LED driving circuit

Abstract

The application provides an LED driving circuit, which has an energy storage path, an energy storage loop, a first driving path and a second driving path that can be sequentially and time-sharingly turned on; when the energy storage loop is turned on, a first energy storage unit in the energy storage loop can charge a second energy storage unit; when the energy storage path is turned on, an input voltage of an input end can charge the first energy storage unit in the energy storage path; when the first driving path is turned on, a voltage on the second energy storage unit and the input voltage jointly supply power to an LED load; and when the second driving path is turned on, the input voltage supplies power to the LED load. When the input voltage is low, the voltage on the second energy storage unit can be superimposed on the input voltage, so as to raise the input voltage, and the LED load can be supplied with power even when the input voltage is low, so that the input current of the LED load is in a three-step ladder shape, the power factor is improved, the THD is reduced, the current ripple problem can be avoided, and the purpose of reducing loss and improving efficiency can be achieved.

Description

Technical Field

[0001] This invention relates to the field of electronic circuit technology, and more particularly to an LED driver circuit. Background Technology

[0002] LED (Light Emitting Diode) lighting is gradually replacing traditional light sources such as incandescent and fluorescent lamps due to its advantages such as high luminous efficiency, long lifespan, high reliability, and zero pollution. With the widespread application of LED lighting, LED driving technology is also maturing. LED driver circuits are used to convert the input voltage provided by the power grid into a constant current signal and output it to the LED load to drive the LED lamp to work normally.

[0003] Currently, to improve the safety of power grid use, the LED industry has increasingly higher requirements for power factor and total harmonic distortion (THD). At the same time, due to energy and environmental considerations, efficiency has also gradually become a goal pursued by the LED industry. Existing single-segment linear LED driver circuits cannot simultaneously achieve efficiency, power factor, and THD, while multi-segment linear LED driver circuits, although able to achieve efficiency, power factor, and THD, struggle to solve the current ripple problem. Summary of the Invention

[0004] The purpose of this invention is to provide an LED driving circuit that solves the problems of existing LED driving circuits being unable to balance efficiency, power factor, and THD, as well as the inability to solve current ripple.

[0005] To achieve the above objectives, the present invention provides an LED driving circuit for driving an LED load, comprising an energy storage path, an energy storage loop, a first driving path, and a second driving path. The energy storage path and the energy storage loop are both connected to the input terminal of the LED driving circuit. The energy storage path contains a first energy storage unit, and the energy storage loop contains both the first energy storage unit and a second energy storage unit. The first driving path connects the second energy storage unit to the LED load, and the second driving path connects the input terminal to the LED load.

[0006] The energy storage loop, the energy storage path, the first drive path, and the second drive path are sequentially and time-divisionally turned on; when the energy storage loop is turned on, the first energy storage unit charges the second energy storage unit; when the energy storage path is turned on, the input voltage at the input terminal charges the first energy storage unit; when the first drive path is turned on, the voltage on the second energy storage unit and the input voltage together supply power to the LED load; when the second drive path is turned on, the input voltage supplies power to the LED load.

[0007] Optionally, the voltage on the first energy storage unit is a first voltage, and the voltage on the second energy storage unit is a second voltage; and,

[0008] When the input voltage is less than the difference between the first voltage and the second voltage, the energy storage loop is turned on; when the input voltage is greater than or equal to the first voltage and less than the difference between the on-state voltage of the LED load and the second voltage, the energy storage path is turned on; when the input voltage is greater than or equal to the difference between the on-state voltage of the LED load and the second voltage and less than the on-state voltage of the LED load, the first driving path is turned on; when the input voltage is greater than or equal to the on-state voltage of the LED load, the second driving path is turned on.

[0009] Optionally, the energy storage path, the energy storage loop, the first drive path, and the second drive path are all unidirectional.

[0010] Optionally, the first energy storage unit and the second energy storage unit have the same capacity.

[0011] Optionally, the energy storage path further includes a first diode, a first constant current unit, and a first sampling resistor, wherein the first diode, the first energy storage unit, the first constant current unit, and the first sampling resistor are sequentially connected between the input terminal and the ground terminal.

[0012] Optionally, the energy storage loop further includes a second diode, a second constant current unit, and a first constant current unit. The second diode, the second energy storage unit, the second constant current unit, the first constant current unit, and the first energy storage unit are sequentially connected to form a loop. The node between the second energy storage unit and the second constant current unit is connected to the input terminal.

