches Q1~Q7 have at least two forward switches (such as but not limited to switches Q2, Q3, Q5, Q7) with diodes connected in the forward direction toward the second voltage V2, when they are constantly turned on, one end of the corresponding inductance L is turned on. The at least two forward switches (for example, switches Q3 and Q7 and/or switches Q2 and Q5 ) that are constantly turned on are turned on at the DC potential, so that the inductor current IL flowing toward the second voltage V2 is a linear ramp current.

FIG. 6B is a schematic diagram showing signal waveforms of related signals of a switched capacitor voltage conversion circuit according to an embodiment of the present invention. The second voltage V2, the second current I2, the inductor current IL, the capacitor voltage VC1, and the capacitor voltage VC2 are shown in FIG. 6B. It can be seen from FIG. 6B that the switched capacitor voltage conversion circuit can further reduce the inrush current by gradually increasing the length of the conduction period during the mode switching period.

FIG. 7 is a schematic circuit diagram showing a switched capacitor voltage conversion circuit according to yet another embodiment of the present invention. As shown in FIG. 7 , the switched capacitor converter 602 of the switched capacitor voltage conversion circuit 60 of the present invention includes capacitors C1 - C3 , switches Q1 - Q10 , and an inductor L. As shown in FIG. The switches Q1-Q3 are connected in series with the corresponding capacitors C1-C3 respectively, and the switch Q4 is connected in series with the inductor L.

The switches Q1-Q10 can switch the electrical connection relationship between the corresponding capacitors C1-C3 and the inductor L according to the corresponding operation signal. In the charging process, according to the charging operation signal GA, the switches Q1-Q4 are turned on, and the switches Q5-Q10 are turned off, so that the capacitors C1-C3 are connected in series with each other and the inductor L is connected in series to the first voltage V1 and the second voltage V2. Between to form a charging path. In the discharge process, according to the discharge operation signal GB, the switches Q5-Q10 are turned on, and the switches Q1-Q4 are not turned on, so that the capacitors C1-C3 are connected in parallel and the inductance L is connected in series between the second voltage V2 and the ground potential to form Multiple discharge paths. It should be noted that the above-mentioned charging process and the above-mentioned discharging process are repeatedly interleaved in different time periods, but not simultaneously, so as to convert the first voltage V1 into the second voltage V2 or convert the second voltage V2 into the first voltage V2. Voltage V1. In this embodiment, the DC bias voltage of each of the capacitors C1 - C3 is the second voltage V2 , so the capacitors C1 - C3 in this embodiment need to withstand a lower rated voltage, so capacitors with smaller volumes can be used.

The control circuit 601 and the operation method of this embodiment can be implemented similarly to the control circuit structure and operation method of FIGS. 2A, 2C, 3A, 4A, 5A and 6A. Please refer to FIGS. The detailed description. The freewheeling mode of the inductor current during mode switching is similar to that shown in FIGS. 5A and 6A , such as but not limited to switches Q2, Q3, Q4, Q6, Q8, and Q10. Please refer to the detailed description of 5A and 6A.

FIG. 8 is a schematic circuit diagram showing a switched capacitor voltage conversion circuit according to yet another embodiment of the present invention. As shown in FIG. 8 , the switched capacitor converter 702 of the switched capacitor voltage conversion circuit 70 of the present invention includes capacitors C1 - C4 , switches Q1 - Q13 , and an inductor L. As shown in FIG. The switches Q1-Q4 are connected in series with the corresponding capacitors C1-C4 respectively, and the switch Q5 is connected in series with the inductor L.

The switches Q1-Q13 can switch the electrical connection relationship between the corresponding capacitors C1-C4 and the inductor L according to the corresponding operation signal. In the charging process, according to the charging operation signal GA, the switches Q1-Q5 are turned on, and the switches Q6-Q13 are turned off, so that the capacitors C1-C4 are connected in series with each other and the inductor L is connected in series to the first voltage V1 and the second voltage V2. Between to form a charging path. In the discharge process, according to the discharge operation signal GB, the switches Q6-Q13 are turned on, and the switches Q1-Q5 are not turned on, so that the capacitors C1~C4 are connected in parallel and the inductance L is connected in series between the second voltage V2 and the ground potential to form Multiple discharge paths. It should be noted that the above-mentioned charging process and the above-mentioned discharging process are repeatedly interleaved in different time periods, but not simultaneously, so as to convert the first voltage V1 into the second voltage V2 or convert the second voltage V2 into the first voltage V2. Voltage V1. In this embodiment, the DC bias voltage of each of the capacitors C1 - C4 is the second voltage V2 , so the capacitors C1 - C4 in this embodiment need to withstand a lower rated voltage, so capacitors with smaller volumes can be used.

