Drive circuit and lighting device
By designing the current limiting module as an external module connected in series with the power supply module, and combining it with the control circuit to regulate the current, the complexity and high cost caused by high-voltage devices in the existing technology are solved. This achieves the integrated and miniaturized design of the LED driver circuit, improving robustness and energy conversion efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-12
- Publication Date
- 2026-03-10
AI Technical Summary
Existing LED driver circuits require high-voltage devices for current limiting components and power supply modules, resulting in complex circuits, high costs, and difficulties in integrated design. Furthermore, the placement of diodes increases space costs.
The current limiting module is designed as a separate external module, which is connected in series with the power module, then connected to the load module and the control circuit. The control circuit adjusts the current according to the operating parameters of the load module. The low voltage characteristics of the energy storage module are achieved by using the current in the circuit of the energy storage module, thus avoiding direct connection of high-voltage devices to the power supply.
It reduces production costs, enables integrated and miniaturized circuit design, improves the robustness and energy conversion efficiency of the drive circuit, and reduces flicker problems.
Smart Images
Figure CN121645609A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of drive circuit technology, and more specifically to a drive circuit and a lighting device. Background Technology
[0002] LED light sources are increasingly used in lighting devices across various fields due to their numerous advantages, such as energy saving, environmental friendliness, and long lifespan. Since LED light sources cannot be directly connected to AC mains power, a driver circuit is required to rectify the AC power and provide a stable current to drive the LED light source.
[0003] like Figure 1 As shown, a driving circuit is provided in the prior art, with power supply U S The generated AC power is rectified by the rectifier bridge BR0 and sent to the energy storage capacitor C0 to power the energy storage capacitor C0 and the load L0 connected in parallel. The above-mentioned drive circuit also includes a current limiting control circuit composed of a first current limiting element Q1 and a second current limiting element Q2. The first current limiting element Q1 is directly connected in series with the energy storage capacitor C0, and the second current limiting element Q2 is directly connected in series with the load L0. The first current limiting element Q1 and the second current limiting element Q2 limit the current of the energy storage capacitor C0 and the load L0 connected in series with them, respectively, so as to achieve constant current stability in the drive circuit and improve the power factor of the drive circuit.
[0004] However, in Figure 1 In the driving circuit shown, when the power supply U S When the output voltage is greater than the operating voltage of the energy storage capacitor C0, the power supply U S Simultaneously, power is supplied to the parallel energy storage capacitor C0 and the load L0. The current in the energy storage capacitor C0 flows from the positive terminal (+) to the negative terminal (-), passes through diode D1, and flows to the first current-limiting element Q1; when the power supply U... S When the output voltage is less than the operating voltage of the energy storage capacitor C0, the energy storage capacitor C0 supplies power to the load L0. The current in the energy storage capacitor C0 flows out from the positive terminal (+), through the load L0 and diode D2, and then flows back into the energy storage capacitor C0 from the negative terminal (-). Diodes D1 and D2 are reverse-biased to prevent the current in the first current-limiting element Q1 from reversing when the energy storage capacitor C0 discharges. However, in the prior art, the space and manufacturing costs required for setting up the aforementioned diodes D1 and D2 are relatively high, which is not conducive to the integration and low-cost design of the overall circuit. Moreover, both the first current-limiting element Q1 and the second current-limiting element Q2 need to withstand the power supply U. S Higher output voltage and power supply U S Higher surge voltages during switching on / off cycles or various fluctuations typically require high-voltage withstand devices of 500V or higher. Furthermore, components or circuits such as the power supply module VR, when connected to the aforementioned drive circuit, need to be connected in parallel to the power supply U. SBoth ends also need to be directly facing the power supply U. S Higher output voltage and power supply U S The higher surge voltage generated during switching requires devices with a withstand voltage of 700V or even higher, making the circuit structure of the drive circuit more complex and the cost higher. Summary of the Invention
[0005] To address the above problems, this invention provides a driving circuit and a lighting device. In the driving circuit, the current limiting module that controls the current of the energy storage module is set as a separate external module, which is connected in series with the power supply module and then connected to the load module and the control circuit. The components in the load module and the control circuit do not need to be directly exposed to the power supply voltage and therefore do not need to be set as high-voltage devices. This can reduce manufacturing costs and facilitate the integrated and miniaturized design of the circuit.
