CN212305714U

CN212305714U - LED drive circuit and lamp

Info

Publication number: CN212305714U
Application number: CN202020382973.7U
Authority: CN
Inventors: 李敬
Original assignee: Shenzhen Het Data Resources and Cloud Technology Co Ltd
Current assignee: Shenzhen Hetai Intelligent Home Appliance Controller Co ltd
Priority date: 2020-03-23
Filing date: 2020-03-23
Publication date: 2021-01-05
Anticipated expiration: 2030-03-23

Abstract

The utility model discloses a LED drive circuit, including isolation transformer, a plurality of LED unit, a plurality of switch circuit and microprocessor. The isolation transformer is used for coupling alternating current, each LED unit comprises a first LED lamp and a second LED lamp, the anode of the first LED lamp and one end of a secondary winding of the isolation transformer are electrically connected at a first node, the anode of the second LED lamp and the other end of the secondary winding are electrically connected at a second node, the switch circuits are in one-to-one correspondence with the LED units, each switch circuit comprises a first end, a second end and a control end, the cathodes of the first LED lamp and the second LED lamp are electrically connected with the first end, the second end is grounded, each IO interface of the microprocessor is electrically connected with each corresponding control end, therefore, the microprocessor sends a control signal to the switch circuits, the switch circuits are in a path state, and when the switch circuits are in the path state, coupled current can flow through the first LED lamp or the second LED lamp to drive the LED lamps to work.

Description

LED drive circuit and lamp

Technical Field

The utility model relates to a drive circuit field especially relates to a LED drive circuit and lamps and lanterns.

Background

A light Emitting diode (led), which is a solid semiconductor device capable of converting electrical energy into visible light, can directly convert electricity into light. The heart of the LED is a semiconductor wafer, one end of the wafer is attached to a support, the other end of the wafer is a cathode, and the other end of the wafer is connected with an anode of a power supply, so that the whole wafer is packaged by epoxy resin. The LED lamp has the characteristics of energy conservation, environmental protection, impact resistance, controllability and the like, so the LED lamp has wide application.

In the current electronic application, the working state of the LED lamp is driven and controlled by the LED driving circuit, so that the LED lamp is turned on or off, and is combined with other circuits to complete specific circuit functions. The design of the LED driving circuit becomes particularly important. In the existing LED lamp driving circuit adopting the triodes, one triode can only drive one LED lamp, and each triode occupies an IO port of a microprocessor, so that the driving circuit provided with a plurality of LED lamps is complex in structure and high in circuit cost.

SUMMERY OF THE UTILITY MODEL

An object of the embodiment of the utility model is to provide a LED drive circuit, it can drive LED lamp work.

In order to solve the above technical problem, an embodiment of the present invention provides the following technical solution:

in a first aspect, an embodiment of the present invention provides an LED driving circuit, including:

an isolation transformer for coupling alternating current;

the LED lamp comprises a plurality of LED units, each LED unit comprises a first LED lamp and a second LED lamp, the anode of the first LED lamp and one end of a secondary winding of the isolation transformer are electrically connected at a first node, and the anode of the second LED lamp and the other end of the secondary winding of the isolation transformer are electrically connected at a second node;

the switch circuits correspond to the LED units one by one, each switch circuit comprises a first end, a second end and a control end, the cathodes of the first LED lamp and the second LED lamp are electrically connected with the first ends, and the second ends are grounded; and

the microprocessor comprises a plurality of IO interfaces, each IO interface is electrically connected with each corresponding control end, the microprocessor sends a control signal to the switch circuit through the IO interfaces, so that the switch circuit is in a path state, and when the switch circuit is in the path state, the coupled current can flow through the first LED lamp or the second LED lamp.

In some embodiments, the LED driving circuit further includes a zero-cross sampling circuit, the zero-cross sampling circuit includes a first sampling terminal and a second sampling terminal, the first sampling terminal is electrically connected to the first node, the second sampling terminal is electrically connected to the second node, and the zero-cross sampling circuit is further electrically connected to the microprocessor, and is configured to transmit a sampling voltage to the microprocessor, so that the microprocessor controls an operating state of the switching circuit according to the sampling voltage, where the operating state includes a pass state or a stop state.

In some embodiments, the zero-cross sampling circuit includes a first resistor and a second resistor, one end of the first resistor is connected to the first node, the other end of the first resistor and one end of the second resistor are commonly connected to the microprocessor, and the other end of the second resistor is further connected to the second node.

