TW202145685A - Resonant switching power converter - Google Patents

Abstract

The present invention provides a resonant switching power converter including: a plurality of capacitors; a plurality of switches; at least one charging inductor; at least one discharging inductor; and a controller configured to operably generate a charging operation signal and a plurality of discharging operation signals to correspond to a charging process and a plurality of discharging processes respectively, so as to operate corresponding switches for switching electrical connections of corresponding capacitors. In a charging process, the switches are controlled and switched by the controller with the charging operation signal to render the plural capacitors to be electrically connected to the charging inductor in series between an input voltage and an output voltage to form a charging path. In the plural discharging processes, the switches are controlled and switched by the controller with the plural discharging operation signals to render the capacitors to be electrically connected to the corresponding discharging inductor in series between the output voltage and a ground level individually and alternately to form a plurality of discharging paths.

Description

Resonant Switching Power Converters

The present invention relates to a resonant switching power converter, in particular, to a resonant switching power converter with alternating discharge.

FIG. 1 shows a conventional power converter. During the charging operation, the switches Q1, Q2, Q3, and Q4 are turned on, and the switches Q5, Q6, Q7, Q8, Q9, and Q10 are turned off, so that the capacitors C1, C2, and C3 are connected in series with each other between the input voltage Vin and the output voltage Vout. between. During the discharge operation, the switches Q5, Q6, Q7, Q8, Q9, and Q10 are turned on, and the switches Q1, Q2, Q3, and Q4 are turned off, so that the capacitors C1, C2, and C3 are connected in parallel between the ground potential and the output voltage Vout. . The capacitor of the conventional power converter has a very large inrush current. If the capacitance values of the capacitors C1 , C2 and C3 are different, a circulating current will occur between the capacitors during the discharge operation.

In view of this, the present invention proposes an innovative power converter aiming at the above-mentioned deficiencies of the prior art.

In one aspect, the present invention provides a resonant switching power converter for converting an input voltage into an output voltage, the resonant switching power converter comprising: a complex capacitor; a complex switch, which is correspondingly coupled to the complex capacitor ; at least one charging inductor, corresponding to at least one of the complex capacitors in series; at least one discharging inductor, corresponding to at least one of the complex capacitors in series; and a controller for generating a charging operation signal and A plurality of discharge operation signals respectively correspond to a charging procedure and a plurality of discharging procedures, and operate the corresponding plurality of switches to switch the electrical connection relationship of the corresponding capacitors; wherein, the charging operation signal and each of the plurality of discharging operation signals , respectively switch to a conduction level for a conduction period, and the plurality of conduction periods do not overlap each other, so that the charging process and the plurality of discharging processes do not overlap each other; wherein, in the charging process, the controller uses The charging operation signal controls the switching of the plurality of switches, so that the plurality of capacitors and the at least one charging inductor are connected in series between the input voltage and the output voltage to form a charging path; wherein, in each discharging process, The controller controls the switching of the plurality of switches through the corresponding discharge operation signal, so that the corresponding capacitor and the corresponding discharge inductor are connected in series between the output voltage and a ground potential to form a corresponding discharge path; wherein , the plurality of discharge procedures alternately form the corresponding discharge path; wherein, the charging procedure and the plurality of discharge procedures are repeatedly interleaved and sequenced with each other, so as to convert the input voltage into the output voltage.

In one embodiment, the resonant switching power converter further includes a zero-current detection circuit, coupled between the controller and the output voltage, for detecting a charging resonant current during the charging process or during the charging process. In the complex discharging process, a discharge resonance current is detected, and a zero current detection signal is generated to the controller when the zero current detection circuit detects that the charging resonance current or the discharging resonance current is zero.

In one embodiment, the zero-current detection circuit includes: a current-sensing circuit for sensing the charging resonant current during the charging process or sensing the discharging resonant current during the multiple discharging process to generate a a current sensing signal; and a comparator for comparing the current sensing signal with a reference signal to generate the zero current sensing signal.

In one embodiment, the resonant switching power converter further includes a plurality of switch drivers, which are respectively coupled between the controller and the corresponding switch, and are used for the corresponding charging operation signal or the corresponding discharging operation signal. , and control the complex switches respectively.

In one embodiment, after the plurality of discharge procedures are completed, the next charging procedure starts after a delay time, and during the delay time, all the corresponding switches are turned off.

In one embodiment, the at least one charging inductor is a single charging inductor, and the at least one discharging inductor is a single discharging inductor.

In one embodiment, the inductance value of the single charging inductor is equal to the inductance value of the single discharging inductor.

In one embodiment, the at least one charging inductor and the at least one discharging inductor are a single same inductor.

In one embodiment, the single identical inductor is a variable inductor.

In one embodiment, during the charging process and the complex discharging process, the resonant switching power converter keeps at least one specific one of the plurality of switches on and at least two specific ones of the plurality of switches are not conductive. or to change the voltage conversion ratio of the input voltage to the output voltage.

In one embodiment, the charging process has a charging resonant frequency, and the complex discharging process has a discharging resonant frequency, and the charging resonant frequency is the same as the discharging resonant frequency.

In one embodiment, the charging process has a charging resonant frequency, and the complex discharging process has a discharging resonant frequency, and the charging resonant frequency is different from the discharging resonant frequency.

In one embodiment, the duration of the charging procedure is adjusted to achieve zero-voltage switching for soft switching.

