CN209526913U - LED turn signal step-up/step-down circuit - Google Patents
LED turn signal step-up/step-down circuit Download PDFInfo
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- CN209526913U CN209526913U CN201821605027.3U CN201821605027U CN209526913U CN 209526913 U CN209526913 U CN 209526913U CN 201821605027 U CN201821605027 U CN 201821605027U CN 209526913 U CN209526913 U CN 209526913U
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- inductance
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Abstract
A kind of LED turn signal step-up/step-down circuit, including π type differential mode filter circuit, switching power circuit, common mode inductance, output differential mode capacitor, common-mode filter and turn signal LED light string.π type differential mode filter circuit includes differential mode inductance, the first filter capacitor and the second filter capacitor；The first end and second end of first filter capacitor is separately connected the anode and cathode of external dc power.Switching power circuit includes switching tube, controller, power inductance, freewheeling diode, output filter capacitor and output current sampling circuit；The first end of power inductance is connect with the first end of the second filter capacitor.The first input end of common mode inductance and the second input terminal are separately connected the first end and second end of output filter capacitor, and the first output end and second output terminal of common mode inductance are separately connected the first end and second end of output differential mode capacitor.The utility model can drive high-power LED to turn to lamp load in a manner of constant current, and can effectively inhibit electromagnetic interference noise.
Description
Technical field
The utility model relates to automotive lighting technologies.
Background technique
Turn signal is the indicator light for prompting vehicle front, rear, left and right vehicle and pedestrian to pay attention to when the vehicle is turning.With LED
(light emitting diode) is universal in terms of lamp applications, and LED replaces traditional light bulb to have become the development trend of turn signal.
LED needs special driving power to power for it due to its unique electrical characteristic, and LED generallys use Switching Power Supply drive at present
It is dynamic.But since the cell voltage of household small-size automobile generally only has 12V or so, current LED turns to lamp drive circuit can not
High-power, high brightness LED is driven to turn to lamp load.
On the other hand, Switching Power Supply can generate stronger electromagnetic interference noise due to the mechanism of itself power conversion.It should
Electromagnetic interference noise can interfere other electronic products on automobile, influence the Electro Magnetic Compatibility of automobile.
Summary of the invention
It, can be with the technical problem to be solved by the utility model is to provide a kind of LED turn signal step-up/step-down circuit
The mode of constant current drives high-power LED to turn to lamp load, and can effectively inhibit electromagnetic interference noise.
In order to solve the above technical problems, the utility model embodiment provides a kind of LED turn signal step-up/step-down circuit, including
π type differential mode filter circuit, switching power circuit, common mode inductance, output differential mode capacitor, common-mode filter and turn signal LED light
String；π type differential mode filter circuit includes differential mode inductance, the first filter capacitor and the second filter capacitor；The first of first filter capacitor
End and second end are used to be separately connected the anode and cathode of external dc power；The first end of differential mode inductance and the first filter capacitor
First end connection, the second end of differential mode inductance connect with the first end of the second filter capacitor；The second end of second filter capacitor
It is connect with the second end of the first filter capacitor；Switching power circuit include switching tube, controller, power inductance, freewheeling diode,
Output filter capacitor and output current sampling circuit；The first end of power inductance is connect with the first end of the second filter capacitor, function
The second end of rate inductance is connect with the anode of the first conduction terminal of switching tube and freewheeling diode respectively；Second conducting of switching tube
End is connect with the second end of the second filter capacitor；The first end of output filter capacitor and the first end of power inductance connect, output
The second end of filter capacitor and the cathode of freewheeling diode connect；The output end of current detection circuit and the input terminal of controller connect
It connects, current detection circuit is used to detect the output electric current of output filter capacitor；The output end of controller and the control terminal of switching tube
Connection；The first input end of common mode inductance and the second input terminal are separately connected the first end and second end of output filter capacitor, altogether
The first output end and second output terminal of mould inductance are separately connected the first end and second end of output differential mode capacitor；Common-mode filter
Including the first common mode capacitance and the second common mode capacitance；The first end of first common mode capacitance and the first end of output differential mode capacitor connect
It connects, the first end of the second common mode capacitance is connect with the second end of output differential mode capacitor, the second end of the first common mode capacitance and second
The second end of common mode capacitance is grounded；Turn signal LED light string is made of the multiple LED being one another in series together；Turn signal LED light
The anode of string is connect with the first end of the second common mode capacitance, the first end of the cathode of turn signal LED light string and the first common mode capacitance
Connection.