In some embodiments, the LED lamp further comprises a plurality of first half-wave rectifying circuits, each first half-wave rectifying circuit corresponds to each first LED lamp, and the first half-wave rectifying circuits are electrically connected between the first node and the positive electrodes of the first LED lamps.

In some embodiments, the first half-wave rectifier circuit includes a first diode, an anode of the first diode is connected to the first node, and a cathode of the first diode is connected to an anode of the first LED lamp.

In some embodiments, a second plurality of second half-wave rectification circuits are further included, each of the second half-wave rectification circuits corresponding to each of the second LED lamps, and the second half-wave rectification circuit 70 is electrically connected between the second node and the positive electrode of the second LED lamp.

In some embodiments, the second half-wave rectification circuit 70 includes a second diode. The anode of the second diode is connected with the second node, and the cathode of the second diode is connected with the anode of the second LED lamp.

In some embodiments, the control signal is a PWM signal.

In a second aspect, an embodiment of the present invention provides a lamp, including the LED driving circuit as described above.

In various embodiments of the present invention, the LED driving circuit includes an isolation transformer, a plurality of LED units, a plurality of switching circuits, and a microprocessor. The isolation transformer is used for coupling alternating current, each LED unit comprises a first LED lamp and a second LED lamp, the anode of the first LED lamp and one end of a secondary winding of the isolation transformer are electrically connected at a first node, the anode of the second LED lamp and the other end of the secondary winding of the isolation transformer are electrically connected at a second node, the switch circuits correspond to the LED units one by one, each switch circuit comprises a first end, a second end and a control end, the cathodes of the first LED lamp and the second LED lamp are electrically connected with the first end, the second end is grounded, each IO interface of the microprocessor is electrically connected with each corresponding control end, and the microprocessor sends a control signal to the switch circuits through the IO interfaces, so that the switch circuits are in a circuit state, and when the switch circuits are in the circuit state, coupled current can flow through the first LED lamp or the second LED lamp. Therefore, when the LED lamp needs to be driven, the microprocessor controls the switching circuit to be conducted through the IO interface, and then the coupled current flows through the corresponding LED lamp to drive the LED lamp to work. In addition, the LED drive circuit can respectively control a plurality of LED lamps through one switch circuit, so that the LED drive circuit is simple in structure and low in circuit cost.

Drawings

One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.

Fig. 1 is a schematic diagram of a structural block diagram of an LED driving circuit according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a block diagram of an LED driving circuit according to another embodiment of the present invention;

fig. 3 is a schematic circuit diagram of an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention.

Referring to fig. 1, an embodiment of the present invention provides a block diagram structure schematic diagram of an LED driving circuit, as shown in fig. 1, the LED driving circuit 100 includes an isolation transformer 10, a plurality of LED units 20, a plurality of switch circuits 30, and a microprocessor 40. Wherein, the isolation transformer 10 is used for coupling alternating current, each LED unit 20 comprises a first LED lamp 201 and a second LED lamp 202, the anode of the first LED lamp 201 and one end of the secondary winding of the isolation transformer 10 are both electrically connected at a first node 203, the anode of the second LED lamp 202 and the other end of the secondary winding of the isolation transformer 10 are both electrically connected at a second node 204, the switch circuits 30 are in one-to-one correspondence with the LED units 20, each switch circuit 30 comprises a first end, a second end and a control end, the cathodes of the first LED lamp 201 and the second LED lamp 202 are both electrically connected with a first end 301, the second end is grounded, and each IO interface of the microprocessor 40 is electrically connected to each corresponding control terminal, the microprocessor 40 sends a control signal to the switch circuit 30 through the IO interface, so that the switch circuit 30 is in a pass state, and when the switching circuit 30 is in the on state, the coupled current may flow through the first LED lamp 201 or the second LED lamp 202.

Taking an LED unit 20 and a switch circuit 30 as an example, when two LED lamps in the LED unit 20 need to be driven to operate, firstly, the ac power supply 200 is coupled to the secondary winding through the isolation transformer 10, the ac power supply 200 may be a sine wave, the coupled ac current obtained by the secondary winding is transmitted to the first LED lamp 201 or the second LED lamp 202, and meanwhile, the microprocessor 40 sends a control signal to the switch circuit 30 through its own IO interface, so that the switch circuit 30 is in an on state, and the coupled current reaches the ground through the first LED lamp 201 or the second LED lamp 202 and the switch circuit 30, so that the coupled current can flow through the first LED lamp 201 or the second LED lamp 202, and further drive the LED lamps to operate, specifically, turn on the LED lamps.