The control circuit 701 and the operation mode of this embodiment can be implemented similarly to the control circuit structure and operation mode of Fig. 2A, 2C, 3A, 4A, 5A and 6A, please refer to Fig. The detailed description. The freewheeling mode of the inductor current during mode switching is similar to that shown in Figures 5A and 6A, such as but not limited to switches Q2, Q3, Q4, Q5, Q7, Q9, Q11, Q13, please refer to the detailed description of 5A and 6A .

As mentioned above, the present invention provides a switched capacitor voltage conversion circuit, which reduces the duty cycle generated during the mode switching period by reducing the duty cycle to a preset value and gradually increasing the duty cycle while allowing the inductor current to freewheel. The inrush current can provide more operating modes with different voltage conversion ratios, the switching current can be limited during mode switching, and there is no need to stop or reset the switched capacitor converter during mode switching.

In the above-mentioned embodiments, the circuit for converting the first voltage V1 to the second voltage V2 is also applicable to converting the second voltage V2 to the first voltage V1. The control circuit selects the ratio between the first voltage V1 and the second voltage V2 according to the level of the second voltage V2, and then generates a control signal to convert the second voltage V2 into the first voltage V1. Wherein, the control circuit 201 selects to make the switched capacitor converter 202 operate in one of the second conversion mode, the first conversion mode (simultaneous discharge) and the first conversion mode (rotational discharge) according to the first voltage V1; the same circuit It can also be operated such that the control circuit 201 selects to operate the switched capacitor converter 202 in one of the one-to-two mode, one-to-three mode (simultaneous discharge) and one-to-three mode (alternate discharge) according to the second voltage V2.

It should be noted that, in all the above embodiments, the switched capacitor voltage conversion circuit has a bidirectional conversion function, that is, the first voltage V1 can be converted into the second voltage V2 or the second voltage V2 can be converted into the first voltage V1. When the switched capacitive voltage conversion circuit is applied to convert the second voltage V2 into the first voltage V1, during the mode switching, the unidirectional communication signal is used to control the forward switch in the plurality of switches to operate in the unidirectional conduction mode, wherein in the single In the conduction mode, each switch in the forward switch needs to have a current channel forward conducting towards the first voltage V1.

The present invention has been described above with regard to preferred embodiments, but the above description is only for making the content of the present invention easy for those skilled in the art, and is not intended to limit the broadest scope of rights of the present invention. The various embodiments described are not limited to single application, and can also be used in combination. For example, two or more embodiments can be used in combination, and some components in one embodiment can also be used to replace another embodiment. corresponding components. In addition, under the same spirit of the present invention, those skilled in the art can think of various equivalent changes and various combinations. For example, the term "processing or computing according to a certain signal or generating a certain output result" in the present invention is not limited to According to the signal itself, it also includes performing voltage-current conversion, current-voltage conversion, and/or ratio conversion on the signal when necessary, and then processing or computing the converted signal to generate a certain output result. It can be seen that under the same spirit of the present invention, those skilled in the art can think of various equivalent changes and various combinations, and there are many combinations, which will not be listed here. Accordingly, the scope of the invention should encompass the above and all other equivalent variations.

10: Resonant Switched Capacitor Voltage Converter 20, 30, 40, 60, 70: Switched capacitive voltage conversion circuits 201, 601, 701: Control circuits 2011: Current sensing circuit 2012: Control signal generation circuit 2013: Voltage sensing circuit 202, 602, 702: Switched capacitor converters C1~C4 , Ca, CV2: capacitance Cd: current sense signal CLK: clock signal CS2: Current Source GA: charging operation signal GA’: mode switching charging signal GB, GC: discharge operation signal GB’, GC’: mode switching discharge signal GD’: one-way communication number I1: first current I2: second current IC1: capacitive current IL: inductor current L: inductance Lgc-H: signal Q1~Q13: switch S2: Reset switch Srst: reset signal t1~t4: conduction period V1: first voltage V2: second voltage Va: rising voltage Vd: voltage sensing signal Vin: input voltage Vm: intermediate signal Vout: output voltage Vramp: periodic waveform signal

FIG. 1 is a schematic diagram of a conventional resonant switched capacitor voltage converter.

