WO2021237658A1

WO2021237658A1 - Device and method of controlling charge pump

Info

Publication number: WO2021237658A1
Application number: PCT/CN2020/093202
Authority: WO
Inventors: Qiuxiang MAO; Shengdie Lin; Shuanghong Wang
Original assignee: Tridonic Gmbh & Co Kg
Priority date: 2020-05-29
Filing date: 2020-05-29
Publication date: 2021-12-02
Also published as: EP4133585A1; EP4133585A4; CN115461974A

Abstract

A device and method of controlling charge pump are provided. The device of controlling charge pump includes: a charge pump circuit connected to an input circuit; a first capacitor coupled to the charge pump circuit and provided as an element of a resonant circuit; a first switching element connected to the first capacitor; and a controller configured to read an input current and/or an input voltage from the input circuit, generate a pulse width modulation signal according to the input current and/or the input voltage, and output the pulse width modulation signal to control the first switching element. Therefore, THD and harmonic can be improved while the cost of the circuit is decreased.

Description

DEVICE AND METHOD OF CONTROLLING CHARGE PUMP

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to the field of power control circuits, and more particularly, to a device and method of controlling charge pump.

BACKGROUND

Nowadays, more and more resonant circuits are used in power control circuits, for example a single-stage LLC circuit is often used for a low output ripple current and low-cost product. Meanwhile, a charge pump circuit is often applied in a power control circuit. For example, series charge pump caps are added in some solutions for improving THD (Total Harmonic Distortion) and/or harmonic.

Reference document 1: WO2013/113836A1.

Reference document 2: US2009/0128057A1.

Reference document 3: US6366027B1

This section introduces aspects that may facilitate a better understanding of the disclosure. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.

SUMMARY

The inventors found that series charge pump caps need to be added to improve THD and harmonic for a widen voltage product, such as a light emitting diode (LED) . In this solution, for each one of loads, a charge pump cap is constant with a certain load, therefore it is a high cost solution.

In some solutions, one stage power factor correction (PFC) function may be added for different loads, however the cost of the PFC function is also high. Furthermore, these solutions are time consuming during development, and bad performance of harmonic will limit an operation range.

In order to solve at least part of the above problems, methods, apparatus, devices are provided in the present disclosure. Features and advantages of embodiments of the present disclosure will also be understood from the following description of specific embodiments when read in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of embodiments of the present disclosure.

In general, embodiments of the present disclosure provide a device and method of controlling charge pump. It is expected to decrease the number of components and the cost while improving THD and/or harmonic with a simple structure.

In a first aspect, a device of controlling charge pump is provided. The device of controlling charge pump includes: a charge pump circuit connected to an input circuit and an output circuit; a first capacitor coupled to the charge pump circuit and provided as an element of a resonant circuit; a first switching element connected to the first capacitor; wherein a capacitance value of the first capacitor is changed by a switching operation of the first switching element; and a controller configured to read an input current and/or an input voltage from the input circuit, generate a pulse width modulation signal according to the input current and/or the input voltage, and output the pulse width modulation signal to control the first switching element.

In some embodiments, the controller is configured to adjust the pulse width modulation signal to improve a power factor or a total harmonic distortion or a harmonic of the resonant circuit.

In some embodiments, the controller is configured to modify a charge pump cap value of the charge pump circuit in a power frequency cycle.

In some embodiments, the charge pump cap value of the charge pump circuit is modified along with the changed capacitance value of the first capacitor which is controlled by the pulse width modulation signal.

In some embodiments, the controller is configured to find a charge pump cap value of the charge pump circuit under one of a plurality of different loads.

In some embodiments, the controller is configured to change a duty cycle of the pulse width modulation signal to modify the charge pump cap in a certain load, determine whether an input power or the input voltage or an input frequency is changed, and maintain the pulse width modulation signal when the input power or the input voltage or the input frequency is not changed.

In some embodiments, the device further comprises: a second capacitor coupled to the charge pump circuit and provided as an element of the resonant circuit; wherein the second capacitor is connected in parallel with the first capacitor.

In some embodiments, the device further comprises: a second switching element configured between the first switching element and the controller; wherein the pulse width modulation signal from the controller is used to control the second switching element, and the second switching element is configured to generate a signal to control the first switching element.