In some embodiments, the ac power source 200 includes a first ac power source and a second ac power source, the first ac power source and the second ac power source have a phase difference, which may be a sine wave with a time difference, the first ac power source is coupled to be transmitted to the first LED lamp 201, if the switching circuit 30 is in the on state, the coupled current flows through the first LED lamp 201 to drive the first LED lamp 201 to operate, the second ac power source is coupled to be transmitted to the second LED lamp 202, and if the switching circuit 30 is in the on state, the coupled current flows through the second LED lamp 202 to drive the second LED lamp 202 to operate. Therefore, the LED lamp driving circuit 100 can realize the individual control of the turning on or off of the first LED lamp 201 and the turning on or off of the second LED, respectively.

Therefore, when the LED lamp needs to be driven, the microprocessor 40 in the LED driving circuit 100 controls the switching circuit 30 to be turned on through the IO interface, so that the coupled current flows through the corresponding LED lamp to drive the LED lamp to operate. In addition, the LED driving circuit 100 can control a plurality of LED lamps by using one switching circuit, so that the LED driving circuit has a simple structure and a low circuit cost.

In some embodiments, the microprocessor 40 may be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a single chip, an ARM (Acorn RISC machine) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination of these components. Also, the controller may be any conventional processor, controller, microcontroller, or state machine. A controller may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP, or any other such configuration.

Referring to fig. 2, fig. 2 is a block diagram of an LED driving circuit according to another embodiment of the present invention, as shown in fig. 2, the LED driving circuit 100 further comprises a zero-crossing sampling circuit 50, wherein the zero-crossing sampling circuit 50 comprises a first sampling terminal and a second sampling terminal, the first sampling terminal is electrically connected to the first node 203, the second sampling terminal is electrically connected to the second node 204, and, the zero-cross sampling circuit 50 is also electrically connected to the microprocessor 40, the zero-cross sampling circuit 50 samples the voltages of the first node 203 and the second node 204, and transmits the sampled voltage to the microprocessor 40, specifically to the IO interface of the microprocessor 40, the microprocessor 40 sends a control signal to the switching circuit 30 according to the sampled voltage, to control the operating state of the switch circuit 30, the operating state of the switch circuit 30 includes two states, which are an on state and an off state, respectively. If the sampled voltage is the sampled voltage of the first node 203, the microprocessor 40 controls the switch circuit 30 to operate in the on state, and then the first LED lamp 201 is turned on, and if the sampled voltage is the sampled voltage of the second node 204, the microprocessor 40 controls the switch circuit 30 to operate in the on state, and then the second LED lamp 202 is turned on. Therefore, the LED driving circuit 100 can control the states of the first LED lamp 201 and the second LED lamp 202 through one switch circuit 30.

In some embodiments, with reference to fig. 2, the LED driving circuit 100 further includes a first half-wave rectifying circuit 60, the first half-wave rectifying circuit 60 is in one-to-one correspondence with the first LED lamp 201, and the first half-wave rectifying circuit 60 is electrically connected between the first node 203 and the anode of the first LED lamp 201. The first half-wave rectifier circuit 60 is configured to rectify a current coupled to the secondary winding through the isolation transformer 10, and if the ac power source 200 is a sine wave, the current coupled to the secondary winding is also a sine wave, and the sine wave is rectified by the first half-wave rectifier circuit 60, and a current of a positive half-cycle portion is transmitted to the positive electrode of the first LED lamp 201, thereby providing a condition for lighting the first LED lamp 201.

In some embodiments, with continued reference to fig. 2, the LED driving circuit 100 further includes a second half-wave rectifying circuit 70, the second half-wave rectifying circuit 70 is in one-to-one correspondence with the second LED lamp 202, and the second half-wave rectifying circuit 70 is electrically connected between the second node 204 and the anode of the second LED lamp 202. The second half-wave rectifier circuit 70 is used to rectify the current coupled to the secondary winding through the isolation transformer 10, and if the ac power source 200 is a sine wave, the current coupled to the secondary winding is also a sine wave, which is rectified by the second half-wave rectifier circuit 70, and the current of the positive half-cycle part is transmitted to the positive electrode of the second LED lamp 202, so as to provide a condition for lighting the second LED lamp 202. The ac power supply 200 in this embodiment is out of phase with the ac power supply 200 that lights the first LED lamp 201, and both are coupled to the secondary winding at a certain time interval.