In one embodiment, the duration of the complex discharge procedure is adjusted to achieve zero-voltage switching of soft switching.

In one embodiment, the resonant switching power converter is a bidirectional resonant switching power converter.

In one embodiment, the voltage conversion ratio of the input voltage to the output voltage of the resonant switching power converter is 4:1, 3:1 or 2:1.

In one embodiment, in the charging process, the corresponding turn-on time and non-conduction time of the plurality of switches are synchronized with the start time and end time of a positive half-wave of a charging resonant current in the charging process, so as to achieve flexibility. Zero current switching of soft switching.

In one embodiment, in the complex discharge process, the corresponding turn-on time point and non-conduction time point of the complex switch are synchronized with the start time and The end point to achieve zero-current switching of flexible switching.

One of the advantages of the present invention is that the present invention can solve the inrush current problem and the circulating current problem.

Another advantage of the present invention is that the present invention is easy to achieve flexible switching with zero current switching and/or zero voltage switching and can mask component changes due to DC bias or operating temperature, such as capacitance changes.

Another advantage of the present invention is that the present invention can reduce the switching frequency to improve the efficiency at light load conditions, has better current and voltage balance, and can support resonant switched capacitor power supplies with a voltage conversion ratio of 3:1 or more converter.

The following describes in detail with specific embodiments, when it is easier to understand the purpose, technical content, characteristics and effects of the present invention.

The drawings in the present invention are schematic, mainly intended to represent the coupling relationship between the circuits and the relationship between the signal waveforms, and the circuits, signal waveforms and frequencies are not drawn to scale.

2A shows a schematic circuit diagram of a resonant switching power converter according to an embodiment of the present invention; FIG. 2B shows a schematic diagram of signal waveforms of related signals in the resonant switching power converter shown in FIG. 2A . In this embodiment, a plurality of capacitors share a charging inductor or a discharging inductor, so that no matter how many capacitors there are, only one charging inductor and one discharging inductor are needed, which can further reduce the number of inductors. As shown in FIG. 2A, the resonant switching power converter 20 of the present invention includes capacitors C1, C2, C3, switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, Q10, a charging inductor L1, a discharging Inductor L2 , controller 201 , zero current detection circuit 202 and switch driver 203 . The switches Q1-Q3 are respectively connected in series with the corresponding capacitors C1-C3, and the switch Q4 is connected in series with the charging inductor L1. It should be noted that the number of capacitors in the resonant switching power converter of the present invention is not limited to three in this embodiment, but can also be two or more than four. The number of components shown in this embodiment is only for illustration. The present invention is not intended to limit the present invention.

As shown in FIG. 2A , one end of the switch Q5 is coupled to the node between the switch Q1 and the capacitor C1, one end of the switch Q6 is coupled to the node between the switch Q2 and the capacitor C2, and one end of the switch Q7 is coupled to the switch Q3 and capacitor C3. One end of the switch Q8 is coupled to the node between the capacitor C1 and the switch Q2, one end of the switch Q9 is coupled to the node between the capacitor C2 and the switch Q3, and one end of the switch Q10 is coupled to the node between the capacitor C3 and the switch Q4. node. As shown in FIG. 2A , after the other ends of the switches Q5 - Q7 are electrically connected to a node in common, they are connected in series to the discharge inductor L2 . The other ends of the switches Q8-Q10 are commonly coupled to the ground potential. The other ends of the charging inductor L1 and the discharging inductor L2 are commonly coupled to the output voltage Vout, and the other end of the switch Q1 is coupled to the input voltage Vin. The controller 201 is used for generating a charging operation signal G1, a discharging operation signal G2, G3, and G4, respectively corresponding to a charging procedure and a plurality of discharging procedures, and operates the corresponding plurality of switches Q1-Q10 to switch the corresponding capacitors C1- The electrical connection relationship of C3. The zero current detection circuit 202 is coupled between the controller 201 and the output voltage Vout for detecting a charging resonant current on the node between the charging inductor L1 and the output voltage Vout during the charging process or in the complex discharging process When detecting a discharge resonant current at the node between the discharge inductor L2 and the output voltage Vout. When the zero current detection circuit 202 detects that the charging resonance current or the discharging resonance current is zero, a zero current detection signal is generated to the controller 201 . The zero current detection circuit 202 may include a current sensing circuit 2021 for sensing the charging resonant current during the charging process or sensing the discharging resonant current during the complex discharging process. The zero current detection circuit 202 may further include a comparator 2022 for comparing the sensed charging resonance current or discharging resonance current with a reference signal Vref1 to generate a zero current detection signal. The switch driver 203 is coupled between the controller 201 and the plurality of switches Q1-Q10 for controlling the plurality of switches Q1-10 according to the charging operation signal G1 or the plurality of discharging operation signals G2, G3 and G4.