[0006] The driving circuit provided in the technical solution of the present invention includes a power supply module, a current limiting module, an energy storage module, and a load module connected in series. The driving circuit also includes a control circuit. The power supply terminal of the control circuit is connected to the energy storage module. One end of the load module is connected to the junction of the current limiting module and the energy storage module, and the other end is connected to the input terminal of the control circuit. The output terminal of the control circuit is connected to the control terminal of the current limiting module. The control circuit controls the current flowing through the current limiting module according to the operating parameters of the load module.
[0007] According to the technical solution of the present invention, the power supply module in the drive circuit supplies power to the energy storage module and / or the load module. As the power supply voltage output by the power supply module changes, the energy storage module exhibits different charging and discharging states. When the power supply voltage is greater than the operating voltage of the energy storage module, the power supply module supplies power to both the energy storage module and the load module simultaneously. The power supply module, current limiting module, and energy storage module form a series circuit in the drive circuit. The current in this series circuit, i.e., the charging current of the energy storage module, is controlled by the current limiting circuit. Simultaneously, the voltage across the energy storage module is also limited, and the voltage across the load module is limited by the voltage across the energy storage module. When the power supply voltage is less than the operating voltage of the energy storage module, the current limiting module does not conduct, and the energy storage module supplies power to the load module alone. The voltage across the load module is limited by the voltage across the energy storage module. The control circuit can generate a control signal to control the current limiting module based on changes in the operating voltage of the load module, thereby adaptively adjusting the charging current of the energy storage module to improve the power factor of the overall drive circuit. Similarly, the power supply terminal of the control circuit is connected to the energy storage module, and the supply voltage of the control circuit is limited by the voltage across the energy storage module. In summary, neither the load module nor the control circuit needs to be directly connected to the power supply module. They do not need to be exposed to the high voltage surge of the power supply module and therefore do not need to be configured as high-voltage devices. This reduces manufacturing costs and facilitates the integrated and miniaturized design of the circuit.
[0008] In the technical solution of the present invention, the control circuit in the driving circuit includes: a first current limiting circuit, which is connected in series with the load module; and a second current limiting circuit, one end of which is connected between the load module and the first current limiting circuit, and the other end of which is connected to the control terminal of the current limiting module.
[0009] According to the technical solution of the present invention, when the power module / energy storage module supplies power to the load module, the first current limiting circuit is connected in series with the load module. The current in the first current limiting circuit, i.e., the operating current of the load module, is controlled by the first current limiting circuit. The first current limiting circuit stabilizes the operating current of the load module to a constant current, thereby reducing or eliminating the flicker problem when the load module, i.e., the light source, is working. The second current limiting circuit detects the operating voltage of the load module and generates a control signal based on the change in the operating voltage of the load module to control the current limiting circuit, thereby adaptively adjusting the charging current of the energy storage module. The first current limiting circuit and the second current limiting circuit can respectively regulate the current in the energy storage module and the load module powered by the power module, but they do not need to be directly connected to the power module, and do not need to be directly exposed to the high voltage impact of the power module, and therefore do not need to be set as high-voltage withstand devices.
[0010] Preferably, in the technical solution of the present invention, the first current limiting circuit in the driving circuit includes: a first field-effect transistor, the drain of the first field-effect transistor is connected to the load module, and the source is connected to the ground terminal; a first resistor, one end of which is connected to the source of the first field-effect transistor and the other end of which is connected to the ground terminal; a first operational amplifier, the non-inverting input terminal of the first operational amplifier is connected to a first reference voltage, the inverting input terminal is connected between the source of the first field-effect transistor and the first resistor, and the output terminal is coupled to the gate of the first field-effect transistor.
[0011] According to the technical solution of the present invention, the first operational amplifier detects the voltage across the first resistor and the first reference voltage respectively, and adjusts the gate signal of the first field-effect transistor according to the calculation result, thereby adjusting the current flowing through the first field-effect transistor, i.e., the operating current of the load module.
[0012] Preferably, in the technical solution of the present invention, the second current limiting circuit in the driving circuit includes: a second field-effect transistor, the drain of the second field-effect transistor being connected to the control terminal of the current limiting module, and the source being connected to the ground terminal; a second operational amplifier, the non-inverting input terminal of the second operational amplifier being connected to the second reference voltage, the inverting input terminal being connected between the load module and the drain of the first field-effect transistor, and the output terminal being coupled to the gate of the second field-effect transistor.