[0013] Optionally, the energy storage loop also includes a second sampling resistor, one end of which is connected to the second constant current unit, and the other end of which is connected to the first constant current unit and the first sampling resistor.

[0014] Optionally, the first driving path includes a third diode, a third constant current unit, and a third sampling resistor, wherein the third diode, the third constant current unit, and the third sampling resistor are sequentially connected between the second energy storage element and the LED load; and / or,

[0015] The second driving path has a fourth diode, a fourth constant current unit and a fourth sampling resistor, which are connected sequentially between the input terminal and the LED load.

[0016] Optionally, the third sampling resistor and the fourth sampling resistor are the same resistor.

[0017] Optionally, the first constant current unit, the third constant current unit, and the fourth constant current unit all include a MOS transistor and an operational amplifier. One input terminal of the operational amplifier is used to input a reference voltage, the other input terminal is connected to the source of the MOS transistor, and the output terminal is connected to the gate of the MOS transistor.

[0018] Optionally, when the energy storage path is on, the charging current of the first energy storage unit is the quotient of the reference voltage input to the first constant current unit and the first sampling resistor; when the first driving path is on, the input current of the LED load is the quotient of the reference voltage input to the third constant current unit and the third sampling resistor; when the second driving path is on, the input current of the LED load is the quotient of the reference voltage input to the fourth constant current unit and the fourth sampling resistor.

[0019] Optionally, the reference voltage input to the first constant current unit is less than the reference voltage input to the third constant current unit, and the reference voltage input to the third constant current unit is less than the reference voltage input to the fourth constant current unit.

[0020] The LED driving circuit provided by this invention has an energy storage path, an energy storage loop, a first driving path, and a second driving path that can be sequentially and time-divisionally turned on. When the energy storage loop is on, the first energy storage unit in the energy storage loop can charge the second energy storage unit. When the energy storage path is on, the input voltage at the input terminal can charge the first energy storage unit in the energy storage path. When the first driving path is on, the voltage on the second energy storage unit and the input voltage together supply power to the LED load. When the second driving path is on, the input voltage supplies power to the LED load. In this invention, the first energy storage unit can charge the second energy storage unit, and then the first energy storage unit can be charged using the input voltage. When the input voltage is low, the voltage on the second energy storage unit can be superimposed on the input voltage, thereby raising the input voltage. Even when the input voltage is low, it can still supply power to the LED load, making the input current of the LED load present in a three-stage stepped manner, improving the power factor and reducing THD, and avoiding the problem of current ripple. At the same time, this invention utilizes the first and second energy storage units for energy storage and energy conversion to achieve the purpose of reducing losses and improving efficiency. Attached Figure Description

[0021] Figure 1 A circuit diagram of an LED driving circuit provided in an embodiment of the present invention;

[0022] Figure 2 This is a timing diagram of the steady-state operation of the LED driving circuit provided in an embodiment of the present invention;

[0023] The attached figures are labeled as follows:

[0024] Q1 - First MOSFET; Q2 - Second MOSFET; Q3 - Third MOSFET; Q4 - Fourth MOSFET; D1 - First diode; D2 - Second diode; D3 - Third diode; D4 - Fourth diode; C1 - First capacitor; C2 - Second capacitor; OP1 - First operational amplifier; OP2 - Second operational amplifier; OP3 - Third operational amplifier; OP4 - Fourth operational amplifier; Rcs1 - First sampling resistor; Rcs2 - Second sampling resistor; Rcs3 - Third sampling resistor; Rcs4 - Fourth sampling resistor; Vref1 - First reference voltage; Vref2 - Second reference voltage; Vref3 - Third reference voltage; Vref4 - Fourth reference voltage; R LED -LED load; Vin -Input voltage; PGND -Ground; Id1 -Current in the energy storage path; Id2 -Current in the energy storage loop; Id3 -Current in the first drive path; Id4 -Current in the second drive path. Detailed Implementation

[0025] The specific embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0026] Figure 1 This is a circuit diagram of the LED driver circuit provided in this embodiment. Figure 1 As shown, the LED driver circuit is used to drive an LED load R. LED It includes a rectifier unit, an energy storage path, an energy storage loop, a first drive path, and a second drive path.