The switches Q1-Q10 can be controlled by the switch driver 203 according to the charging operation signal G1, the discharging operation signals G2, G3, and G4 generated by the controller 201 to switch the corresponding capacitors C1-C3 and the power of the charging inductor L1 and the discharging inductor L2. connection relationship. In one embodiment, the charging operation signal G1 and the discharging operation signals G2 , G3 , and G4 are respectively switched to a conduction level for one conduction period, and the plurality of conduction periods do not overlap with each other. In a charging process, according to the charging operation signal G1, 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 charging inductor L1 is connected in series with the input voltage Vin and the output voltage Vout. between to form a charging path. In the complex discharge procedure, according to the discharge operation signals G2, G3 and G4, the switches Q5-Q10 are turned on in turn, and the switches Q1-Q4 are turned off, so that the capacitor C1, the capacitor C2 and the capacitor C3 are respectively connected in series with the discharge inductor L2, and A complex discharge path is formed. That is to say, a plurality of discharge procedures take turns to form corresponding discharge paths. For example, in the first time period, according to the discharge operation signal G2, the switches Q5 and Q8 are turned on, and the switches Q1-Q4, Q6-Q7 and Q9-Q10 are turned off, so that the capacitor C1 is connected in series with the discharge inductor L2 at the ground potential and the output A discharge path is formed between the voltages Vout; in the second time period, according to the discharge operation signal G3, the switches Q6 and Q9 are turned on, and the switches Q1-Q5, Q7, Q8 and Q10 are turned off, so that the capacitor C2 is discharged in series The inductor L2 is between the ground potential and the output voltage Vout to form another discharge path; in the third time period, according to the discharge operation signal G4, the switches Q7 and Q10 are turned on, and the switches Q1-Q6 and Q8-Q9 are turned off , the capacitor C3 is connected in series with the discharge inductor L2 between the ground potential and the output voltage Vout to form another discharge path. It should be noted that each of the above-described charging process and the above-described plurality of discharging processes are repeatedly and staggered at different time periods, rather than simultaneously. Wherein, each of the charging process and the plurality of discharging processes are repeatedly interleaved with each other to convert the input voltage Vin into the output voltage Vout. In this embodiment, the DC bias voltage of each of the first capacitors C1, C2, and C3 is Vo, so the first capacitors C1, C2, and C3 in this embodiment have the same input voltage and output as the prior art. In voltage applications, only lower rated voltages are required, so smaller capacitors can be used.

In one embodiment, the charging resonant frequency of the above-mentioned charging procedure is the same as the discharging resonant frequency of the above-mentioned complex discharging procedure. In one embodiment, the charging resonant frequency of the above-mentioned charging procedure is different from the discharging resonant frequency of the above-mentioned complex discharging procedure. In one embodiment, the resonant switching power converter 20 can be a bidirectional resonant switching power converter. The so-called bidirectional resonant switching power converter means that the roles of the input terminal (providing the input voltage Vin) and the output terminal (providing the output voltage Vout) are reversed, which means that in the embodiment shown in FIG. 2A , the resonant switching power conversion The converter 20 can convert the output voltage Vout to the input voltage Vin. In one embodiment, the voltage conversion ratio of the input voltage Vin to the output voltage Vout of the resonant switching power converter 20 may be 4:1, 3:1 or 2:1.

In one embodiment, the duration of the charging process (Ton1) is related to the charging resonant frequency (fr1) of the charging process. In a preferred embodiment, the duration of the charging process (Ton1) is related to the positive half-wave of the charging resonant current during the charging process. For example, the on-time and off-time of the switches Q1-Q4 are substantially synchronized with the charging process. The start time and end time of the positive half-wave of a charging resonant current. In one embodiment, the duration (Ton2) of the complex discharge process is related to the discharge resonance frequency (fr2) of the complex discharge process. In a preferred embodiment, the duration of the complex discharge process (Ton2) is related to the positive half-wave of the discharge resonant current of the complex discharge process. For example, the on-time and off-time of the switches Q5-Q10 are substantially synchronized respectively. The start time and end time of the positive half-wave of the discharge resonant current in each of the complex discharge procedures.

In the embodiment in which the charging resonant frequency (fr1) of the above-mentioned charging procedure is equal to the discharging resonant frequency (fr2) of the above-mentioned complex discharging procedure, when the duration of the above-mentioned charging procedure (Ton1) is equal to the duration of each of the above-mentioned complex discharging procedures (Ton2), for example, when the duty cycle is approximately equal to 25%, the current flowing through the switch can be switched at a relatively low level of the positive half-wave, so as to achieve flexible switching. In a preferred embodiment, zero current switch (ZCS) can be achieved.

In addition, it should be noted that due to the parasitic effect of the circuit components or the mutual matching between components is not necessarily ideal, therefore, although the duration of the charging process is intended to be equal to the duration of the discharging process (that is, in this embodiment The duration of the charging procedure is 25% of the duty cycle) to achieve zero-current switching for soft switching. However, it may not be exactly 25% duty cycle in practice, but only close to 25% duty cycle, that is, according to the present invention, it is acceptable to charge the battery due to circuit imperfections. There is a certain degree of error between the duration of the program and the 25% duty cycle, which means that the aforementioned discharge to "substantially" is the 25% duty cycle. Roughly" is the same.