[0013] According to the technical solution of the present invention, the second operational amplifier detects the voltage of the first current limiting circuit, i.e., the load module, and the second reference voltage, respectively. Based on the calculation result, it adjusts the gate signal of the second field-effect transistor to adjust the current flowing through the second field-effect transistor, and outputs the current flowing through the second field-effect transistor as a control signal to the control terminal of the current limiting module to control the current flowing through the current limiting module, i.e., the charging current of the energy storage module.
[0014] In the technical solution of the present invention, the control circuit further includes a power supply module. One end of the power supply module is connected between the current limiting module and the energy storage module, and the other end is connected to the ground terminal. The first output terminal of the power supply module outputs a first reference voltage, and the second output terminal outputs a second reference voltage.
[0015] According to the technical solution of the present invention, the power supply module provides a first reference voltage and a second reference voltage, and the power supply module is connected in parallel with the energy storage module. The operating voltage of the power supply module is limited by the voltage value across the energy storage module. Due to the low impedance characteristics and strong surge absorption capability of the energy storage module itself, the power supply module does not need to directly face the impact of high voltage surges from the power supply module, which greatly reduces or even eliminates the possibility of the power supply module failing or being damaged due to high surge voltage impact, extends the service life of the power supply module, and improves the robustness of the overall drive circuit.
[0016] Preferably, in the technical solution of the present invention, the driving circuit further includes a dimming module, which includes a dimming circuit connected to the first current limiting circuit and sends a dimming signal to the first current limiting circuit; and a switching power supply connected in parallel with the energy storage module to supply power to the dimming circuit.
[0017] According to the technical solution of the present invention, the dimming circuit in the dimming module dims the load module (i.e., the LED light source) by adjusting the current in the first current limiting circuit, i.e., the operating current of the load module. The switching power supply and energy storage module in the dimming module are connected in parallel. The low impedance characteristics of the energy storage module help reduce electromagnetic interference generated by the switching power supply and also prevent the switching power supply from directly facing the high-voltage surge of the power supply module.
[0018] Preferably, in the technical solution of the present invention, the current limiting module of the driving circuit is a transistor, with the emitter of the transistor connected to the power supply module, the collector connected to the energy storage module, and the base connected to the control circuit. Of course, a field-effect transistor can also be used, and / or a circuit combination can be used to meet the intent of the present invention. Those skilled in the art can implement it as needed. For the sake of simplicity, the present invention will only use a PNP transistor as an example for explanation.
[0019] According to the technical solution of the present invention, the current flowing through the second field-effect transistor is output as a control signal to the base of the transistor, controlling the conduction and cutoff between the emitter and collector of the transistor, as well as the magnitude of the conduction current when conducting, thereby realizing the indirect control of the current flowing through the current limiting module, i.e. the charging current of the energy storage module, through the second current limiting circuit.
[0020] Preferably, in the technical solution of the present invention, the driving circuit further includes an extended current limiting module, which is connected in parallel across the two ends of the current limiting module.
[0021] According to the technical solution of the present invention, the extended current limiting module is connected in parallel with the current limiting module, which can be used to extend the current in the current limiting module and share the heat generated in the circuit to achieve greater power application. In the simplest case, the extended current limiting module may only include one or more resistors.
[0022] In the technical solution of the present invention, a lighting device is also provided, which includes the above-mentioned driving circuit. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of a driving circuit provided in the prior art;
[0024] Figure 2 This is a schematic diagram of a driving circuit provided in the first embodiment of the present invention;
[0025] Figure 3 This is a schematic diagram of a driving circuit provided in the second embodiment of the present invention;
[0026] Figure 4 This is a schematic diagram of a driving circuit provided in the third embodiment of the present invention.
[0027] Explanation of reference numerals in the attached diagram: 1-Power supply module, 2-Energy storage module, 3-Load module, 4-Current limiting module, 5-Control circuit, 51-First current limiting circuit, 52-Second current limiting circuit, 6-Dimming module, 61-Dimming circuit, 62-Switching power supply, 7-Extended current limiting module. Detailed Implementation
[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.
[0029] [First Implementation Method]
[0030] Figure 2 This is a schematic diagram of a driving circuit provided in the first embodiment of the present invention.