In a second aspect, a method of controlling charge pump is provided, wherein a charge pump circuit is connected to an input circuit and an output circuit; a first capacitor is coupled to the charge pump circuit and provided as an element of a resonant circuit; a first switching element is connected to the first capacitor;

the method comprises: reading an input current and/or an input voltage from the input circuit; generating a pulse width modulation signal according to the input current and/or the input voltage, and outputting the pulse width modulation signal to control the first switching element; wherein a capacitance value of the first capacitor is changed by a switching operation of the first switching element.

In some embodiments, the method further comprises: adjusting the pulse width modulation signal to improve a power factor or a total harmonic distortion or a harmonic of the resonant circuit.

In some embodiments, the method further comprises: modifying a charge pump cap value of the charge pump circuit in a power frequency cycle.

In some embodiments, the method further comprises: finding a charge pump cap value of the charge pump circuit under one of a plurality of different loads.

In some embodiments, the method further comprises: changing a duty cycle of the pulse width modulation signal to modify the charge pump cap in a certain load; determining whether an input power or the input voltage or an input frequency is changed, and maintaining the pulse width modulation signal when the input power or the input voltage or the input frequency is not changed.

In a third aspect, a power driver is provided. The power driver includes: a charge pump circuit connected to an input circuit and an output circuit; a resonant circuit coupled to the charge pump circuit; a switching element connected to a capacitor of the resonant circuit; wherein a capacitance value of the capacitor is changed by a switching operation of the switching element; and a controller configured to read an input current and/or an input voltage from the input circuit, generate a pulse width modulation signal according to the input current and/or the input voltage, and output the pulse width modulation signal to control the switching element.

According to various embodiments of the present disclosure, a first switching element and a controller are provided and a capacitance value of a first capacitor is changed by a switching operation of the first switching element. Therefore, THD and harmonic can be improved while the cost of the circuit is decreased.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and benefits of various embodiments of the disclosure will become more fully apparent, by way of example, from the following detailed description with reference to the accompanying drawings, in which like reference numerals or letters are used to designate like or equivalent elements. The drawings are illustrated for facilitating better understanding of the embodiments of the disclosure and not necessarily drawn to scale, in which:

Fig. 1 is a diagram which shows a device of controlling charge pump in accordance with an embodiment of the present disclosure;

Fig. 2 is a diagram which shows a waveform example without capacitance controlling in accordance with an embodiment of the present disclosure;

Fig. 3 is a diagram which shows a waveform example with capacitance controlling in accordance with an embodiment of the present disclosure.

Fig. 4 is a diagram which shows a method of controlling charge pump in accordance with an embodiment of the present disclosure;

Fig. 5 is another diagram which shows a method of controlling charge pump in accordance with an embodiment of the present disclosure;

Fig. 6 is a diagram which shows a power driver in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION

The present disclosure will now be described with reference to several example embodiments. It should be understood that these embodiments are discussed only for the purpose of enabling those skilled persons in the art to better understand and thus implement the present disclosure, rather than suggesting any limitations on the scope of the present disclosure.

It should be understood that when an element is referred to as being “connected” or “coupled” or “contacted” to another element, it may be directly connected or coupled or contacted to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” or “directly contacted” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between” , “adjacent” versus “directly adjacent” , etc. ) .

As used herein, the terms “first” and “second” refer to different elements. The singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises, ” “comprising, ” “has, ” “having, ” “includes” and/or “including” as used herein, specify the presence of stated features, elements, and/or components and the like, but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof.

The term “based on” is to be read as “based at least in part on” . The term “cover” is to be read as “at least in part cover” . The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment” . The term “another embodiment” is to be read as “at least one other embodiment” . Other definitions, explicit and implicit, may be included below.

In this disclosure, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In this disclosure, a digital controlling manner is provided to perform stable controlling with a simple structure. For example, a controller in the disclosure is a micro controller unit (MCU) , and it is not limited thereto.

A first aspect of embodiments

A device of controlling charge pump is provided in the embodiments.

Fig. 1 is a diagram which shows a device of controlling charge pump in accordance with an embodiment of the present disclosure.

As shown in Fig 1. a device 100 of controlling charge pump includes: a charge pump circuit 101 connected to an input circuit 1011; a first capacitor 102 (C4) coupled to the charge pump circuit 101 and provided as an element of a resonant circuit (such as a LLC circuit) ; a first switching element 103 (Q1) connected to the first capacitor 102.

