Drive circuit and LED lighting device

Abstract

The invention provides a driving circuit and an LED lighting device, and relates to the technical field of lighting circuits. The driving circuit comprises an output unit and a constant power unit, wherein a first end of the output unit is used for being electrically connected with an output end of a light-emitting device; the first end and the second end of the constant power unit are electrically connected with the first end and the second end of the output unit respectively, and the constant power unit is used for outputting power when the input voltage of the first end of the output unit is lower than a first preset voltage or the input voltage of the first end of the output unit is higher than a second preset voltage. And the constant power output current output by the second end of the constant power unit is controlled to be reduced, so that the voltage drop from the second end of the output unit to the third end of the output unit is reduced, and the output voltage of the third end of the output unit is increased. The output power of the light-emitting device is improved, and the constant power effect of the light-emitting device is further improved.

Description

Technical Field

[0001] The present application relates to the technical field of lighting circuits, and more specifically, to a driving circuit and an LED lighting device. Background Art

[0002] Lighting devices usually use commercial power supplies. In order to ensure the efficiency of the system and the stability of the chip operation during use, the driver chip usually integrates a constant power function.

[0003] Taking the light-emitting diode (LED) lighting device as an example, when the line voltage of the traditional constant power circuit fluctuates, when the input line voltage is low, the duty cycle of the current driven by the input voltage to the LED is small, and the output power is low. When the input line voltage is high, the duty cycle of the current is large, but the efficiency of the light-emitting device is low and the output power is low, resulting in a poor constant power effect of the light-emitting device. Summary of the invention

[0004] The present application proposes a driving circuit and an LED lighting device to solve the technical problem of poor constant power effect of light-emitting devices in the related art.

[0005] In a first aspect, an embodiment of the present application provides a driving circuit, including: An output unit, a first end of which is used to be electrically connected to an output end of the light emitting device; A constant power unit, wherein the first end and the second end are electrically connected to the first end and the second end of the output unit respectively, and is used to control the constant power output current output by the second end of the constant power unit to decrease when the input voltage of the first end of the output unit is lower than the first predetermined voltage or the input voltage of the first end of the output unit is higher than the second predetermined voltage, so as to reduce the voltage drop from the second end of the output unit to the third end of the output unit and increase the output voltage of the third end of the output unit; the first predetermined voltage is not greater than the second predetermined voltage.

[0006] In a possible implementation, the constant power unit includes: a current mirror module, a first power modulation module, and a second power modulation module; The first end and the second end of the current mirror module serve as the first end and the second end of the constant power unit respectively, and the current mirror module is electrically connected to the input end and the output end of the first power modulation module, and the input end and the output end of the second power modulation module; The current mirror module is used to mirror the constant power input current of the first end of the constant power unit to the first power modulation module and the second power modulation module; The first power modulation module is used for controlling the constant power output current outputted from the second end of the current mirror module to decrease based on the constant power input current when the input voltage of the first end of the output unit is lower than the first predetermined voltage; The second power modulation module is used for reducing the constant power output current output by the second end of the current mirror module based on the constant power input current control when the input voltage of the first end of the output unit is higher than the second predetermined voltage.

[0007] In a possible implementation, the first power modulation module is specifically used to control the first sub-output current at the output end of the first power modulation module to increase based on the constant power input current, and output the first sub-output current to the current mirror module, so that the current mirror module controls the constant power output current to decrease based on the first sub-output current; The second power modulation module is specifically used to control the increase of the second sub-output current at the output end of the second power modulation module based on the constant power input current, and output the second sub-output current to the current mirror module, so that the current mirror module controls the constant power output current to decrease based on the second sub-output current.

[0008] In a possible implementation, the current mirror module includes: a first mirror submodule, a second mirror submodule, a third mirror submodule and a fourth mirror submodule; The first end of the first mirror submodule serves as the first end of the current mirror module; The first mirror submodule, the input end of the first power modulation module and the input end of the second power modulation module are all electrically connected, and are used to mirror the constant power input current to the first power modulation module and the second power modulation module; The second end of the first mirror submodule, the first end of the second mirror submodule, and the output end of the second power modulation module are all electrically connected, and the third end of the first mirror submodule is grounded; The second end of the second mirror submodule, the first end of the third mirror submodule and the output end of the first power modulation module are all electrically connected, and the third end of the second mirror submodule is electrically connected to the predetermined voltage end; The second end of the third mirror submodule is electrically connected to the first end of the fourth mirror submodule, and the third end of the third mirror submodule is grounded; The second end of the fourth mirror submodule serves as the second end of the current mirror module, and the third end of the fourth mirror submodule is electrically connected to the predetermined voltage end.