The utility model at least has following technical effect that
It 1, can either be with the side of constant current according to the power circuit of the LED turn signal step-up/step-down circuit of the utility model embodiment
Formula decompression driving LED turns to lamp load, can also be boosted in a manner of constant current and LED is driven to turn to lamp load, therefore even if outside
In the lower situation of the service voltage of portion's DC power supply, high-power, high brightness LED can be also driven to turn to lamp load, and really
The electric current that guarantor flows through each LED is constant always, and brightness is uniform；
2, according to the LED turn signal step-up/step-down circuit of the utility model embodiment using π type differential mode filter circuit, common mode electricity
Sense, output differential mode capacitor and common-mode filter are filtered, and can not only obtain ideal constant output current, and can inhibit
The various electromagnetic interference noises such as DM EMI and common mode interference are avoided and are interfered to other electronic products on automobile, mention
High Electro Magnetic Compatibility；
3, according in the LED turn signal step-up/step-down circuit of the utility model embodiment, output filter capacitor is using polyester electricity
Hold, can effectively inhibit high frequency spikes pulse.
Detailed description of the invention
Fig. 1 shows a kind of circuit diagram of one embodiment of LED turn signal step-up/step-down circuit of the utility model.
Specific embodiment
The utility model is described in detail in the following with reference to the drawings and specific embodiments.
Fig. 1 shows a kind of circuit diagram of one embodiment of LED turn signal step-up/step-down circuit of the utility model.
Please refer to Fig. 1.A kind of LED turn signal step-up/step-down circuit according to an embodiment of the present invention includes π type differential mode filter circuit
1, switching power circuit 2, common mode inductance 3, output differential mode capacitor C6, common-mode filter 5 and turn signal LED light string 6.
π type differential mode filter circuit 1 includes differential mode inductance L1, the first filter capacitor C1 and the second filter capacitor C2.First filter
The first end and second end of wave capacitor C1 is used to be separately connected the anode and cathode of external dc power VD.The of differential mode inductance L1
One end is connect with the first end of the first filter capacitor C1, and the first end of the second end of differential mode inductance L1 and the second filter capacitor C2 connect
It connects；The second end of second filter capacitor C2 is connect with the second end of the first filter capacitor C1.π type differential mode filter circuit 1 can be high
Filter out difference mode signal to effect.
Further, π type differential mode filter circuit further includes third filter capacitor C3 and the 4th filter capacitor C4, third filtering
Capacitor C3, the 4th filter capacitor C4 and the first filter capacitor C1 are parallel with one another, to further enhance filter effect.
Switching power circuit 2 includes switching tube Q1, controller 22, power inductance L3, sustained diode 1, output filtered electrical
Hold C5 and output current sampling circuit 26.The first end of power inductance L3 is connect with the first end of the second filter capacitor C2, power
The second end of inductance L3 is connect with the anode of the first conduction terminal of switching tube Q1 and sustained diode 1 respectively, and the of switching tube Q1
Two conduction terminals are connect with the second end of the second filter capacitor C2.The first end of output filter capacitor C5 and the first of power inductance L3
End connection, the second end of output filter capacitor C5 are connect with the cathode of sustained diode 1.The output end of current detection circuit 26
It is connect with the input terminal of controller 22, current detection circuit 26 is used to detect the output electric current of output filter capacitor C5.Controller
22 output end is connect with the control terminal of switching tube Q1.