[0031] like Figure 2 As shown, in the first embodiment of the present invention, a driving circuit is provided, including a power supply module 1, an energy storage module 2, a load module 3, a current limiting module 4, and a control circuit 5.
[0032] In this circuit, power module 1 is an AC power source. The AC voltage output from power module 1 is rectified and then output as the power supply voltage to the circuit connected to power module 1 to power it. The sinusoidal signal of the AC voltage from power module 1, after rectification, outputs a signal whose direction remains constant but whose magnitude changes periodically; this signal is the output voltage U of power module 1. IN Energy storage module 2 is connected in series with power module 1. Energy storage module 2 can be configured as a capacitor, battery, or other circuit or electrical component with charging and discharging functions. The voltage across energy storage module 2 is U. C The load module 3 is an LED light source. One end of the load module 3 is connected to the junction of the current limiting module 4 and the energy storage module 3, and the other end is connected to the input terminal of the control circuit 5. Both the power supply module 1 and the energy storage module 2 can supply power to the load module 3 to drive the LED light source for lighting.
[0033] The current limiting module 4 is connected in series between the power supply module 1 and the energy storage module 2. When the power supply module 1 supplies power to the energy storage module 2, the output voltage U of the power supply module 1 is... IN The voltage value changes periodically, and the charging current I of the current limiting module 4 to the energy storage module 2... C Limit the charging current I C The peak current decreases, thereby reducing the charging current I. C The effective work time within a cycle is extended, thereby achieving the purpose of improving the power factor of the overall drive circuit. In embodiments of the present invention, the current limiting module 4 can be configured as a combination of one or more current control devices or circuits such as transistors, field-effect transistors, and controlled current sources, without limitation.
[0034] The power supply terminal of the control circuit 5 is connected to the energy storage module 2, the input terminal of the control circuit 5 is connected to the load module 3, and the output terminal of the control circuit 5 is connected to the control terminal of the current limiting module 4. The control circuit 5 generates a control signal according to the working parameters of the load module 3 to control the current flowing through the current limiting module 4, so as to improve the power factor of the overall drive circuit.
[0035] In embodiments of the present invention, the control circuit 5 may be configured as a combination of one or more chips or integrated circuits, components, etc., which are devices or circuits capable of achieving voltage-controlled current effects, and no limitations are imposed here.
[0036] Specifically, in the first embodiment of the present invention, the driving circuit, along with the output voltage U of the power supply module 1, IN The magnitude of the voltage change affects the power supply module 1, which supplies power to the energy storage module 2 and / or the load module 3. When the output voltage U of the power supply module 1 changes... IN The voltage U across energy storage module 2 is greater than the voltage U across energy storage module 2. CAt the same time, power module 1 supplies power to both energy storage module 2 and load module 3. In the drive circuit, power module 1, current limiting module 4, and energy storage module 2 form a charging circuit, and the current in this charging circuit is the charging current I of energy storage module 2. C Controlled by the current limiting module 4, and simultaneously the voltage U across the energy storage module 2 C It is also limited that the voltage U across the load module is... L The voltage U directly received from the two ends of energy storage module 2 C Limitation; when the output voltage U of power module 1 IN The voltage U across energy storage module 2 is less than C At this time, the series circuit consisting of power module 1, current limiting module 4, and energy storage module 2 is not conducting. Energy storage module 2 and load module 3 form a discharge circuit. Energy storage module 2 supplies power to load module 3 alone. The voltage U across load module 3 is... L The voltage U across the energy storage module 2 C limit.
[0037] Compared to Figure 1 In the existing technical solution shown, in the first embodiment of the present invention, the current limiting module 4 is treated as a separate module and is first connected in series with the power supply module 1 to limit the charging current I of the energy storage module 2. C Then, the load module 3 and control circuit 5 are connected to the current-limited energy storage module 2, meaning that neither the load module 3 nor the control circuit 5 needs to be directly connected to the power supply module 1. The low impedance characteristics and strong surge absorption capability of the energy storage module 2 itself mean that the load module 3 and control circuit 5 do not need to directly face the impact of the high output voltage and high surge voltage in the power supply module 1. Therefore, the components in the load module 3 and control circuit 5 do not need to be configured as high-voltage withstand devices, thereby reducing the overall manufacturing cost of the drive circuit and facilitating its integrated and miniaturized design. Furthermore, compared to... Figure 1 In the prior art solution shown, the current limiting module 4 in the first embodiment of the present invention is only turned on when the energy storage module 2 is charging, and the current limiting module 4 cannot be turned on when the energy storage module 2 is discharging. Therefore, in this embodiment, there is no need to set up components such as diodes to prevent reverse conduction, which further facilitates the miniaturization and cost reduction of the overall drive circuit.