In this disclosure, a capacitance value of the first capacitor 102 is changed by a switching operation (ON/OFF) of the first switching element 103. For example, a capacitance value C _on of the first capacitor 102 when the first switching element 103 is ON is different from a capacitance value C _off of the first capacitor 102 when the first switching element 103 is OFF.

As shown in Fig 1. the device 100 of controlling charge pump further includes: a controller 104 configured to read an input current and/or an input voltage (Vin) from the input circuit 1011, generate a pulse width modulation (PWM) signal according to the input current and/or the input voltage, and output the pulse width modulation signal to control the first switching element 103.

It should be appreciated that some components or elements are illustrated only as examples in Fig. 1. However, it is not limited thereto, for example, connections or positions of the components or elements may be adjusted, and/or, some components or elements may be omitted.

Moreover, some components or elements not shown in Fig. 1 may be added, while components or elements such as C1-C5, D1-D5, R1-R5, and Vcc shown in Fig. 1 but not explained can be referred in the relevant art.

In some embodiments, the controller 104 is configured to adjust the pulse width modulation signal to improve a power factor (PF) or a total harmonic distortion (THD) or a harmonic of the resonant circuit.

For an example, the controller 104 is configured to operation in an open-loop manner. The controller 104 read the input current and the input voltage, and calculate an input power according to the input current and the input voltage. Then the controller 104 compares the calculated input power and a predefined power, and change the PWM signal when the calculated input power is not consistent with the predefined power.

For another example, the controller 104 is configured to operation in a close-loop manner. The controller 104 read the input current and the input voltage, and calculate an input power according to the input current and the input voltage. Then the controller 104 change the PWM signal, correspondingly, the input current and/or input voltage is/are changed along with the changed PWM signal. Then controller 104 determines a PWM signal when the input power is stable.

Therefore, a power factor (PF) or a total harmonic distortion (THD) or a harmonic of the resonant circuit can be improved.

In some embodiments, the controller 104 is configured to modify a charge pump cap value of the charge pump circuit in a power frequency cycle.

For example, the charge pump cap value of the charge pump circuit 101 is modified along with the changed capacitance value of the first capacitor 102 which is controlled by the pulse width modulation signal.

Therefore, series charge pump caps are nor needed for a widen voltage product, such as a light emitting diode (LED) . THD and harmonic can be improved while the cost of the circuit is decreased.

In some embodiments, the controller 104 is configured to find a charge pump cap value of the charge pump circuit under one of a plurality of different loads. For example, the controller 104 may analyze which value is best for PF, THD and/or harmonic at a certain load, and maintain the charge pump cap value and the PWM signal at the load.

In some embodiment, the controller 104 is configured to change a duty cycle of the pulse width modulation signal to modify the charge pump cap in a certain load, determine whether an input power or the input voltage or an input frequency is changed, and maintain the pulse width modulation signal when the input power or the input voltage or the input frequency is not changed.

Therefore, the charge pump cap value can be modified under different loads, performance of the circuit can be improved while the cost of the circuit is not high.

As shown in Fig 1. the device 100 of controlling charge pump further includes: a second capacitor 105 (C3) coupled to the charge pump circuit 101 and provided as an element of the resonant circuit; the second capacitor 105 is connected in parallel with the first capacitor 102.

As shown in Fig 1. the device 100 of controlling charge pump further includes: a second switching element 106 (Q2) configured between the first switching element 103 and the controller 104; the pulse width modulation signal from the controller 104 is used to control the second switching element 106, and the second switching element 106 is configured to generate a signal to control the first switching element 103.

Therefore, a stable controlling with a simple structure is performed.

Fig. 2 is a diagram which shows a waveform example without capacitance controlling in accordance with an embodiment of the present disclosure. For example, C4, Q1 and controller 104 in the Fig. 1 are not used. In this situation, as shown in Fig. 2, a waveform of zero crossing (shown as 201) need to be improved.

Fig. 3 is a diagram which shows a waveform example with capacitance controlling in accordance with an embodiment of the present disclosure. For example, C4, Q1 and controller 104 in the Fig. 1 are used. In this situation, as shown in Fig. 3, a waveform of zero crossing (shown as 301) is improved. Therefore, THD and harmonic can be improved while the cost of the circuit is decreased.

In some embodiments, the resonant circuit (such as an LLC circuit) is used to drive a light emitting diode (LED) as an output load. However, it is not limited thereto, the resonant circuit (such as an LLC circuit) also can be used to drive other output loads.

