CN101309540B - Electronic trigger and HID light - Google Patents

Abstract

The invention discloses an electronic trigger and an HID lamp. The electronic trigger comprises a first transformer and a second transformer, wherein a resonance circuit is formed between the primary side of the first transformer and a first capacitor, and an electronic switch is arranged on the resonance circuit, and the electronic switch is connected with a chip. The low frequency square-wave signals output through an electronic ballast are input to the chip after passing through a rectification circuit and a voltage stabilizing tube voltage reducing circuit in sequence. When the HID lamp is started, the low frequency square-wave signal voltage output by the electronic ballast is higher, a high frequency pulse signal is output by the chip, and then the trigger works, and thereby the starting of the HID lamp is realized; when the HID lamp works normally, the low frequency square-wave signal voltage output by the electronic ballast is lower, the chip stops to output the high frequency pulse signal, and the trigger dose not work. The first transformer and the second transformer work under the high frequency state, therefore, the weight and the volume of the entire circuit are reduced, simultaneously, automatic triggering can be performed according to the terminal voltage of the lamp, and the multi-trigger phenomenon can not be caused, and thereby the stability of the system is enhanced. The low frequency square-wave signals output by the electronic ballast are input to the chip after passing through the rectification circuit and the voltage stabilizing tube voltage reducing circuit in sequence.

Description

Electronic trigger and HID light

technical field

The invention relates to an electronic trigger device, in particular to an electronic trigger and an HID lamp.

Background technique

HID (High Intensity Discharge) lamp is a new type of high-efficiency electric light source, with high luminous efficiency and color temperature close to the ideal light source (such as sunlight), and has been widely used in automobiles, industrial and commercial, film and television stage lighting, etc. occasion.

In the prior art, the volt-ampere characteristics of a typical HID lamp when it is started are shown in Figure 1. After the lamp is triggered, the lamp current drops and the terminal voltage rises, showing a negative resistance characteristic. It is necessary to connect an electronic circuit between the power supply grid and the lamp. ballast to limit the inrush current when the lamp is started.

The circuit block diagram of the electronic ballast is shown in Figure 2. The PFC circuit is a typical Boost type power factor correction circuit to improve the power factor at the input end; the DC-DC converter is a Buck type step-down circuit to ensure the stable start of the lamp and Provide constant power control for the steady-state operation of the lamp; the DC-AC converter is a full-bridge inverter circuit, in order to suppress the acoustic resonance when the lamp is working at high frequency, output a low-frequency AC square wave power signal to drive the HID lamp.

When the HID lamp is started, it is necessary to use a trigger to apply a high-amplitude trigger voltage across the lamp to ionize and discharge the gas filled in the lamp.

The circuit structure of the inductive trigger in the prior art is shown in Figure 3. When the switch S is closed, the AC signal is applied to the primary side of the first transformer _T1 , and the secondary side of the first transformer _T1 is connected to the sixth capacitor C ₆ fast charging, when the voltage of the sixth capacitor _C6 reaches the breakdown voltage of the air gap switch SG, the air gap switch SG is turned on, the sixth capacitor _C6 and the primary side of the second transformer _T2 form a series resonant circuit, because The resonant frequency is very high, the fifth capacitor _C5 is equivalent to a short circuit, and the high voltage generated by the secondary side of the second transformer _T2 is all added between the two electrodes of the bulb to ionize and discharge the gas to realize the triggering of the lamp. When the switch S is turned off, the trigger circuit does not work, and the electronic ballast outputs a low-frequency constant power signal to realize the steady-state operation of the HID lamp.

Above-mentioned prior art has following shortcoming at least:

Since the first transformer _T1 works in a low frequency state, the size and weight of the inductive trigger is relatively large. In applications such as small and medium power with special requirements on volume and weight, its large size and weight limit the application of the inductive trigger. In addition, when the switch S is disturbed and operated multiple times, the lamp will be triggered multiple times, which will accelerate the ionization loss of the two electrodes of the lamp and reduce the working life of the lamp.

Contents of the invention

The object of the present invention is to provide an electronic trigger and HID lamp with light weight, small volume and stable working state.