[0027] The LED driver circuit has an input terminal for receiving the input voltage Vin. A rectifier unit rectifies the input voltage Vin, converting AC voltage to DC voltage. The rectifier unit can be, for example, a bridge rectifier circuit consisting of four diodes. Since the structure of a bridge rectifier circuit is well-known, it will not be elaborated upon here.

[0028] The energy storage path includes a first diode D1, a first energy storage unit, a first constant current unit, and a first sampling resistor Rcs1. The first diode D1, the first energy storage unit, the first constant current unit, and the first sampling resistor Rcs1 are connected in sequence to form a path and are connected between the output terminal of the rectifier unit and the ground terminal PGND.

[0029] Specifically, the first energy storage unit includes a first capacitor C1, and the first constant current unit includes a first MOSFET Q1 and a first operational amplifier OP1. The anode of the first diode D1 is connected to the output terminal of the rectifier unit to obtain the DC voltage output by the rectifier unit. The cathode of the first diode D1 is connected to one end of the first capacitor C1, and the other end of the first capacitor C1 is connected to the drain of the first MOSFET Q1. The source of the first MOSFET Q1 is connected to one end of the first sampling resistor Rcs1, and the other end of the first sampling resistor Rcs1 is connected to ground PGND. One input terminal of the first operational amplifier OP1 is connected to the first reference voltage Vref1, and the other input terminal of the first operational amplifier OP1 is connected to the source of the first MOSFET Q1. The output terminal of the first operational amplifier OP1 is connected to the gate of the first MOSFET Q1. Due to the unidirectional conduction characteristic of the first diode D1, the energy storage path can only conduct unidirectionally from the input terminal to the ground PGND.

[0030] Of course, the first energy storage unit is not limited to including only one capacitor; it can also include two or more capacitors, as long as they can store energy.

[0031] Furthermore, the energy storage loop includes a second diode D2, a second energy storage unit, a second constant current unit, a second sampling resistor Rcs2, a first constant current unit, and a first energy storage unit. These components are sequentially connected to form a loop, and the energy storage path is also connected to the output terminal of the rectifier unit. In other words, the energy storage loop includes a portion of the energy storage path.

[0032] Specifically, the second energy storage unit includes a second capacitor C2, and the second constant current unit includes a second MOSFET Q2 and a second operational amplifier OP2. The anode of the second diode D2 is connected to one end of the first capacitor C1, and the cathode of the second diode D2 is connected to one end of the second capacitor C2. The other end of the second capacitor C2 is connected to the drain of the second MOSFET Q2. The node between the other end of the second capacitor C2 and the drain of the second MOSFET Q2 is connected to the output of the rectifier unit to obtain the DC voltage output by the rectifier unit. The source of the second MOSFET Q2 is connected to one end of the second sampling resistor Rcs2, and the other end of the second sampling resistor Rcs2 is connected to the source of the first MOSFET Q1 and one end of the first sampling resistor Rcs1. One input of the second operational amplifier OP2 is connected to the second reference voltage Vref2, and the other input of the second operational amplifier OP2 is connected to the source of the second MOSFET Q2. The output of the second operational amplifier OP2 is connected to the gate of the second MOSFET Q2. Due to the unidirectional conduction characteristic of the second diode D2, the energy storage loop can only conduct unidirectionally along the direction from the first capacitor C1 to the second capacitor C2.

[0033] It should be noted that the energy storage loop and the energy storage path cannot be turned on at the same time. When the second MOSFET Q2 is turned on, the first MOSFET Q1 is turned off. Therefore, the first capacitor C1, the second diode D2, the second capacitor C2, and the second MOSFET Q2 actually form a loop with the body diode of the first MOSFET Q1.

[0034] Similarly, the second energy storage unit is not limited to including only one capacitor; it can also include two or more capacitors, as long as they can store energy.

[0035] In this embodiment, the capacitance values ​​of the second energy storage unit and the first energy storage unit are close, for example, they can be equal. That is, the capacitance values ​​of the first capacitor C1 and the second capacitor C2 are close, for example, they can be equal. Furthermore, the capacitance values ​​of the second energy storage unit and the first energy storage unit cannot be too small, which is beneficial for distinguishing the steps of the input current, thereby facilitating energy conversion between the second energy storage unit and the first energy storage unit and avoiding energy waste. However, this should not be a limitation, and the capacitance values ​​of the second energy storage unit and the first energy storage unit can also be unequal.