FIG. 2A is a schematic circuit diagram showing a switched capacitor voltage conversion circuit according to an embodiment of the present invention.

FIG. 2B is a schematic diagram showing signal waveforms of related signals of a switched capacitor voltage conversion circuit according to an embodiment of the present invention.

FIG. 2C is a block diagram showing a control circuit of a switched capacitor voltage conversion circuit according to an embodiment of the present invention.

FIG. 3A is a schematic circuit diagram showing a switched capacitor voltage conversion circuit according to another embodiment of the present invention.

FIG. 3B is a schematic diagram showing signal waveforms of related signals of a switched capacitor voltage conversion circuit according to an embodiment of the present invention.

FIG. 4A is a schematic circuit diagram showing a switched capacitor voltage conversion circuit according to yet another embodiment of the present invention.

FIG. 4B is a schematic diagram showing signal waveforms of related signals of a switched capacitor voltage conversion circuit according to an embodiment of the present invention.

FIG. 5A shows a list of switch states during mode switching of a switched capacitor voltage conversion circuit according to an embodiment of the present invention.

FIG. 5B is a schematic diagram showing a control circuit in a switched capacitor voltage conversion circuit according to an embodiment of the present invention.

5C is a schematic diagram showing signal waveforms of related signals of a control circuit of a switched capacitive voltage conversion circuit during mode switching according to an embodiment of the present invention.

FIG. 5D is a schematic diagram showing signal waveforms of related signals of a switched capacitor voltage conversion circuit according to an embodiment of the present invention.

FIG. 5E is a partial enlarged view of switching from the second conversion mode to the first conversion mode (in turn) in FIG. 5D .

FIG. 5F is a partial enlarged view of switching from the first conversion mode (in turn) to the second conversion mode in FIG. 5D .

FIG. 6A shows a list of switch states during mode switching of a switched capacitor voltage conversion circuit according to another embodiment of the present invention.

FIG. 6B is a schematic diagram showing signal waveforms of related signals of a switched capacitor voltage conversion circuit according to an embodiment of the present invention.

FIG. 7 is a schematic circuit diagram showing a switched capacitor voltage conversion circuit according to yet another embodiment of the present invention.

FIG. 8 is a schematic circuit diagram showing a switched capacitor voltage conversion circuit according to yet another embodiment of the present invention.

20: Switched capacitive voltage conversion circuit 201: Control circuit 202: Switched Capacitor Converter C1, C2 , CV2: capacitors GA: charging operation signal GA’: mode switching charging signal GB: discharge operation signal GB’: mode switching discharge signal GD’: one-way communication number I1: first current I2: second current IC1: capacitive current IL: inductor current L: inductance Q1~Q7: switch V1: first voltage V2: second voltage

Claims (23)