In the present embodiment, detection circuit 26 includes sampling resistor R1, and sampling resistor R1 is connected on output filter capacitor C5
First end and common mode inductance 3 first input end between.The first end and second end of sampling resistor R1 respectively with controller 22
Input terminal connection.Controller 22 uses the LED drive chip of the model TLD5097 of company, Infineon.Switching tube Q1 is
NMOS tube, grid, drain electrode and the source electrode of NMOS tube Q1 respectively constitute the control terminal of switching tube Q1, the first conduction terminal and the second conducting
End.
Preferably, output filter capacitor C5 is polyester capacitance.The dielectric constant of polyester capacitance is big compared with high, small in size, capacity,
Stability is preferable, and the indexs such as temperature characterisitic, environmental suitability are better than electrolytic capacitor, and polyester capacitance can not only effectively inhibit
Ripple interference, and the service life and reliability of Switching Power Supply can be improved, while being conducive to the miniaturization of Switching Power Supply, integrating
Change and integral layout.
Common mode interference of the common mode inductance 3 for being generated in surge damping circuit.The first input end of common mode inductance 3 and the second input
End is separately connected the first end and second end of output filter capacitor C5, the first output end and second output terminal point of common mode inductance 3
The first end and second end of differential mode capacitor C6 Lian Jie not exported.Differential mode of the output differential mode capacitor C6 for being generated in surge damping circuit
Interference.
Common mode interference of the common-mode filter 5 for being generated in surge damping circuit.Common-mode filter 5 includes the first common mode capacitance C7
With the second common mode capacitance C8.The first end of first common mode capacitance C7 is connect with the first end of output differential mode capacitor C6, the second common mode
The first end of capacitor C8 is connect with the second end of output differential mode capacitor C6, the second end of the first common mode capacitance C7 and the second common mode electricity
The second end for holding C8 is grounded.
Turn signal LED light string 6 is made of the multiple LED61 being one another in series together；Turn signal LED light string 6 anode with
The first end of second common mode capacitance C8 connects, and the cathode of turn signal LED light string 6 is connect with the first end of the first common mode capacitance C7.
When switching tube Q1 conducting, sustained diode 1 is born the backward voltage of input and is ended, and voltage acts directly on
The two sides of power inductance L3, while inductive current linear rise, power inductance L3 converts electrical energy into Magnetic Energy Storage and rises during this
Come.When switching tube Q1 cut-off, entire circuit cutting supply power supply, power inductance L3 stops charging, due in power inductance L3
It is stored with energy and is formed into a loop with turn signal LED light string 6, power inductance L3 can generate inverse electromotive force, drive afterflow two
Pole pipe D1 forward conduction forms continuous current circuit.Power inductance L3 is the power supply of LED light string 6 during this, and inductive current linearly reduces.
The relationship of the output voltage U2 and input voltage U1 of switching power circuit 2 are as follows: U2=DU1/ (1-D), wherein D is duty ratio.Due to
The value of duty ratio D between 0 to 1, according to above formula output voltage U2 can less than, greater than or equal to input voltage U1,
So as to realize boost or depressurization.When switching power circuit 2 works in pressure-increasning state, in the supply of external dc power VD
In the lower situation of voltage (for example, external dc power is 12V car battery), can also it drive high-power, high brightness
LED turns to lamp load.
For the output electric current kept constant, controller 22 by the institute of current detection circuit 26 it is collected with output electric currents at
The output voltage of proportional relationship is compared with internal reference voltage, when being lower than reference voltage, by increasing switching tube Q1's
Turn-on time mentions High Output Current；Conversely, reducing output electric current by reducing turn-on time, it is finally reached constant output electricity
Stream, so that it is guaranteed that the electric current for flowing through each LED is constant always, brightness is uniform.
According to the LED turn signal step-up/step-down circuit of the utility model embodiment using π type differential mode filter circuit, common mode electricity
Sense, output differential mode capacitor and common-mode filter are filtered, and can not only obtain ideal constant output current, and can inhibit
The various electromagnetic interference noises such as DM EMI and common mode interference are avoided and are interfered to other electronic products on automobile, mention
High Electro Magnetic Compatibility.