In one embodiment, the duration of the above-mentioned charging process is less than a predetermined period of 25% of the duty cycle; thus, after the switches Q1-Q4 are turned off in advance, a small current is still maintained, flowing through the charging inductor L1, Therefore, the accumulated charges of the parasitic capacitance stored in the switch Q10 can be discharged through the parasitic diode of the switch Q4, thereby reducing the cross-voltage of the switch Q10, so as to achieve flexible switching. In a preferred embodiment, the preset period is adjusted to achieve zero voltage switch (ZVS). In an embodiment, relatively, the duration of the last one of the above-mentioned multiple discharge procedures is greater than 25% of the duty cycle for a predetermined period; thereby, the inductance L2 is discharged after the non-conducting switches Q7 and Q10 are delayed. The negative current of the switch Q1 will charge the parasitic capacitance of the switch Q1 through the parasitic diode of the switch Q5, thereby reducing the cross-voltage of the switch Q1, so as to achieve flexible switching. In a preferred embodiment, the preset period is adjusted to achieve zero voltage switching.

(1)

(2) 且如上所述欲使fr 1=fr 2，則結合式(1)與(2)可得下式

進而可導出L2與L1的電感值需符合下式

(3) 亦即欲使fr 1=fr 2時，L2與L1的電感值需設置符合式(3)的關係。The charging resonant frequency (fr1) of the above-mentioned charging procedure and the discharging resonant frequency (fr2) of each of the above-mentioned complex discharging procedures are as follows, assuming C 1 = C 2 = C 3 = C .

(1)

(2) And if fr 1 = fr 2 as mentioned above, the following formula can be obtained by combining formulas (1) and (2)

Then it can be derived that the inductance values of L2 and L1 must conform to the following formula

(3) That is to say, when fr 1 = fr 2, the inductance values of L2 and L1 should be set according to the relationship of formula (3).

FIG. 2B shows a schematic diagram of signal waveforms of related signals in the resonant switching power converter shown in FIG. 2A . The output voltage Vout, charging resonant current IL1, discharging resonant current IL2, capacitor C1 current Ic1, capacitor C2 current Ic2, and capacitor C3 current Ic3 are shown in FIG. 2B. In this embodiment, the charge resonant frequency is equal to the discharge resonant frequency and the duration of the charge procedure and each of the plurality of discharge procedures is approximately twenty-five percent of the duty cycle.

由上式中可理解到，當L1的電感值等於L2的電感值時，充電諧振頻率與放電諧振頻率是不相等的，在此條件下，若欲達成零電流切換，則持續時間(Ton1)及持續時間(Ton2)需各自對應設置為充電諧振頻率(fr1)及充電諧振頻率(fr2)的半週期，如下式所示:

若欲達成零電流切換，綜合以上公式可知，持續時間(Ton1)及持續時間(Ton2)需符合下式的關係:

(4)In another embodiment, when the inductance value of L1 is equal to the inductance value of L2, and assuming that C 1 = C 2 = C 3 = C , equations (1) and (2) can be rewritten as follows:

It can be understood from the above formula that when the inductance value of L1 is equal to the inductance value of L2, the charging resonant frequency and the discharging resonant frequency are not equal. Under this condition, if zero current switching is to be achieved, the duration (Ton1) and the duration (Ton2) need to be set to the half cycle of the charging resonant frequency (fr1) and the charging resonant frequency (fr2), respectively, as shown in the following formula:

If you want to achieve zero-current switching, the above formula can be combined to know that the duration (Ton1) and the duration (Ton2) must conform to the following relationship:

(4)

倍。亦即，充電程序之持續時間(Ton1)大致上等於百分之十六之工作週期，複數放電程序之每一者之持續時間(Ton2)大致上等於百分之二十八之工作週期，仍可達成前述之零電流切換。That is, when the inductance value of L1 is equal to the inductance value of L2, the duration of the discharge procedure (Ton2) should be set to be equal to the duration of the charging procedure (Ton1).

times. That is, the duration of the charging procedure (Ton1) is approximately equal to sixteen percent of the duty cycle, and the duration of each of the multiple discharge procedures (Ton2) is approximately equal to twenty-eight percent of the duty cycle, still The aforementioned zero-current switching can be achieved.

It is worth noting that a special case where the inductance value of L1 is equal to the inductance value of L2 is that the charging inductance L1 and the discharging inductance L2 can share the same inductance, and function as the charging inductance and the discharging inductance respectively at different times.

Therefore, please refer to FIG. 3A, which is a schematic circuit diagram showing a resonant switching power converter according to another embodiment of the present invention; FIG. 3B is a diagram showing the correspondence between a charging procedure and a plurality of discharging procedures according to an embodiment of the present disclosure. Schematic diagram of the signal waveforms of the operation signal and the corresponding capacitor current; FIG. 3C is a schematic diagram of the signal waveforms of related signals of a resonant switching power converter according to an embodiment of the present invention. In this embodiment, the charging inductance and the discharging inductance can be the same inductance L3 , and such arrangement can further reduce the number of inductances. As shown in FIG. 3A , the resonant switching power converter 30 of the present invention includes capacitors C1 , C2 , C3 , switches Q1 , Q2 , Q3 , Q4 , Q5 , Q6 , Q7 , Q8 , Q9 , Q10 , an inductor L3 , and a controller. 301 , a zero current detection circuit 302 and a switch driver 303 . The switches Q1-Q3 are respectively connected in series with the corresponding capacitors C1-C3, and the switch Q4 is connected in series with the inductor L3. It should be noted that the number of capacitors in the resonant switching power converter of the present invention is not limited to three in this embodiment, but can also be two or more than four. The number of components shown in this embodiment is only for illustration. The present invention is not intended to limit the present invention.