[0009] In a possible implementation, the first mirror submodule includes a first transistor and a second transistor, and the first mirror submodule is used to mirror the current of the first transistor to the second transistor, so that the current passing through the first transistor and the second transistor is the same; The second mirror submodule includes a third transistor and a fourth transistor, and the second mirror submodule is used to mirror the current of the third transistor to the fourth transistor, so that the current passing through the third transistor and the current passing through the fourth transistor are the same; The third mirror submodule includes a fifth transistor and a sixth transistor, and the third mirror submodule is used to mirror the current of the fifth transistor to the sixth transistor, so that the currents passing through the fifth transistor and the sixth transistor are the same; The fourth mirror submodule includes a seventh transistor and an eighth transistor. The fourth mirror submodule is used to mirror the current of the seventh transistor to the eighth transistor, so that the currents passing through the seventh transistor and the eighth transistor are the same.

[0010] In a possible implementation, the first power modulation module includes a first constant current source, a ninth transistor, and a fifth mirror submodule; The first constant current source, the first end of the ninth transistor and the first end of the fifth mirror submodule are all electrically connected, the control end of the ninth transistor serves as the input end of the first power modulation module, and the second end of the ninth transistor is grounded; the current mirror module is used to mirror the constant power input current to the ninth transistor; The second end of the fifth mirror submodule serves as the output end of the first power modulation module, and the third end of the fifth mirror submodule is grounded.

[0011] In a possible implementation, the fifth mirror submodule includes a tenth transistor and an eleventh transistor, and the fifth mirror submodule is used to mirror the current of the tenth transistor to the eleventh transistor, so that the currents passing through the tenth transistor and the eleventh transistor are the same; The first end of the tenth transistor and the control end are electrically connected and serve together as the first end of the fifth mirror submodule, and the first end of the eleventh transistor serves as the second end of the fifth mirror submodule; The control terminal of the tenth transistor is electrically connected to the control terminal of the eleventh transistor; The second terminal of the tenth transistor and the second terminal of the eleventh transistor are both grounded.

[0012] In a possible implementation, the second power modulation module includes a second constant current source, a twelfth transistor, and a sixth mirror submodule; The second constant current source, the first end of the twelfth transistor and the first end of the sixth mirror submodule are all electrically connected, the control end of the twelfth transistor serves as the input end of the second power modulation module, and the second end of the twelfth transistor is grounded; the current mirror module is used to mirror the constant power input current to the twelfth transistor; The second end of the sixth mirror submodule serves as the output end of the second power modulation module, and the third end of the sixth mirror submodule is electrically connected to the predetermined voltage end.

[0013] In a possible implementation, the sixth mirror submodule includes a thirteenth transistor and a fourteenth transistor, and the sixth mirror submodule is used to mirror the current of the thirteenth transistor to the fourteenth transistor, so that the currents passing through the thirteenth transistor and the fourteenth transistor are the same; The first end of the thirteenth transistor is electrically connected to the control end and serves as the first end of the sixth mirror submodule, and the first end of the fourteenth transistor serves as the second end of the sixth mirror submodule; The control terminal of the fourteenth transistor is electrically connected to the control terminal of the thirteenth transistor; The second terminal of the thirteenth transistor and the second terminal of the fourteenth transistor are both electrically connected to the predetermined voltage terminal.

[0014] In a possible implementation, the output unit includes an operational amplifier, an adjustment resistor, and a fifteenth transistor; The positive input terminal of the operational amplifier is electrically connected to the reference voltage terminal; the first end of the adjustment resistor and the reverse input terminal of the operational amplifier are electrically connected and serve together as the second end of the output unit; The output end of the operational amplifier is electrically connected to the control end of the fifteenth transistor, and the second end of the regulating resistor is electrically connected to the second end of the fifteenth transistor and both serve as the third end of the output unit; A first terminal of the fifteenth transistor serves as one terminal of the output unit.

[0015] In a possible implementation, the driving circuit further includes: a rectifier bridge group, a diode and a first capacitor; The rectifier bridge group is electrically connected to the positive electrode of the diode, and the negative electrode of the diode is electrically connected to the first end of the first capacitor; The first end and the second end of the first capacitor are respectively used to be electrically connected to the input end and the output end of the light emitting device; The rectifier bridge group is used to convert the line network voltage into a first voltage of the anode of the diode, so that the first voltage outputs the input voltage through the output end of the light emitting device.

[0016] In a second aspect, an embodiment of the present application provides an LED lighting device, comprising: a light-emitting device and the driving circuit of the first aspect; the light-emitting device is an LED lamp.

[0017] The beneficial technical effects brought about by the technical solution provided by the embodiment of the present application include: The first end of the output unit of the driving circuit of the embodiment of the present application can be electrically connected to the output end of the light-emitting device of the lighting device, so that the input voltage of the first end of the output unit is the voltage of the output end of the light-emitting device. When the line voltage fluctuates, the input voltage of the first end of the output unit may be lower than the first predetermined voltage or the input voltage of the first end of the output unit may be higher than the second predetermined voltage. At this time, the constant power unit can control the constant power output current output by the second end of the constant power unit to decrease, thereby reducing the voltage drop from the second end of the output unit to the third end of the output unit, increasing the output voltage of the third end of the output unit, and increasing the output current of the third end of the output unit, which is equivalent to increasing the output power of the light-emitting device, thereby improving the constant power effect of the light-emitting device.