[0036] In some embodiments, the second sampling resistor Rcs2 can be omitted, in which case the source of the second MOSFET Q2 is connected to the source of the first MOSFET Q1.

[0037] Furthermore, the first driving path includes a third diode D3, a third constant current unit, and a third sampling resistor Rcs3. The third diode D3, the third constant current unit, and the third sampling resistor Rcs3 are sequentially connected to form a path, and connected to the second energy storage unit and the LED load R. LED between.

[0038] Specifically, the third constant current unit includes a third MOSFET Q3 and a third operational amplifier OP3. The anode of the third diode D3 is connected to one end of the second capacitor C2, the cathode of the third diode D3 is connected to the drain of the third MOSFET Q3, the source of the third MOSFET Q3 is connected to one end of the third sampling resistor Rcs3, and the other end of the third sampling resistor Rcs3 is connected to the LED load R. LED At one end, the LED load R LED The other end is connected to one end of the first sampling resistor Rcs1; one input terminal of the third operational amplifier OP3 is connected to the third reference voltage Vref3, the other input terminal of the third operational amplifier OP3 is connected to the source of the third MOSFET Q3, and the output terminal of the third operational amplifier OP3 is connected to the gate of the third MOSFET Q3. Due to the unidirectional conduction characteristic of the third diode D3, the first driving path can only run along the second capacitor C2 to the LED load R. LED The direction is unidirectional.

[0039] Furthermore, the second driving path includes a fourth diode D4, a fourth constant current unit, and a fourth sampling resistor Rcs4. The fourth diode D4, the fourth constant current unit, and the fourth sampling resistor Rcs4 are sequentially connected to form a path and connected to the input terminal and the LED load R. LED between.

[0040] Specifically, the fourth constant current unit includes a fourth MOSFET Q4 and a fourth operational amplifier OP4. The anode of the fourth diode D4 is connected to the output terminal of the rectifier unit to obtain the DC voltage output by the rectifier unit. The cathode of the fourth diode D4 is connected to the drain of the fourth MOSFET Q4. The source of the fourth MOSFET Q4 is connected to one end of the fourth sampling resistor Rcs4, and the other end of the fourth sampling resistor Rcs4 is connected to the LED load R. LED At one end, the LED load R LED The other end is connected to one end of the first sampling resistor Rcs1; one input terminal of the fourth operational amplifier OP4 is connected to the fourth reference voltage Vref4, the other input terminal of the fourth operational amplifier OP4 is connected to the source of the fourth MOSFET Q4, and the output terminal of the fourth operational amplifier OP4 is connected to the gate of the fourth MOSFET Q4. Due to the unidirectional conduction characteristic of the fourth diode D4, the second driving path can only extend from the input terminal to the LED load R. LED The direction is unidirectional.

[0041] It should be understood that in this embodiment, the fourth sampling resistor Rcs4 and the third sampling resistor Rcs3 are the same resistor, that is, the second driving path and the first driving path share the sampling resistor, thereby simplifying the circuit structure and reducing costs. In some embodiments, the fourth sampling resistor Rcs4 and the third sampling resistor Rcs3 can each be a single resistor. In this case, the fourth sampling resistor Rcs4 is located alone in the second driving path, and the third sampling resistor Rcs3 is located alone in the first driving path. This does not affect the implementation of the present invention.

[0042] It should be understood that the first, second, third, and fourth constant current units are all constant current circuits composed of operational amplifiers and MOSFETs. They mainly utilize the "voltage follower characteristic" of operational amplifiers. According to the "virtual short" principle of operational amplifiers, that is, the voltages at the two input terminals of the operational amplifier are equal, when a stable reference voltage is input to one input terminal of the operational amplifier, the voltage at the source of the MOSFET (one end of the sampling resistor) is also the reference voltage. Therefore, no matter how the external circuit changes, the current flowing through the sampling resistor remains unchanged, achieving the effect of constant current.

[0043] Of course, in some embodiments, the first constant current unit, the second constant current unit, the third constant current unit, and the fourth constant current unit can also be other constant current circuits, such as constant current circuits based on voltage regulator chips, constant current circuits based on transistors, etc., which will not be described in detail here.