It should be noted that, in this embodiment, the charging inductance and the discharging inductance are a single identical inductance L3, and in the complex discharging process, by switching the switches Q1-Q10, the capacitors C1-C3 are alternately connected in series with a single identical inductance L3. Inductor L3. The so-called charging inductance and discharging inductance are a single same inductance L3, which means that in the charging process and the complex discharging process, the charging resonant current IL3 and the discharging resonant current IL3 respectively only flow through a single inductance L3, and do not flow through other inductances. element. In one embodiment, the inductor L3 can be a variable inductor.

As shown in FIG. 3A, one end of the switch Q5 is coupled to the node between the switch Q1 and the capacitor C1, one end of the switch Q6 is coupled to the node between the switch Q2 and the capacitor C2, and one end of the switch Q7 is coupled to the switch Q3 and capacitor C3. One end of the switch Q8 is coupled to the node between the capacitor C1 and the switch Q2, one end of the switch Q9 is coupled to the node between the capacitor C2 and the switch Q3, and one end of the switch Q10 is coupled to the node between the capacitor C3 and the switch Q4. node. As shown in FIG. 3A , after the other ends of the switches Q5-Q7 are electrically connected to a node in common, they are coupled to the node between the switch Q4 and the inductor L3, and the other ends of the switches Q8-Q10 are commonly coupled to the ground potential. The other end of the inductor L3 is coupled to the output voltage Vout, and the other end of the switch Q1 is coupled to the input voltage Vin. The controller 301 is used for generating a charging operation signal G1, a discharging operation signal G2, G3, and G4, respectively corresponding to a charging procedure and a plurality of discharging procedures, and operates the corresponding plurality of switches Q1-Q10 to switch the corresponding capacitors C1- The electrical connection relationship of C3. The zero current detection circuit 302 is coupled between the controller 301 and the output voltage Vout for detecting a charging resonant current on the node between the inductor L3 and the output voltage Vout during the charging process or during the complex discharging process A discharge resonant current at the node between the inductor L3 and the output voltage Vout is detected. When the zero current detection circuit 302 detects that the charging resonance current or the discharging resonance current is zero, a zero current detection signal is generated to the controller 301 . The zero current detection circuit 302 may include a current sensing circuit 3021 for sensing the charging resonant current during the charging process or sensing the discharging resonant current during the complex discharging process. The zero current detection circuit 302 may further include a comparator 3022 for comparing the sensed charging resonance current or discharging resonance current with a reference signal Vref1 to generate a zero current detection signal. The switch driver 303 is coupled between the controller 301 and the plurality of switches Q1-Q10 for controlling the plurality of switches Q1-10 according to the charging operation signal G1 or the plurality of discharging operation signals G2, G3 and G4.

The switches Q1-Q10 can be controlled by the switch driver 303 according to the charging operation signal G1, the discharging operation signal G2, G3, and G4 generated by the controller 301 to switch the electrical connection relationship between the corresponding capacitors C1-C3 and the inductor L3. In one embodiment, the charging operation signal G1 and the discharging operation signals G2 , G3 , and G4 are respectively switched to a conduction level for one conduction period, and the plurality of conduction periods do not overlap with each other. 3A and 3B at the same time, in a charging process, during the duration (Ton1), according to the charging operation signal G1, the switches Q1-Q4 are turned on, and the switches Q5-Q10 are turned off, so that the capacitor C1- C3 is connected in series with the inductor L3 between the input voltage Vin and the output voltage Vout to form a charging path. In the complex discharge procedure, according to the discharge operation signals G2, G3, and G4, the switches Q5-Q10 are turned on in turn, and the switches Q1-Q4 are turned off, so that the capacitors C1, C2, and C3 are connected in series with the inductor L3, respectively, and the A complex discharge path is formed. For example, please refer to FIG. 3A and FIG. 3B at the same time, during the duration (Ton2), according to the discharge operation signal G2, the switches Q5 and Q8 are turned on, and the switches Q1-Q4, Q6-Q7 and Q9-Q10 are turned off, so that the capacitors C1 is connected in series with the inductor L3 between the ground potential and the output voltage Vout to form a discharge path; during the duration (Ton3), according to the discharge operation signal G3, the switches Q6 and Q9 are turned on, and the switches Q1-Q5, Q7, Q8 and Q10 is non-conductive, so that the capacitor C2 is connected in series with the inductor L3 between the ground potential and the output voltage Vout to form another discharge path; during the duration (Ton4), according to the discharge operation signal G4, the switches Q7 and Q10 are turned on, and the switches Q1-Q6 and Q8-Q9 are non-conductive, so that the capacitor C3 is connected in series with the inductor L3 between the ground potential and the output voltage Vout to form yet another discharge path. It should be noted that each of the above-described charging process and the above-described plurality of discharging processes are repeatedly and staggered at different time periods, rather than simultaneously. Wherein, the charging procedure and the complex discharging procedure are repeatedly and interleaved with each other, so as to convert the input voltage Vin into the output voltage Vout. In this embodiment, the DC bias voltage of each of the first capacitors C1, C2, and C3 is Vo, so the first capacitors C1, C2, and C3 in this embodiment have the same input voltage and output as the prior art. In voltage applications, only lower rated voltages are required, so smaller capacitors can be used.