A switched capacitor voltage conversion circuit for converting a first voltage into a second voltage, the switched capacitor voltage conversion circuit comprising: a switched capacitor converter coupled between the first voltage and the second voltage and a control circuit for determining, according to a voltage conversion ratio, that the switched capacitor converter operates in a conversion mode having the voltage conversion ratio, and generating a control signal to control the switched capacitor converter according to the conversion mode, and converting the first voltage to the second voltage; wherein the switched capacitor converter includes: at least two capacitors; a plurality of switches coupled to the at least two capacitors; and at least one inductor; wherein the control signal includes a charging operation signal and at least one discharge operation signal to control the switching of the plurality of switches to convert the first voltage to the second voltage; wherein, in a charging process of the conversion mode, the plurality of Switching of the switch makes at least one capacitor and the corresponding inductor connected in series between the first voltage and the second voltage to form a charging path and resonant operation; wherein, in at least one discharging process of the switching mode, The switching of the plurality of switches is controlled by the discharge operation signal, so that the capacitor and the corresponding inductance are connected in series between the second voltage and a DC potential, and simultaneously or alternately form a plurality of discharge paths and operate in resonance; wherein, in In the conversion mode, the charging procedure and the at least one discharging procedure are repeatedly interleaved with each other, so as to convert the first voltage into the second voltage; Wherein, in the switching mode, the charging operation signal and the at least one discharging operation signal are respectively switched to a conduction level for a period of conduction, and the plurality of conduction periods do not overlap with each other, so that the charging process and the at least one discharge operation signal A discharge procedure does not overlap with each other; wherein, when the control circuit switches the current conversion mode to a mode switching period between the next conversion mode, the control signal is changed to a mode switching control signal, which includes a mode switching charging signal, at least one mode switching discharge signal, and a unidirectional communication signal; wherein the unidirectional communication signal is used to control at least two forward switches in the plurality of switches, operating in a unidirectional conduction mode, wherein in the unidirectional conduction mode , each of the forward switches has a current channel forwardly conducting toward the second voltage; wherein, the mode switching charging signal and the mode switching discharging signal control the at least two forward direction switches operating in the unidirectional conduction mode Switching of the switch other than the switch converts the first voltage into the second voltage. The switched capacitive voltage conversion circuit as described in claim 1, wherein the at least two forward switches operating in the unidirectional conduction mode are constant conduction, or constant non-conduction but have a forward direction toward the second voltage. polar body. The switched capacitor voltage conversion circuit as described in claim 1, wherein during the mode switching period, the duty cycle of the mode switching charging signal and/or the mode switching discharging signal is correspondingly lower than the previous charging operation signal and/or The duty ratio of the discharge operation signal, and the duty ratio of the mode switching charging signal and/or the mode switching discharging signal gradually increases from a preset value, so that during the mode switching period, the corresponding capacitance of the capacitor The trans-pressure gradually increases or decreases. The switched capacitive voltage conversion circuit as described in Claim 1, wherein the control circuit includes: a duty cycle determining circuit, which is used to compare a gradually rising voltage of a gradually rising node with a periodic waveform signal to generate a duty cycle A ratio signal; a duty distribution circuit for generating the mode switching charging signal and the at least one mode switching discharging signal respectively according to the duty ratio signal; and a gradually rising voltage generation circuit, and the duty ratio determination circuit coupled to generate the ramp-up voltage of the ramp-up node during the mode switching period; wherein the ramp-up voltage of the ramp-up node is gradually increased during the mode switching period, so that the mode switching charging signal and the The duty cycle of the at least one mode switching discharge signal correspondingly increases gradually. The switched capacitor voltage conversion circuit as claimed in Claim 1, wherein the switched capacitor converter includes a series-parallel switched capacitor converter (series-parallel switched capacitor converter). The switched capacitive voltage conversion circuit as claimed in Claim 1, wherein the DC potential is ground potential. The switched capacitive voltage conversion circuit as described in Claim 1, wherein the control circuit includes: A current sensing circuit, used for sensing the current flowing through the at least one inductor, to generate at least one current sensing signal; and a control signal generating circuit, coupled with the current sensing circuit, for according to the current sensing The test signal is used to generate the control signal. The switched capacitor voltage conversion circuit as claimed in claim 7, wherein the control circuit further includes a voltage sensing circuit for sensing the second voltage to generate a voltage sensing signal. The switched capacitive voltage conversion circuit as described in claim 1, wherein during the mode switching period, the control circuit lowers the duty cycle of the mode switching charging signal and/or the mode switching discharging signal to a preset value, so as to limit the inductor current flowing through one of the inductors. The switched capacitive voltage conversion circuit as described in claim 9, wherein the conversion mode includes a first conversion mode and a second conversion mode, when the control circuit lowers the mode switching charging signal and/or the mode switching discharging signal After the duty cycle reaches the preset value, the control circuit gradually increases the duty cycle of the mode switching charging signal and/or the mode switching discharging signal until the mode switching charging signal and/or the mode switching discharging signal A switching period of the signal corresponds to a resonant frequency of the switched capacitor converter in the first conversion mode or the second conversion mode. The switched capacitive voltage conversion circuit as described in claim 2, wherein the conversion mode includes a first conversion mode and a second conversion mode, and during the mode switching period, when the second voltage reaches the second conversion mode or the The first conversion mode is a preset voltage for a preset period when the Among the plurality of switches, the at least two