WO2020014919A1

WO2020014919A1 - Power supply circuit, controlling method and lighting device driver

Info

Publication number: WO2020014919A1
Application number: PCT/CN2018/096288
Authority: WO
Inventors: Zaosheng HU; Wang Lu; Yueliang WANG; Cui ZHOU
Original assignee: Tridonic Gmbh & Co Kg; Yueliang WANG
Priority date: 2018-07-19
Filing date: 2018-07-19
Publication date: 2020-01-23
Also published as: GB2587286B; GB2587286A; GB202019116D0

Abstract

A power supply circuit, a controlling method and a lighting device driver are provided. The power supply circuit includes: a voltage convertor circuit, configured to be input an input voltage and output an output voltage and an output current, the voltage convertor circuit having a primary side and a secondary side, the primary side having at least one switch unit which controls the primary side to rectify the input voltage, the secondary side outputting the output voltage and the output current; a voltage control circuit, configured to generate a constant voltage feedback signal, according to a current in the voltage convertor circuit; a current control circuit, configured to generate a constant current feedback signal, according to a voltage in the voltage convertor circuit; a controller, configured to generate a controlling signal to control the switch unit, according to the constant voltage feedback signal or the constant current feedback signal; and a selecting circuit, configured to select one of the constant voltage feedback signal and the constant current feedback signal to be fed to the controller. Therefore, an easy way is provided to select CC output or CV output without change the power supply circuit to another driver.

Description

POWER SUPPLY CIRCUIT, CONTROLLING METHOD AND LIGHTING DEVICE DRIVER

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to the field of voltage conversion, and more particularly, to a power supply circuit, a controlling method and alighting device driver.

BACKGROUND

This section introduces aspects that may facilitate better understanding of the present 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 related art.

In the field of power supply, a switching element and a transformer may be included in a power supply circuit. The switching element may be controlled to be switched on or off, a voltage and current generated in a primary wind of the transformer changes, and an induced voltage and current may be generated in a secondary wind of the transformer. The voltage and current generated in the secondary wind will be rectified and filtered, so as to generate an output voltage and output current.

Therefore, the input voltage is converted into the output voltage and the output current. The output voltage and output current may change according to the switching frequency and duty ratio of a controlling signal that controls the switching element.

The controlling signal may be generated and provide by a controller.

At present, power supply in the market may be divided into constant current (CC) power supply and constant voltage (CV) power supply by the output characteristics. For CC power supply, the output current keeps constant, and the loads of the CC power supply may be connected in series. For CV power supply, the output voltage keeps constant, and the loads of the CV power supply may be connected in parallel.

SUMMARY

Inventors of this disclosure found that the existing power supply in market was either CC power supply or CV power supply, when the connection of loads changed; different power supply may be needed so that the needed output characteristic could be provided. For example, when the loads changed from series connection into parallel connection, the CC power supply may be altered to the CV power supply.

In general, embodiments of the present disclosure provide a power supply circuit, a controlling method and equipment lighting device. In the embodiments, CC output and CV output are combined in the power supply circuit, and a selecting circuit may be used to choose CC feedback signal or CV feedback signal to be fed to a controller, so that CC output characteristic or CV output characteristic could be realized. Therefore, an easy way is provided to select CC output or CV output without change the power supply circuit to another driver.

In a first aspect, a power supply circuit is provided, the power supply includes: a voltage convertor circuit, configured to be input an input voltage and output an output voltage and an output current, the voltage convertor circuit having a primary side and a secondary side, the primary side having at least one switch unit which controls the primary side to rectify the input voltage, the secondary side outputting the output voltage and the output current; a voltage control circuit, configured to generate a constant voltage feedback signal, according to a current in the voltage convertor circuit; a current control circuit, configured to generate a constant current feedback signal, according to a voltage in the voltage convertor circuit; a controller, configured to generate a controlling signal to control the switch unit, according to the constant voltage feedback signal or the constant current feedback signal; and a selecting circuit, configured to select one of the constant voltage feedback signal and the constant current feedback signal to be fed to the controller, when the selecting circuit selects the constant voltage feedback signal, the controller generates the controlling signal to control the switch unit, so that the output voltage is constant, when the selecting circuit selects the constant current feedback signal, the controller generates the controlling signal to control the switch unit, so that the output current is constant.

