CN109413805B - Non-isolated dimming constant-current power supply and control system - Google Patents
Non-isolated dimming constant-current power supply and control system Download PDFInfo
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
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Abstract
The invention provides a non-isolated dimming constant current power supply which comprises a power supply control IC, a micro control unit MCU and a transformer. The MCU receives a dimming control signal from a user, analyzes dimming power corresponding to the dimming control signal, generates a linear dimming mode control signal if the dimming power is larger than preset power, and generates an intermittent mode control signal if the dimming power is smaller than the preset power; when the power supply control IC works in the linear dimming mode, the received PWM signal is converted into a linear voltage signal, the output current Io of the load LED is adjusted by utilizing the linear voltage signal, and when the power supply control IC works in the intermittent mode, a frequency signal in a preset range is generated according to the received PWM signal and is provided for the transformer, and the output current Io of the load LED is adjusted by utilizing the received PWM signal. The noise which can be perceived by human ears produced by the transformer in the constant current power supply is effectively eliminated by combining the linear dimming mode and the intermittent dimming mode.
Description
Technical Field
The invention relates to the technical field of illumination, in particular to a non-isolated dimming constant current power supply and a control system.
Background
With the continuous development of lighting technology, the requirements of people on lighting are also increasing. Currently, in order to increase the dimming depth, PWM (Pulse Width Modulation ) dimming is generally adopted, and when PWM is high, the power loop of the circuit is operated, and when PWM is low, the power loop of the circuit is stopped. Because PWM dimming frequency is the range that people's ear can feel, therefore the vibration sound production of transformer also is in the perception range of people's ear, usually adopts the transformer to impregnate and the mode of gluing to eliminate the noise, and this kind of mode can only reduce the noise, and can not fundamentally eliminate the noise, and people's ear still can hear the sound that the power sent. In addition, open circuit protection is adopted for the circuit, the traditional power supply can realize open circuit protection restarting, and repeated restarting can cause ignition and combustion of the load light source plate.
Disclosure of Invention
The present invention has been made in view of the above problems, and it is an object of the present invention to provide a non-isolated dimming constant current power supply and control system which overcomes or at least partially solves the above problems.
According to one aspect of the invention, a non-isolated dimming constant current power supply is provided, which comprises a power supply control IC, a micro control unit MCU and a transformer which are respectively connected with the power supply control IC,
the micro control unit MCU is configured to receive a dimming control signal from a user, analyze the dimming control signal, generate a corresponding PWM signal and a corresponding working mode control signal, and send the PWM signal and the corresponding working mode control signal to the power supply control IC;
the micro control unit MCU analyzes that the dimming power corresponding to the dimming control signal is larger than the preset power, and generates a linear dimming mode control signal; analyzing that the dimming power corresponding to the dimming control signal is smaller than the preset power, and generating an intermittent mode control signal;
the power supply control IC works in a linear dimming mode if receiving a linear dimming mode control signal, converts the received PWM signal into a linear voltage signal, and adjusts the output current Io of the load LED by using the linear voltage signal; if the intermittent mode control signal is received, the device works in the intermittent mode, generates a frequency signal in a preset range according to the received PWM signal, supplies the frequency signal to the transformer, and adjusts the output current Io of the load LED by utilizing the received PWM signal.
Optionally, the micro control unit MCU has a first communication port, a PWM port, and a receiving port, and is configured to receive a dimming control signal from a user through the receiving port, analyze the dimming control signal and generate a corresponding PWM signal and an operation mode control signal, send the PWM signal to the power control IC through the PWM port, and send the operation mode control signal to the power control IC through the first communication port;
the power supply control IC is provided with a PWM pin connected with the PWM port and a communication pin in communication connection with the first communication port, the PWM signal is received by the PWM pin, and the working mode control signal is received by the communication pin.
Optionally, a driving resistor R1, a switching element are also included, wherein,
the power supply control IC comprises a drive pin GD, one end of the drive resistor R1 is connected, and the other end of the drive resistor R1 is connected with the switching element; the switching element is connected with one end of the primary side of the transformer, and the other end of the primary side of the transformer is connected with the negative electrode of the load LED;
the power supply control IC works in an intermittent mode, and sends the generated frequency signal in the preset range to the switching element through the driving resistor R1, and the switching element provides the frequency signal for the transformer.