forward switches having the internally connected diodes forward towards the second voltage are controlled by the charge operation signal and/or the discharge operation signal. The switched capacitive voltage conversion circuit according to claim 1, wherein the switched capacitive voltage conversion circuit has a bidirectional conversion function. A switched capacitor voltage conversion method for converting a first voltage of a switched capacitor converter into a second voltage. The switched capacitor converter includes at least two capacitors, a plurality of switches and at least one inductor. The switched capacitor voltage The conversion method includes: according to a voltage conversion ratio, determining that the switched capacitor converter operates in a conversion mode with the voltage conversion ratio, and generating a control signal according to the conversion mode to control the plurality of switches in the switched capacitor converter switch, and convert the first voltage to the second voltage, wherein the control signal includes a charging operation signal and at least one discharging operation signal; in a charging procedure of the conversion mode, the plurality of Switching of the switch makes at least one capacitor and the corresponding inductor connected in series between the first voltage and the second voltage to form a charging path and resonant operation; in at least one discharging process of the switching mode, by The discharge operation signal controls the switching of the plurality of switches, so that the capacitance and the corresponding inductance are connected in series between the second voltage and a DC potential, and simultaneously or alternately form a plurality of discharge paths and operate in resonance; in the switching mode , the charging procedure and the at least one discharging procedure are repeatedly interleaved with each other, so as to convert the first voltage into the second voltage; In the conversion mode, the charge operation signal and the at least one discharge operation signal are respectively switched to a conduction level for a period of conduction, and the plurality of conduction periods do not overlap with each other, so that the charge process and the at least one discharge The procedures do not overlap with each other; during a mode switching between the current conversion mode and the next conversion mode, the control signal is changed to a mode switching control signal, which includes a mode switching charging signal, at least one mode switching discharge signal and a unidirectional communication signal; use the unidirectional communication signal to control at least two forward switches in the plurality of switches to operate in a unidirectional conduction mode, wherein in the unidirectional conduction mode, each of the forward switches having a current channel forward conducting toward the second voltage; and using the mode switching charging signal and the mode switching discharging signal to control the other switches except the at least two forward switches operating in the unidirectional conduction mode switch to convert the first voltage to the second voltage. The switched capacitive voltage conversion method as described in claim 13, wherein the at least two forward switches operating in the unidirectional conduction mode are constant conduction, or constant non-conduction but have a forward direction toward the second voltage. polar body. The switched capacitive voltage conversion method as described in claim 13, further comprising: during the mode switching period, adjusting the duty cycle of the mode switching charging signal and/or the mode switching discharging signal to be lower than the previous charging operation signal and/or the duty cycle of the discharge operation signal; and During the mode switching period, adjusting the duty cycle of the mode switching charging signal and/or the mode switching discharging signal is gradually increased from a preset value, so that during the mode switching period, the corresponding capacitance across the capacitor is gradually increased. increase or decrease. The switched capacitive voltage conversion method as described in claim 13, further comprising: comparing a gradually rising voltage of a gradually rising node with a periodic waveform signal to generate a duty ratio signal; and generating respectively according to the duty ratio signal The mode switching charging signal and the at least one mode switching discharging signal; and during the mode switching period, generating the ramping up voltage of the ramping up node; wherein the ramping up voltage of the ramping up node is gradually rising during the mode switching period , so that the duty cycle of the mode-switching charging signal and the at least one mode-switching discharging signal increases gradually. The switched capacitor voltage conversion method as claimed in claim 13, wherein the switched capacitor converter includes a series-parallel switched capacitor converter (series-parallel switched capacitor converter). The switched capacitive voltage conversion method as claimed in claim 13, wherein the DC potential is a ground potential. The switched capacitive voltage conversion method as described in claim 13, further comprising: sensing the current flowing through the at least one inductor to generate at least one current sensing signal; and generating the charging operation signal according to the current sensing signal and the at least one discharge operation signal. The switched capacitive voltage conversion method as claimed in claim 19 further includes: sensing the second voltage to generate a voltage sensing signal. The switched capacitive voltage conversion method as described in claim 13 further includes: during the mode switching period, lowering the duty cycle of the mode switching charging signal and/or the mode switching discharging signal to a preset value to limit The inductor current flows through one of the inductors. The switched capacitive voltage conversion method as described in claim 21, wherein the conversion mode includes a first conversion mode and a second conversion mode, and the duty of the mode switching charging signal and/or the mode switching discharging signal is lowered After the duty cycle reaches the preset value, it further includes: gradually increasing the duty cycle of the mode switching charging signal and/or the mode switching discharging signal until one of the mode switching charging signal and/or the mode switching discharging signal The switching period corresponds to a resonant frequency of the switched capacitor converter in the first conversion mode or the second conversion mode. The switched capacitive voltage conversion method as described in claim 14, wherein the conversion mode includes a first conversion mode and a second conversion mode, and when switching from the first conversion mode to the second conversion mode or from the second After the conversion mode is switched to the first conversion mode, when the second voltage reaches a preset voltage of the second conversion mode or the first conversion mode for a preset period, the plurality of switches have a sequence toward the second voltage The at least two forward switches to the inner diode are controlled by the charge operation signal and/or the discharge operation signal.

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