Saga of LED lamps. Part 4
Just want to say that I did not forget about the survey . His results are taken into account, the lamps are ordered and go to me. They come, apparently, from afar, but nonetheless. So this material will be. In the meantime, so that no one (and I including) would miss, I suggest looking at two more light bulbs from my bins.
The first will be Philips 5W. Specifically, this friend was very interested in one of my friends, and recently, being in a store, I saw it and bought it for the sake of interest. No code or article was found either on it or on the package, so I’ll quote a photo of the box:
')
The measured ripple factor was 13%, the power factor was 0.64. Not bad. Let's see how this is achieved.
The plastic lens is removable easily.
Under it we see a matrix of eight half-watt diodes, an aluminum part screwed on a millimeter thickness.
I must say that getting to the driver turned out to be incredibly difficult, since this same aluminum part was pressed into the aluminum glass in the manner of a tin can (and welded?). Yes, in fact, the case is also almost entirely aluminum, plastic is only the top layer. I had to use an abrasive disc and metal shears.
In general, the design is very durable, strong, and, I would say, anti-vandal. Thick aluminum surely removes heat well.
The driver was eventually removed:
It looks very difficult. I understood the order of time how it works, and did not believe my eyes for a long time. What do you think, which of the previously considered topologies corresponds to this driver?
The correct answer is no. A very unusual solution for LED lamps has been applied here - in fact, this is a ballast for compact fluorescent lamps, adapted for LEDs. Apparently, this was done to reduce the cost of reconfiguring the production line and changing the procurement scheme of the components — they used what is already being purchased by millions.
The solution is very clever from the point of view of the compromise “production optimization / parameters”, but still in the sense of the LED mode and efficiency is not the best. Well, from the point of view of circuit engineering philosophy, it is somehow strange.
So that the article is not too short, let's look at something else. In general, from more or less similar I had until now only Gauss 3W. Judging by the inscriptions on the package, this lamp is also positioned as the equivalent of a 40 watt incandescent lamp. Item on the box - HA105201103.
Formally, it’s not quite correct to put them near - this three-watt Gauss has an E14 base and is generally declared as decorative. However, if you click on the link written on the box, you can read that the variants of this lamp for the E27 base also seem to be available .
The measured ripple factor is about 1%, the power factor is about 0.6.
To disassemble the lamp, I barbarously otkovyryal base.
As it turned out, doing this was not at all necessary. See the thread on the plastic part? She gets out. That is, the lamp can not only be disassembled, but also painlessly assembled. She maintainable!
In part of the driver no surprises. Inside there is a flyback converter based on the MT7952 (just the case when the current is controlled on the primary side).
Inclusion, apparently, typical.
On the board is visible electrolytic capacitor brand BERYL . Not Rubycon, but still not bad . The operating time of such capacitors to failure, as stated , is about 10,000 hours at temperatures of the LED lamp. What pleases, it is located in the colder part, closer to the base. In general, electrolytic capacitors are one of the determining factors for the durability of LED lamps, so if you believe the figures given in the link above, this lamp has every chance to work happily ever after. The only thing that may cause concern is the heat dissipation from the LEDs. Nevertheless, judging by the heating of the case, it is also more or less in order with it (the “stamens” on which the aluminum LEDs are sealed, this is MCPCB ).
In general, today we saw two decent lamps. Philips, however, was astonished at the driver’s decision, but his parameters are quite good (pulsations 13%, cos (φ) is about 0.6), and the quality of the design itself is excellent, as it should be for a brand of this level.
The lamp from Gauss is just a good lamp (pulsations 1%, cos (φ) is also around 0.6). Standard circuit design, moderately high quality components. But for my taste, its main feature is maintainability. This is in my memory the first lamp, which can not only be disassembled, but also assembled. For example, it is possible within the DIY framework to solder a capacitor when it does dry.
The first will be Philips 5W. Specifically, this friend was very interested in one of my friends, and recently, being in a store, I saw it and bought it for the sake of interest. No code or article was found either on it or on the package, so I’ll quote a photo of the box:
')
The measured ripple factor was 13%, the power factor was 0.64. Not bad. Let's see how this is achieved.
The plastic lens is removable easily.
Under it we see a matrix of eight half-watt diodes, an aluminum part screwed on a millimeter thickness.
I must say that getting to the driver turned out to be incredibly difficult, since this same aluminum part was pressed into the aluminum glass in the manner of a tin can (and welded?). Yes, in fact, the case is also almost entirely aluminum, plastic is only the top layer. I had to use an abrasive disc and metal shears.
To the question of why when using an abrasive disk you need to wear safety glasses
In general, the design is very durable, strong, and, I would say, anti-vandal. Thick aluminum surely removes heat well.
The driver was eventually removed:
It looks very difficult. I understood the order of time how it works, and did not believe my eyes for a long time. What do you think, which of the previously considered topologies corresponds to this driver?
The correct answer is no. A very unusual solution for LED lamps has been applied here - in fact, this is a ballast for compact fluorescent lamps, adapted for LEDs. Apparently, this was done to reduce the cost of reconfiguring the production line and changing the procurement scheme of the components — they used what is already being purchased by millions.