Optionally, the switching element includes a power field effect transistor MOS;
and the grid electrode of the power field effect transistor MOS is connected with the driving resistor R1, the source electrode is grounded, and the drain electrode is connected with one end of the primary side of the transformer.
Optionally, the LED driving circuit further comprises a voltage dividing resistor R2 and a voltage dividing resistor R3, wherein one end of the voltage dividing resistor R3 is connected with the negative electrode of the load LED, the other end of the voltage dividing resistor R3 is connected with the voltage dividing resistor R2, and the other end of the voltage dividing resistor R2 is grounded;
the power supply control IC comprises a first detection pin, wherein the first detection pin is connected to a connection point of the voltage dividing resistor R2 and the voltage dividing resistor R3 and is configured to detect the voltage division of the voltage dividing resistor R2 and then compare the detected voltage division with a preset reference voltage Vref, and if the voltage division of the voltage dividing resistor R2 obtained through comparison is larger than the preset reference voltage Vref, the switching element is controlled to be in an off state and the current off state is kept in preset time.
Optionally, an RC integrating circuit is integrated in the power control IC, where the power control IC works in a linear dimming mode, converts a received PWM signal into a linear voltage signal through the RC integrating circuit, and if the duty ratio of the PWM signal increases, the value of the converted linear voltage signal increases, the preset reference voltage Vref increases, and the output current Io of the load LED increases.
Optionally, the circuit further comprises a resistor R4, wherein one end of the resistor R4 is connected with the switching element, and the other end of the resistor R is grounded;
the first detection pin of the power supply control IC detects the output voltage of the load LED by detecting the voltage division of the voltage division resistor R2;
the power supply control IC comprises a CS pin which is connected with one end of the resistor R4 which is not grounded, and the power supply control IC works in a linear dimming mode and detects the average current of the load LED by detecting the peak current on the resistor R4 through the CS pin;
the power control IC determines the output power of the load LED by using the output voltage and average current of the load LED.
Optionally, the circuit further comprises a resistor R4, wherein one end of the resistor R4 is connected with the switching element, and the other end of the resistor R is grounded;
the first detection pin of the power supply control IC detects the output voltage of the load LED by detecting the voltage division of the voltage division resistor R2;
the power supply control IC comprises a CS pin which is connected with one end of the resistor R4 which is not grounded, and the power supply control IC works in an intermittent mode, utilizes the CS pin to detect the peak voltage on the resistor R4, amplifies the peak voltage on the resistor R4, and calculates the average current of the load LED after the peak voltage is processed by the RC integrating circuit;
the power control IC determines the output power of the load LED by using the output voltage and average current of the load LED.
Optionally, the device further comprises a resistor R4 and a resistor R5 connected in series with the resistor R4;
the first detection pin of the power supply control IC detects the output voltage of the load LED by detecting the voltage division of the voltage division resistor R2;
the power supply control IC comprises a second detection pin, the second detection pin is connected to the connection point of the resistor R4 and the resistor R5, the partial pressure of the resistor R5 is detected, and after the partial pressure of the resistor R5 is amplified, the average current of the load LED is calculated;
the power control IC determines the output power of the load LED by using the output voltage and average current of the load LED.
Optionally, the method further comprises: the interface is respectively connected with the MCU and the external control end;
the micro control unit MCU receives the dimming control signal sent by a user through the external control end through the interface;
the power supply control IC sends the output power of the load LED to the micro control unit MCU; and the MCU sends the received output power of the load LED to the external control end through the interface.
Optionally, the interface is connected with the power supply control IC, the power supply control IC detects a fault state of each device connected with the power supply control IC, and the detected fault state is sent to the external control terminal through the interface.
Optionally, wireless communication modules are respectively arranged in the interface and the external control end, and the micro control unit MCU receives the dimming control signal from the external control end through the wireless communication module in the interface and sends the output power of the load LED to the external control end.
Optionally, the external control terminal includes a mobile terminal.
