EP4613067A1

EP4613067A1 - Power supply circuit, controlling method and lighting equipment

Info

Publication number: EP4613067A1
Application number: EP22968233.1A
Authority: EP
Inventors: Jianning XIE; Hongzhang HE; ShiYu Ding; Yuli Chen
Original assignee: Tridonic GmbH and Co KG
Current assignee: Tridonic GmbH and Co KG
Priority date: 2022-12-16
Filing date: 2022-12-16
Publication date: 2025-09-10
Also published as: WO2024124526A1; EP4613067A4; CN120323085A

Abstract

A power supply circuit, a controlling method and a lighting equipment. The power supply circuit includes: input terminals, configured to receive input voltage; a rectifying circuit, configured to be connected with one of the input terminals; a voltage converting circuit, configured to be connected with the rectifying circuit, and output a DC voltage (Vo); a controller, configured to output a controlling signal to the voltage converting circuit; a voltage detector, configured to detect whether the input voltage is DC voltage or AC voltage, and output a detecting signal corresponding to the detecting result; and an oscillation circuit, configured to output an oscillation signal when DC voltage is detected by the voltage detector, and stop output the oscillation signal when AC voltage is detected by the voltage detected; the oscillation signal outputted by the oscillation circuit is provided to the controller to change an operating frequency of the controller. Therefore, an EMI result of the power supply circuit under DC input will be improved with lower cost and smaller space.

Description

POWER SUPPLY CIRCUIT, CONTROLLING METHOD AND LIGHTING EQUIPMENT

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to the field of electrical circuit, and more particularly, to a power supply circuit, a controlling method and a lighting equipment.

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 prior art.
LED (Light Emitting Diode) driver usually needs to work at AC (Alternative Current) input and DC (Direct Current) input (176V-280V) which is emergency application. If LED driver is connected with AC main, it’s operating frequency ranges from tens to hundreds kHz. Thus the noise energy is dispersed to the various frequency points. And it is easier to pass CISPER. When working at DC input, LED driver works under conduction mode at fix operating frequency, so it is hard to pass CISPER.
Existing solution in the market normally uses a MCU (Micro Controlling Unit) to generate signal with jitter frequency and input the signal to a controller of the LED driver. This technology will change the operating frequency under DC input, so that can get better EMI (Electro Magnetic Interference) result.
SUMMARY
Fig. 1 is a diagram of an LED driver in related art. As shown in Fig. 1, a MCU 10 is used to detect whether the input signal is AC signal or DC signal. When the input signal is DC signal, the MCU 10 generate signal with jitter frequency and input the signal to a controller 11 to achieve changing operate frequency under DC input, thus can help to improve the EMI result of the LED driver 100. A shown in Fig. 1, the MCU 10 is located at a secondary side of a transformer 12 of the LED driver 100, and optical couplers 13, 14 are used to isolate a primary side and the secondary side of the transformer 12.
Inventor of this disclosure found the following limitation in Fig. 1. For example, MCU is expensive, software is needed and optical couplers may occupy space on a PCBA (Printed Circuit Board Assembly) .
In general, embodiments of the present disclosure provide a power supply circuit, a controlling method and lighting equipment. In the embodiments, a voltage detector may detect whether the input voltage is DC voltage or AC voltage, when it is detected DC voltage is input, an oscillation circuit will output an oscillation signal to a controller to change an operating frequency thereof. Therefore, an EMI result of the power supply circuit under DC input will be improved with lower cost and smaller space.
In a first aspect, there is provided a power supply circuit, including:
input terminals (x1-a, x1-b) , configured to receive input voltage;
a rectifying circuit, configured to be connected with one of the input terminals;
a voltage converting circuit, configured to be connected with the rectifying circuit, and output a DC voltage (Vo) ;
a controller, configured to output a controlling signal to the voltage converting circuit;
a voltage detector, configured to detect whether the input voltage is DC voltage or AC voltage, and output a detecting signal corresponding to the detecting result; and
an oscillation circuit, configured to output an oscillation signal when DC voltage is detected by the voltage detector, and stop output the oscillation signal when AC voltage is detected by the voltage detected;
the oscillation signal outputted by the oscillation circuit is provided to the controller to change an operating frequency of the controller.
In at least one embodiment, when DC voltage is detected by the voltage detector, the detecting signal enables the oscillation circuit;
when AC voltage is detected by the voltage detector, the detecting signal disables the oscillation circuit.
In at least one embodiment, the voltage detector is connected with an output node of the rectifying circuit, and detect, according to a voltage at the output node, whether the input voltage is DC voltage or AC voltage.
In at least one embodiment, the voltage detector includes:
a first switch (M60) ;
a first resistor (R64) and a first capacitor (C64) connected in parallel between the output node of the rectifying circuit and a controlling terminal of the first switch (M60) ; and
a second resistor (R63) and a second capacitor (C49) connected in parallel between the controlling terminal of the first switch (M60) and a ground terminal (GND) ;
a first terminal of the first switch is connected with the ground terminal, and a second terminal of the first switch is connected with the oscillation circuit.
In at least one embodiment, the voltage detector further includes:
a first diode (D22) , an anode of the first diode is connected with a first connecting node of the first resistor (R64) and the first capacitor (C64) , a cathode of the first diode is connected with a second connecting node of the second resistor (R63) and the second capacitor (C49) .
In at least one embodiment, the voltage detector further includes:
a second diode (D23) , an anode of the second diode is connected with the ground terminal, a cathode of the second diode is connected with the first connecting node of the first resistor (R64) and the first capacitor (C64) .
In at least one embodiment, the oscillation circuit includes:
a self-excited oscillator, which outputs a rectangular wave from an output terminal.
In at least one embodiment, the oscillation circuit further includes:
a third resistor (R58) and a third capacitor (C47) connected in serial between the output terminal and the ground terminal.
In at least one embodiment, a third connecting node of the third resistor (R58) and the third capacitor (C47) is connected with the voltage detector, to receive the detecting signal.
In a second aspect, there is provided a controlling method of a power supply circuit, the method includes:
rectifying an input voltage;
detecting whether the input voltage is DC voltage or AC voltage, and output a detecting signal corresponding to the detecting result;
generating an oscillation signal when DC voltage is detected by the voltage detector, and stop output the oscillation signal when AC voltage is detected by the voltage detected;
outputting a controlling signal according to the oscillation signal; and
converting the rectified voltage into output voltage.
In a third aspect, there is provided a lighting equipment, includes a lighting module and the power supply circuit according to any one of the embodiments, the power supply circuit is connected with the lighting module, and provides DC voltage to the lighting module.
According to various embodiments of the present disclosure, a voltage detector may detect whether the input voltage is DC voltage or AC voltage, when it is detected DC voltage is input, an oscillation circuit will output an oscillation signal to a controller to change an operating frequency thereof. Therefore, an EMI result of the power supply circuit under DC input will be improved with lower cost and smaller space.

