Review: KD 7135 V2 drivers 3040/2280/1520 mA with mode configuration

Flashlight Modding and DIY Parts
1

KD 7135 V2 drivers 3040/2280/1520 mA 8 modes

Reviewer's Overall Rating: ★★★☆☆

Summary:

Size: 17mm
Voltage: 2.5-4.5V
Regulation
 Linear Regulator
Current: 3040mA
Modes: 8 groups selectable
Price Paid: $4.79
From:

Kaidomain

Pros:

  • Well regulated and efficient driver
  • Has memory (enabled by soldering)
  • Has 3-level groups low-med-high and high-med-low
  • Has a very high PWM frequency giving a steady light
  • Has a sort of low voltage protection

Cons:

  • Low mode is far too low, only glowing
  • Memory kicks in 0.5-1 sec after switching on (would prefer after switch off)
  • Selection of groups and memory involves soldering
  • Can only be used with 1 Li-Ion cell due to power dissipation

KD 7135 V2 drivers 3040/2280/1520 mA 8 modes

Reviewer's Overall Rating: ★★★☆☆

Summary:

Size: 17mm
Voltage: 2.5-4.5V
Regulation
 Linear Regulator
Current: 3040mA
Modes: 8 groups selectable
Price Paid: $4.79
From:

Kaidomain

Pros:

  • Well regulated and efficient driver
  • Has memory (enabled by soldering)
  • Has 3-level groups low-med-high and high-med-low
  • Has a very high PWM frequency giving a steady light
  • Has a sort of low voltage protection

Cons:

  • Low mode is far too low, only glowing
  • Memory kicks in 0.5-1 sec after switching on (would prefer after switch off)
  • Selection of groups and memory involves soldering
  • Can only be used with 1 Li-Ion cell due to power dissipation

2280mA version here

1520 mA version here

Features / Value: ★★★★☆

Mode Groups

The 8 groups are as follows:

1. default (no solder blobs): Low(glowing) - Medium(35%) - High(100%) - Low(glowing) - Medium(35%) - High(100%) -Strobe(10Hz) - Blink(2Hz) - SOS(slooow) - Beacon

2. High(100%) - Medium(35%) - Low(glowing) - High(100%) - Medium(35%) - Low(glowing) - Strobe(10Hz) - Blink(2Hz) - SOS(slooow) - Beacon

3. High(100%) - Medium(35%)

4. High(100%) - Strobe(10Hz)

5. Medium(35%) - High(100%) - Blink(2Hz)

6. High(100%) - Medium(35%) - Blink(2Hz)

7. Low(glowing) - Medium(35%) - High(100%)

8. High(100%) - Medium(35%) - Low(glowing)

The Beacon mode is 2 sec on - 10 sec off.

The SOS mode is super slow (12 sec signal, 8 sec pause).

The PWM frequency (for low and medium) is very high at 15000 Hz.


Mode switching

The KD 7135 V2 has four soldering pads (numbered S4,S3,S2,S1 from left to right) on the bottom side to select mode groups by applying a solder blob connecting one or more of the pads to the corresponding ground pad.

[EDIT]: Beware of the schematics on KD's site. It is faulty for the last 4 modes. KD's site seems to be corrected now.

the mode selection should be:

1: no solder blobs

2: connect S2 to ground with a solder blob.

3: connect S2 and S3 to ground with solder blobs.

4: solder blobs on S2, S3 and S4

5: solder blobs on S3 and S4

6: solder blob on S4

7: solder blobs on S2 and S4

8: solder blob on S3

Mode Memory

This can be selected by applying a solder blob at S1. The mode memory snaps in about 0.5-1 second after a mode switch. I normally prefers memory after switch-off so I do'nt have to tap twice to shift level.

Build Quality: ★★★★★

Seems to be fine (like NANJG drivers). In fact I don't know which brand this is. The circuit board is marked: L3AD4S TM. But it should withstand normal soldering with a fine tipped soldering iron.

The MCU is without marking but is connected like a PIC12F629. So home programming is not as easy as for the ATtiny13 (BLF project by Tido).


Battery Life: ★★★☆☆

Linear regulators with 7135 devices normally are well regulated and efficient. At lower battery voltages the drive becomes direct with a very little loss. The high current is hard to the battery and demands a quality type battery (low internal resistance). The driver is not suited to use two LiIon cells as it will become too hot (4 additional Watts has to be dispersed for each ampere drawn). The low voltage protection is activated at 2.9 V where the current draw jumped from 0.69 A to 0.13 A. This is still a much too high current draw from an un-attended battery at 2.9 V. At 2.65 V the current draw was down to 10 mA. The MCU itself draws about 2 mA.