In this embodiment where the charging inductance and the discharging inductance are set as a single same inductance L3, the ratio of the duration of the charging procedure (Ton1) and the duration of the discharging procedure (Ton2) can be appropriately configured according to the aforementioned formula, so as to achieve flexibility Switching with zero current switching. Specifically, in one embodiment, the duration of the charging process is approximately equal to, for example, sixteen percent of the duty cycle; thereby, the switch can be at a relatively low level of the positive half-wave of the current flowing through the switch. time-point switching to achieve flexible switching. In a preferred embodiment, zero current switch (ZCS) can be achieved. In one embodiment, the duration of the above-mentioned charging process is less than 16% of the duty cycle for a predetermined period; thereby, after the switches Q1-Q4 are turned off in advance, a small current is still maintained, flowing through the inductor L3, therefore, That is, the accumulated charge of the parasitic capacitance stored in the switch Q10 is discharged through the parasitic diode of the switch Q4, thereby reducing the cross-voltage of the switch Q10, so as to achieve flexible switching. In a preferred embodiment, the preset period is adjusted to achieve zero voltage switch (ZVS). In one embodiment, relatively, the duration of the last one of the above-mentioned multiple discharge procedures is greater than 28% of the duty cycle for a predetermined period; thereby, the inductor L3 is delayed after the switches Q7 and Q10 are turned off. The negative current will charge the parasitic capacitance of the switch Q1 through the parasitic diode of the switch Q5, thereby reducing the cross-voltage of the switch Q1, so as to achieve flexible switching. In a preferred embodiment, the preset period is adjusted to achieve zero voltage switch (ZVS).

In one embodiment, the resonant switching power converter 30 can be a bidirectional resonant switching power converter. In one embodiment, the voltage conversion ratio of the input voltage Vin to the output voltage Vout of the resonant switching power converter 30 may be 4:1, 3:1 or 2:1. In one embodiment, the voltage conversion ratio of the resonant switching power converter 30 can be adjusted flexibly, for example, by selectively keeping switch Q7 on and switches Q10 and Q4 off during charging and discharging procedures. When turned on, the voltage conversion ratio of the resonant switching power converter 30 can be adjusted to 3:1. Likewise, for example, the switch Q6 can be selected to be turned on and the switches Q9 , Q3 , Q7 , Q10 and Q4 can be selected to be non-conductive, so that the voltage conversion ratio of the resonant switching power converter 30 can be adjusted to 2:1.

倍，同理第二放電程序之持續時間(Ton3)亦需設置為充電程序之持續時間(Ton1)的

倍，第三放電程序之持續時間(Ton4)亦需設置為充電程序之持續時間(Ton1)的

倍。圖3C顯示圖3A所示之諧振切換式電源轉換器中，相關訊號之訊號波形示意圖。輸出電壓Vout、充電諧振電流IL3、輸入電流Iin、電容C1電流Ic1、電容C2電流Ic2以及電容C3電流Ic3如圖3C所示。在本實施例中，充電諧振頻率與複數放電諧振頻率之每一者相等且充電程序的持續時間大致上為百分之十六之工作週期，複數放電程序之每一者的持續時間大致上為百分之二十八之工作週期。3B is a schematic diagram showing signal waveforms of corresponding operation signals and corresponding capacitor currents of a charging process and a plurality of discharging processes according to an embodiment of the present invention. As shown in FIG. 3B, the duration of the first discharge procedure (Ton2) needs to be set to be equal to the duration of the charging procedure (Ton1)

times, the duration of the second discharge procedure (Ton3) should also be set to the same as the duration of the charging procedure (Ton1).

times, the duration of the third discharge procedure (Ton4) should also be set to the same as the duration of the charging procedure (Ton1).

times. FIG. 3C shows a schematic diagram of signal waveforms of related signals in the resonant switching power converter shown in FIG. 3A . The output voltage Vout, the charging resonant current IL3, the input current Iin, the capacitor C1 current Ic1, the capacitor C2 current Ic2, and the capacitor C3 current Ic3 are shown in FIG. 3C. In the present embodiment, the charging resonant frequency and the complex discharging resonant frequency are each equal and the duration of the charging procedure is approximately sixteen percent of the duty cycle, and the duration of each of the complex discharging procedures is approximately Twenty-eight percent of the duty cycle.

4A is a schematic diagram showing signal waveforms of corresponding operation signals and corresponding inductor currents in a charging process and a discharging process according to an embodiment of the present invention. Please refer to FIG. 2A at the same time. In the embodiment shown in FIG. 4A, the charging operation signal G1 of the switches Q1-Q4 is at a high level during the charging process, and the discharging operation signals G2-G4 of the switches Q5-Q10 are at a high level during the discharging process. allow. In the embodiment of FIG. 4A, the duration of the charging process is approximately twenty-five percent of the duty cycle; thus, the switch Q1 can be used when the current flowing through the switch is at a relatively low level of its positive half-wave. Switching is also switching when the current of the charging inductor L1 is zero current, so as to achieve flexible switching. In a preferred embodiment, zero current switching can be achieved.