[0018] Additional aspects and advantages of the present application will be partially given in the following description, which will become apparent from the following description, or will be understood through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which: Figure 1 A schematic diagram of the structure of a driving circuit provided in an embodiment of the present application; Figure 2 A structural schematic diagram of a constant power unit provided in an embodiment of the present application; Figure 3 A schematic diagram of the structure of a first power modulation module provided in an embodiment of the present application; Figure 4 A schematic diagram of the structure of a second power modulation module provided in an embodiment of the present application; Figure 5 A schematic diagram of the structure of an output unit provided in an embodiment of the present application; Figure 6 A waveform diagram of output current changing with line network voltage provided in an embodiment of the present application; Figure 7 A waveform diagram of output current changing with line network voltage when the line network voltage is low provided in an embodiment of the present application; Figure 8 A waveform diagram of output current changing with line network voltage when the line network voltage is high provided in an embodiment of the present application. Reference numerals: 10- output unit; 20-constant power unit, 21-current mirror module, 211-first mirror submodule, 212-second mirror module, 213-third mirror submodule, 214-fourth mirror submodule, 22-first power modulation module, 221-first constant current source, 222-fifth mirror submodule, 23-second power modulation module, 231-second constant current source, 232-sixth mirror submodule; Rectifier bridge group 30. DETAILED DESCRIPTION

[0020] The embodiments of the present application are described below in conjunction with the drawings in the present application. It should be understood that the implementation methods described below in conjunction with the drawings are exemplary descriptions for explaining the technical solutions of the embodiments of the present application and do not constitute a limitation on the technical solutions of the embodiments of the present application.

[0021] It will be understood by those skilled in the art that, unless specifically stated, the "said" and "the" used herein may also include plural forms. It should be further understood that the wording "including" used in the specification of the present application refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the implementation of other features, information, data, steps, operations, elements, components and / or combinations thereof supported by the present technical field. It should be understood that when we say that an element is "connected" or "coupled" to another element, the element may be directly connected or coupled to the other element, or it may refer to the connection relationship between the element and the other element through an intermediate element. In addition, the "connection" or "coupling" used herein may include wireless connection or wireless coupling. The term "and / or" used herein refers to at least one of the items defined by the term, for example, "A and / or B" may be implemented as "A", or as "B", or as "A and B".

[0022] The following is a detailed description of the technical solution of the present application and how the technical solution of the present application solves the above technical problems with specific embodiments. It should be noted that the following implementations can refer to, draw on or combine with each other, and the same terms, similar features and similar implementation steps in different implementations will not be described repeatedly.

[0023] See also Figure 1 As shown, an embodiment of the present application provides a schematic diagram of the structure of a driving circuit. Figure 1 As shown, the driving circuit includes: an output unit 10 and a constant power unit 20.

[0024] The first end of the output unit 10 is used to be electrically connected to the output end of the light-emitting device; the first end and the second end of the constant power unit 20 are electrically connected to the first end and the second end of the output unit 10 respectively, and the constant power unit 20 is used to control the constant power output current output by the second end of the constant power unit 20 to decrease when the input voltage of the first end of the output unit 10 is lower than the first predetermined voltage or the input voltage of the first end of the output unit 10 is higher than the second predetermined voltage, so as to reduce the voltage drop from the second end of the output unit 10 to the third end of the output unit 10 and increase the output voltage of the third end of the output unit 10; the first predetermined voltage is not greater than the second predetermined voltage.

[0025] Optionally, the first end of the constant power unit 20 is electrically connected to the first end of the output unit 10 via a constant power resistor. The first predetermined voltage and the second predetermined voltage can be set according to actual applications.

[0026] The first end of the output unit 10 of the driving circuit of the embodiment of the present application can be electrically connected to the output end of the light-emitting device of the lighting device, so that the input voltage of the first end of the output unit 10 is the voltage of the output end of the light-emitting device. When the line voltage fluctuates, the input voltage of the first end of the output unit 10 (i.e., the OUT voltage) is lower than the first predetermined voltage or the input voltage of the first end of the output unit 10 is higher than the second predetermined voltage. At this time, the constant power unit 20 can control the constant power output current output by the second end of the constant power unit 20 to decrease, thereby reducing the voltage drop from the second end of the output unit 10 to the third end of the output unit 10, increasing the output voltage of the third end of the output unit 10, that is, increasing the output current of the third end of the output unit 10, which is equivalent to increasing the output power of the light-emitting device, thereby improving the constant power effect of the light-emitting device.

[0027] The constant power effect of the embodiment of the present application is for the power of the light emitting device, and can keep the power of the light emitting device constant, for example: the power of the LED, etc. The output current of the third terminal of the output unit 10 increases, that is, the load current of the LED also increases, thereby increasing the power of the LED.