In an embodiment, the power supply circuit according to claim 1, wherein, the power supply circuit further includes: a voltage sampling resistor, configured to sample the output voltage to generate a sampled voltage, the voltage control circuit compares the sampled voltage with a reference voltage, and generate the constant voltage feedback signal according to the comparison result.

In an embodiment, the power supply circuit further includes: a current voltage sampling resistor, configured to sample the output current to generate a sampled current, the current control circuit compares the sampled current with a reference current, and generate the constant current feedback signal according to the comparison result.

In an embodiment, the selecting circuit includes a first switch element, when the first switch element is switched on, one of the constant current feedback signal and the constant voltage feedback signal is fed to the controller, when the first switch element is switched off, the other one of the constant current feedback signal and the constant voltage feedback signal is fed to the controller.

In an embodiment, the selecting circuit further includes: a second switch element (M01) , arranged in a first branch feeding the constant current feedback signal to a ground port of the selecting circuit; and a third switch element (M02) , arranged in a second branch feeding the constant voltage feedback signal to the ground port, when the first switch element is switched on, the second switch element (M01) is switched on, and the constant current feedback signal is fed to the ground port through the first branch, the third switch element (M02) is switched off, and the constant voltage feedback signal is fed to the controller, when the first switch element is switched off, the second switch element (M01) is switched off, and the constant current feedback signal is fed to the controller, the third switch element (M02) is switched on, and the constant voltage feedback signal is fed to the ground port through the second branch.

In an embodiment, the selecting circuit further includes: a fourth switch element (M03) , arranged in a third branch connecting an operating voltage input port of the selecting circuit and the ground port, the first switch element is connected between a controlling terminal of the fourth switch element (M03) and the operating voltage input port; and a fifth switch element (Q01) , arranged in a fourth branch connecting the operating voltage input port and the ground port, a controlling terminal of the fifth switch element (Q01) connects to a receiving terminal of the fourth switch element, current flows in the fourth switch element (M03) from the receiving terminal, a controlling terminal of the second switch element (M01) is coupled to a first node in the third branch, a controlling terminal of the third switch element (M02) is coupled to a second node in the fourth branch, the operating voltage input port is input an operating voltage.

In a second aspect, a controlling method of a power supply circuit is provided, the method includes: a voltage convertor circuit being input an input voltage and outputting an output voltage and an output current, the voltage convertor circuit is configured to have a primary side and a secondary side, the primary side having at least one switch unit which controls the primary side to rectify the input voltage, the secondary side outputting the output voltage and the output current; a voltage control circuit generating a constant voltage feedback signal, according to a current in the voltage convertor circuit; a current control circuit generating a constant current feedback signal, according to a voltage in the voltage convertor circuit; a controller generating a controlling signal to control the switch unit, according to the constant voltage feedback signal or the constant current feedback signal; and a selecting circuit selecting one of the constant voltage feedback signal and the constant current feedback signal to be fed to the controller, when the selecting circuit selects the constant voltage feedback signal, the controller generates the controlling signal to control the switch unit, so that the output voltage is constant, when the selecting circuit selects the constant current feedback signal, the controller generates the controlling signal to control the switch unit, so that the output current is constant.

In a further aspect, a lighting device driver is provided, includes the power supply circuit according to first aspect.

According to various embodiments of the present disclosure, CC output and CV output are combined in the power supply circuit, and a selecting circuit may be used to choose CC feedback signal or CV feedback signal to be fed to a controller, so that CC output characteristic or CV output characteristic could be realized. Therefore, an easy way is provided to select CC output or CV output without change the power supply circuit to another driver.

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 of a power supply circuit in accordance with an embodiment of the present disclosure;

Fig. 2 is a flowchart of a controlling method 600 of the power supply circuit.

DETAILED DESCRIPTION

The present disclosure will now be discussed 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.

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 “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 the description and drawings, particular embodiments of the disclosure have been disclosed in detail as being indicative of some of the ways in which the principles of the disclosure may be employed, but it is understood that the disclosure is not limited correspondingly in scope. Rather, the disclosure includes all changes, modifications and equivalents coming within the spirit and terms of the appended claims.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

It should be emphasized that the term “includes/including” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. To facilitate illustrating and describing some parts of the disclosure, corresponding portions of the drawings may be exaggerated in size, e.g., made larger in relation to other parts than in an exemplary device actually made according to the disclosure. Elements and features depicted in one drawing or embodiment of the disclosure may be combined with elements and features depicted in one or more additional drawings or embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views and may be used to designate like or similar parts in more than one embodiment.