The purpose of the present invention is achieved through the following technical solutions:

The electronic trigger of the present invention includes a first transformer and a second transformer, the primary side of the first transformer receives a voltage signal, the secondary side of the second transformer outputs a trigger voltage, and the primary side of the first transformer is connected in series The first capacitor, and a resonant circuit is formed between the primary side of the first transformer and the first capacitor, the resonant circuit is provided with an electronic switch, the electronic switch is connected to a chip, and the chip outputs high-frequency pulses The signal controls the switching state of the electronic switch.

In the HID lamp of the present invention, the HID lamp is connected with the above-mentioned electronic trigger.

As can be seen from the above-mentioned technical solutions provided by the present invention, the electronic trigger and the HID lamp of the present invention, because the primary side of the first transformer of the electronic trigger is connected in series with a first capacitor to form a resonant circuit, the resonant circuit is provided with Electronic switch, the electronic switch controls the switch state by the high-frequency pulse signal output by the chip, and then realizes the control of the trigger state of the trigger. Light weight, small size, and stable working condition.

Description of drawings

FIG. 1 is a schematic diagram of a volt-ampere characteristic curve for starting a HID lamp in the prior art;

FIG. 2 is an electrical schematic diagram of an electronic ballast in the prior art;

Fig. 3 is the electrical schematic diagram of the inductive trigger in the prior art;

Fig. 4 is the electrical schematic diagram of electronic trigger of the present invention;

Fig. 5 is the original diagram of the first-stage equivalent circuit of the electronic trigger of the present invention;

Fig. 6 is the original diagram of the second-stage equivalent circuit of the electronic trigger of the present invention;

Fig. 7 is the original diagram of the simplified second-stage equivalent circuit of the electronic trigger of the present invention;

Fig. 8 is the original diagram of the third-stage equivalent circuit of the electronic trigger of the present invention.

Detailed ways

The preferred embodiment of the electronic trigger of the present invention is shown in FIG. 4 , comprising a first transformer T ₁ and a second transformer T ₂ , the primary side of the first transformer T ₁ receives a voltage signal and is coupled to the secondary side; The secondary side of the first transformer _T1 transfers the energy of the voltage signal to the primary side of the second transformer _T2 step by step, and the secondary side of the second transformer _T2 outputs the trigger voltage.

Specifically, the primary side of the first transformer T ₁ is connected in series with the first capacitor C ₁ , and a resonant circuit is formed between the primary side of the first transformer T ₁ and the first capacitor C ₁ , the resonant circuit is provided with an electronic switch Q, and the electronic switch Q is connected to There is a chip IP, and the chip IP controls the switching state of the electronic switch Q by outputting a high-frequency pulse signal.

The chip IP receives an external low-frequency square wave signal (such as the low-frequency square wave signal output by an electronic ballast), and decides to output or stop outputting a high-frequency pulse signal according to the voltage level of the low-frequency square wave signal, specifically: when the low-frequency square wave signal When the voltage of the square wave signal is higher than the set threshold, the chip IP outputs a high-frequency pulse signal; when the voltage of the low-frequency square wave signal is lower than the set threshold, the chip IP stops outputting a high-frequency pulse signal.

When it is applied to the start of HID lamps, when the HID lamps first start, the voltage of the low-frequency square wave signal output by the electronic ballast is relatively high, the chip IP outputs a high-frequency pulse signal, the trigger works, and the trigger voltage is output to realize the control of HID. Start the lamp; when the HID lamp is working normally, the voltage of the low-frequency square wave signal output by the electronic ballast is low, the chip IP stops outputting the high-frequency pulse signal, the trigger does not work, and stops outputting the trigger voltage.

The external low-frequency square wave signal can first be rectified by the rectifier circuit and then input to the chip IP; it can also be input to the chip IP after being stepped down by the Zener tube step-down circuit.