[0028] In some embodiments, the driving circuit further includes: a rectifier bridge group 30, a diode, and a first capacitor. The rectifier bridge group 30 is electrically connected to the anode of the diode, and the cathode of the diode is electrically connected to the first end of the first capacitor; the first end and the second end of the first capacitor are respectively used to be electrically connected to the input end and the output end of the light-emitting device; the rectifier bridge group 30 is used to convert the line network voltage into a first voltage of the anode of the diode, so that the first voltage becomes the input voltage of the first end of the output unit 10 after passing through the light-emitting device.

[0029] See also Figure 1 As shown, Z1 represents the rectifier bridge group 30, R1 is the constant power resistor, D0 is the diode, C0 is the first capacitor, R2 is the output resistor, and ZD is the LED load. 120Vac is the line voltage, OUT is the input voltage VOUT, that is, the OUT voltage, REXT corresponds to the output voltage of the third terminal of the output unit 10, that is, the port voltage of REXT, VT is the voltage of the first terminal of the constant power unit 20, IVT is the constant power output current, and VREF is the reference voltage.

[0030] See also Figure 1 As shown, the embodiment of the present application takes the LED driving circuit as an example, and the working process of the LED driving circuit is: in each mains cycle, the mains with a sine waveform is shaped into a DC half-wave with a steamed bun-shaped periodic waveform after passing through the rectifier bridge group 30. The mains is output at the output port of the rectifier bridge group 30 after rectification. One path of the output voltage at the output end of the rectifier bridge group 30 is coupled to the OUT port of the load branch through the diode D0 and the first capacitor C0.

[0031] In each half-wave cycle of the mains, when the voltage is lower than the LED lamp voltage, the OUT channel is closed. When the line voltage gradually increases and is greater than the LED lamp voltage, the OUT current channel is opened. The OUT current is the port voltage of REXT divided by the output resistance R2.

[0032] In the embodiment of the present application, the output voltage of the third terminal of the output unit 10 is increased, that is, the port voltage of REXT is increased, thereby increasing the output current and further improving the power of the lighting device.

[0033] See also Figure 1 As shown, the constant power resistor R1 converts the OUT voltage into a constant power input current at the first end of the constant power unit 20. The constant power input current is automatically adjusted according to the line network voltage. The ratio of the constant power input current to the OUT voltage is defined as the constant power current slope, which is approximately a fixed value. The constant power unit 20 processes the input current signal with a fixed slope and generates a constant power output current with multiple slopes according to the constant power input current; the constant power unit 20 injects the constant power output current into the output unit 10.

[0034] When the line voltage is greater than the lamp voltage, the rectifier bridge group 30 charges the first capacitor C0 through the diode D0, and the output unit 10 (ie, the OUT module) is turned on. When the line voltage is less than the lamp voltage, the OUT module is turned off, and the capacitor provides a voltage to maintain the current to the LED. The overall current of the drive circuit is determined by the REXT port voltage, the output resistor R2 of the REXT port, the LED lamp voltage, and the constant power resistor R1. The constant power range can be freely configured according to actual usage.

[0035] Optionally, the OUT voltage is input to the constant power unit 20 through the constant power resistor R1 , and the constant power unit 20 processes the constant power input current with a multi-stage slope operation and then acts on the output unit 10 .

[0036] See also Figure 2 As shown, the present application embodiment provides a structural schematic diagram of a constant power unit 20. Figure 2 As shown, the constant power unit 20 includes: a current mirror module 21, a first power modulation module 22 and a second power modulation module 23.

[0037] The first end and the second end of the current mirror module 21 serve as the first end and the second end of the constant power unit 20 respectively. The current mirror module 21 is electrically connected to the input end and the output end of the first power modulation module 22, and the input end and the output end of the second power modulation module 23.

[0038] The current mirror module 21 is used to mirror the constant power input current of the first end of the constant power unit 20 to the first power modulation module 22 and the second power modulation module 23 .

[0039] The first power modulation module 22 is used to control the constant power output current output from the second end of the current mirror module 21 to decrease based on the constant power input current when the input voltage of the first end of the output unit 10 is lower than the first predetermined voltage.

[0040] The second power modulation module 23 is used to control the constant power output current output by the second end of the current mirror module 21 to decrease based on the constant power input current when the input voltage of the first end of the output unit 10 is higher than the second predetermined voltage.

[0041] In some embodiments, the first power modulation module 22 is specifically used to control the increase of the first sub-output current at the output end of the first power modulation module 22 based on the constant power input current, and output the first sub-output current to the current mirror module 21, so that the current mirror module 21 controls the constant power output current to decrease based on the first sub-output current.

[0042] The second power modulation module 23 is specifically used to control the increase of the second sub-output current at the output end of the second power modulation module 23 based on the constant power input current, and output the second sub-output current to the current mirror module 21, so that the current mirror module 21 controls the constant power output current to decrease based on the second sub-output current.