4B and 4C are schematic diagrams showing signal waveforms of corresponding operation signals and corresponding inductor currents in a charging process and a discharging process according to another embodiment of the present invention. Please refer to FIG. 2A at the same time. In the embodiment shown in FIG. 4B, the charging operation signal G1 of the switches Q1-Q4 is at a high level during the charging process, and the discharging operation signal G2 of the switches Q5 and Q8 is at a high level during the discharging process. In the embodiment of FIG. 4B , the duration of the charging process is substantially less than 25% of the duty cycle for a predetermined period T1; thus, a small current flow is maintained even after the switches Q1-Q4 are turned off in advance. After charging the inductor L1, the accumulated charge of the parasitic capacitance stored in the switch Q10 can be discharged through the parasitic diode of the switch Q4, thereby reducing the cross-voltage of the switch Q10, so as to achieve flexible switching. In a preferred embodiment, the preset period T1 is adjusted to achieve zero voltage switching. Please also refer to FIG. 2A, in the embodiment shown in FIG. 4C, the charging operation signal G1 of the switches Q1-Q4 is at a high level during the charging process, and the discharging operation signal G4 of the switches Q7 and Q10 is at a high level during the discharging process. In the embodiment of FIG. 4C , the duration of the discharge process is approximately a predetermined period T2+T3 greater than 25% of the duty cycle; thereby, the discharge inductance L2 is delayed after the switches Q7 and Q10 are turned off. The negative current will charge the parasitic capacitance of the switch Q1 through the parasitic diode of the switch Q5, thereby reducing the cross-voltage of the switch Q1, so as to achieve flexible switching. In a preferred embodiment, the preset periods T2 and T3 are adjusted to achieve zero voltage switching. In one embodiment, it should be noted that the embodiments of Figures 4B and 4C may be implemented together or only one of them. In addition, please refer to FIG. 4D , which is a schematic diagram of signal waveforms of corresponding operation signals and corresponding capacitor currents of a charging process and a discharging process according to another embodiment of the present invention. Please refer to FIG. 2A at the same time, as shown in FIG. 4D , the duration of the charging process and/or the duration of the multiple discharging processes can be adjusted, for example, a delay time Td is added to the duration of the last one of the multiple discharging processes to adjust the input voltage Vin proportional to the output voltage Vout. All the complex switches are turned off during the delay time Td.

It should be noted that the so-called turn-on time and non-conduction time of the switch are synchronized with the start time and end time of the positive half-wave of the charging resonant current in the charging process, which refer to the difference between the turn-on time and non-conduction time of the switch and the charging resonant current. The starting time and ending time of the positive half-wave are the same, or are separated by a fixed period; and the on-time and non-conducting time of the switch are synchronized with the starting and ending time of the positive half-wave of the discharge resonant current in the discharge procedure. It means that the on-time and off-time of the switch are the same as the starting time and ending time of the positive half-wave of the discharge resonant current, or they are separated by a fixed period.

The present invention provides a resonant switching power converter as described above, which can solve the problem of inrush current and circulating current through special circuit design, easily achieve flexible switching with zero current switching and/or zero voltage switching, and can Masks component changes due to DC bias or operating temperature, such as capacitance changes, can reduce switching frequency to improve efficiency at light loads, has better current and voltage balance, and can support 3:1 or more Voltage conversion ratio of resonant switched capacitive power converters.

The present invention has been described above with respect to the preferred embodiments, but the above descriptions are only intended to make the content of the present invention easy for those skilled in the art to understand, and are not intended to limit the broadest scope of rights of the present invention. The described embodiments are not limited to be used alone, but 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 those in 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. According to the signal itself, when necessary, the signal is subjected to voltage-to-current conversion, current-to-voltage conversion, and/or ratio conversion, etc., and then processed or calculated according to the converted signal to generate an output result. It can be seen from this 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 are not listed and described here. Accordingly, the scope of the present invention should cover the above and all other equivalent changes.

20,30: Resonant switching power converters 201, 301: Controller 202,302: Zero current detection circuit 2021, 3021: Current Sensing Circuits 2022, 3022: Comparator 203, 303: Switch Drivers C1~C3: Capacitor Co: output capacitance G1: Charging operation signal G2, G3, G4: Discharge operation signal Ic1: Capacitor C1 current Ic2: Capacitor C2 current Ic3: Capacitor C3 current Iin: input current IL1: charging resonant current IL2: Discharge resonant current IL3: Charge (discharge) resonant current L1: charging inductance L2: Discharge inductance L3: Inductance Q1~Q10: switch RL: load resistance T1,T2,T3: Period Td: delay time Ton1, Ton2, Ton3, Ton4: Duration Vin: input voltage Vout: output voltage

FIG. 1 shows a conventional power converter.

2A and 2B are schematic diagrams showing signal waveforms of a circuit and related signals of a resonant switching power converter according to an embodiment of the present invention.

3A is a schematic circuit diagram showing a resonant switching power converter according to another embodiment of the present invention.

3B is a schematic diagram showing signal waveforms of corresponding operation signals and corresponding capacitor currents of a charging process and a plurality of discharging processes according to an embodiment of the present invention.

3C is a schematic diagram showing signal waveforms of related signals of a resonant switching power converter according to an embodiment of the present invention.

4A , 4B and 4C are schematic diagrams showing signal waveforms of corresponding operation signals and corresponding inductor currents in a charging process and a discharging process according to an embodiment of the present invention.

4D is a schematic diagram showing signal waveforms of corresponding operation signals and corresponding capacitor currents in a charging process and a discharging process according to an embodiment of the present invention.