Current Output: ★★★★★

The output current of 3.04 A is fine to drive the XM-L fully but I would prefere to remove a few of the 7135 with a heat gun and use them as cheap spare parts.

The driver has no boost capability so it must be expected that the output falls at lower battery voltages where the drive becomes direct with no regulation.

The driver comes complete with a (rather thin) red and a black lead to connect to the LED.

Summary: ★★★☆☆

This driver could have been the answer to many peoples prayers regarding drivers with its low-med-high and high-med-low modes without blinking modes, but the glowing Low is a deal breaker. There is the possibility to make a two level (100% - 35%) light though and the choice of memory or no memory is very fine. But compared to the late NANJG 105C I have to withdraw a star for the unusable low and the hard-to-reprogram MCU.

2

Is the current really 3040mA? I mean they are the same AMC7135 chips as with the Nanjg 105C.

3

Look at this datasheet.

Some manufacturers sort the 7135's in bins. I have a NANJG 105 with 7135's marked "35V". This stands for 350 mA.

You can see on the picture of the KD V2 driver that the 7135's are marked "38K". This is the 380 mA bin.

4

Seems promising..

very interesting how you can actually set the modes yourself!
But I guess you shouldnt have shaky hands to do this..

all on a diameter of 17mm... wow

5

I understand.

Mine have 35S and 35B. I've seen aslo 35V, 35W. And on this driver they are 38K.

Sorry to ask this again, but have you actually got that 3040mA reading?

6

You do the same on the Nanjg 105C, set the modes yourself or even write new ones in the Atiny chip.

Actually I do not find useful the blink modes or the crowded modes on this driver.

7

Thanks for the review, sixty545!

Do you think it can work well with 3xAA configuration, as in the MCU-C88? Most likely Eneloop or Energizer Ultimate batteries.

The medium-high-blink mode could make a perfect keep-in-car flashlight, but if the low isn't too low to read a map, the default mode could also be great for this use.

8

Writing new ones in the Atiny chip? sounds complicated!

at least looks like you need to have more tools than the usual screwdriver and solder iron

9

You don't need more tools, just the corrent tool. There's a whole thread going on for a year now, only regarding that matter. https://budgetlightforum.com/t/-/744

The same soldering iron for changing modes on the Nanjg 105C, you need also for this new driver available on KD. You don't need a screwdriver :)

10

I could only get 2Amps from my equipment because of resistances in battery, leads and switch. But I am confident that the driver will deliver the full current when build into a flashlight. I checked the ratio between high and mid by observing the waveform in mid mode with an oscilloscope. It gave me about 33% (specs said 35%). The current waveform in low was really ugly, just some thin spikes at 15000 Hz resulting in a current of 5 mA of which the MCU uses 2 mA.

11

Sorry for the basic question but I want to drive a XPE R2 at close to 2 amps so can I use the 2280mA and simply unsolder one of the 7135 chips to give approx 1930mA? TIA.

12

Thanks for the reply sixty545.

I asked that becasue you know how specs are in general, they need to be tested. Even though the 7135 "35" chips have been proved until now, these are new and not proven yet.

2A it's pretty low so far. Hopefully someone mounts it in a flashlight and we'll get a "in the field" reading of the current.

13

That can be done, the resulting drive current will be 2280 - 380 = 1900 mA. I think I would choose the 1520 mA type as it is not a very easy task to remove a chip if you have not tried it before and the benefit of driving the XPE that hard is little. It can be done thougt with a heat gun with a small nose and pliers or with a medium big soldering iron, but it is easy to overdo the heating.

14

Awesome info. I had no idea these were binned...does each get tested individually?

Do you have any sources for the bare chips by chance?

Thanks for the review.

15

If you really want 2A it might be easier to just grab some of these.

16

Thanks guys, I'm not worried about giving it a try with the soldering iron and I quite like the user selectable modes so I'll give it a go.

17

Mine came the other day , got the 2A and 3A ones ..

Certainly look interesting ..

18

Id be most interested to know if the 3A versions actually test out at 3A. Do you plan on installing one soon? Are your 7135's also marked as "38K"?

Ive got my fingers crossed for this one. Lets hope it performs as expected.

19

What is that part on the left side of the solder pads? It is missing on one of my drivers.

20

That's a decoupling capacitor for the µC to stabilize it's power supply.

Probably works without it.