First aspect of embodiments

A power supply circuit is provided in a first embodiment.

Fig. 1 is a diagram of a power supply circuit in accordance with an embodiment of the present disclosure. As shown in Fig. 1, the power supply circuit 100 includes a voltage convertor circuit 101, a voltage control circuit 102, a current control circuit 103, a controller 104, and a selecting circuit 105.

In the embodiment, the voltage convertor circuit 101 is configured to be input an input voltage Vin and output an output voltage Vout and an output current Iout. The voltage convertor circuit 101 may have a primary side 101a and a secondary side 101b.

The power supply circuit 100 with the voltage convertor circuit 101 may form a part of a lighting device driver. A lighting device, e.g. one or more light emitting diodes (LEDs) , may be connected to the output voltage Vout. In an alternative embodiment a further driver circuit like a buck converter or buck-boost converter may be connected to the output voltage Vout and may be used to drive a lighting device. The output voltage Vout may be provided by output terminals X1 and X2 in order to be able to connect a lighting device to the power supply circuit 100.

The voltage convertor circuit 101 may be also configured to provide a stable output voltage Vout at a defined output current Iout. The output current may be defined depending on the intended use of LED as lighting device.

The primary side 101a has at least one switch unit S1 which controls the primary side 101a to rectify the input voltage Vin. The secondary side 101b has at least a rectifying diode D03, which is used to rectify voltage coupled from the primary side 101b.

In the embodiment, the voltage control circuit 102 may be configured to generate a constant voltage feedback signal Vfb, according to a current in the voltage convertor circuit. The current may be from the primary side 101a or the secondary side 101b.

In the embodiment, the current control circuit 103 may be configured to generate a constant current feedback signal Ifb, according to a voltage in the voltage convertor circuit. The voltage may be from the primary side 101a or the secondary side 101b.

In the embodiment, when the current and voltage are from the primary side 101a, PSR (Primary Side Regulation) can be performed in the power supply circuit 100. When the current and voltage are from the secondary side 101b, SSR (Secondary Side Regulation) can be performed in the power supply circuit 100.

In the embodiment, the controller 104 may be configured to generate a controlling signal Cs to control the switch unit S1, according to the constant voltage feedback signal Vfb or the constant current feedback signal Ifb.

In the embodiment, the selecting circuit 105 may be configured to select one of the constant voltage feedback signal Vfb and the constant current feedback signal Ifb to be fed to the controller 102.

In the embodiment, when the selecting circuit 105 selects the constant voltage feedback signal Vfb, the controller 104 may generate the controlling signal Cs to control the switch unit S1, in order that the output voltage Vout is constant, and the power supply circuit 100 has a CV (Constant Voltage) output characteristic.

In the embodiment, when the selecting circuit 105 selects the constant current feedback signal Ifb, the controller 104 generates the controlling signal Cs to control the switch unit S1, in order that the output current Iout is constant, and the power supply circuit 100 has a CC (Constant Current) output characteristic.

According to the embodiments, CC output and CV output are combined in the power supply circuit, and a selecting circuit may be used to choose CC feedback signal or CV feedback signal to be fed to a controller, so that CC output characteristic or CV output characteristic could be realized. Therefore, an easy way is provided to select CC output or CV output without change the power supply circuit to another driver.

In the embodiment, the voltage control circuit 102 may generate the constant voltage feedback signal Vfb according to the output voltage in the voltage convertor circuit 101.

For example, as shown in Fig. 1, a voltage sampling resistor R12 may be used to sample the output voltage to generate a sampled voltage Vsp, the voltage control circuit 102 may compare the sampled voltage Vsp with a reference voltage Vref, and generate the constant voltage feedback signal Vfb according to the comparison result.

However, the embodiment is not limited there to, the voltage control circuit 102 may generate the constant voltage feedback signal Vfb according to a voltage from the primary side 101a.

In the embodiment, the current control circuit 103 may generate the constant current feedback signal Ifb according to the output current in the voltage convertor circuit 101.

For example, as shown in Fig. 1, a current sampling resistor R11 may be used to sample the output current to generate a sampled current Isp, the current control circuit 102 may compare the sampled current Isp with a reference current Iref, and generate the constant current feedback signal Ifb according to the comparison result.