After the specific low-frequency square wave signal passes through the rectifier circuit, the positive and negative poles of the output can be respectively connected to the resonant circuit formed between the primary side of the first transformer _T1 and the first capacitor _C1 , wherein a current limiter is set between the positive pole and the resonant circuit Resistor R. The value of the current limiting resistor R is greater than 4L ₁ /C ₁ , where L ₁ is the value of the primary inductance of the first transformer T ₁ ; C ₁ is the value of the first capacitor C ₁ .

The Zener tube step-down circuit includes two Zener diodes, and the two Zener diodes are connected in series between the anode and cathode of the output of the rectifier circuit, and the connection point between the two Zener diodes is connected to the input terminal of the chip IP. Realize the voltage regulation and step-down of the chip IP input voltage.

The secondary side of the first transformer _T1 is connected to the primary side of the second transformer _T2 through a half-wave voltage doubler rectifier circuit. The specific half-wave voltage doubler rectifier circuit includes a third capacitor _C3 , a second capacitor C2, a first two Diode D1, second diode D2. Wherein, the third capacitor _C3 is connected with the primary side of the second transformer _T2 to form a resonant circuit, and an air gap switch SG is arranged on the resonant circuit; the first diode D1 is connected in parallel with the third capacitor C3; the second two The diode D2 is connected between the first diode D1 and the third capacitor C3; the second capacitor C2 is connected between the first diode D1 and the secondary side of the first transformer T1.

The capacitance of the third capacitor C3 is much larger than that of the second capacitor C2, and may be greater than or equal to 10 times the capacitance of the second capacitor C2.

A preferred embodiment of the HID lamp of the present invention is that the HID lamp is connected with the above-mentioned electronic trigger to start the HID lamp.

The operating principle of the electronic trigger for the HID lamp of the present invention is:

When the lamp is not started, the DC-AC converter in the electronic ballast is equivalent to no-load, and outputs a low-frequency square wave AC voltage of 300VRMS. The rectified DC voltage VDC of the square wave AC voltage is stepped down by the voltage regulator tube. Afterwards, the chip IC outputs a high-frequency driving pulse signal to control the electronic switch Q. When the electronic switch Q is turned off, the DC voltage VDC passes through the current limiting resistor R, and the primary side of the first transformer _T1 charges the first capacitor _C1 . The initial voltage of the first capacitor C ₁ is zero, which is equivalent to a short circuit; the initial current value of the primary side inductance L ₁ of the first transformer T ₁ is VDC/R, because the current limiting resistor R (1K) is relatively large, much larger than 4L ₁ /C ₁ (L ₁ =20uH, C ₁ =0.033u), so the circuit is an over-damped oscillation, which can be simplified as a capacitor charging circuit; when the electronic switch Q is closed, the primary side of the first transformer T ₁ and the first capacitor C ₁ constitutes a series resonant circuit, which transmits energy to the secondary side of the first transformer _T1 through magnetic field coupling, and consists of the first diode _D1 , the second diode _D2 , the second capacitor _C2 and the third capacitor _C3 A half-wave voltage doubler rectifier circuit is formed. When the voltage applied to both ends of the third capacitor _C3 reaches the breakdown voltage of the air gap switch SG, the air gap switch SG is turned on, and the third capacitor _C3 and the second transformer _T2 The primary side of the T2 forms a series resonant circuit, and the energy is transferred to the secondary side of the second transformer T2 through magnetic field coupling to trigger the HID lamp.

When the lamp starts to work in a steady state, the AC square wave voltage at both ends of the lamp is very low (<100VRMS). After rectification and step-down of the voltage regulator tube, the chip IC stops vibrating, and the entire trigger circuit stops working. The ballast outputs a low frequency AC square wave power signal to the HID lamp.

The theoretical analysis of the flip-flop of the present invention and the design method of main parameters are described in detail below:

For the convenience of analysis, it is assumed that the starting point of the time is set to the moment when the electronic switch Q is turned off. The equivalent circuit of the first stage charging is shown in Figure 5, where R is the current limiting resistor at the input terminal and the primary side _L1 of the first transformer T1. The sum of the winding resistance and the series equivalent resistance of the first capacitor _C1 . The rectified DC voltage V _in linearly charges C 1 through R and L ₁ , the terminal voltage u ₁ of C ₁ rises exponentially, the inductance L ₁ is equivalent to a _short circuit, and the output voltage u ₃ is approximately zero. After time t elapses, $u_1\left(t_0\right)=V_{\mathrm{in}}\left({1-e}^{-\frac{{\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="S2008101164836E00011.png"\; state="\{\{state\}\}">t</figure-callout>}}_0}{{\mathrm{RC}}_1}}\right),$ Where t ₀ is the off time of the electronic switch Q.