[0044] In this embodiment, the energy storage loop, the energy storage path, the first drive path, and the second drive path can be turned on in sequence and分时导通; when the energy storage loop is turned on, the first capacitor C1 charges the second capacitor C2; when the energy storage path is turned on, the input voltage Vin charges the first capacitor C1; when the first drive path is turned on, the voltage on the second capacitor C2 and the input voltage Vin jointly supply power to the LED load R LED Power supply; when the second drive path is turned on, the input voltage Vin supplies power to the LED load R LED Power supply. It can be seen that the first capacitor C1 can charge the second capacitor C2, and then the first capacitor C1 can be charged by the input voltage Vin. When the input voltage Vin is low, the voltage on the second capacitor C2 can be superimposed on the input voltage Vin, thereby raising the input voltage Vin, and when the input voltage Vin is low, it can also supply power to the LED load R LED Power supply, so that the input current of the LED load R LED Is a three-stage step type, improving the power factor and reducing the THD, and can avoid the problem of current ripple. At the same time, this embodiment uses the first capacitor C1 and the second capacitor C2 for energy storage and energy conversion, achieving the purpose of reducing losses and improving efficiency.

[0045] Figure 2 This is the working timing diagram of the LED drive circuit provided in this embodiment at steady state. Combined with Figure 1 And Figure 2 As shown, let the voltage on the first capacitor C1 be the first voltage VC1, and the voltage on the second capacitor C2 be the second voltage VC2.

[0046] When the LED drive circuit is in a steady state, the input voltage Vin slowly rises. During the time t1, the input voltage Vin is less than the difference between the first voltage VC1 and the second voltage VC2 (Vin < VC1 - VC2), the second MOS transistor Q2 is turned on (the first MOS transistor Q1, the third MOS transistor Q3, and the fourth MOS transistor Q4 are turned off), the energy storage loop is turned on, the first capacitor C1 charges the second capacitor C2, the first voltage VC1 gradually decreases, and the second voltage VC2 gradually increases. At this time, the current Id2 in the energy storage loop is the quotient of the second reference voltage Vref2 and the second sampling resistor Rcs2 (Id2 = Vref2 / Rcs2).

[0047] During the time t2, the input voltage Vin is greater than or equal to the first voltage VC1 and less than the LED load R LED It should be noted that the term "分时导通" in the original text seems to be a specific technical term in Chinese, and a more accurate English expression may need to be determined according to the specific technical context. The above translation is a rough attempt.The difference between the conduction voltage VC3 and the second voltage VC2 (VC1 ≤ Vin < VC3 - VC2), the first MOS transistor Q1 conducts (the second MOS transistor Q2, the third MOS transistor Q3, and the fourth MOS transistor Q4 are turned off), the energy storage path conducts, the input voltage Vin charges the first capacitor C1, the first voltage VC1 gradually increases, and the second voltage VC2 remains unchanged. At this time, the charging current Id1 in the energy storage path is the quotient of the first reference voltage Vref1 and the first sampling resistor Rcs1 (Id1 = Vref1 / Rcs1).

[0048] During the time t3, the input voltage Vin is greater than or equal to the conduction voltage VC3 of the LED load R LED minus the second voltage VC2 and less than the conduction voltage VC3 of the LED load R LED (VC3 - VC2 ≤ Vin < VC3), the third MOS transistor Q3 conducts (the first MOS transistor Q1, the second MOS transistor Q2, and the fourth MOS transistor Q4 are turned off), the first drive path conducts, and the voltage on the second capacitor C2 and the input voltage Vin jointly supply power to the LED load R LED . At this time, the current Id3 on the first drive path (i.e., the input current Iin of the LED load R LED ) is the quotient of the third reference voltage Vref3 and the third sampling resistor Rcs3 (Id3 = Vref3 / Rcs3).

[0049] During the time t4, the input voltage Vin is greater than or equal to the conduction voltage VC3 of the LED load R LED (Vin ≥ VC3), the fourth MOS transistor Q4 conducts (the first MOS transistor Q1, the second MOS transistor Q2, and the third MOS transistor Q3 are turned off), the second drive path conducts, and the input voltage Vin supplies power to the LED load R LED alone. At this time, the current Id4 on the second drive path (i.e., the input current Iin of the LED load R LED ) is the quotient of the fourth reference voltage Vref4 and the fourth sampling resistor Rcs4 (Id4 = Vref4 / Rcs4).