Therefore, according to the sampling voltage sampled by the zero-crossing sampling circuit 50, the microprocessor 40 controls the operating state of the switching circuit 30, and then drives the two LED lamps to operate, so that the LED lamps are turned on or off.

Referring to fig. 3, fig. 3 is a schematic circuit structure diagram of an LED driving circuit according to an embodiment of the present invention. As shown in fig. 3, the neutral line ACN and the live line ACL of the ac power supply 200 are coupled and stepped down by the isolation transformer T, and output low-voltage ac power.

The first half-wave rectifier circuit 60 includes a first diode D1, an anode of the first diode D1 is connected to the first node 203, a cathode of the first diode D1 is connected to an anode of the first LED lamp LED1, the first second half-wave rectifier circuit 70 includes a second diode D2, an anode of the second diode D2 is connected to the second node 204, and a cathode of the second diode D2 is connected to an anode of the second LED lamp LED 2.

Each LED unit 20 includes two LED lamps, the first LED unit 20 includes a first LED lamp LED1 and a second LED lamp LED2, and cathodes of the first LED lamp LED1 and the second LED lamp LED2 are commonly connected to the first end 301 of the switch circuit 30. The LED driving circuit 100 further includes other LED units 20, each LED unit 20 includes two LED lamps, and the cathodes of the two LED lamps in one LED unit 20 are both commonly connected to the first end of the corresponding switch circuit 30. For example, as shown in fig. 3, two LED lamp cathodes of the second LED unit 20 are both commonly connected to the first end 302 of the corresponding switch circuit 30, and two LED lamp cathodes of the third LED unit 20 are both commonly connected to the first end 303 of the corresponding switch circuit 30.

Each of the switch circuits 30 includes a resistor and a transistor, wherein the first switch circuit 30 includes a first transistor Q1 and a third resistor R3, one end of the third resistor R3, that is, the first end 301 of the switch circuit 30, is connected to the cathode of the first LED lamp LED1 and the cathode of the second LED lamp LED2, the other end of the third resistor R3 is connected to the collector of the first transistor Q1, the emitter of the first transistor Q1 is grounded, the base of the first transistor Q1 is connected to port I O1 of the microprocessor 40, and the microprocessor 40 can send a first PWM control signal to the base of the first transistor Q1 through the IO port 1 to control the operating state of the first transistor Q1.

The circuit composition and connection relationship of the other first half-wave rectifier circuits 60 are the same as those of the first half-wave rectifier circuit 60, the circuit composition and connection relationship of the other second half-wave rectifier circuits 70 are the same as those of the first second half-wave rectifier circuit 70, the circuit composition and connection relationship of the other LED units 20 are the same as those of the first LED unit 20, and the circuit composition and connection relationship of the other switch circuits 30 are the same as those of the first switch circuit 30, for example, as shown in fig. 3, the second first half-wave rectifier circuit 60 includes a third diode D3, the second half-wave rectifier circuit 70 includes a fourth diode D4, the second LED unit 20 includes a third LED lamp LED3 and a fourth LED lamp LED4, the second switch circuit 30 includes a second triode Q2, an anode of the third diode D3 and an anode of the fourth diode D4 are respectively connected to the first node 203 and the second node 204, a base of the second transistor Q2 is connected to the IO port 3 of the microprocessor 40, similarly, the third first half-wave rectifier circuit 60 includes a fifth diode D5, the second half-wave rectifier circuit 70 includes a sixth diode D6, the third LED unit 20 includes a fifth LED lamp LED5 and a sixth LED lamp LED6, the third switch circuit 30 includes a third transistor Q3, an anode of the fifth diode D5 and an anode of the sixth diode D6 are respectively connected to the first node 203 and the second node 204, a base of the third transistor Q3 is connected to the IO port 4 of the microprocessor 40, and the microprocessor 40 controls operating states of the second transistor Q2 and the third transistor Q3 through different IO ports, thereby controlling operating states of the LED units. The working principle of each LED unit and the switching circuit is the same as that of the first LED unit and the switching circuit, and the description thereof is omitted.

