Test/Review of 17mm 7135x3 AK47A MCU Dimming 1000mAh 5Mode

Flashlight Modding and DIY Parts
1

17mm 7135x3 AK47A MCU Dimming 1000mAh 5Mode





Driver is from banggood.com

  • Product name: 7135x3 AK47A Circuit Board
  • Model:AK47
  • Size: Board diameter:17mm
  • PCB thickness: 1.2mm
  • Input voltage:3.0v-4.2v
  • The maximum current:1A
  • 2-Mode: Low 10%--High 100%
  • 3-Mode: Low5%--Middle30%-High100%
  • 5-Mode: Low5%—Middle30%—High100%—Strobe---Police Flash—SOS
  • Suitable LED:Single core LED flashlight(white/blue/purple light)




Features:
It’s with reverse polarity protection.
Low voltage indication function. If the voltage is lower than 2.9V-3V, it will reduces the minimum brightness automatically. And will prompt you by flash once a second.
Power supply by Single lithium battery or 3xAA battery. It’s the best when Input is more than Output about 0.2V-1V. This section can be efficient, and can also constant current.

Please note:
The drive current is not higher than the maximum current of LED lamp.




Measurements

The description of this driver is wrong, the software is different
Multi mode linear driver
Tested with Cree XP-G2 led
Diameter: 17mm
Thickness: 3.2mm
The modes are: 10%, 20%, 30%, 40%, 60%, 80% and 100%
The driver remembers last selected mode.
If the driver voltage get below 2.95 volt the driver changes to warning mode.
When the driver goes into warning mode, it stays there until another mode is selected.
Pwm frequency is 4.75 kHz

The percent names I uses for the modes are not entirely accurate, I have rounded them.
For 100% mode power and efficiency calculations are fairly accurate, for all other mode they are only valid above 3.3 volt to 3.4 volt.



100%



Full brightness is depends on the Vf of the led. Warning mode is activated if the voltage drops below 2.95 volt.
As usual with linear drivers the efficiency is best when the battery voltage is only slightly above led voltage.






When the voltage starts at a low value the driver will switch to warning mode and stay there until another mode is selected.



High mode is not without pwm. It is just adjusted very close to 100% on time.



80%








60%









40%









30%








20%









10%









Warning mode



If the voltage gets below 2.95 volt the driver will switch to warning mode and also remember it. In warning mode the light turns off/on shortly each 1.2 second.
To get out of warning mode, do a fast power cycle, this will select another mode.



The pwm is at 10%.



Conclusion

The hardware of the driver works as well as any 7135 driver, but I do not like the program. There is too many modes with to little difference between them and it does not disable pwm at 100% (This is a very minor detail).



Notes

How do I test a led driver
List of all tested drivers

2

Do I miss something? Your headline say: 3A, 5.5-12.6V and the description :

  • Input voltage:3.0v-4.2v, the maximum current:1A

    I have never seen a driver with 7135 chips, which should resist 6V+
3

Sounds like a case of a copy-paste gone wrong.

4

3*7135 is 1050mA

These are pretty decent little drivers if you don't plan on pushing an emitter incredibly hard

And these are single cell only drivers, unless there is a zener on the Vcc pin of the ATtiny on the board

Either way, good review...kinda odd the PWM on 100%

Noone is as thorough as HKJ

Same thing at FT (Nanjg AK-47A)...with better description [quote]

Details:
  • Constant current
  • Each AMC7135 regulator provides 350mA
  • Reverse polarity protection
  • Low input voltage warning: blinks once per second when voltage drops below 2.9V to 3V
  • Perfect for use with 1 lithium battery or 3 AA/AAA batteries
  • Works with Cree R5 T4 T5 T6 U2 MCE, and other similar LEDs
  • PCB height: 1.2mm
  • PCB height (including components): 1.5mm
Mode groups:
  • Selected by connecting one of the four stars to ground (the golden rim of the PCB)
  • Rotate the four stars to the bottom of the PCB:
    • Connect the 2nd star from the left to ground: 3-mode: Lo (5%) > Hi (100%) > Strobe
    • Connect the 3rd star from the left to ground: 3-mode: Lo (5%) > Mid (30%) > Hi (100%)
    • Connect the 4th star from the left to ground: 2-mode: Lo (10%) > Hi (100%)
    • Default (shorting no star): 5-mode: Lo (5%) > Mid (30%) > Hi (100%) > Strobe > SOS

[/quote]

5

Oops.

Correct, or rather a missing copy-paste, I usual starts with a old review as basis and then modify it.

6

Help me understand a thing about driver descriptions —

You write:

“Please note:
The drive current is not higher than the maximum current of LED lamp.”

I think this is a caution about how to use the driver?
I’m reading that as meaning something like

“… this driver goes to 1000, so would push too much current through an LED rated for 700mAh, overdriving it, getting it too hot, reducing its lifetime ….”

(and I know better heatsinking can allow overdriving, and I doubt any of us are going to keep a flashlight around for 50000 hours of use at the rate this stuff improves — I’m just trying to make sure I understand how to match a LED with a driver by the mAh rating number.)

7

That sentence is in specification list that is a direct copy of the sellers specifications, my result and comments are in measurements and conclusion sections.

With a 3x7135 driver the maximum current will be around 1A and it will be safest to use a led rated for 1A or more. You can get away with a led rated for less, if you are very careful with cooling.

8

Very nice test, thx HKJ.

It’s interesting to see that this driver stays in regulation much better than the Qlite, when it comes to low and mid modes.
So Qlite’s 16 kHz is simply too much for a good regulation, but standard Nanjg 4 kHz produces an audible whine. Just can’t have it all. :_(