However, the embodiment is not limited there to, the current control circuit 103 may generate the constant feedback signal Ifb according to a current from the primary side 101a.

In the embodiment, as shown in Fig. 1, the constant feedback signal Ifb or constant voltage feedback signal Vfb may be fed to the controller 104 through an optical coupler (OC) 106.

The an optical coupler 106 may be connected to a feedback signal input pin FB (pin number 5) of the controller 104, in order that the constant feedback signal Ifb or constant voltage feedback signal Vfb may be fed to the feedback signal input pin FB.

The controller 104 may generate the controlling signal Cs to control the switch unit S1, in order that the CC output characteristic or CV output characteristic may be realized.

In the embodiment, the controller 104 may have a VCC pin (pin number 8) , VIN pin (pin number 5) and a GND pin (pin number 1) , their functions can be referred to the related art.

In the embodiment, as shown in Fig. 1, the selecting circuit 105 may include a first switch element K1. When the first switch element K1 is switched on, one of the constant current feedback signal Ifb and the constant voltage feedback signal Vfb is fed to the controller 104; when the first switch element K1 is switched off, the other one of the constant current feedback signal Ifb and the constant voltage feedback signal Vfb is fed to the controller 104.

As shown in Fig. 1, the selecting circuit 105 may further include a second switch element (M01) and a third switch element (M02) .

The second switch element (M01) is arranged in a first branch B1 feeding the constant current feedback signal Ifb to a ground port (not shown) of the selecting circuit 105; and the third switch element (M02) is arranged in a second branch B2 feeding the constant voltage feedback Vfb signal to the ground port.

When the first switch element K1 is switched on, the second switch element (M01) is switched on, and the constant current feedback signal Ifb is fed to the ground port through the first branch B1; the third switch element (M02) is switched off, and the constant voltage feedback signal Vfb is fed to the controller 104.

When the first switch element K1 is switched off, the second switch element (M01) is switched off, and the constant current feedback signal Ifb is fed to the controller 104, the third switch element (M02) is switched on, and the constant voltage feedback signal Vfb is fed to the ground port through the second branch B2.

As shown in Fig. 1, the selecting circuit 105 may further include a fourth switch element (M03) and a fifth switch element (Q01) . The fourth switch element (M03) and the fifth switch element (Q01) are used to control the third switch element (M02) .

The fourth switch element (M03) may be arranged in a third branch B3 connecting an operating voltage input port Y of the selecting circuit 105 and the ground port. The first switch element K1 is connected between a controlling terminal (gate) of the fourth switch element (M03) and the operating voltage input port.

The fifth switch element (Q01) may be arranged in a fourth branch B4 connecting the operating voltage input port Y and the ground port. A controlling terminal of the fifth switch element (Q01) connects to a receiving terminal of the fourth switch element (M03) , current may flow in the fourth switch element (M03) from the receiving terminal.

In the embodiment, a controlling terminal (gate) of the second switch element (M01) is coupled to a first node N1 in the third branch B3, for example, the controlling terminal (gate) of the second switch element (M01) is coupled to the first node N1 via the resistor R04.

In the embodiment, a controlling terminal (gate) of the third switch element (M02) is coupled to a second node N2 in the fourth branch B4, for example, the second node N2 connects resistor R08 to R07 in the second branch, and the controlling terminal (gate) of the third switch element (M02) is connected to the second node N2.

In the embodiment, second switch element (M01) , the third switch element (M02) , the fourth switch element (M03) and the fifth switch element (Q01) may be MOSFET or BJT. For MOSFET, the controlling terminal may be gate of the MOSFET, and the receiving terminal may be drain of the MOSFET. For BJT, the controlling terminal of the BJT may be base, and the receiving terminal may be collector.

In Fig. 1, the second switch element (M01) , the third switch element (M02) and the fourth switch element (M03) are N-channel MOSFETs, the fifth switch element (Q01) is PNP BJT. However, the embodiment may not be limited thereto.

As shown in Fig. 1, when the first switch element K1 is switched on, first node N1 in the first branch is high level, the second switch element (M01) and the fourth switch element (M03) are switched on, the constant current feedback signal Ifb is fed to the ground through the first branch B1. Voltage of the receiving terminal (drain) of the fourth switch element (M03) is low level, the fifth switch element (Q01) is switched off, the third switch element (M02) is switched off, and the constant voltage feedback signal is fed to the controller 104 via the OC 106.