The zero-cross sampling circuit 50 includes a first resistor R1 and a second resistor R2, one end of the first resistor R1 is connected to the first node 203, the other end is connected to one end of the second resistor R2 and the IO port 2 of the microprocessor 40, and the other end of the second resistor R2 is connected to the second node 204. The zero-cross sampling circuit 50 samples the ac current flowing through the secondary winding and transmits the sampled voltage to the IO port 2 of the microprocessor 40, and the microprocessor 40 controls the first transistor Q1 to be turned on or off according to the sampled voltage.

Referring to fig. 3, the operating principle of the LED driving circuit 100 for driving the LED lamp can be described as follows:

taking the ac power supply 200 as an example of a sine wave, the first sine wave is coupled by the isolation transformer T, an ac current is formed in the secondary winding, a part of the ac current is rectified by the first diode D1 to provide a positive voltage for the positive electrode of the first LED lamp LED1, another part of the ac current is sampled by the first sampling resistor R1 and the second sampling resistor R2, the sampled voltage is transmitted to the IO port 2 of the microprocessor 40, the microprocessor 40 sends a first control signal to the base of the first triode Q1 according to the received sampled voltage, the first control signal is sent in the form of PWM, when the PWM wave is in the positive half cycle, the first triode Q1 is turned on, the first LED lamp LED1 is turned on, the first LED lamp LED1 is turned on, when the PWM wave is in the negative half cycle, the first triode Q1 is turned off, the first LED lamp LED1 is turned off, and the first LED lamp LED1 is turned off.

Similarly, after the second sine wave having a phase difference with the first sine wave is coupled by the isolation transformer T, the coupled ac current is rectified by the second diode D2 to provide a forward voltage to the anode of the second LED lamp LED2, another part of the ac current is sampled by the second resistor R2 and the first resistor R1 and transmitted to the IO port 2 of the microprocessor 40, and the microprocessor 40 determines that the current ac power supply 200 is the second sine wave according to the sampled voltage, and then sends a second control signal, which is also in the form of a PWM wave, to the base of the first triode Q1, so as to control the on/off of the second LED lamp LED 2.

In summary, the LED driving circuit sends different control signals to the switching circuit according to the voltage sampled by the zero-cross sampling circuit, so as to control the operating state of the switching circuit, and further separately drive the first LED lamp and the second LED lamp to operate, so as to turn on or turn off the first LED lamp and the second LED lamp. The LED driving circuit can use one switch circuit to respectively control the states of two LED lamps, and has the advantages of lower circuit cost and more accurate control.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; within the idea of the invention, also technical features in the above embodiments or in different embodiments can be combined, steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An LED driving circuit, comprising:

an isolation transformer for coupling alternating current;

2. The LED driving circuit according to claim 1, further comprising a zero-cross sampling circuit, wherein the zero-cross sampling circuit comprises a first sampling terminal and a second sampling terminal, the first sampling terminal is electrically connected to the first node, the second sampling terminal is electrically connected to the second node, and the zero-cross sampling circuit is further electrically connected to the microprocessor for transmitting a sampled voltage to the microprocessor, so that the microprocessor controls an operating state of the switching circuit according to the sampled voltage, wherein the operating state includes an on state or an off state.

3. The LED driving circuit according to claim 2, wherein the zero-cross sampling circuit comprises a first resistor and a second resistor, one end of the first resistor is connected to the first node, the other end of the first resistor and one end of the second resistor are commonly connected to the microprocessor, and the other end of the second resistor is further connected to the second node.

4. The LED driving circuit according to claim 1, further comprising a plurality of first half-wave rectifying circuits, the first half-wave rectifying circuits corresponding to the first LED lamps one to one, the first half-wave rectifying circuits being electrically connected between the first node and the anodes of the first LED lamps for rectifying the coupled current.

5. The LED driving circuit according to claim 4, wherein the first half-wave rectifying circuit comprises a first diode, an anode of the first diode is connected to the first node, and a cathode of the first diode is connected to an anode of the first LED lamp.

6. The LED driving circuit according to claim 1, further comprising a plurality of second half-wave rectifying circuits, the second half-wave rectifying circuits corresponding to the second LED lamps one to one, the second half-wave rectifying circuits being electrically connected between the second node and the anode of the second LED lamp for rectifying the coupled current.

7. The LED driving circuit according to claim 6, wherein the second half-wave rectification circuit comprises a second diode, an anode of the second diode is connected to the second node, and a cathode of the second diode is connected to an anode of the second LED lamp.

8. The LED driving circuit according to any one of claims 1 to 7, wherein the control signal is a PWM signal.

9. A luminaire comprising the LED driving circuit according to any one of claims 1 to 8.