According to another aspect of the present invention, there is also provided a control system comprising an interface, an external control terminal, a load LED, the non-isolated dimming constant current power supply of any of the above embodiments, wherein,
the interface is respectively connected with the external control end and the non-isolated dimming constant current power supply;
the non-isolated dimming constant current power supply is provided with an input end and an output end, wherein the input end is connected with a power supply, the output end is connected with the load LED and is configured to provide constant current for the load LED;
the non-isolated dimming constant current power supply is further configured to receive the dimming control signal sent by a user through the external control end through the interface, so as to adjust the output current Io of the load LED by utilizing the dimming control signal; and determining the output power of the load LED by detecting the output voltage and average current of the load LED, and sending the output power of the load LED to the external control terminal through the interface.
In the embodiment of the invention, a micro control unit MCU in a non-isolated dimming constant current power supply adopts a linear dimming mode by analyzing a dimming control signal provided by a user when dimming power corresponding to the dimming control signal is larger than preset power; when the dimming power corresponding to the dimming control signal is smaller than the preset power, an intermittent dimming mode is adopted, and the working frequency of the transformer is controlled to be in a preset frequency range. The noise which can be perceived by human ears produced by the transformer in the constant current power supply is effectively eliminated by combining the linear dimming mode and the intermittent dimming mode. And the intermittent dimming mode can also effectively increase the dimming depth of the power supply, and improve the lighting experience of a user.
Further, since the operating frequency of the power supply cannot be raised without limit, too high a frequency will cause an increase in loss of the element, and the EMI (Electronic Magnetic Interference, electromagnetic interference) performance of the power supply will also be deteriorated. Therefore, by adjusting the operating frequency of the transformer to a preset frequency range, good EMI performance and good efficiency characteristics of the power supply circuit can also be maintained.
The foregoing description is only an overview of the present invention, and is intended to be implemented in accordance with the teachings of the present invention in order that the same may be more clearly understood and to make the same and other objects, features and advantages of the present invention more readily apparent.
The above, as well as additional objectives, advantages, and features of the present invention will become apparent to those skilled in the art from the following detailed description of a specific embodiment of the present invention when read in conjunction with the accompanying drawings.
Drawings
For a reading of the following detailed description of the preferred embodiments, various other advantages and benefits to the art as will become apparent to those of ordinary skill. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:
fig. 1 shows a schematic diagram of a part of a non-isolated dimming constant current power supply according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a part of a non-isolated dimming constant current power supply according to another embodiment of the present invention;
fig. 3 shows a schematic structural diagram of a control system according to an embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
In order to solve the above-mentioned technical problems, the embodiment of the invention provides a non-isolated dimming constant current power supply. Fig. 1 shows a schematic structural diagram of a non-isolated dimming constant current power supply according to one embodiment of the present invention. Referring to fig. 1, the non-isolated dimming constant current power supply comprises a micro control unit MCU, a micro control unit MCU connected with a power supply control IC, and a transformer T1. Wherein,
the micro control unit MCU (Microcontroller Unit) is configured to receive the dimming control signal from the user, analyze the dimming control signal and generate a corresponding PWM (Pulse Width Modulation) signal and operation mode control signal, and send the PWM signal and operation mode control signal to the power control IC.
In this embodiment, the MCU generates the linear dimming mode control signal when it is analyzed that the dimming power corresponding to the dimming control signal is greater than the preset power, and generates the discontinuous mode control signal when it is analyzed that the dimming power corresponding to the dimming control signal is less than the preset power.
The power supply control IC works in a linear dimming mode when receiving the linear dimming mode control signal, converts the received PWM signal into a linear voltage signal, adjusts the output current Io of the load LED by using the linear voltage signal, works in an intermittent mode when receiving the intermittent mode control signal, generates a frequency signal in a preset range according to the received PWM signal and provides the frequency signal to the transformer T1, and adjusts the output current Io of the load LED by using the received PWM signal.
In the embodiment of the invention, the micro control unit MCU in the non-isolated dimming constant current power supply adopts a linear dimming mode when the dimming power corresponding to the dimming control signal is larger than the preset power by analyzing the dimming control signal provided by a user, adopts an intermittent dimming mode when the dimming power corresponding to the dimming control signal is smaller than the preset power, and controls the working frequency of the transformer to be in a preset frequency range. The noise which can be perceived by human ears produced by the transformer in the constant current power supply is effectively eliminated by combining the linear dimming mode and the intermittent dimming mode. And the intermittent dimming mode can also effectively increase the dimming depth of the power supply, and improve the lighting experience of a user. Further, since the operating frequency of the power supply cannot be raised without limit, too high a frequency will cause an increase in loss of the element, and the EMI (Electronic Magnetic Interference, electromagnetic interference) performance of the power supply will also be deteriorated. Therefore, by adjusting the operating frequency of the transformer to a preset frequency range, good EMI performance and good efficiency characteristics of the power supply circuit can also be maintained.