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 an LED driver in related art;
Fig. 2 is a diagram of a power supply circuit in accordance with at least one embodiment of the present disclosure
Fig. 3 is a diagram of a power supply circuit in accordance with at least one embodiment of the present disclosure
Fig. 4 shows a flowchart of a controlling method 400 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.
First aspect of embodiments
A power supply circuit is provided in a first aspect of embodiments.
Fig. 2 is a diagram of a power supply circuit in accordance with at least one embodiment of the present disclosure. As shown in Fig. 2, a power supply circuit 2 includes input terminals x1-a and x1-b, a rectifying circuit 21, a voltage converting circuit 22, a controller 23, a voltage detector 24 and an oscillation circuit 25.
In at least one embodiment, the input terminals x1-a and x1-b are configured to receive input voltage Vin.
The rectifying circuit 21 is configured to be connected with the input terminal x1-a. For example, the rectifying circuit 21 is a rectifier bridge composed of 4 diodes D 01A, D01B, D01C and D01D. An output node N1 of the rectifying circuit 21 output a rectified voltage Uo.
The voltage converting circuit 22 is configured to be connected with the rectifying circuit 21 and output a DC voltage Vo. For example, the voltage converting circuit 22 includes a switch M10 (for example, a MOS transistor) , a transformer T and at least one resistor (for example, resistors R13, R14 and R15, which are connected in parallel) . A primary coil of the transformer T is connected between the output node N1 and a drain of the switch M10. The at least one resistor is connected between a source of the switch M10 and a ground terminal GND.
As shown in Fig. 2, the voltage converting circuit 22 further includes a diode D02C and a capacitor C80A. The diode D02C and the capacitor C80A are connected with a secondary coil of the transformer T. A connecting node of the diode D02C and the capacitor C80A outputs the DC voltage Vo.
The controller 23 is configured to output a controlling signal to the voltage converting circuit 22, so as to control the operation of voltage converting. For example, the controlling signal is PWM (Pulse Width Modulation) signal and is provided to a gate of the switch M10 to control conduction state of the switch M10.
The voltage detector 24 is configured to detect whether the input voltage Vin is DC voltage or AC voltage, and output a detecting signal DS corresponding to the detecting result.
The oscillation circuit 25 is configured to output an oscillation signal when DC voltage is detected by the voltage detector 24, and stop output the oscillation signal when AC voltage is detected by the voltage detected 24.
The oscillation signal outputted by the oscillation circuit 25 is provided to the controller 23 to change an operating frequency of the controller 23. For example, the oscillation signal is provided to MULT or COMP pin of the controller 23.
The oscillation signal outputted by the oscillation circuit 25 may affect controller 23 work, make input current of the controller 23 to follow waveform of the oscillation signal, so as an operate frequency of the controller 23 also follow the waveform. Therefore the noise energy of the supply circuit 2 will be dispersed at different frequency points. Thus the supply circuit 2 is easier to pass the CISPER when input voltage is DC voltage.
In at least one embodiment, when DC voltage is detected by the voltage detector 24, the detecting signal DS enables the oscillation circuit 25, so that the oscillation signal can be applied to the controller 23.
When AC voltage is detected by the voltage detector 24, the detecting signal disables the oscillation circuit 25, so that there is no oscillation signal generated by the oscillation circuit 25, and operation of the controller 23 under AC input may not be affected by the oscillation circuit 25.
Fig. 3 is a diagram of a power supply circuit in accordance with at least one embodiment of the present disclosure. Fig. 3 shows an example of the voltage detector 24 and the oscillation circuit 25.
In at least one embodiment, as shown in Fig. 3, the voltage detector 24 is connected with the output node N1 of the rectifying circuit 22. The voltage detector 24 may detect, according to the voltage Uo at the output node N1, whether the input voltage Vin is DC voltage or AC voltage.
As shown in Fig. 3, the voltage detector 24 may include:
a first switch M60, for example, a MOS transistor;
a first resistor R64 and a first capacitor C64 connected in parallel between the output node N1 of the rectifying circuit 22 and a controlling terminal (for example, a gate) of the first switch M60; and