[0050] In this embodiment, the first reference voltage Vref1 is less than the third reference voltage Vref3, and the third reference voltage Vref3 is less than the fourth reference voltage Vref4, that is, Vref1 < Vref3 < Vref4. Further, the first sampling resistor Rcs1, the third sampling resistor Rcs3, and the fourth sampling resistor Rcs4 can be designed as resistors with equal resistance values, so that it is easier to make the LED load R LEDThe input current Iin has a three-stage stepped structure, but this should not be a limitation. The first reference voltage Vref1, the third reference voltage Vref3, the fourth reference voltage Vref4, the first sampling resistor Rcs1, the third sampling resistor Rcs3, and the fourth sampling resistor Rcs4 can adopt other design schemes, as long as the LED load R LED The input current Iin can be in a three-step manner.

[0051] It should be noted that before the LED driver circuit reaches steady state, the first capacitor C1 has not yet stored energy and cannot charge the second capacitor C2. Therefore, the LED driver circuit has a voltage establishment process before reaching steady state, which is the process of charging the first capacitor C1.

[0052] During voltage build-up, the input voltage Vin gradually rises until the first MOSFET Q1 turns on (the second MOSFET Q2, the third MOSFET Q3, and the fourth MOSFET Q4 are off), the energy storage path is open, and the input voltage Vin charges the first capacitor C1, causing the first voltage VC1 to gradually increase. The input voltage Vin continues to rise until the fourth MOSFET Q4 turns on (the first MOSFET Q1, the second MOSFET Q2, and the third MOSFET Q3 are off), the second drive path is open, and the input voltage Vin supplies power to the LED load R. LED Power is supplied. After that, the LED driver circuit reaches a steady state.

[0053] In summary, the LED driving circuit provided in this embodiment of the invention has an energy storage path, an energy storage loop, a first driving path, and a second driving path that can be sequentially turned on in a time-division manner. When the energy storage loop is on, the first energy storage unit in the energy storage loop can charge the second energy storage unit. When the energy storage path is on, the input voltage at the input terminal can charge the first energy storage unit in the energy storage path. When the first driving path is on, the voltage on the second energy storage unit and the input voltage together supply power to the LED load. When the second driving path is on, the input voltage supplies power to the LED load. In this invention, the first energy storage unit can charge the second energy storage unit, and then the first energy storage unit can be charged using the input voltage. When the input voltage is low, the voltage on the second energy storage unit can be superimposed on the input voltage, thereby raising the input voltage. Even when the input voltage is low, it can still supply power to the LED load, making the input current of the LED load present in a three-stage stepped manner, improving the power factor and reducing THD, and avoiding the problem of current ripple. At the same time, this invention utilizes the first and second energy storage units for energy storage and energy conversion to achieve the purpose of reducing losses and improving efficiency.

[0054] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and relevant parts can be referred to the method section.

[0055] It should also be noted that although the present invention has been disclosed above with reference to preferred embodiments, these embodiments are not intended to limit the present invention. For any person skilled in the art, many possible variations and modifications can be made to the technical solutions of the present invention based on the disclosed technical content, or equivalent embodiments can be modified accordingly, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention shall still fall within the scope of protection of the present invention.

[0056] It should also be understood that, unless otherwise specified or indicated, the terms “first,” “second,” “third,” etc., in the specification are used only to distinguish the various components, elements, and steps in the specification, and not to indicate the logical or sequential relationships between the various components, elements, and steps.

[0057] Furthermore, it should be recognized that the terminology described herein is used only to describe particular embodiments and not to limit the scope of the invention. It must be noted that the singular forms “a” and “an” used herein and in the appended claims include plural bases unless the context clearly indicates otherwise. For example, a reference to “a step” or “an apparatus” means a reference to one or more steps or apparatuses, and may include secondary steps and secondary apparatuses. All conjunctions used should be understood in the broadest sense. Also, the word “or” should be understood to have the definition of logical “or” rather than logical “exclusive OR”, unless the context clearly indicates otherwise. Furthermore, implementation of the methods and / or devices in embodiments of the invention may include performing selected tasks manually, automatically, or in combination.