When the electronic switch Q is closed, the second-stage equivalent circuit is shown in Figure 6, where _K1 is the series equivalent resistance of the winding resistance of the primary side _L1 of the first transformer T1 and the first capacitor _C1 and the switch Q The sum of the on-resistance; R ₂ is the sum of the winding resistance of the secondary side L ₂ of the transformer T1 and the series equivalent resistance of the second capacitor C ₂ . In the actual circuit, K ₁ <1ohm is very small, R ₂ >100ohm, L ₁ is approximately equal to dozens of uH, L ₂ is approximately equal to dozens of mH, C ₁ is approximately equal to tens of nF, and C ₂ is approximately equal to hundreds of pF , C ₃ is approximately equal to several thousand pF, so the two second-order circuits of the primary and secondary sides of the first transformer T ₁ both meet the free resonance condition of R ₂ <4L/C, so when the switch Q changes from open to closed state, C ₁ , L ₁ and R ₁ and C ₂ , L ₂ and R ₂ form two second-order series free resonant circuits, and the initial value of the terminal voltage of capacitor C ₁ is u ₁ (t ₀ ), since C ₂ ≤ 10C ₃ , so the equivalent circuit shown in Figure 6 can be further simplified to the equivalent circuit shown in Figure 7.

The circuit equation shown in Figure 7 is shown in formula (1):

$\left\{\begin{array}{c}{L}_1{C}_1\frac{d^2{u}_1}{{\mathrm{<figure-callout\; id="2"\; label="dt"\; filenames="S2008101164836E00011.png"\; state="\{\{state\}\}">dt</figure-callout>}}^2}+{\mathrm{MC}}_2\frac{d^2{\mathrm{<figure-callout\; id="2"\; label="u"\; filenames="S2008101164836E00011.png"\; state="\{\{state\}\}">u</figure-callout>}}_2}{{\mathrm{<figure-callout\; id="2"\; label="dt"\; filenames="S2008101164836E00011.png"\; state="\{\{state\}\}">dt</figure-callout>}}^2}+R_1{C}_1\frac{{\mathrm{du}}_1}{\mathrm{dt}}+u_1\left(t\right)=0\\ L_2{C}_2\frac{d^2{\mathrm{<figure-callout\; id="2"\; label="u"\; filenames="S2008101164836E00011.png"\; state="\{\{state\}\}">u</figure-callout>}}_2}{{\mathrm{<figure-callout\; id="2"\; label="dt"\; filenames="S2008101164836E00011.png"\; state="\{\{state\}\}">dt</figure-callout>}}^2}+{\mathrm{MC}}_1\frac{d^2{u}_1}{{\mathrm{<figure-callout\; id="2"\; label="dt"\; filenames="S2008101164836E00011.png"\; state="\{\{state\}\}">dt</figure-callout>}}^2}+u_2\left(t\right)=0\end{array}\right.$ Formula 1)

The initial value is u ₁ (0 ⁺ )＝u ₁ (t ₀ ), u′ ₁ (0 ⁺ )＝i _L1 (0 ⁺ )/C ₁ ＝0, u ₂ (0 ⁺ )＝0, u′ ₂ ( 0 ⁺ ) = i _L2 (0 ⁺ )/C ₂ =0

When the resonance condition (L ₁ C ₁ =L ₂ C ₂ ) is satisfied, the energy transmission efficiency η=1;

At the same time, when the coupling coefficient $k=\frac{2\mathrm{no}+1}{{2\mathrm{no}}^2+2\mathrm{no}+1}(\mathrm{no}=\mathrm{0,1,2,3}\&Center\; Dot;\&CenterDot;\&CenterDot;)$ When , the output voltage u ₂ (t) is maximum,

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}_{\mathrm{<span\; class="notranslate">\; max</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>\sqrt{\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}}<span\; class="notranslate">\; .</span>$

In actual engineering, a coupling transformer with n=1 and k=0.6 is often used.