[0043] In some embodiments, the current mirror module 21 includes: a first mirror submodule 211 , a second mirror submodule 212 , a third mirror submodule 213 and a fourth mirror submodule 214 .

[0044] The first end of the first mirror submodule 211 serves as the first end of the current mirror module 21; the first mirror submodule 211, the input end of the first power modulation module 22 and the input end of the second power modulation module 23 are all electrically connected, for mirroring the constant power input current to the first power modulation module 22 and the second power modulation module 23.

[0045] The second end of the first mirror submodule 211, the first end of the second mirror submodule 212, and the output end of the second power modulation module 23 are all electrically connected, and the third end of the first mirror submodule 211 is grounded; the second end of the second mirror submodule 212, the first end of the third mirror submodule 213, and the output end of the first power modulation module 22 are all electrically connected, and the third end of the second mirror submodule 212 is electrically connected to the predetermined voltage end.

[0046] The second end of the third mirror submodule 213 is electrically connected to the first end of the fourth mirror submodule 214, and the third end of the third mirror submodule 213 is grounded; the second end of the fourth mirror submodule 214 serves as the second end of the current mirror module 21, and the third end of the fourth mirror submodule 214 is electrically connected to the predetermined voltage end.

[0047] In some embodiments, the first mirror submodule 211 includes a first transistor and a second transistor, and the first mirror submodule 211 is used to mirror the current of the first transistor to the second transistor, so that the currents passing through the first transistor and the second transistor are the same.

[0048] The second mirror submodule 212 includes a third transistor and a fourth transistor. The second mirror submodule 212 is used to mirror the current of the third transistor to the fourth transistor, so that the currents passing through the third transistor and the fourth transistor are the same.

[0049] The third mirror submodule 213 includes a fifth transistor and a sixth transistor. The third mirror submodule 213 is used to mirror the current of the fifth transistor to the sixth transistor, so that the currents passing through the fifth transistor and the sixth transistor are the same.

[0050] The fourth mirror submodule 214 includes a seventh transistor and an eighth transistor. The fourth mirror submodule 214 is used to mirror the current of the seventh transistor to the eighth transistor, so that the currents passing through the seventh transistor and the eighth transistor are the same.

[0051] Optionally, the voltage at the predetermined voltage terminal is a voltage provided by a power supply inside the chip.

[0052] See also Figure 2 As shown, the current mirror module 21 includes current mirror tubes M1-M8, M1 is a first transistor, M2 is a second transistor, M3 is a third transistor, M4 is a fourth transistor, M5 is a fifth transistor, M6 is a sixth transistor, M7 is a seventh transistor, and M8 is an eighth transistor. VBN is the voltage of the input end of the first power modulation module 22 and the input end of the second power modulation module 23. TVT1 is the first sub-output current, and TVT2 is the second sub-output current.

[0053] In some embodiments, the first power modulation module 22 includes a first constant current source 221 , a ninth transistor and a fifth mirror submodule 222 .

[0054] The first constant current source 221, the first end of the ninth transistor and the first end of the fifth mirror submodule 222 are all electrically connected, the control end of the ninth transistor serves as the input end of the first power modulation module 22, and the second end of the ninth transistor is grounded; the current mirror module 21 is used to mirror the constant power input current to the ninth transistor. The second end of the fifth mirror submodule 222 serves as the output end of the first power modulation module 22, and the third end of the fifth mirror submodule 222 is grounded.

[0055] In some embodiments, the fifth mirror submodule 222 includes a tenth transistor and an eleventh transistor, and the fifth mirror submodule 222 is used to mirror the current of the tenth transistor to the eleventh transistor, so that the currents passing through the tenth transistor and the eleventh transistor are the same.

[0056] The first end of the tenth transistor and the control end are electrically connected and serve together as the first end of the fifth mirror submodule 222 , and the first end of the eleventh transistor serves as the second end of the fifth mirror submodule 222 .

[0057] The control end of the tenth transistor is electrically connected to the control end of the eleventh transistor; the second end of the tenth transistor and the second end of the eleventh transistor are both grounded.

[0058] See also Figure 3 As shown, the embodiment of the present application provides a structural schematic diagram of a first power modulation module 22. M9 is the ninth transistor, M10 is the tenth transistor, and M11 is the eleventh transistor. The first power modulation module 22 is a low-voltage modulation module, and the first constant current source 221 provides a current bias Ibias1. When the OUT voltage is low, the input current of the first power modulation module 22 is small. When the current flowing through M9 is smaller than the current Ibias1, current will flow through M10 and M11. The current on M10 and M11 is reduced by the operation of the current mirror module 21 to reduce the current IVT.

[0059] In some embodiments, the second power modulation module 23 includes a second constant current source 231 , a twelfth transistor and a sixth mirror submodule 232 .