Technical details for those interested
Fluorescent lamps in terms of power requirements are quite similar to LEDs - they also need to stabilize the current. Kanonichno as the ballast for them used inductance coil. However, in the last article we already figured out that, in general, the inductor inductance for the range of currents, frequencies and voltages we are interested in is obscenely large. However, it can, in principle, be reduced due to the fact that the reactance of the coil increases with increasing operating frequency. Thus, if we transform the network 50 Hz into several tens of kilohertz, it will be possible to do with inductance in the region of several milligenres. That is exactly what they do in compact fluorescent lamps.
The traditional driver circuit of a compact fluorescent lamp, with some variations found in 90% of cases, consists of a rectifier, to which a converter is connected, which is a self-generating half bridge. A gas-discharge tube is connected to this structure through the choke, and everything works happily.
The driver of the lamp in question is made exactly the same, but instead of a gas-discharge tube there is a block with LEDs (indicated by 1).
I didn’t draw up the whole scheme, for illustration I just took the base from the Philips reference design . Judging by the details on the board, the coincidence in this part, if not 100%, is at least very large.
Here is the copied part of the scheme, corresponding to the block "1":
On the thyristor D6, a protection node is assembled in case of a break in the chain of LEDs (so that C2 does not explode). It would be possible to simply put C2 at a higher voltage (400 V), but this, firstly, is more expensive, and, secondly, the capacitor of the same capacity, with the necessary voltage, has much larger dimensions.
The traditional driver circuit of a compact fluorescent lamp, with some variations found in 90% of cases, consists of a rectifier, to which a converter is connected, which is a self-generating half bridge. A gas-discharge tube is connected to this structure through the choke, and everything works happily.
The driver of the lamp in question is made exactly the same, but instead of a gas-discharge tube there is a block with LEDs (indicated by 1).
I didn’t draw up the whole scheme, for illustration I just took the base from the Philips reference design . Judging by the details on the board, the coincidence in this part, if not 100%, is at least very large.
Here is the copied part of the scheme, corresponding to the block "1":
On the thyristor D6, a protection node is assembled in case of a break in the chain of LEDs (so that C2 does not explode). It would be possible to simply put C2 at a higher voltage (400 V), but this, firstly, is more expensive, and, secondly, the capacitor of the same capacity, with the necessary voltage, has much larger dimensions.
The solution is very clever from the point of view of the compromise “production optimization / parameters”, but still in the sense of the LED mode and efficiency is not the best. Well, from the point of view of circuit engineering philosophy, it is somehow strange.
So that the article is not too short, let's look at something else. In general, from more or less similar I had until now only Gauss 3W. Judging by the inscriptions on the package, this lamp is also positioned as the equivalent of a 40 watt incandescent lamp. Item on the box - HA105201103.
Formally, it’s not quite correct to put them near - this three-watt Gauss has an E14 base and is generally declared as decorative. However, if you click on the link written on the box, you can read that the variants of this lamp for the E27 base also seem to be available .
Speaking of decorative
Since in this lamp there are point sources of light, being screwed into the ceiling with a pattern, it, unlike the matte ones, will give the curly shades loved by many, such as:
(photo courtesy of my friend).
Who knows, maybe it’s declared as decorative that’s why it’s a completely traditional form, and there’s no other kind of decorative bias.
(photo courtesy of my friend).
Who knows, maybe it’s declared as decorative that’s why it’s a completely traditional form, and there’s no other kind of decorative bias.
The measured ripple factor is about 1%, the power factor is about 0.6.
To disassemble the lamp, I barbarously otkovyryal base.
As it turned out, doing this was not at all necessary. See the thread on the plastic part? She gets out. That is, the lamp can not only be disassembled, but also painlessly assembled. She maintainable!
In part of the driver no surprises. Inside there is a flyback converter based on the MT7952 (just the case when the current is controlled on the primary side).
Inclusion, apparently, typical.
On the board is visible electrolytic capacitor brand BERYL . Not Rubycon, but still not bad . The operating time of such capacitors to failure, as stated , is about 10,000 hours at temperatures of the LED lamp. What pleases, it is located in the colder part, closer to the base. In general, electrolytic capacitors are one of the determining factors for the durability of LED lamps, so if you believe the figures given in the link above, this lamp has every chance to work happily ever after. The only thing that may cause concern is the heat dissipation from the LEDs. Nevertheless, judging by the heating of the case, it is also more or less in order with it (the “stamens” on which the aluminum LEDs are sealed, this is MCPCB ).
In general, today we saw two decent lamps. Philips, however, was astonished at the driver’s decision, but his parameters are quite good (pulsations 13%, cos (φ) is about 0.6), and the quality of the design itself is excellent, as it should be for a brand of this level.
The lamp from Gauss is just a good lamp (pulsations 1%, cos (φ) is also around 0.6). Standard circuit design, moderately high quality components. But for my taste, its main feature is maintainability. This is in my memory the first lamp, which can not only be disassembled, but also assembled. For example, it is possible within the DIY framework to solder a capacitor when it does dry.
Source: https://habr.com/ru/post/363917/
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