The maximum output voltage on the third capacitor C ₃ $u_3{\left(t\right)}_{\max }={2u}_2{\left(t\right)}_{\max }={2u}_1\left(t_0\right)\sqrt{\frac{L_2}{L_1}}.$

The third-level equivalent circuit is shown in Figure 8, where _R3 is the difference between the winding resistance of the primary side _L3 of the second transformer T2, the series equivalent resistance of the third capacitor _C3 , and the on-resistance of the air-gap switch SG And, the secondary side _L2 of the first transformer T1 charges the capacitor _C3 through the voltage doubler rectifier circuit. When the voltage of the capacitor _C3 reaches the saturation breakdown voltage of the air gap switch SG, SG is equivalent to a short circuit, and the capacitors _C3 and L ₃ and R ₃ form a second-order series resonant circuit, C ₄ is the equivalent capacitance between the two electrodes of the HID lamp, and the circuit equation is shown in formula (2):

$\left\{\begin{array}{c}{L}_3{C}_3\frac{d^2{u}_3}{{\mathrm{<figure-callout\; id="2"\; label="dt"\; filenames="S2008101164836E00011.png"\; state="\{\{state\}\}">dt</figure-callout>}}^2}+{\mathrm{MC}}_4\frac{d^2{\mathrm{<figure-callout\; id="4"\; label="u"\; filenames="S2008101164836E00011.png,S2008101164836E00012.png"\; state="\{\{state\}\}">u</figure-callout>}}_4}{{\mathrm{<figure-callout\; id="2"\; label="dt"\; filenames="S2008101164836E00011.png"\; state="\{\{state\}\}">dt</figure-callout>}}^2}+R_3{C}_3\frac{{\mathrm{du}}_3}{\mathrm{dt}}+u_3\left(t\right)=0\\ L_4{C}_4\frac{d^2{\mathrm{<figure-callout\; id="4"\; label="u"\; filenames="S2008101164836E00011.png,S2008101164836E00012.png"\; state="\{\{state\}\}">u</figure-callout>}}_4}{{\mathrm{<figure-callout\; id="2"\; label="dt"\; filenames="S2008101164836E00011.png"\; state="\{\{state\}\}">dt</figure-callout>}}^2}+{\mathrm{MC}}_3\frac{d^2{u}_3}{{\mathrm{<figure-callout\; id="2"\; label="dt"\; filenames="S2008101164836E00011.png"\; state="\{\{state\}\}">dt</figure-callout>}}^2}+u_4\left(t\right)=0\end{array}\right.$ Formula (2)

Similar to the above analysis, it can be obtained: to maximize the energy transmission efficiency, the primary and secondary sides of the second transformer T ₂ also need to meet the resonance condition: ω ₃ =ω ₄ , that is, L ₃ C ₃ =L ₄ C ₄ , in order to achieve the maximum output Voltage, coupling coefficient k=0.6.

The quality of the manufacturing process of the trigger for HID lamps has a great impact on the performance of the entire circuit. During the production process, each parameter value should be reasonably determined so that it can meet the start-up characteristics of the lamp and at the same time extend the lamp to the maximum extent. lifespan. According to the simulation results and experimental data, in the process of making the trigger for the HID lamp of the present invention, try to achieve:

1) When wiring the circuit, try to shorten the length of various leads to reduce the loss of stray inductance and wire resistance and increase the output voltage;

2) The driving duty cycle of the electronic switch Q should be as small as possible (the driving duty cycle in the prototype of the specific embodiment is set to 1.3%, and the frequency is 14KHz), so that the terminal voltage _u1 of the first capacitor _C1 can be charged to the input voltage as much as possible. In addition, in order to reduce the line loss, capacitors C ₁ and C ₃ should choose high-frequency capacitors with low ESR resistance, (the prototype uses WIMA FKP series polypropylene film capacitors, tanδ≤10·10 ^-4 @100KHz) ;