In one embodiment of the present invention, with continued reference to figure 1, the micro control unit MCU has a first communication port A, PWM port B, a reception port C. The micro control unit MCU is configured to receive a dimming control signal from a user by using the receiving port C, analyze the dimming control signal and generate a corresponding PWM signal and an operating mode control signal, send the PWM signal to the power control IC through the PWM port B, and send the operating mode control signal to the power control IC through the first communication port A.
The power supply control IC has a PWM pin D connected to the PWM port B and a communication pin E connected to the first communication port A in communication, receives a PWM signal via the PWM pin D, and receives an operation mode control signal via the communication pin E.
In an embodiment of the present invention, an RC integrating circuit (not shown in the figure) is integrated in the power control IC, and the power control IC works in a linear dimming mode and converts a received PWM signal into a linear voltage signal through the RC integrating circuit, and when the micro control unit MCU controls the duty ratio of the PWM signal generated by the micro control unit MCU to increase according to the dimming control signal of the user, the value of the linear voltage signal obtained by the power control IC through conversion according to the increased PWM signal is correspondingly increased, so that the preset reference voltage Vref is increased, and further, the output current Io of the load LED is controlled to increase. In this embodiment, the preset reference voltage Vref is a voltage value preset inside the power control IC, the specific numerical values of the embodiments of the invention are not limited. The signal output by the RC integrating circuit in this embodiment may be proportional to the time-integrated value of the signal input thereto.
The embodiment of the invention can adjust the output current Io by changing the reference voltage Vref for determining the output current. In this embodiment, the non-isolated dimming constant current power supply further includes a resistor R4, where one end of the resistor R4 is connected to the switching element Q1 (e.g. the source of the power field effect transistor MOS), and the other end is grounded. Since the power supply is operating in the critical mode, the output current io=vref/2R 4.
In this embodiment, a calculation formula of the inductance value L of the transformer T1 is l= (Ui-Uo) D/(ip×f), where Ui is a power supply input voltage, uo is a power supply output voltage, D is a duty cycle of the power supply control IC driving the power fet MOS, and F is an operating frequency of the transformer T1. Further, when the peak current ip=vref/R4 in the resistor R4 becomes smaller, it is found that the Ip value becomes smaller and the F frequency becomes higher. However, the operating frequency of the power supply cannot be increased without limitation, and excessive frequency will cause MOS loss to increase, MOS generates heat greatly, and the EMI performance of the power supply will be deteriorated. Therefore, it is necessary that the reference voltage is not changed any more when the frequency of the transformer T1 is raised to a certain degree, maintaining good EMI performance and good efficiency characteristics of the circuit.
The embodiment of the invention adjusts the output current of the load LED by adopting the intermittent dimming mode when the dimming power (low power) corresponding to the dimming control signal is smaller than the preset power, to maintain the transformer T1 to operate in a predetermined frequency range, for example, a frequency range greater than 20KHz, the transformer T1 does not emit noise that can be perceived by human ears.
With continued reference to fig. 1, in an embodiment of the present invention, the non-isolated dimming constant current power supply further includes a driving resistor R1 and a switching element Q1 (e.g. a power field effect transistor MOS in fig. 1), where the power control IC includes a driving pin GD connected to one end of the driving resistor R1, and the other end of the driving resistor R1 is connected to the switching element Q1. The switching element Q1 is connected with one end of the primary side of the transformer T1, and the other end of the primary side of the transformer T1 is connected with the negative electrode of the load LED. When the power control IC operates in the intermittent mode, the generated frequency signal of the preset range may be transmitted to the switching element Q1 through the driving resistor R1, and the frequency applied to the switching element Q1, that is, the operating frequency of the transformer T1, so that the switching element Q1 may provide the frequency signal to the transformer T1.
