BLF17DD
This driver is an open source driver that uses direct drive. It uses a high power transistor, making it possible to drive high current through the led(s).
The processor used is a Atmel Tiny13A and it is possible to use same software as the typical 7135 driver.
The driver can be ordered as a unpopulated circuit board or a fully mounted board with firmware in the microprocessor, depending on where you order it.
The reference thread for the driver can be found here.
For the fully populated board is sold by Ledsmoke on BLF in EU, in US you can get it from mtnelectronics.com
Because it is fairly easy to change the firmware, you might get another firmware than I tested with. This can affect modes, user interface and options.
Measurements
Tested with Cree XM-L2 led
Driver diameter 17.0mm
Driver height 5.5mm without spring
Driver is direct drive with pwm regulation
Pwm frequency 14.3kHz
User interface is a bit special: A single off/on will not change mode, it has to be two off/on.
Default the driver has mode memory, but it can be removed with a solder link.
Modes are: (moonlight), low, medium low, medium high, high.
Moonlight is optional, it requires a solder link to enable.
Modes can be reversed with a solder link.
Moonlight mode is 3.4% pwm
Low mode is 5% pwm
Medium low is 15% pwm
Medium high is 38% pwm
High does not have any pwm
DC resistance in driver is 24mOhm measured from spring tip to the end of the supplied led wires at 3.5A (This will depend on transistor used).
Because the driver uses pwm, power and efficiency is only correct in high mode
High
I did not go higher than 3.9 volt, there my led had 6A through it. Being direct drive the brightness will never stabilize, but follows the battery voltage.
The driver steps brightness down at about 2.9 volt.
The driver has a very low power loss, because it is direct drive without any series resistor.
No pwm at high.
The runtime on high is limited, the driver steps brightness down after two minutes to medium high.
When I increased the voltage from a low voltage, the driver did remember that last mode was high, but due to the low voltage it reduced the output and keeps it at a low setting. It would not increase brightness when the voltage was high enough for it (This is perfectly fine).
Medium high
The current is lower in this mode, but remember that it is a pwm driver, it is still pulsing above 6A or more through the led (Notice I have increased the voltage to 4.2 volt).
Driver voltage is average voltage, this makes the power calculation invalid.
Led voltage is average voltage, this makes the power calculation invalid.
The pwm frequency is 14.3 kHz with 38% pwm.
All the bumps in the curve are mostly due to my equipment.
Medium low
Driver voltage is average voltage, this makes the power calculation invalid.
Led voltage is average voltage, this makes the power calculation invalid.
The pwm frequency is 14.3 kHz with 15% pwm.
Low
Driver voltage is average voltage, this makes the power calculation invalid.
Led voltage is average voltage, this makes the power calculation invalid.
The pwm frequency is 14.3 kHz with 5% pwm.
Moonlight
The moonlight mode is not very different from low and it is a very bright moonlight.
Driver voltage is average voltage, this makes the power calculation invalid.
Led voltage is average voltage, this makes the power calculation invalid.
The pwm frequency is 14.3 kHz with 3.4% pwm.
Conclusion
This driver looks like a good driver for high power direct drive lights. With all the possibilities for modifications, it can be adapted for many different requirements and wishes. Want another set of modes or another user interface, just replace the program in the microprocessor (both dealers I have listed at the top will help with it).
Notes
The driver was supplied by BLF user Ledsmoke for review.
How do I test a led driver
List of all tested drivers
LEDs are not very efficient when PWM driven at 6A or more. Isn’t it?
No, this driver is for making very high power lights, where you want to get as much current as possible through one or more leds.
For more moderate use, the last driver I reviewed is much better: https://budgetlightforum.com/t/-/27995
Great review HKJ…thanks
BLF DD drivers are for pushing the light to it’s maximum…recommended to have LED’s on copper direct thermal connection stars and have VERY good thermal management.
The beauty is due to ingenious coders (I only assisted in the tweaking of the design and layout of the boards for V1.0 ), the lights automatically throttle from a WIDE OPEN (turbo) to a lower current flow PWM mode automatically (to prevent overheating and damage to the emitter)
This way you have a full bore wide open barn burner that will step down at a pre-determined time frame.
Thank you for the review :-)
What PWM values were used in that firmware?