Claims (7)
1. a kind of LED turn signal step-up/step-down circuit, which is characterized in that including π type differential mode filter circuit, switching power circuit, be total to
Mould inductance, output differential mode capacitor, common-mode filter and turn signal LED light string；
The π type differential mode filter circuit includes differential mode inductance, the first filter capacitor and the second filter capacitor；First filtered electrical
The first end and second end of appearance is used to be separately connected the anode and cathode of external dc power；The first end of the differential mode inductance with
The first end of first filter capacitor connects, and the second end of the differential mode inductance is connect with the first end of second filter capacitor；
The second end of second filter capacitor is connect with the second end of the first filter capacitor；
The switching power circuit includes switching tube, controller, power inductance, freewheeling diode, output filter capacitor and output
Current sampling circuit；The first end of the power inductance is connect with the first end of second filter capacitor, and the of power inductance
Two ends are connect with the anode of the first conduction terminal of the switching tube and the freewheeling diode respectively；The second of the switching tube is led
Go side is connect with the second end of second filter capacitor；The first end of the output filter capacitor and the first end of power inductance
Connection, the second end of output filter capacitor are connect with the cathode of the freewheeling diode；The output end of the current detection circuit
It is connect with the input terminal of the controller, current detection circuit is used to detect the output electric current of output filter capacitor；The control
The output end of device is connect with the control terminal of the switching tube；
The first input end of the common mode inductance and the second input terminal are separately connected the first end and of the output filter capacitor
Two ends, the first output end and second output terminal of the common mode inductance are separately connected the first end and the of the output differential mode capacitor
Two ends；
The common-mode filter includes the first common mode capacitance and the second common mode capacitance；The first end of first common mode capacitance and institute
State the first end connection of output differential mode capacitor, the second end of the first end of second common mode capacitance and the output differential mode capacitor
The second end of connection, the second end of the first common mode capacitance and the second common mode capacitance is grounded；
The turn signal LED light string is made of the multiple LED being one another in series together；The turn signal LED light string anode with
The first end of second common mode capacitance connects, and the cathode of turn signal LED light string is connect with the first end of the first common mode capacitance.
2. LED turn signal step-up/step-down circuit according to claim 1, which is characterized in that the π type differential mode filter circuit packet
Include third filter capacitor and the 4th filter capacitor；The third filter capacitor, the 4th filter capacitor and first filtering
Capacitor is parallel with one another.
3. LED turn signal step-up/step-down circuit according to claim 1, which is characterized in that the output filter capacitor is poly-
Ester capacitor.
4. LED turn signal step-up/step-down circuit according to claim 1, which is characterized in that the detection circuit includes adopting
Sample resistance；The sampling resistor be connected on the output filter capacitor first end and the common mode inductance first input end it
Between；The first end and second end of the sampling resistor is connect with the input terminal of the controller respectively.
5. LED turn signal step-up/step-down circuit according to claim 1, which is characterized in that the controller is Infineon
The LED drive chip of the model TLD5097 of company.
6. LED turn signal step-up/step-down circuit according to claim 1, which is characterized in that the switching tube is NMOS tube,
Grid, drain electrode and the source electrode of the NMOS tube respectively constitute the control terminal of the switching tube, the first conduction terminal and the second conduction terminal.
7. LED turn signal step-up/step-down circuit according to claim 1, which is characterized in that the external dc power is
12V car battery.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821605027.3U CN209526913U (en) | 2018-09-29 | 2018-09-29 | LED turn signal step-up/step-down circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821605027.3U CN209526913U (en) | 2018-09-29 | 2018-09-29 | LED turn signal step-up/step-down circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN209526913U true CN209526913U (en) | 2019-10-22 |
Family
ID=68211559
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201821605027.3U Active CN209526913U (en) | 2018-09-29 | 2018-09-29 | LED turn signal step-up/step-down circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN209526913U (en) |
-
2018
- 2018-09-29 CN CN201821605027.3U patent/CN209526913U/en active Active
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