In this embodiment, the switching element Q1 may be a power field effect transistor MOS, where a gate of the power field effect transistor MOS is connected to the driving resistor R1, a drain of the power field effect transistor MOS is connected to one end of a primary side of the transformer T1 (i.e., 10 ends of the transformer T1), and a source of the power field effect transistor MOS is grounded via the resistor R4. The 6 end of the transformer T1 is connected with the negative electrode of the load LED, and the 3 end is grounded. In addition, in this embodiment, the load LED may be formed by combining a plurality of LEDs, for example, a combination of LEDs connected in series or parallel, which is not particularly limited in the embodiment of the present invention.
In order to protect the load LEDs, the conventional power supply can control the output to be open circuit in some cases, and the power supply is continuously restarted, and the repeated restarting can cause the light source board of the load LEDs to be ignited, so that the light source board of the load LEDs is easy to burn. In order to solve this problem, the constant-current power supply provided by the embodiment of the invention adopts an open-circuit locking mode to avoid restarting and ignition. And, when the power is turned on again, the power-off restarting is also required.
With continued reference to fig. 1, the non-isolated dimming constant current power supply according to the embodiment of the invention may further include a voltage dividing resistor R2 and a voltage dividing resistor R3, wherein one end of the voltage dividing resistor R3 is connected to the negative electrode of the load LED, the other end is connected to the voltage dividing resistor R2, and the other end of the voltage dividing resistor R2 is grounded.
The power control IC further comprises a first detection pin G connected to a connection point of the voltage dividing resistor R2 and the voltage dividing resistor R3 and configured to detect the divided voltage of the voltage dividing resistor R2 and compare with a preset reference voltage Vref, if the voltage division of the voltage division resistor R2 is greater than the preset reference voltage Vref, the power control IC enters an open-circuit protection state, controls the switching element Q1 to be in an off state, and maintains the current off state for a preset time. When the load LED is open circuit, V LED+ ＝V LED- 。
In this embodiment, the preset time may be set for any period of time, and of course, the time may also be set to be relatively long, so that the power control IC is always in the open circuit protection state after entering the open circuit protection state and before restarting the next power on, and the time is cleared after restarting the power off, and the power circuit enters the normal working state.
Therefore, the embodiment of the invention can cut off the loop of the load LED to the ground by locking the power supply when the load is opened, so that the bad ignition of the load LED is relieved, and the phenomenon of ignition and combustion is avoided.
With the conventional power supply circuit, a user cannot intuitively understand the output power and power consumption of the load LED. The embodiment of the invention can realize the real-time monitoring of the output power of the load LED by monitoring the voltage and the current of the load LED in real time, thereby improving the use experience of users. Three ways of monitoring the output power of the load LED are described below.
Mode one
With continued reference to fig. 1, one end of the resistor R4 is connected to the switching element Q1 (e.g., the source of the power fet MOS), and the other end is grounded. The first detection pin G of the power control IC detects the output voltage of the load LED by detecting the voltage division of the voltage dividing resistor R2. Assuming that the voltage value divided by the voltage dividing resistor R2 is V1, the formula is adoptedThe voltage value V of Vled-can be calculated led- And then pass through formula V o ＝V in -V led- And calculating to obtain the output voltage of the load LED. Wherein V is in Is the input voltage of the constant-current power supply, V (V) o Is the output voltage of the constant current power supply.
In this embodiment, the power control IC further has a CS pin connected to an ungrounded end of the resistor R4, and operates in the linear dimming mode to detect the average current Io of the load LED by detecting the peak current Ip on the resistor R4 using the CS pin. In this embodiment, the peak current across resistor R4Average current of load LED +.>
Further, the power control IC may determine the output power P of the load LED using the output voltage and the average current of the load LED, wherein the output power p=vo×io of the load LED.
Mode two
With continued reference to fig. 1, in this manner, resistor R4 is connected at one end to switching element Q1 (e.g., the source of power fet MOS) and at the other end to ground. The first detection pin G of the power control IC detects the output voltage of the load LED by detecting the voltage division of the voltage dividing resistor R2. The output voltage calculation of the load LED can be seen in the first mode above.
In this embodiment, the power control IC also has a CS pin, which is connected to an end of the resistor R4 that is not grounded, and the power control IC operates in the discontinuous mode, and detects the peak voltage on the resistor R4 by using the CS pin, amplifies the peak voltage on the resistor R4, and calculates the average current of the load LED by using the formula i=v/R after processing the peak voltage by the RC integrating circuit.