As shown in Fig. 1, when the first switch element K1 is switched off, voltage of the receiving terminal (drain) of the fourth switch element (M03) and the controlling terminal (base) of the fifth switch element (Q01) is high level, and the fifth switch element (Q01) is switched on, and the controlling terminal (gate) of the third switch element (M02) is high level, and the third switch element (M02) is switched on, the constant voltage feedback signal Vfb is fed to the ground via the second branch B2. The second switch element (M01) is switched off, and the constant current feedback signal Ifb is fed to the controller 104 via the OC 106.

In the embodiment, the operating voltage input port Y is input an operating voltage Vop, the operating voltage Vop may be output from the Vin pin (pin number 5) of the controller 104.

In the embodiment, other elements may be included in the selecting circuit 105 such as resistors R01～R10, diodes D01, D02, and a Zener diode Z01. The function of these elements can be referred to related arts.

In the embodiment, as shown in Fig. 1, the voltage convertor circuit 101 may further include a transformer T1, and a primary winding T1-a is contained in the primary side 101a, and secondary windings T1-b is contained in the secondary side 101b.

The switch unit S1 may include at least one switch element (not shown) , the at least one switch element maybe MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) or BJT (Bipolar Junction Transistor) .

In the embodiment, other elements contained in the primary side 101a are not shown in Fig. 1, these elements may include at least a capacitor, at least a diodes, and at least an inductor. The function of these elements can be referred to related arts.

The primary side 101a of the voltage convertor circuit 101 may have the topology of a half bridge circuit with transformer T1, e.g. LLC resonant circuit, LC resonant circuit or PWM (Pulse Width Modulation) circuit. However, the embodiment is not limited there to, the primary side 101a may have other kind of topology.

The output voltage or output current may change according to the switching frequency and /or duty ratio of the controlling signal Cs provided by the controller 104.

In the embodiment, the secondary side 101b of the voltage convertor circuit 101 may include a half bridge rectifier or a full bridge rectifier. The secondary side 101b of the voltage convertor circuit 101 may further include a capacitor C12 to filter the output voltage Vout.

Second aspect of embodiments

A controlling method of a power supply circuit of the first aspect of embodiments is provided in an embodiment. The same contents as those in the first aspect of embodiments are omitted.

Fig. 2 shows a flowchart of a controlling method 200 of the power supply circuit.

As shown in Fig. 2, the method 200 includes:

Block 201: a voltage convertor circuit is input an input voltage and outputs an output voltage and an output current;

Block 202: a voltage control circuit generates a constant voltage feedback signal, according to a current in the voltage convertor circuit;

Block 203: a current control circuit generates a constant current feedback signal, according to a voltage in the voltage convertor circuit;

Block 204: a controller generates a controlling signal to control the switch unit, according to the constant voltage feedback signal or the constant current feedback signal;

Block 205: a selecting circuit selects one of the constant voltage feedback signal and the constant current feedback signal to be fed to the controller.

In the block 205, when the selecting circuit selects the constant voltage feedback signal, the controller generates the controlling signal to control the switch unit, so that the output voltage is constant; when the selecting circuit selects the constant current feedback signal, the controller generates the controlling signal to control the switch unit, so that the output current is constant.

The description for each block can be referred to the description for corresponding elements in the in the first aspect of embodiments.

As can be seen from the above embodiments, CC output and CV output are combined in the power supply circuit, and a selecting circuit may be used to choose CC feedback signal or CV feedback signal to be fed to a controller, so that CC output characteristic or CV output characteristic could be realized. Therefore, an easy way is provided to select CC output or CV output without change the power supply circuit to another driver.

Third aspect of embodiments

A lighting device driver is provided in an embodiment. The lighting device driver includes the power supply circuit according to the first aspect of embodiments.

In the embodiment, the power supply circuit is configured to convert an input voltage into an output voltage, according to a controlling signal, as described in the first aspect of embodiments. The output voltage and output current may be provided to drive a lighting device connected to the terminals for the output voltage or to a driver to drive a lighting device, the lighting device may be LED.