[0060] The second constant current source 231, the first end of the twelfth transistor and the first end of the sixth mirror submodule 232 are all electrically connected, the control end of the twelfth transistor serves as the input end of the second power modulation module 23, and the second end of the twelfth transistor is grounded; the current mirror module 21 is used to mirror the constant power input current to the twelfth transistor; the second end of the sixth mirror submodule 232 serves as the output end of the second power modulation module 23, and the third end of the sixth mirror submodule 232 is electrically connected to the predetermined voltage end.

[0061] In some embodiments, the sixth mirror submodule 232 includes a thirteenth transistor and a fourteenth transistor, and the sixth mirror submodule 232 is used to mirror the current of the thirteenth transistor to the fourteenth transistor, so that the currents passing through the thirteenth transistor and the fourteenth transistor are the same.

[0062] The first end and the control end of the thirteenth transistor are electrically connected and together serve as the first end of the sixth mirror sub-module 232, and the first end of the fourteenth transistor serves as the second end of the sixth mirror sub-module 232; the control end of the fourteenth transistor is electrically connected to the control end of the thirteenth transistor; the second end of the thirteenth transistor and the second end of the fourteenth transistor are both electrically connected to the predetermined voltage end.

[0063] See also Figure 4 As shown, the embodiment of the present application provides a structural schematic diagram of a second power modulation module 23. M12 is a twelfth transistor, M13 is a thirteenth transistor, and M14 is a fourteenth transistor. The second power modulation module 23 is a high-voltage modulation module, and the second constant current source 231 provides a current bias Ibias2. When the OUT voltage is high, the input current of the second power modulation module 23 is large. When the current flowing through M12 is larger than the current Ibias2, current will flow through M13 and M14. The current on M13 and M14 is reduced by the operation of the current mirror module 21 to reduce the current IVT.

[0064] In some embodiments, the output unit 10 includes an operational amplifier, an adjustment resistor, and a fifteenth transistor.

[0065] The positive input terminal of the operational amplifier is electrically connected to the reference voltage terminal; the first end of the adjustment resistor and the reverse input terminal of the operational amplifier are electrically connected and serve together as the second end of the output unit 10; the output end of the operational amplifier is electrically connected to the control end of the fifteenth transistor, the second end of the adjustment resistor is electrically connected to the second end of the fifteenth transistor and serve together as the third end of the output unit 10; the first end of the fifteenth transistor serves as one end of the output unit 10.

[0066] See also Figure 5 As shown, the present embodiment provides a schematic diagram of the structure of an output unit 10. Figure 5 As shown, AMP represents an operational amplifier, M15 represents a fifteenth transistor, and R3 represents an adjustment resistor. The VREF signal sets a suitable port voltage for the REXT port, and the constant power output current IVT is provided by the constant power unit 20. The constant power output current IVT generates a corresponding voltage drop on the adjustment resistor R3 according to the size of the line network voltage, thereby reducing the port voltage of REXT.

[0067] Optionally, when the OUT voltage rises to a certain value, M15 is turned on, and the voltage at the positive input terminal of the operational amplifier is approximately equal to the voltage at the reverse input terminal, so that the port voltage of REXT is VREF-IVT×R3.

[0068] See also Figure 6 As shown, the embodiment of the present application provides a waveform diagram of output current changing with line network voltage. When the line network voltage is a standard value, the first power modulation module 22 and the second power modulation module 23 work together, and the output current waveform is as shown in FIG. Figure 6 The output current is the output current of the third terminal of the output unit 10.

[0069] See also Figure 7 As shown, the embodiment of the present application provides a waveform diagram of the output current changing with the line voltage when the line voltage is low. When the line voltage is low, the first power modulation module 22 is dominant. At this time, due to the reduction of the current duty cycle, the first power modulation module 22 will reduce the IVT current to increase the power of the lighting device. The output current waveform when the line voltage is low is as follows: Figure 7 shown.

[0070] See also Figure 8 As shown, the embodiment of the present application provides a waveform diagram of the output current changing with the line network voltage when the line network voltage is high. When the line network voltage is high, the second power modulation module 23 is dominant. At this time, the efficiency of the lighting device is low. The second power modulation module 23 will reduce the IVT current to increase the power of the lighting device to ensure the output power of the LED. The output current waveform when the line network voltage is high is as follows Figure 8 shown.

[0071] Based on the technical solution of the embodiment of the present application, the driving circuit of the embodiment of the present application can be an LED constant power driving method, and a multi-stage constant power method can be adopted. The constant power current slope is set externally through a resistor, and the starting point of the constant power compensation is set internally, as well as different current slopes and dividing points of different current slopes.

[0072] The embodiment of the present application is aimed at the problem of poor constant power effect in the prior art, and proposes a multi-stage constant power drive circuit. The constant power is used to work in a mains power environment, and its function is to ensure that the output power of the lighting device is relatively constant when the mains voltage fluctuates, thereby improving the problem that the existing LED drive circuit has poor constant power effect with different current duty cycles.

[0073] The embodiment of the present application provides a novel constant power driving circuit, which can be used in LED high-voltage linear applications. The constant power unit 20 adopts a multi-stage constant power method, which improves the problem of low output power of traditional constant power circuits when the line voltage is low due to small current duty cycle and low output power when the line voltage is high due to reduced system efficiency.