Further, the power control IC may determine the output power P of the load LED using the output voltage and the average current of the load LED, wherein the output power p=vo×io of the load LED.
Mode three
Referring to fig. 1 and fig. 2, in this manner, a resistor R5 is further provided in the non-isolated dimming constant current power supply, one end of the resistor R4 is connected to a switching element Q1 (e.g. a source electrode of a power field effect transistor MOS), the other end is connected to the resistor R5, and the other end of the resistor R5 is grounded. The first detection pin G of the power control IC detects the output voltage of the load LED by detecting the voltage division of the voltage dividing resistor R2. The output voltage calculation of the load LED can be seen in the first mode above.
In this embodiment, the power control IC is further provided with a second detection pin H, where the second detection pin H is connected to a connection point between the resistor R4 and the resistor R5, and the average current of the load LED is calculated by detecting the partial voltage of the resistor R5 and amplifying the detected partial voltage of the resistor R5.
Further, the power control IC may determine the output power P of the load LED using the output voltage and the average current of the load LED, wherein the output power p=vo×io of the load LED.
In an embodiment of the present invention, an interface is further provided on the non-isolated dimming constant current power supply, and the interface is connected to the MCU and an external control terminal (not shown in fig. 1) respectively.
And the micro control unit MCU receives a dimming control signal sent by a user through an external control end through an interface. The power supply control IC sends the calculated output power of the load LED to the micro control unit MCU, and the micro control unit MCU sends the received output power of the load LED to an external control end through an interface.
In this embodiment, the external control terminal may be a removable device, such as a mobile terminal, or may be a non-removable device, such as a computer. The external control end is provided with a corresponding client, so that the received output power of the load LED can be displayed in a display interface of the client.
In another embodiment of the present invention, the power control IC is further provided with a transmitting pin I, and the transmitting pin I may be further connected to the interface, so that the power control IC may transmit the detected fault state to the external control terminal through the interface by detecting the fault state of each device connected thereto. Of course, the external control terminal can display the fault state of the power supply by using the corresponding client terminal.
The above description indicates that the external control terminal can realize signal transmission with the power control IC and the micro control unit MCU through the interface, and the signal transmission mode can be a wired transmission mode or a wireless transmission mode.
For example, if a wireless transmission method is used to transmit signals, wireless communication modules may be respectively disposed in the interface and the external control terminal. Further, the micro control unit MCU receives a dimming control signal from an external control terminal through a wireless communication module in the interface, and transmits output power of the load LED to the external control terminal. And the power supply control IC sends the fault state of the power supply to the external control terminal through the wireless communication module in the interface.
In this embodiment, the wireless communication module may be a wireless wifi module, a bluetooth module, or the like, which is not specifically limited in the embodiment of the present invention.
In the embodiment of the invention, the non-isolated dimming constant current power supply further comprises a diode D1 and a capacitor C1. The positive electrode of the diode D1 is connected with the drain electrode of the MOS tube, the negative electrode of the diode D1 is connected with the negative electrode of the load LED, the positive electrode of the capacitor C1 is connected with the positive electrode of the load LED, and the negative electrode of the capacitor C1 is connected with the negative electrode of the load LED.
When the switching element Q1 is in the on state, the output current of the load LED flows from the positive electrode to the negative electrode of the load LED, flows to the switching element Q1 through the transformer T1, and flows to the ground through the resistor R4. When the switching element Q1 is controlled to be in an off state, the transformer T1 is reversed, and the output current of the load LED flows from the negative electrode of the load LED to the transformer T1, and then flows to the positive electrode of the load LED through the diode D1.
Based on the same inventive concept as the one in the previous example, the embodiment of the invention also provides a control system, referring to figure 3, the control system 10 comprises the non-isolated dimming constant current power supply 11, the interface 12, the external control terminal 13 and the load LED in any of the above embodiments. Wherein,
the interface 12 is respectively connected with the external control end 13 and the non-isolated dimming constant current power supply 11.
The non-isolated dimming constant current power supply 11 has an input terminal (not shown in fig. 3) connected to the power supply (not shown in fig. 3) and an output terminal (not shown in fig. 3) connected to the load LED and configured to supply a constant current to the load LED.