Claims

1. An LED driving circuit for driving an LED load, characterized in that, The device includes an energy storage path, an energy storage loop, a first driving path, and a second driving path. Both the energy storage path and the energy storage loop are connected to the input terminal of the LED driving circuit. The energy storage path contains a first energy storage unit, and the energy storage loop contains both the first energy storage unit and a second energy storage unit. The first driving path connects the second energy storage unit to the LED load, and the second driving path connects the input terminal to the LED load. The energy storage loop, the energy storage path, the first drive path, and the second drive path are sequentially and time-divisionally turned on; when the energy storage loop is turned on, the first energy storage unit charges the second energy storage unit; when the energy storage path is turned on, the input voltage at the input terminal charges the first energy storage unit; when the first drive path is turned on, the voltage on the second energy storage unit and the input voltage together power the LED load; when the second drive path is turned on, the input voltage powers the LED load. Wherein, the voltage on the first energy storage unit is a first voltage, and the voltage on the second energy storage unit is a second voltage; the energy storage loop, the energy storage path, the first drive path, and the second drive path are sequentially and time-divisionally activated, including: When the input voltage is less than the difference between the first voltage and the second voltage, the energy storage loop is turned on; when the input voltage is greater than or equal to the first voltage and less than the difference between the on-state voltage of the LED load and the second voltage, the energy storage path is turned on; when the input voltage is greater than or equal to the difference between the on-state voltage of the LED load and the second voltage and less than the on-state voltage of the LED load, the first driving path is turned on; when the input voltage is greater than or equal to the on-state voltage of the LED load, the second driving path is turned on.

2. The LED driving circuit as described in claim 1, characterized in that, The energy storage path, the energy storage loop, the first drive path, and the second drive path are all unidirectional.

3. The LED driving circuit as described in claim 1, characterized in that, The first energy storage unit has the same capacity as the second energy storage unit.

4. The LED driving circuit as described in any one of claims 1 to 3, characterized in that, The energy storage path also includes a first diode, a first constant current unit, and a first sampling resistor, which are connected sequentially between the input terminal and the ground terminal.

5. The LED driving circuit as described in claim 4, characterized in that, The energy storage loop also includes a second diode, a second constant current unit, and a first constant current unit. The second diode, the second energy storage unit, the second constant current unit, the first constant current unit, and the first energy storage unit are sequentially connected to form a loop. The node between the second energy storage unit and the second constant current unit is connected to the input terminal.

6. The LED driving circuit as described in claim 5, characterized in that, The energy storage loop also includes a second sampling resistor, one end of which is connected to the second constant current unit, and the other end of which is connected to the first constant current unit and the first sampling resistor.

7. The LED driving circuit as described in claim 5, characterized in that, The first driving path includes a third diode, a third constant current unit, and a third sampling resistor, wherein the third diode, the third constant current unit, and the third sampling resistor are sequentially connected between the second energy storage element and the LED load; and / or, The second driving path has a fourth diode, a fourth constant current unit and a fourth sampling resistor, which are connected sequentially between the input terminal and the LED load.

8. The LED driving circuit as described in claim 7, characterized in that, The third sampling resistor and the fourth sampling resistor are the same resistor.

9. The LED driving circuit as described in claim 7, characterized in that, The first constant current unit, the third constant current unit, and the fourth constant current unit all include a MOS transistor and an operational amplifier. One input terminal of the operational amplifier is used to input a reference voltage, the other input terminal is connected to the source of the MOS transistor, and the output terminal is connected to the gate of the MOS transistor.

10. The LED driving circuit as described in claim 9, characterized in that, When the energy storage path is turned on, the charging current of the first energy storage unit is the quotient of the reference voltage input to the first constant current unit and the first sampling resistor; when the first driving path is turned on, the input current of the LED load is the quotient of the reference voltage input to the third constant current unit and the third sampling resistor; when the second driving path is turned on, the input current of the LED load is the quotient of the reference voltage input to the fourth constant current unit and the fourth sampling resistor.

11. The LED driving circuit as described in claim 10, characterized in that, The reference voltage input to the first constant current unit is less than the reference voltage input to the third constant current unit, and the reference voltage input to the third constant current unit is less than the reference voltage input to the fourth constant current unit.

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