Eurolite LED PAR-16 3CT Review
Mar 29, 2024
This article is a short review of the LED PAR-16 3CT from Eurolite.
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Construction
The Eurolite LED PAR-16 3CT seems to use a standard PAR-16 enclosure and simply adds an LED light source inside. The electronics is split into two different PCB ‒ a power supply and a dimmer.
The power supply
The power supply is a primary-side regulated flyback converter that converts the 230V AC grid power to approximately 42V DC. Being primary-side regulated, the output voltage is expected to vary.
The controller IC's marking is BEVDTF. Unfortunately, I was unable to find the corresponding part number or datasheet for this IC.
Dimmer
The dimmer PCB mainly consists of 3 ICs:
- H5112A from Dongguan Huihai Semiconductor ‒ Constant current led driver
- N76E003AT20 from Nuvoton ‒ 8051-based Microcontroller
- 591N5 marked SOT23-6 package ‒ Buck converter
The constant current converter
The H5112A is a purpose-built constant current driver IC for LED dimming from a company called Dongguan Huihai Semiconductor that seems to specialize in LED driver ICs.
Apart from some marketing material, I was not able to find much information about this IC. Below is, what seems to be, the typical application of this chip:
This picture was found on this website.
The Microcontroller
The used microcontroller is an N76E003AT20 from Nuvoton.
The datasheet can be found here.
LED Assembly
The LED
The used LED is a TX-H1512SW from TYANSHINE. The datasheet can be found here.
Noise
Unfortunately, both the power supply and the dimmer produce audible noise.
On a low setting, the power supply generates a loud audible beeping noise.
On a high setting the LED chip itself, in combination with the dimmer circuit, produces a very well noticeable 4kHz tone. More about this in the measurement section.
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Measurements
Spectrum
The spectrum was measured using an Ocean Optics HR2000+ Spectrometer. The results for the 3 measurements have been normalized to a maximum value of 1000.
Keep in mind that there is only a warm-white and a cold-white LED in this light fixture while the neutral-white setting is a combination of both.
LED Current
Unfortunately, the LED current is not constant at all.
The PWM frequency, for no apparent reason besides the absolute incompetence of the programmer who implemented this, is 4 kHz. In combination with the
Depending on the mode (warm-/cold-white or neutral-white), the PWM duty-cycle is limited to either 50% or 25%.
The plot below shows the PWM signal from the microcontroller (yellow) and the resulting LED current (red) at 100% brightness.
The current ripple itself is 90mA at a frequency of 270kHz.
The switching frequency can be adjusted by changing the resistor between the CS pins (3 and 4) and GND.
I tried a 1 Ohm resistor instead of the original 560Ohm and got a frequency of about 550kHz instead of 270kHz. The output current was unaffected by this change.
I did not find a way to change the current setpoint. It seems that this converter output is constant at 300mA and not adjustable. Therefore, dimming is only possible via PWM, and analog dimming is not supported. I assume this is the reason why the PWM duty cycle is limited to 50% instead of reducing the driver current to 150mA.
Light Output
To measure the light output I used a UNI-T UT383S in a mostly dark room at 1 meter distance.
| Color Temperature | Datasheet | Measurement |
|---|---|---|
| 3000K | 2283lx | 1300lx |
| 4000K | 1788lx | 1500lx |
| 5000K | 2893lx | 1850lx |
I am not sure how accurate my lux meter or test methodology is, therefore I will not comment on the discrepancy. In fact, I am almost certain that my measurements are wrong.
However, one observation I have is that the 4000K setpoint is a combination of 3000K and 5000K at half power each. Therefore, it would make sense that the 4000K light output equals the average of the 3000K and 5000K settings. The datasheet is far off from that., while it is reflected in my measurements.
Power Consumption
The measured power consumption is about 6.6W at a power factor of 0.75. This equals about 9.5VA of apparent power and is in line with the 10W specified in the datasheet.
If I would want to be pedantic about this, I could point out the difference between W and VA and argue that the 10W in the datasheet is inaccurate.
Temperature
After about one hour of operation at about 25°C ambient temperature, the outside of the unit was just a bit warm and could be touched without feeling uncomfortable. Considering the high surface area and low power rating this is not too surprising. Thermals do not seem to be an issue with this device so I decided not to measure the temperature.
In Conclusion
The Eurolite LED PAR-16 3CT is, in principle, a good light fixture for a reasonable price. I paid about 45CHF (≈ 45€) for one.
The mechanical construction and build quality are good. Unfortunately, the electronics and firmware design is not. Not at all. Choosing a PWM frequency inside the audible range and not using a real adjustable constant current driver for dimming is, in a product like this, absolutely inexcusable.
This product is once more an example of a product that would have been great if only the designers and engineers had paid slightly more attention to detail.
If you would like to read about a light fixture that is implemented well, see my article about the Viltrox L132T.
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