[0038] In the first embodiment of the present invention, the control circuit 5 in the drive circuit includes: a first current limiting circuit 51, which is connected in series with the load module 3; and a second current limiting circuit 52, one end of which is connected between the load module 3 and the first current limiting circuit 51, and the other end of which is connected to the control terminal of the current limiting module 4.
[0039] In the first embodiment of the present invention, when the power module 1 / energy storage module 2 supplies power to the load module 3, the first current limiting circuit 51 is connected in series with the load module 3, and the current in the first current limiting circuit 51 is the operating current I of the load module 3.L Controlled by the first current limiting circuit 51, the operating current I of the load module 3 is limited by the first current limiting circuit 51. L A stable constant current is maintained to reduce or eliminate flickering during the operation of the load module 3, i.e., the LED light source. The second current limiting circuit 52 detects the voltage U across the load module 3. L And based on the voltage U across load module 3 L The change in the current generated by the signal controls the current flowing through the current limiting module 4, which is the charging current I of the energy storage module 2. C The first current limiting circuit 51 and the second current limiting circuit 52 can respectively regulate the current in the energy storage module 2 and the load module 3 powered by the power supply module 1, but they do not need to be directly connected to the power supply module 1. Therefore, there is no need to set high-voltage withstand devices in the first current limiting circuit 51 and the second current limiting circuit 52 to withstand the impact of high output voltage and high surge voltage in the power supply module 1.
[0040] Specifically, in the first embodiment of the present invention, the power supply module 1 in the driving circuit is configured as a power supply U. S And the rectifier bridge BR0, power supply U S The power supply voltage is rectified by the rectifier bridge BR0 to obtain the output voltage U of power module 1. IN Energy storage module 2 is configured as energy storage capacitor C0; load module 3 is configured as LED light source L0; current limiting module 4 is configured as transistor Q0, with the emitter e of transistor Q0 connected to power module 1, the collector c connected to energy storage module 2, and the base b serving as the control terminal of current limiting module 4 connected to the output terminal of control circuit 5.
[0041] The first current limiting circuit 51 includes a first field-effect transistor Q1, a first resistor R1, and a first operational amplifier A1. The drain d of the first field-effect transistor Q1 is connected to the load module 3, and the source s is connected to the ground terminal GND through the first resistor R1. One end of the first resistor R1 is connected to the source s of the first field-effect transistor Q1, and the other end is connected to the ground terminal GND. The non-inverting input terminal of the first operational amplifier A1 is connected to the first reference voltage V1, the inverting input terminal is connected between the source s of the first field-effect transistor Q1 and the first resistor R1, and the output terminal is coupled to the gate g of the first field-effect transistor Q1.
[0042] The second current limiting circuit 52 includes a second field-effect transistor Q2, a second operational amplifier A2, and a compensation capacitor C. The drain d of the second field-effect transistor Q2 is connected to the control terminal of the current limiting module 4, i.e., the base b of the transistor Q0, and the source s is connected to the ground terminal GND. The non-inverting input terminal of the second operational amplifier A2 is connected to the second reference voltage V2, the inverting input terminal is connected between the load module 3 and the drain d of the first field-effect transistor Q1, and the output terminal is coupled to the gate g of the second field-effect transistor Q2. One end of the compensation capacitor C is connected to the output terminal of the second operational amplifier A2, and the other end is connected to the ground terminal GND.
[0043] The control circuit 5 also includes a power supply module 53. One end of the power supply module 53 is connected between the current limiting module 4 and the energy storage module 2, and the other end is connected to the ground terminal GND. The power supply module 53 is equipped with a power supply unit VR. Its first output terminal VR1 outputs a first reference voltage V1, and its second output terminal VR2 outputs a second reference voltage V2.