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 power supply circuit, comprising:

a voltage convertor circuit, configured to be input an input voltage and output an output voltage and an output current, the voltage convertor circuit having a primary side and a secondary side, the primary side having at least one switch unit which controls the primary side to rectify the input voltage, the secondary side outputting the output voltage and the output current;

a voltage control circuit, configured to generate a constant voltage feedback signal, according to a current in the voltage convertor circuit;

a current control circuit, configured to generate a constant current feedback signal, according to a voltage in the voltage convertor circuit;

a controller, configured to generate a controlling signal to control the switch unit, according to the constant voltage feedback signal or the constant current feedback signal; and

a selecting circuit, configured to select one of the constant voltage feedback signal and the constant current feedback signal to be fed to the controller,

when the selecting circuit selects the constant voltage feedback signal, the controller generates the controlling signal to control the switch unit, so that the output voltage is constant,

when the selecting circuit selects the constant current feedback signal, the controller generates the controlling signal to control the switch unit, so that the output current is constant.
The power supply circuit according to claim 1, wherein, the power supply circuit further comprises:

a voltage sampling resistor, configured to sample the output voltage to generate a sampled voltage,

the voltage control circuit compares the sampled voltage with a reference voltage, and generate the constant voltage feedback signal according to the comparison result.
The power supply circuit according to claim 1, wherein, the power supply circuit further comprises:

a current voltage sampling resistor, configured to sample the output current to generate a sampled current,

the current control circuit compares the sampled current with a reference current, and generate the constant current feedback signal according to the comparison result.
The power supply circuit according to claim 1, wherein, the selecting circuit comprises a first switch element,

when the first switch element is switched on, one of the constant current feedback signal and the constant voltage feedback signal is fed to the controller,

when the first switch element is switched off, the other one of the constant current feedback signal and the constant voltage feedback signal is fed to the controller.
The power supply circuit according to claim 4, wherein, the selecting circuit further comprises:

a second switch element (M01) , arranged in a first branch feeding the constant current feedback signal to a ground port of the selecting circuit; and

a third switch element (M02) , arranged in a second branch feeding the constant voltage feedback signal to the ground port,

when the first switch element is switched on, the second switch element (M01) is switched on, and the constant current feedback signal is fed to the ground port through the first branch, the third switch element (M02) is switched off, and the constant voltage feedback signal is fed to the controller,

when the first switch element is switched off, the second switch element (M01) is switched off, and the constant current feedback signal is fed to the controller, the third switch element (M02) is switched on, and the constant voltage feedback signal is fed to the ground port through the second branch.
The power supply circuit according to claim 5, wherein, the selecting circuit further comprises:

a fourth switch element (M03) , arranged in a third branch connecting an operating voltage input port of the selecting circuit and the ground port, the first switch element is connected between a controlling terminal of the fourth switch element (M03) and the operating voltage input port; and

a fifth switch element (Q01) , arranged in a fourth branch connecting the operating voltage input port and the ground port, a controlling terminal of the fifth switch element (Q01) connects to a receiving terminal of the fourth switch element, current flows in the fourth switch element (M03) from the receiving terminal,

wherein,

a controlling terminal of the second switch element (M01) is coupled to a first node in the third branch,

a controlling terminal of the third switch element (M02) is coupled to a second node in the fourth branch,

the operating voltage input port is input an operating voltage.
A lighting device driver, comprising the power supply circuit according to one of claims 1-6.
A controlling method of a power supply circuit, the method comprising:

a voltage convertor circuit being input an input voltage and outputting an output voltage and an output current, the voltage convertor circuit is configured to have a primary side and a secondary side, the primary side having at least one switch unit which controls the primary side to rectify the input voltage, the secondary side outputting the output voltage and the output current;

a voltage control circuit generating a constant voltage feedback signal, according to a current in the voltage convertor circuit;

a current control circuit generating a constant current feedback signal, according to a voltage in the voltage convertor circuit;

a controller generating a controlling signal to control the switch unit, according to the constant voltage feedback signal or the constant current feedback signal; and

a selecting circuit selecting one of the constant voltage feedback signal and the constant current feedback signal to be fed to the controller,

when the selecting circuit selects the constant voltage feedback signal, the controller generates the controlling signal to control the switch unit, so that the output voltage is constant,

when the selecting circuit selects the constant current feedback signal, the controller generates the controlling signal to control the switch unit, so that the output current is constant.