The non-isolated dimming constant current power supply 11 is further configured to receive a dimming control signal sent by a user through the external control terminal 13 through the interface 12, so as to adjust the output current Io of the load LED by using the dimming control signal. The non-isolated dimming constant current power supply 11 calculates the output power of the load LED by detecting the output voltage and average current of the load LED, and further transmits the output power of the load LED to the external control terminal 13 through the interface 12.
The external control terminal 13 can realize signal transmission between the non-isolated dimming constant current power supply 11 through the interface 12, and the signal transmission mode can be a wired transmission mode or a wireless transmission mode. For example, if a wireless transmission manner is adopted to transmit signals, wireless communication modules may be respectively disposed in the interface 12 and the external control terminal 13, and the wireless communication modules may be a wireless wifi module, a bluetooth module, or the like, which is not limited in particular in the embodiment of the present invention.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all technical features thereof can be replaced by others within the spirit and principle of the present invention; such modifications and substitutions do not depart from the scope of the invention.
Claims (14)
1. A non-isolated dimming constant current power supply, which comprises a power supply control IC, a micro control unit MCU and a transformer which are respectively connected with the power supply control IC,
the micro control unit MCU is configured to receive a dimming control signal from a user, analyze the dimming control signal, generate a corresponding PWM signal and a corresponding working mode control signal, and send the PWM signal and the corresponding working mode control signal to the power supply control IC;
the micro control unit MCU analyzes that the dimming power corresponding to the dimming control signal is larger than the preset power, and generates a linear dimming mode control signal; analyzing that the dimming power corresponding to the dimming control signal is smaller than the preset power, and generating an intermittent mode control signal;
the power supply control IC works in a linear dimming mode if receiving a linear dimming mode control signal, converts the received PWM signal into a linear voltage signal, and adjusts the output current Io of the load LED by using the linear voltage signal; if the intermittent mode control signal is received, the device works in the intermittent mode, generates a frequency signal in a preset range according to the received PWM signal, supplies the frequency signal to the transformer, and adjusts the output current Io of the load LED by utilizing the received PWM signal.
2. The non-isolated dimming constant current power supply of claim 1, wherein,
the micro control unit MCU is provided with a first communication port, a PWM port and a receiving port, and is configured to receive a dimming control signal from a user by utilizing the receiving port, analyze the dimming control signal and generate a corresponding PWM signal and a corresponding working mode control signal, send the PWM signal to the power supply control IC through the PWM port and send the working mode control signal to the power supply control IC through the first communication port;
the power supply control IC is provided with a PWM pin connected with the PWM port and a communication pin in communication connection with the first communication port, the PWM signal is received by the PWM pin, and the working mode control signal is received by the communication pin.
3. The non-isolated dimming constant current power supply according to claim 1 or 2, further comprising a driving resistor R1, a switching element, wherein,
the power supply control IC comprises a drive pin GD, one end of the drive resistor R1 is connected, and the other end of the drive resistor R1 is connected with the switching element; the switch element is connected with one end of the primary side of the transformer, the other end of the primary side of the transformer is connected with the negative electrode of the load LED;
the power supply control IC works in an intermittent mode, and sends the generated frequency signal in the preset range to the switching element through the driving resistor R1, and the switching element provides the frequency signal for the transformer.
4. The non-isolated dimming constant current power supply according to claim 3, wherein the switching element comprises a power field effect transistor MOS,
and the grid electrode of the power field effect transistor MOS is connected with the driving resistor R1, and the drain electrode of the power field effect transistor MOS is connected with one end of the primary side of the transformer.
5. The non-isolated dimming constant current power supply according to claim 3, further comprising a voltage dividing resistor R2 and a voltage dividing resistor R3, wherein one end of the voltage dividing resistor R3 is connected with the negative electrode of the load LED, the other end of the voltage dividing resistor R3 is connected with the voltage dividing resistor R2, and the other end of the voltage dividing resistor R2 is grounded;
the power supply control IC comprises a first detection pin, wherein the first detection pin is connected to a connection point of the voltage dividing resistor R2 and the voltage dividing resistor R3 and is configured to detect the voltage division of the voltage dividing resistor R2 and then compare the detected voltage division with a preset reference voltage Vref, and if the voltage division of the voltage dividing resistor R2 obtained through comparison is larger than the preset reference voltage Vref, the switching element is controlled to be in an off state and the current off state is kept in preset time.