[0044] In the first embodiment of the present invention, the working principle of the above-mentioned driving circuit is as follows:
[0045] When the output voltage U of power module 1 IN The voltage U across energy storage module 2 is greater than the voltage U across energy storage module 2. C At the same time, power module 1 supplies power to both energy storage module 2 and load module 3. The charging circuit consisting of power module 1, current limiting module 4, energy storage capacitor C0, and power module 1 is activated, and the charging current I of energy storage capacitor C0 is increased. C The current is controlled by the current limiting module 4, i.e., the conduction current of transistor Q0. Simultaneously, the load circuit consisting of power module 1 - current limiting module 4 - LED light source L0 - first field-effect transistor Q1 - first resistor R1 - power module 1 is activated, and the operating current I of LED light source L0 is controlled. L Controlled by the first current limiting circuit 51, i.e., the conduction current of the first field-effect transistor Q1; when the output voltage U of the power supply module 1... IN The voltage U across energy storage module 2 is less than C At this time, the energy storage module 2 supplies power to the load module 3 alone, and the discharge circuit consisting of energy storage capacitor C0, LED light source L0, first field-effect transistor Q1, first resistor R1 and energy storage capacitor C0 is turned on.
[0046] The first operational amplifier A1 detects the voltage U across the first resistor R1. R1 And the first reference voltage V1, and adjust the output signal of the first operational amplifier A1, i.e., the gate signal of the first field-effect transistor Q1, according to the calculation result. In U R1 When V1 > V1, the gate signal of the first field-effect transistor Q1 decreases, causing the conduction current of the first field-effect transistor Q1, i.e., the operating current I of the LED light source L0, to decrease. L The voltage U across the first resistor R1 decreases. R1 Consequently, it decreases; in U R1 When V<1, the gate signal of the first field-effect transistor Q1 increases, causing the conduction current of the first field-effect transistor Q1, i.e., the operating current I of the LED light source L0, to increase. L As the voltage increases, the voltage U across the first resistor R1 increases. R1 As a result, the voltage U across the first resistor R1 increases; R1 If the first reference voltage V1 is maintained at approximately, then the operating current I of the LED light source L0 will be... LApproximately equal to V1 / R1, this achieves the operating current I of the LED light source L0. L Maintain a constant current to reduce or eliminate flicker during LED light source L0 operation.
[0047] The second operational amplifier A2 detects the voltage U of the first field-effect transistor Q1. Q1 The second reference voltage V2 is used to adjust the output signal of the second operational amplifier A2, i.e., the gate signal of the second field-effect transistor Q2, based on the calculation result. In U Q1 When V > V2, the gate signal of the second field-effect transistor Q2 decreases, which reduces the on-state current of the second field-effect transistor Q2, i.e., the base signal of transistor Q0. The on-state current of transistor Q0 is the charging current I of the energy storage capacitor C0. C Consequently, it decreases; in U Q1 When V<2, the gate signal of the second field-effect transistor Q2 increases, which increases the on-state current of the second field-effect transistor Q2, i.e., the base signal of transistor Q0. The on-state current of transistor Q0 is the charging current I of the energy storage capacitor C0. C This causes the voltage U of the first field-effect transistor Q1 to increase; Q1 By maintaining the voltage at around the second reference voltage V2, the energy storage capacitor C0 is prevented from being charged to a higher voltage, thus saving the energy drawn by the energy storage capacitor C0 from the power supply module 1 and improving the overall energy conversion efficiency of the drive circuit.
[0048] To obtain a smoother conduction current for transistor Q0, in this embodiment of the invention, a capacitor C is connected in parallel at the output terminal of the second amplifier A2 to integrate the output signal of amplifier A2. In practical applications, other methods can also be used, such as an integrating circuit. Furthermore, to obtain a smoother load current, the voltage U of the first field-effect transistor Q1 needs to be appropriately controlled. Q1 The minimum value is typically achieved by setting the absolute value of the increase rate of the gate signal of the second field-effect transistor Q2 to be greater than the absolute value of the decrease rate.
[0049] [Second Implementation Method]
[0050] Figure 3 This is a schematic diagram of a driving circuit provided in the second embodiment of the present invention.
[0051] like Figure 3 As shown, in the second embodiment of the present invention, the driving circuit further includes a dimming module 6, which includes a dimming circuit 61 connected to the first current limiting circuit 51 and sending a dimming signal to the first current limiting circuit 51; and a switching power supply 62 connected in parallel with the energy storage module 2 to supply power to the dimming circuit 61. The remaining electrical components and connection circuits in this embodiment are the same as in the first embodiment.