[0074] The transistors in the embodiments of the present application can be MOS tubes, and the control end of each transistor is the gate of the MOS tube. Among the first end and the second end of each transistor, one is the source of the MOS tube and the other is the drain of the MOS tube. The specific arrangement of each MOS tube can be shown in the drawings of the embodiments of the present application. The drawings of the embodiments of the present application are only used as examples. The various circuit structures based on the technical solutions of the embodiments of the present application or the technical solutions consistent with the technical ideas of the embodiments of the present application all belong to the protection scope of the embodiments of the present application.

[0075] The embodiment of the present application provides an LED lighting device, comprising: a light emitting device and a driving circuit of the embodiment of the present application; the light emitting device is an LED lamp. The LED lighting device is a lighting device using LED as a light source.

[0076] The LED lighting device provided in the embodiment of the present application includes a driving circuit in the embodiment of the present application, which has the same inventive concept and the same beneficial effects as the various embodiments described in the previous driving circuit. The contents not shown in detail in the LED lighting device can be referred to the various embodiments described in the previous embodiments and will not be repeated here.

[0077] Those skilled in the art will appreciate that the various operations, methods, steps, measures, and schemes in the processes discussed in this application may be alternated, changed, combined, or deleted. Furthermore, other steps, measures, and schemes in the various operations, methods, and processes discussed in this application may also be alternated, changed, rearranged, decomposed, combined, or deleted. Furthermore, steps, measures, and schemes in the related art that are similar to those disclosed in this application may also be alternated, changed, rearranged, decomposed, combined, or deleted.

[0078] In the description of the present application, the directions or positional relationships indicated by words such as "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the exemplary directions or positional relationships shown in the accompanying drawings. They are for the convenience of describing or simplifying the description of the embodiments of the present application, and do not indicate or imply that the referred device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present application.

[0079] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0080] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0081] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0082] The above is only a partial implementation method of the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the technical concept of the scheme of the present application, other similar implementation methods based on the technical ideas of the present application are also within the protection scope of the embodiments of the present application.

Claims

1. A driving circuit, characterized in that: include: An output unit, a first end of which is used to be electrically connected to an output end of the light emitting device; A constant power unit, wherein the first end and the second end are electrically connected to the first end of the output unit and the second end of the output unit respectively, and is used to control the constant power output current output by the second end of the constant power unit to decrease when the input voltage of the first end of the output unit is lower than the first predetermined voltage or the input voltage of the first end of the output unit is higher than the second predetermined voltage, so as to reduce the voltage drop from the second end of the output unit to the third end of the output unit and increase the output voltage of the third end of the output unit; the first predetermined voltage is not greater than the second predetermined voltage.

2. The driving circuit according to claim 1, characterized in that: The constant power unit comprises: a current mirror module, a first power modulation module and a second power modulation module; The first end and the second end of the current mirror module serve as the first end and the second end of the constant power unit respectively, and the current mirror module is electrically connected to the input end and the output end of the first power modulation module, and the input end and the output end of the second power modulation module; The current mirror module is used to mirror the constant power input current of the first end of the constant power unit to the first power modulation module and the second power modulation module; The first power modulation module is used for controlling the constant power output current outputted from the second end of the current mirror module to decrease based on the constant power input current when the input voltage at the first end of the output unit is lower than the first predetermined voltage; The second power modulation module is used for controlling the constant power output current outputted from the second end of the current mirror module to decrease based on the constant power input current when the input voltage at the first end of the output unit is higher than a second predetermined voltage.

3. The driving circuit according to claim 2, characterized in that: The first power modulation module is specifically used to control the first sub-output current of the output end of the first power modulation module to increase based on the constant power input current, and output the first sub-output current to the current mirror module, so that the current mirror module controls the constant power output current to decrease based on the first sub-output current; The second power modulation module is specifically used to control the second sub-output current at the output end of the second power modulation module to increase based on the constant power input current, and output the second sub-output current to the current mirror module, so that the current mirror module controls the constant power output current to decrease based on the second sub-output current.

4. The driving circuit according to claim 2, characterized in that: The current mirror module includes: a first mirror submodule, a second mirror submodule, a third mirror submodule and a fourth mirror submodule; The first end of the first mirror submodule serves as the first end of the current mirror module; The first mirror submodule, the input end of the first power modulation module and the input end of the second power modulation module are all electrically connected, and are used to mirror the constant power input current to the first power modulation module and the second power modulation module; The second end of the first mirror submodule, the first end of the second mirror submodule, and the output end of the second power modulation module are all electrically connected, and the third end of the first mirror submodule is grounded; The second end of the second mirror submodule, the first end of the third mirror submodule and the output end of the first power modulation module are all electrically connected, and the third end of the second mirror submodule is electrically connected to the predetermined voltage end; The second end of the third mirror submodule is electrically connected to the first end of the fourth mirror submodule, and the third end of the third mirror submodule is grounded; The second end of the fourth mirror submodule serves as the second end of the current mirror module, and the third end of the fourth mirror submodule is electrically connected to a predetermined voltage end.