6. The non-isolated dimming constant current power supply according to claim 5, wherein an RC integration circuit is integrated in the power control IC, the power control IC converts the received PWM signal into a linear voltage signal through the RC integration circuit in a linear dimming mode, if the duty ratio of the PWM signal increases, the converted linear voltage signal increases in value, the preset reference voltage Vref increases, and the output current Io of the load LED increases.
7. The non-isolated dimming constant current power supply according to claim 5, further comprising a resistor R4, wherein one end of the resistor R4 is connected with the switching element, and the other end of the resistor R4 is grounded;
the first detection pin of the power supply control IC detects the output voltage of the load LED by detecting the voltage division of the voltage division resistor R2;
the power supply control IC comprises a CS pin which is connected with one end of the resistor R4 which is not grounded, and the power supply control IC works in a linear dimming mode and detects the average current of the load LED by detecting the peak current on the resistor R4 through the CS pin;
the power supply control IC uses the output voltage of the load LED and determining the output power of the load LED by averaging the currents.
8. The non-isolated dimming constant current power supply according to claim 6, further comprising a resistor R4, wherein one end of the resistor R4 is connected with the switching element, and the other end of the resistor R4 is grounded;
the first detection pin of the power supply control IC detects the output voltage of the load LED by detecting the voltage division of the voltage division resistor R2;
the power supply control IC comprises a CS pin which is connected with one end of the resistor R4 which is not grounded, and the power supply control IC works in an intermittent mode, utilizes the CS pin to detect the peak voltage on the resistor R4, amplifies the peak voltage on the resistor R4, and calculates the average current of the load LED after the peak voltage is processed by the RC integrating circuit;
the power control IC determines the output power of the load LED by using the output voltage and average current of the load LED.
9. The non-isolated dimming constant current power supply according to claim 5, further comprising a resistor R4, a resistor R5 connected in series with the resistor R4;
the first detection pin of the power supply control IC detects the output voltage of the load LED by detecting the voltage division of the voltage division resistor R2;
the power supply control IC comprises a second detection pin, the second detection pin is connected to the connection point of the resistor R4 and the resistor R5, the partial pressure of the resistor R5 is detected, and after the partial pressure of the resistor R5 is amplified, the average current of the load LED is calculated;
the power control IC determines the output power of the load LED by using the output voltage and average current of the load LED.
10. The non-isolated dimming constant current power supply of any of claims 5-9, further comprising:
the interface is respectively connected with the MCU and the external control end;
the micro control unit MCU receives the dimming control signal sent by a user through the external control end through the interface;
the power supply control IC sends the output power of the load LED to the micro control unit MCU; and the MCU sends the received output power of the load LED to the external control end through the interface.
11. The non-isolated dimming constant current power supply of claim 10, wherein,
the interface is connected with the power supply control IC, the power supply control IC detects the fault state of each device connected with the power supply control IC, and the detected fault state is sent to the external control end through the interface.
12. The non-isolated dimming constant current power supply according to claim 10, wherein wireless communication modules are arranged in the interface and the external control terminal, and the micro control unit MCU receives a dimming control signal from the external control terminal through the wireless communication module in the interface and sends output power of the load LED to the external control terminal.
13. The non-isolated dimming constant current power supply of claim 10, wherein the external control terminal comprises a mobile terminal.
14. A control system comprising an interface, an external control terminal, a load LED, the non-isolated dimming constant current power supply of any one of claims 1-13, wherein,
the interface is respectively connected with the external control end and the non-isolated dimming constant current power supply;
the non-isolated dimming constant current power supply is provided with an input end and an output end, the input end is connected with a power supply, the output end is connected with the load LED and is configured to provide constant current for the load LED;
the non-isolated dimming constant current power supply is further configured to receive the dimming control signal sent by a user through the external control end through the interface, so as to adjust the output current Io of the load LED by utilizing the dimming control signal; and determining the output power of the load LED by detecting the output voltage and average current of the load LED, and sending the output power of the load LED to the external control terminal through the interface.
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