20: Resonant switching power converters

201: Controller

202: Zero current detection circuit

2021: Current Sensing Circuits

2022: Comparators

203: Switch Driver

C1~C3: Capacitor

Co: output capacitance

G1: Charging operation signal

G2, G3, G4: Discharge operation signal

Ic1: Capacitor C1 current

Ic2: Capacitor C2 current

Ic3: Capacitor C3 current

IL1: charging resonant current

IL2: Discharge resonant current

L1: charging inductance

L2: Discharge inductance

Q1~Q10: switch

RL: load resistance

Vin: input voltage

Vout: output voltage

Claims (18)

A resonant switching power converter for converting an input voltage into an output voltage, the resonant switching power converter comprising: complex capacitance; a complex number of switches, correspondingly coupled to the complex number of capacitors; at least one charging inductor, correspondingly connected in series with at least one of the plurality of capacitors; at least one discharge inductor, correspondingly connected in series with at least one of the plurality of capacitors; and a controller for generating a charging operation signal and a plurality of discharging operation signals, respectively corresponding to a charging procedure and a plurality of discharging procedures, and operating the corresponding plurality of switches to switch the electrical connection relationship of the corresponding capacitors; Wherein, the charge operation signal and each of the plurality of discharge operation signals are respectively switched to a conduction level for a conduction period, and the plurality of conduction periods do not overlap each other, so that the charging process and the plurality of discharging processes do not overlap each other ; Wherein, in the charging procedure, the controller controls the switching of the plurality of switches by the charging operation signal, so that the plurality of capacitors and the at least one charging inductor are connected in series between the input voltage and the output voltage to form a charging path; Wherein, in each discharge procedure, the controller controls the switching of the plurality of switches by the corresponding discharge operation signal, so that the corresponding capacitor and the corresponding discharge inductance are connected in series between the output voltage and a ground potential , and form a corresponding discharge path; Wherein, the plurality of discharge procedures alternately form the corresponding discharge paths; Wherein, the charging procedure and the plurality of discharging procedures are repeatedly and alternately sequenced with each other, so as to convert the input voltage into the output voltage. The resonant switching power converter as claimed in claim 1, further comprising a zero current detection circuit, coupled between the controller and the output voltage, for detecting a charging resonant current or A discharge resonant current is detected during the complex discharge procedure, and a zero current detection signal is generated to the controller when the zero current detection circuit detects that the charging resonant current or the discharging resonant current is zero. The resonant switching power converter as claimed in claim 2, wherein the zero current detection circuit comprises: a current sensing circuit for sensing the charging resonant current during the charging process or sensing the discharging resonant current during the complex discharging process to generate a current sensing signal; and A comparator is used for comparing the current sensing signal with a reference signal to generate the zero current sensing signal. The resonant switching power converter according to claim 1, further comprising a plurality of switch drivers, respectively coupled between the controller and the corresponding switch, for the corresponding charging operation signal or the corresponding discharging operation signal to control the plurality of switches respectively. The resonant switching power converter as claimed in claim 1, wherein after the plurality of discharging procedures are finished, a next charging procedure starts after a delay time, and during the delay time, all the corresponding switches are Not conducting. The resonant switching power converter of claim 1, wherein the at least one charging inductor is a single charging inductor, and the at least one discharging inductor is a single discharging inductor. The resonant switching power converter of claim 6, wherein the inductance value of the single charging inductor is equal to the inductance value of the single discharging inductor. The resonant switching power converter of claim 1, wherein the at least one charging inductor and the at least one discharging inductor are a single same inductor. The resonant switching power converter of claim 8, wherein the single identical inductor is a variable inductor. The resonant switching power converter as claimed in claim 8, wherein the resonant switching power converter keeps at least one specific one of the plurality of switches turned on during the charging process and the complex discharging process, and is kept off. Turning on at least two specific ones of the plurality of switches changes the voltage conversion ratio of the input voltage and the output voltage. The resonant switching power converter of claim 1 or 6, wherein the charging process has a charging resonant frequency, and the complex discharging process has a discharging resonant frequency, and the charging resonant frequency is the same as the discharging resonant frequency. The resonant switching power converter described in 6, 7 or 8, wherein the charging process has a charging resonant frequency, and the complex discharging process has a discharging resonant frequency, and the charging resonant frequency is different from the discharging resonant frequency. The resonant switching power converter of 6, 7 or 8, wherein the duration of the charging procedure is adjusted to achieve zero voltage switching of soft switching. The resonant switching power converter of 6, 7 or 8, wherein the duration of the complex discharge procedure is adjusted to achieve zero-voltage switching with soft switching. The resonant switching power converter described in 6, 7 or 8, wherein the resonant switching power converter is a bidirectional resonant switching power converter. The resonant switching power converter described in 6, 7 or 8, wherein the voltage conversion ratio of the input voltage to the output voltage of the resonant switching power converter is 4:1, 3:1 or 2:1. The resonant switching power converter described in 6, 7 or 8, wherein in the charging process, the corresponding turn-on time and non-conduction time of the plurality of switches are synchronized with the positive half-wave of a charging resonant current in the charging process. Start time point and end time point to achieve zero current switching of soft switching. The resonant switching power converter described in 6, 7 or 8, wherein in the complex discharge process, the corresponding turn-on time and non-conduction time of the complex switch are synchronized with one of the discharge resonances in one of the complex discharge processes The starting time and ending time of the positive half-wave of the current to achieve zero-current switching of flexible switching.

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