It is to be understood that, the above examples or embodiments are discussed for illustration, rather than limitation. Those skilled in the art would appreciate that there may be many other embodiments or examples within the scope of the present disclosure.

It can be seen from the above embodiments, a first switching element and a controller are provided and a capacitance value of the first capacitor is changed by a switching operation of the first switching element. Therefore, THD and harmonic can be improved while the cost of the circuit is decreased.

A second aspect of embodiments

A method of trolling charge pump is provided in the embodiments. The corresponding device 100 are illustrated in the first aspect of embodiments, and the same contents as those in the first aspect of embodiments are omitted.

Fig. 4 is a diagram which shows a method of controlling charge pump in accordance with an embodiment of the present disclosure. For example, the method is executed by the controller 104. As shown in Fig. 4, a method 400 includes:

401, reading an input current and/or an input voltage from the input circuit;

402, generating a pulse width modulation signal according to the input current and/or the input voltage, and

403, outputting the pulse width modulation signal to control the first switching element; wherein a capacitance value of the first capacitor is changed by a switching operation of the first switching element.

It should be appreciated that Fig. 4 is only an example of the disclosure, but it is not limited thereto. For example, the order of operations at blocks or steps may be adjusted, and/or, some blocks or steps may be omitted. Moreover, some blocks or steps not shown in Fig. 4 may be added.

In some embodiments, the method further includes: adjusting the pulse width modulation signal to improve a power factor or a total harmonic distortion or a harmonic of the resonant circuit.

In some embodiments, the method further includes: modifying a charge pump cap value of the charge pump circuit in a power frequency cycle. For example, the charge pump cap value of the charge pump circuit is modified along with the changed capacitance value of the first capacitor which is controlled by the pulse width modulation signal.

Fig. 5 is another diagram which shows a method of controlling charge pump in accordance with an embodiment of the present disclosure. For example, the method is executed by the controller 104. As shown in Fig. 5, a method 500 includes:

501, reading an input current and/or an input voltage from the input circuit;

502, generating a pulse width modulation signal according to the input current and/or the input voltage;

503, finding a charge pump cap value of the charge pump circuit under one of a plurality of different loads.

504, changing a duty cycle of the pulse width modulation signal to modify the charge pump cap in a certain load;

505, determining whether an input power or the input voltage or an input frequency is changed, and

506, maintaining the pulse width modulation signal when the input power or the input voltage or the input frequency is not changed. In this situation, it can be deemed as in a stable state, and the PWM signal and the charge pump cap value can be deemed as available configuration.

As shown in Fig. 5, continuing execute 501 when the input power or the input voltage or the input frequency is changed. In this situation, it can be deemed as in an unstable state, and the PWM signal and the charge pump cap value need to be updated.

As shown in Fig. 5, the method 500 includes:

507, outputting the pulse width modulation signal to control the first switching element; wherein a capacitance value of the first capacitor is changed by a switching operation of the first switching element.

It should be appreciated that Fig. 5 is only an example of the disclosure, but it is not limited thereto. For example, the order of operations at blocks or steps may be adjusted, and/or, some blocks or steps may be omitted. Moreover, some blocks or steps not shown in Fig. 5 may be added.

A third aspect of embodiments

A power driver is provided in the embodiments. The corresponding device 100 and method 500 are illustrated in the first and second aspects of embodiments, and the same contents as those in the first and second aspects of embodiments are omitted.

As shown in Fig. 6, a power driver 600 includes: a charge pump circuit 601 connected to an input circuit 6011 and an output circuit 6012; a resonant circuit 602 coupled to the charge pump circuit 601; a switching element 603 connected to a capacitor C4 of the resonant circuit 602; wherein a capacitance value of the capacitor C4 is changed by a switching operation of the switching element 603.

As shown in Fig. 6, the power driver 600 further includes: a controller 604 configured to read an input current and/or an input voltage from the input circuit 6011, generate a pulse width modulation signal according to the input current and/or the input voltage, and output the pulse width modulation signal to control the switching element 603.

It should be appreciated that some components or elements are illustrated only as examples in Fig. 6. However, it is not limited thereto, for example, connections or positions of the components or elements may be adjusted, and/or, some components or elements may be omitted.

Moreover, some components or elements not shown in Fig. 6 may be added, while components or elements such as C1-C5, D1-D5, R1-R6, L1, P1, S1, S2, D6-D7, C6 and Vcc shown in Fig. 6 but not explained can be referred in the relevant art.