a second resistor R63 and a second capacitor C49 connected in parallel between the controlling terminal (for example, the gate) of the first switch M60 and the ground terminal GND.
As shown in Fig. 3, a first terminal (for example, a source) of the first switch M60 is connected with the ground terminal GND, and a second terminal (for example, a drain) of the first switch M60 is connected with the oscillation circuit 25. The second terminal (for example, the drain) of the first switch M60 may generate the detecting signal.
As shown in Fig. 3, the voltage detector 24 may further include a first diode D22. An anode of the first diode D22 is connected with a first connecting node N12 of the first resistor R64 and the first capacitor C64. A cathode of the first diode D22 is connected with a second connecting node N2 of the second resistor R63 and the second capacitor C49.
The voltage detector 24 may further include a second diode D23. An anode of the second diode D23 is connected with the ground terminal GND, a cathode of the second diode D23 is connected with the first connecting node N12 of the first resistor R64 and the first capacitor C64.
The oscillation circuit 25 includes a self-excited oscillator 251. The self-excited oscillator 251 may output a rectangular wave from an output terminal N3.
The self-excited oscillator 251 may include transistors Q1-a, Q1-b, capacitors C44, C46, resistors R45, R55, R56 and R57. The capacitors C44 and C46 may be charged alternatively, so as to output the rectangular wave from. Working principle of the self-excited oscillator 251 may be referred to related art.
The oscillation circuit 25 may further include: a third resistor R58 and a third capacitor C47 connected in serial between the output terminal and the ground terminal. The third resistor R58 and the third capacitor C47 are used to filter out high frequency components from the rectangular wave from. Besides, a diode D21 is also included in the oscillation circuit 25.
As shown in Fig. 3, a third connecting node N31 of the third resistor R58 and the third capacitor C47 is connected with the voltage detector 24, to receive the detecting signal outputted by the voltage detector 24.
When AC voltage is inputted to X1-a, the first switch M60 conducts, and the third connecting node N31 is set to low level, the oscillation circuit 25 may not output the oscillation signal.
When DC voltage is inputted to X1-a, the first switch M60 may not conduct, and the oscillation circuit 25 outputs the oscillation signal.
As can be seen from the above embodiments, a voltage detector may detect whether the input voltage is DC voltage or AC voltage, when it is detected DC voltage is input, an oscillation circuit will output an oscillation signal to a controller to change an operating frequency thereof. Therefore, an EMI result of the power supply circuit under DC input will be improved with lower cost and smaller space. Besides, the embodiments may be implemented by hardware.
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. 4 shows a flowchart of a controlling method 400 of the power supply circuit.
As shown in Fig. 4, the method 400 includes:
Block 401: rectifying an input voltage;
Block 402: detecting whether the input voltage is DC voltage or AC voltage, and outputting a detecting signal corresponding to the detecting result;
Block 403: generating an oscillation signal when DC voltage is detected by the voltage detector, and stopping output the oscillation signal when AC voltage is detected by the voltage detected;
Block 404: outputting a controlling signal according to the oscillation signal; and
Block 405: converting the rectified voltage into output voltage.
In at least one embodiment, when DC voltage is detected in block 402, the detecting signal enables an oscillation circuit to output the oscillation signal; when AC voltage is detected in block 402, the detecting signal disables the oscillation circuit.
As can be seen from the above embodiments, a voltage detector may detect whether the input voltage is DC voltage or AC voltage, when it is detected DC voltage is input, an oscillation circuit will output an oscillation signal to a controller to change an operating frequency thereof. Therefore, an EMI result of the power supply circuit under DC input will be improved with lower cost and smaller space.
Third aspect of embodiments
A lighting equipment is provided in an embodiment. The lighting equipment includes a lighting module, and the power supply circuit according to the first aspect of embodiments.
In the embodiment, the power supply circuit is connected to the lighting module, and provides DC voltage to the lighting module to drive the lighting module. The lighting module may be LED lighting module.
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:

input terminals (x1-a, x1-b) , configured to receive input voltage;

a rectifying circuit, configured to be connected with one of the input terminals;

a voltage converting circuit, configured to be connected with the rectifying circuit, and output a DC voltage (Vo) ;

a controller, configured to output a controlling signal to the voltage converting circuit;

a voltage detector, configured to detect whether the input voltage is DC voltage or AC voltage, and output a detecting signal corresponding to the detecting result; and

an oscillation circuit, configured to output an oscillation signal when DC voltage is detected by the voltage detector, and stop output the oscillation signal when AC voltage is detected by the voltage detected;

wherein, the oscillation signal outputted by the oscillation circuit is provided to the controller to change an operating frequency of the controller.
The power supply circuit according to claim 1, wherein,

when DC voltage is detected by the voltage detector, the detecting signal enables the oscillation circuit,

when AC voltage is detected by the voltage detector, the detecting signal disables the oscillation circuit.
The power supply circuit according to claim 1, wherein,

the voltage detector is connected with an output node of the rectifying circuit, and detect, according to a voltage at the output node, whether the input voltage is DC voltage or AC voltage.
The power supply circuit according to claim 3, wherein,

the voltage detector comprises:

a first switch (M60) ;

a first resistor (R64) and a first capacitor (C64) connected in parallel between the output node of the rectifying circuit and a controlling terminal of the first switch (M60) ; and

a second resistor (R63) and a second capacitor (C49) connected in parallel between the controlling terminal of the first switch (M60) and a ground terminal (GND) ;

a first terminal of the first switch is connected with the ground terminal, and a second terminal of the first switch is connected with the oscillation circuit.
The power supply circuit according to claim 4, wherein,

the voltage detector further comprises:

a first diode (D22) , an anode of the first diode is connected with a first connecting node of the first resistor (R64) and the first capacitor (C64) , a cathode of the first diode is connected with a second connecting node of the second resistor (R63) and the second capacitor (C49) .
The power supply circuit according to claim 5, wherein,

the voltage detector further comprises:

a second diode (D23) , an anode of the second diode is connected with the ground terminal, a cathode of the second diode is connected with the first connecting node of the first resistor (R64) and the first capacitor (C64) .
The power supply circuit according to claim 4, wherein,

the oscillation circuit comprises:

a self-excited oscillator, which outputs a rectangular wave from an output terminal.
The power supply circuit according to claim 7, wherein,

the oscillation circuit further comprises:

a third resistor (R58) and a third capacitor (C47) connected in serial between the output terminal and the ground terminal.
The power supply circuit according to claim 7, wherein,

a third connecting node of the third resistor (R58) and the third capacitor (C47) is connected with the voltage detector, to receive the detecting signal.
A lighting equipment comprises a lighting module and the power supply circuit according to any one of claims 1-9, wherein, the power supply circuit is connected with the lighting module, and provides DC voltage to the lighting module.
A controlling method of a power supply circuit, comprising:

rectifying an input voltage;

detecting whether the input voltage is DC voltage or AC voltage, and outputting a detecting signal corresponding to the detecting result;

generating an oscillation signal when DC voltage is detected by the voltage detector, and stopping output the oscillation signal when AC voltage is detected by the voltage detected;

outputting a controlling signal according to the oscillation signal; and

converting the rectified voltage into output voltage.