[0052] In the second embodiment of the present invention, the dimming circuit 61 in the dimming module 6 adjusts the current in the first current limiting circuit 51, i.e., the operating current I of the LED light source L0. L This is to achieve dimming control of the LED light source L0 in load module 3. Compared to... Figure 1 In the second embodiment of the present invention, the switching power supply 62 in the dimming module 6 does not need to be directly connected to the power module 1, but is instead connected in parallel with the energy storage module 2. The low impedance characteristics of the energy storage module 2 help to reduce the electromagnetic interference generated by the switching power supply 62, while avoiding the switching power supply 62 directly facing the impact of the high voltage surge in the power module 1.
[0053] [Third Implementation Method]
[0054] Figure 4 This is a schematic diagram of a driving circuit provided in the third embodiment of the present invention.
[0055] like Figure 4 As shown, in the third embodiment of the present invention, the driving circuit further includes an extended current limiting module 7, which is connected in parallel across the two ends of the current limiting module 4. The remaining electrical components and connection circuits in this embodiment are the same as in the first embodiment.
[0056] In the third embodiment of the present invention, the extended current limiting module 7 is connected in parallel with the current limiting module 4, which can be used to extend the current in the current limiting module 4 and share the heat generated in the circuit to achieve greater power application.
[0057] In an embodiment of the present invention, a lighting device is also provided, which includes a combination of one or more driving circuits provided in the above embodiments.
[0058] The technical solution of the present invention has now been described in conjunction with the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to the specific embodiments described above. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions resulting from such changes or substitutions will all fall within the scope of protection of the present invention.
Claims
1. A driving circuit comprising a power supply module, a current limiting module and an energy storage module connected in series, and a load module, characterized in that, The drive circuit further comprises a control circuit, a power supply end of the control circuit is connected to the energy storage module, one end of the load module is connected to the intersection of the current limiting module and the energy storage module, the other end is connected to the input end of the control circuit, the output end of the control circuit is connected to the control end of the current limiting module, and the control circuit controls the current flowing through the current limiting module according to the working parameters of the load module.
2. The drive circuit of claim 1, wherein, The control circuit comprises: a first current limiting circuit connected in series with the load module; a second current limiting circuit connected at one end between the load module and the first current limiting circuit and connected at the other end to the control end of the current limiting module.
3. The drive circuit of claim 2, wherein, The first current limiting circuit comprises: a first field effect transistor, a drain of the first field effect transistor being connected to the load module and a source being connected to a ground end; a first resistor, one end of the first resistor being connected to the source of the first field effect transistor and the other end being connected to the ground end, a first operational amplifier, a non-inverting input end of the first operational amplifier being connected to a first reference voltage, an inverting input end being connected between the source of the first field effect transistor and the first resistor, and an output end being coupled to a gate of the first field effect transistor.
4. The drive circuit of claim 3, wherein, The second current limiting circuit comprises: a second field effect transistor, a drain of the second field effect transistor being connected to the control end of the current limiting module and a source being connected to a ground end; a second operational amplifier, a non-inverting input end of the second operational amplifier being connected to a second reference voltage, an inverting input end being connected between the load module and the drain of the first field effect transistor, and an output end being coupled to a gate of the second field effect transistor.
5. The drive circuit of claim 4, wherein, The control circuit further comprises a power supply module, one end of the power supply module being connected between the current limiting module and the energy storage module and the other end being connected to a ground end, a first output end of the power supply module outputting a first reference voltage, and a second output end outputting a second reference voltage.
6. The drive circuit of claim 5, wherein, Further comprising a dimming module, the dimming module comprising a dimming circuit connected to the first current limiting circuit and sending a dimming signal to the first current limiting circuit; a switching power supply connected in parallel with the energy storage module and supplying power to the dimming circuit.
7. The drive circuit of claim 1, wherein, The current limiting module is a triode, an emitter of the triode being connected to the power supply module, a collector being connected to the energy storage module, and a base being connected to the control circuit.
8. The drive circuit of claim 1, wherein, Further comprising an extended current limiting module, the extended current limiting module being connected in parallel at both ends of the current limiting module.
9. An illumination device, characterized by The lighting device comprises the drive circuit according to any one of claims 1-8.