In some embodiments, the power driver 600 may be used to drive a light emitting diode (LED) . In other embodiments, the power driver 600 is comprised in a light emitting diode (LED) driver, for example, the power driver 600 is a part of a LED driver.

Further, it is expected that one of ordinary skill, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and integrated circuits (ICs) with minimal experimentation.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device.

While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it will be appreciated that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous.

Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A device of controlling charge pump, comprising:

a charge pump circuit connected to an input circuit;

a first capacitor coupled to the charge pump circuit and provided as an element of a resonant circuit;

a first switching element connected to the first capacitor; wherein a capacitance value of the first capacitor is changed by a switching operation of the first switching element; and

a controller configured to read an input current and/or an input voltage from the input circuit, generate a pulse width modulation signal according to the input current and/or the input voltage, and output the pulse width modulation signal to control the first switching element.
The device according to claim 1, wherein the controller is configured to adjust the pulse width modulation signal to improve a power factor or a total harmonic distortion or a harmonic of the resonant circuit.
The device according to claim 1, wherein the controller is configured to modify a charge pump cap value of the charge pump circuit in a power frequency cycle.
The device according to claim 3, wherein the charge pump cap value of the charge pump circuit is modified along with the changed capacitance value of the first capacitor which is controlled by the pulse width modulation signal.
The device according to any one of claims 1-4, wherein the controller is configured to find a charge pump cap value of the charge pump circuit under one of a plurality of different loads.
The device according to claim 5, wherein the controller is configured to change a duty cycle of the pulse width modulation signal to modify the charge pump cap in a certain load, determine whether an input power or the input voltage or an input frequency is changed, and maintain the pulse width modulation signal when the input power or the input voltage or the input frequency is not changed.
The device according to any one of claims 1-4, wherein the device further comprises:

a second capacitor coupled to the charge pump circuit and provided as an element of the resonant circuit; wherein the second capacitor is connected in parallel with the first capacitor.
The device according to any one of claims 1-4, wherein the device further comprises:

a second switching element configured between the first switching element and the controller; wherein the pulse width modulation signal from the controller is used to control the second switching element, and the second switching element is configured to generate a signal to control the first switching element.
The device according to any one of claims 1-4, wherein the resonant circuit is used to drive a light emitting diode (LED) as an output load.
A method of controlling charge pump, wherein a charge pump circuit is connected to an input circuit; a first capacitor is coupled to the charge pump circuit and provided as an element of a resonant circuit; a first switching element is connected to the first capacitor;

wherein the method comprises:

reading an input current and/or an input voltage from the input circuit;

generating a pulse width modulation signal according to the input current and/or the input voltage, and

outputting the pulse width modulation signal to control the first switching element; wherein a capacitance value of the first capacitor is changed by a switching operation of the first switching element.
The method according to claim 10, wherein the method further comprises:

adjusting the pulse width modulation signal to improve a power factor or a total harmonic distortion or a harmonic of the resonant circuit.
The method according to claim 10, wherein the method further comprises:

modifying a charge pump cap value of the charge pump circuit in a power frequency cycle.
The method according to claim 12, wherein the charge pump cap value of the charge pump circuit is modified along with the changed capacitance value of the first capacitor which is controlled by the pulse width modulation signal.
The method according to any one of claims 10-13, wherein the method further comprises:

finding a charge pump cap value of the charge pump circuit under one of a plurality of different loads.
The method according to claim 14, wherein the method further comprises:

changing a duty cycle of the pulse width modulation signal to modify the charge pump cap in a certain load;

determining whether an input power or the input voltage or an input frequency is changed, and

maintaining the pulse width modulation signal when the input power or the input voltage or the input frequency is not changed.
A power driver, comprising:

a charge pump circuit connected to an input circuit;

a resonant circuit coupled to the charge pump circuit;

a switching element connected to a capacitor of the resonant circuit; wherein a capacitance value of the capacitor is changed by a switching operation of the switching element; and

a controller configured to read an input current and/or an input voltage from the input circuit, generate a pulse width modulation signal according to the input current and/or the input voltage, and output the pulse width modulation signal to control the switching element.
The power driver according to claim 16, wherein the power driver is used to drive a light emitting diode (LED) ; or the power driver is comprised in a light emitting diode (LED) driver.