5. The driving circuit according to claim 4, characterized in that: The first mirror submodule includes a first transistor and a second transistor, and the first mirror submodule is used to mirror the current of the first transistor to the second transistor so that the current passing through the first transistor and the current passing through the second transistor are the same; The second mirror submodule includes a third transistor and a fourth transistor, and the second mirror submodule is used to mirror the current of the third transistor to the fourth transistor, so that the current passing through the third transistor and the current passing through the fourth transistor are the same; The third mirror submodule includes a fifth transistor and a sixth transistor, and the third mirror submodule is used to mirror the current of the fifth transistor to the sixth transistor, so that the current passing through the fifth transistor and the current passing through the sixth transistor are the same; The fourth mirror submodule includes a seventh transistor and an eighth transistor, and the fourth mirror submodule is used to mirror the current of the seventh transistor to the eighth transistor, so that the current passing through the seventh transistor and the current passing through the eighth transistor are the same.

6. The driving circuit according to claim 2, characterized in that: The first power modulation module includes a first constant current source, a ninth transistor and a fifth mirror submodule; The first constant current source, the first end of the ninth transistor and the first end of the fifth mirror submodule are all electrically connected, the control end of the ninth transistor serves as the input end of the first power modulation module, and the second end of the ninth transistor is grounded; The current mirror module is used to mirror the constant power input current to the ninth transistor; The second end of the fifth mirror submodule serves as the output end of the first power modulation module, and the third end of the fifth mirror submodule is grounded.

7. The driving circuit according to claim 6, characterized in that: The fifth mirror submodule includes a tenth transistor and an eleventh transistor, and the fifth mirror submodule is used to mirror the current of the tenth transistor to the eleventh transistor, so that the current passing through the tenth transistor and the current passing through the eleventh transistor are the same; The first end and the control end of the tenth transistor are electrically connected and serve together as the first end of the fifth mirror submodule, and the first end of the eleventh transistor serves as the second end of the fifth mirror submodule; The control end of the tenth transistor is electrically connected to the control end of the eleventh transistor; The second terminal of the tenth transistor and the second terminal of the eleventh transistor are both grounded.

8. The driving circuit according to claim 2, characterized in that: The second power modulation module includes a second constant current source, a twelfth transistor and a sixth mirror submodule; The second constant current source, the first end of the twelfth transistor and the first end of the sixth mirror submodule are all electrically connected, the control end of the twelfth transistor serves as the input end of the second power modulation module, and the second end of the twelfth transistor is grounded; The current mirror module is used to mirror the constant power input current to the twelfth transistor; The second end of the sixth mirror submodule serves as the output end of the second power modulation module, and the third end of the sixth mirror submodule is electrically connected to a predetermined voltage end.

9. The driving circuit according to claim 8, characterized in that: The sixth mirror submodule includes a thirteenth transistor and a fourteenth transistor, and the sixth mirror submodule is used to mirror the current of the thirteenth transistor to the fourteenth transistor, so that the current passing through the thirteenth transistor and the fourteenth transistor are the same; The first end and the control end of the thirteenth transistor are electrically connected and serve together as the first end of the sixth mirror submodule, and the first end of the fourteenth transistor serves as the second end of the sixth mirror submodule; The control end of the fourteenth transistor is electrically connected to the control end of the thirteenth transistor; The second end of the thirteenth transistor and the second end of the fourteenth transistor are both electrically connected to a predetermined voltage terminal.

10. The driving circuit according to claim 1, characterized in that: The output unit includes an operational amplifier, an adjustment resistor, and a fifteenth transistor; The positive input terminal of the operational amplifier is electrically connected to the reference voltage terminal; the first end of the regulating resistor and the reverse input terminal of the operational amplifier are electrically connected and serve together as the second end of the output unit; The output end of the operational amplifier is electrically connected to the control end of the fifteenth transistor, and the second end of the regulating resistor is electrically connected to the second end of the fifteenth transistor and both serve as the third end of the output unit; The first end of the fifteenth transistor serves as one end of the output unit.

11. The driving circuit according to claim 1, characterized in that: Also includes: A rectifier bridge group, a diode and a first capacitor; The rectifier bridge group is electrically connected to the positive electrode of the diode, and the negative electrode of the diode is electrically connected to the first end of the first capacitor; The first end and the second end of the first capacitor are respectively used to be electrically connected to the input end and the output end of the light emitting device; The rectifier bridge group is used to convert the line network voltage into a first voltage of the anode of the diode, so that the first voltage outputs the input voltage through the output end of the light emitting device.

12. An LED lighting device, characterized in that: include: A light emitting device and a driving circuit as claimed in any one of claims 1 to 11; The light emitting device is an LED lamp.

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