3) In the voltage doubling and rectifying part, in order to achieve a good voltage doubling effect, the capacitance of the third capacitor _C3 should be much greater than the capacitance of the second capacitor _C2 , ( _C3 =1500P in the prototype of the specific embodiment, _C2 =150P);

4) In order to achieve a good boosting effect, effective insulation measures should be adopted, such as adding insulating bushings on the primary and secondary sides of the second transformer _T2 and adding isolation slots between the high-voltage output terminals to prevent discharge at the high-voltage end. Finally, the entire device Epoxy insulating resin potting is also applied to further improve the reliability of the system.

The electronic trigger model for HID lamps of the present invention makes the first transformer _T1 and the second transformer _T2 work in a high-frequency state, which greatly reduces the weight and volume of the entire circuit, and can automatically Triggering will not cause multiple triggers, which improves the stability of the system. In the present invention, the segmented circuit model and mathematical analysis of the flip-flop for the HID lamp are also given, so that the electrical characteristics can be quantitatively studied. The experimental and simulation results all prove the correctness of the theory in the present invention.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention.

Claims (9)

1. electronic trigger, comprise first transformer, second transformer, the former edge joint of described first transformer is received voltage signal, the secondary trigger output voltage of described second transformer, it is characterized in that, the former limit of described first transformer is in series with first electric capacity, and constitute resonant circuit between the former limit of described first transformer and described first electric capacity, described resonant circuit is provided with electronic switch, described electronic switch is connected with chip, and described chip is controlled the on off state of described electronic switch by the output high-frequency pulse signal;

Described chip receives outside low-frequency square-wave signal, and just determines output or stop to export high-frequency pulse signal according to the voltage of described low-frequency square-wave signal, specifically:

When the voltage of described low-frequency square-wave signal is higher than preset threshold, described chip output high-frequency pulse signal;

When the voltage of described low-frequency square-wave signal was lower than preset threshold, described chip stopped to export high-frequency pulse signal.

2. electronic trigger according to claim 1 is characterized in that described low-frequency square-wave signal is input to described chip by rectification circuit.

3. electronic trigger according to claim 2 is characterized in that described low-frequency square-wave signal is input to described chip by the voltage-stabiliser tube reduction voltage circuit.

4. electronic trigger according to claim 3, it is characterized in that described low-frequency square-wave signal is by behind the rectification circuit, the positive pole of output is connected with described resonant circuit respectively with negative pole, be provided with current-limiting resistance between described positive pole and the described resonant circuit, the value of described current-limiting resistance is greater than 4L ₁/ C ₁, L in the formula ₁Value for the former limit of described first transformer inductance; C ₁Value for described first electric capacity.

5. electronic trigger according to claim 4, it is characterized in that, described voltage-stabiliser tube reduction voltage circuit comprises two voltage stabilizing didoes, be connected between the positive pole and negative pole of described rectification circuit output after described two voltage stabilizing didoes series connection, the tie point between described two voltage stabilizing didoes is connected with the input of described chip.

6. electronic trigger according to claim 1, it is characterized in that, be connected by half-wave voltage doubler between the former limit of the secondary of described first transformer and described second transformer, described half-wave voltage doubler comprises the 3rd electric capacity, the former limit of described the 3rd electric capacity and described second transformer is connected to form resonant circuit, and is provided with air gap switch on this resonant circuit.

7. electronic trigger according to claim 6 is characterized in that, described half-wave voltage doubler comprises second electric capacity, first diode, second diode, and described first diode is in parallel with described the 3rd electric capacity; Described second diode is connected between described first diode and described the 3rd electric capacity; Described second electric capacity is connected between the secondary of described first diode and described first transformer.

8. electronic trigger according to claim 7 is characterized in that, the appearance value of described the 3rd electric capacity is more than or equal to 10 times of the appearance value of described second electric capacity.

9. a HID lamp is characterized in that, this HID lamp is connected with each described electronic trigger of claim 1 to 8.

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