#### moderator007

##### Enlightened

- Joined
- Jan 1, 2010

- Messages
- 990

Well after being a member here for couple years I have come to love the knowledge this place possess. So i felt I should contribute part of my knowlege to cpf.

I have been searching a long time for a affordable PWM driver for a double 18650 maglite conversion (2D). I really liked the Dealextreme sku 20330 driver. I have used this driver in various maglite conversions. With a cree xm-l and a 2 paralleled 20330 for a sst-50. Thanks to ma sha1.

Driver details, Its constant current and constant voltage. Works great for 2.5amps for a single 20330 or 5amps for 2 paralleled 20330's from 7.4 volts in. Current can be changed by changing sense resistor marked r100 and r400. They are wired in parallel so it don't matter which one you change or add to. Calculations for output current is .2 divided by the total of the parallel resistors. Use a online parallel resistor calculator to find the total resistance. R100 is .100 ohms and r400 is .400 ohms. So this gives you a total of .o8 ohms. Divide .2 by .08 and you get 2.5 in amps out to the led. So if you want more current you add a resistor or change it out. I add a 1 ohm 1/4 watt resistor to them to give me a little more current. Gives me .074 ohms for 2.7amps. You can keep adding 1 ohm resistors to give you more current. If you add three 1 ohm resistors you get .0645 ohms for 3.125 amps and the driver will handle it. At least mine did! Gets a little warm. I have run lots of test on this driver. On the newer drivers, I have dx replaced the old Schottky diode (ss24) 2 amp with a (ss34) 3amp thats more like it DX.

I have to thank Manne over at dx forums for informing me of the ic's used on this board. All the boards I have ever received from dx had the part id numbers sanded off them. Manne had some that were not sanded off.

The main ic is a 6 pin QX5241 led driver with low and behold a dim input. So find the datasheet (you will have to use google translate) or look here or here look at pin #2 Dim, its a pwm input. All you have to do is unsolder the resistor marked 000. This breaks the connection back to Vcc at pin #4. So the dim pin is low so its turned off. There is a trace on the board that runs from pin#2 to U2 which is empty. If you look under a magnifying glass you can see it. Solder your pwm signal to the thrid pad down on the left where the trace leads to. Manne also helped me find this. I did not see it until i used the magnifying glass.

For the pwm I used a old trusted 555 timer circuit. It can be found here. Its the bottom circuit for leds. ONLY USE everthing to the left of the npn transistor as you are only after the pwm signal. Get the circuit working first, you can use one 5mm led with a series wired resistor just to make sure you have got your pwm circuit right. I didn't have a 50k linear pot so I used a 100k linear pot. The only modification I made was change the resistor r2 (1k) to a 47 ohm. It would not work with the 1k. Update! It may work now with the 1k resistor, now that the Vcc is not connected to dim pin. When i tested this i did not have the Vcc disconnected from pin#2. Which made the 555 timer and the QX5241 fight for high and low. It still worked but is was not the correct way to do it. This is why you remove the 000 resistor.

Yes the 8 pin chip is a fet. (AO4418) look at the datasheet here, this fet can handle upto 30v and 9.7 amps. Most all of the parts on this board will accept higher voltage than 7.4v. If you change the caps on this board for higher voltage ones I think you could go way beyound 7.4v. If you wanted higher current than 3 amps you could change out the ss34 diode for a more amperage one or maybe parallel another ss34. I may get around to testing that one day. 7.4 volts suits me fine right now. To parallel the driver you would have to run another pwm wire from one board to the other. I have not tested it but it should work. Update: Tested two 20330'S in parallel driving a sst-50 at 5 amps. Works perfect with pwm.

Cost of driver (buy 3 or more) plus the other parts under $5.00 depends on were you shop. Time to build it, priceless!I was having fun! I found a electronic parts store online that sells all the parts cheap and ships here in the usa cheap. My order arrived 3 days later. I am in noway affiliated with them. Just trying to help everyone. If its not stepping on anybodys toes here, I will post the site if its okay. Just let me know. Thanks to all that keep this place running.

I have been searching a long time for a affordable PWM driver for a double 18650 maglite conversion (2D). I really liked the Dealextreme sku 20330 driver. I have used this driver in various maglite conversions. With a cree xm-l and a 2 paralleled 20330 for a sst-50. Thanks to ma sha1.

Driver details, Its constant current and constant voltage. Works great for 2.5amps for a single 20330 or 5amps for 2 paralleled 20330's from 7.4 volts in. Current can be changed by changing sense resistor marked r100 and r400. They are wired in parallel so it don't matter which one you change or add to. Calculations for output current is .2 divided by the total of the parallel resistors. Use a online parallel resistor calculator to find the total resistance. R100 is .100 ohms and r400 is .400 ohms. So this gives you a total of .o8 ohms. Divide .2 by .08 and you get 2.5 in amps out to the led. So if you want more current you add a resistor or change it out. I add a 1 ohm 1/4 watt resistor to them to give me a little more current. Gives me .074 ohms for 2.7amps. You can keep adding 1 ohm resistors to give you more current. If you add three 1 ohm resistors you get .0645 ohms for 3.125 amps and the driver will handle it. At least mine did! Gets a little warm. I have run lots of test on this driver. On the newer drivers, I have dx replaced the old Schottky diode (ss24) 2 amp with a (ss34) 3amp thats more like it DX.

I have to thank Manne over at dx forums for informing me of the ic's used on this board. All the boards I have ever received from dx had the part id numbers sanded off them. Manne had some that were not sanded off.

The main ic is a 6 pin QX5241 led driver with low and behold a dim input. So find the datasheet (you will have to use google translate) or look here or here look at pin #2 Dim, its a pwm input. All you have to do is unsolder the resistor marked 000. This breaks the connection back to Vcc at pin #4. So the dim pin is low so its turned off. There is a trace on the board that runs from pin#2 to U2 which is empty. If you look under a magnifying glass you can see it. Solder your pwm signal to the thrid pad down on the left where the trace leads to. Manne also helped me find this. I did not see it until i used the magnifying glass.

For the pwm I used a old trusted 555 timer circuit. It can be found here. Its the bottom circuit for leds. ONLY USE everthing to the left of the npn transistor as you are only after the pwm signal. Get the circuit working first, you can use one 5mm led with a series wired resistor just to make sure you have got your pwm circuit right. I didn't have a 50k linear pot so I used a 100k linear pot. The only modification I made was change the resistor r2 (1k) to a 47 ohm. It would not work with the 1k. Update! It may work now with the 1k resistor, now that the Vcc is not connected to dim pin. When i tested this i did not have the Vcc disconnected from pin#2. Which made the 555 timer and the QX5241 fight for high and low. It still worked but is was not the correct way to do it. This is why you remove the 000 resistor.

Yes the 8 pin chip is a fet. (AO4418) look at the datasheet here, this fet can handle upto 30v and 9.7 amps. Most all of the parts on this board will accept higher voltage than 7.4v. If you change the caps on this board for higher voltage ones I think you could go way beyound 7.4v. If you wanted higher current than 3 amps you could change out the ss34 diode for a more amperage one or maybe parallel another ss34. I may get around to testing that one day. 7.4 volts suits me fine right now. To parallel the driver you would have to run another pwm wire from one board to the other. I have not tested it but it should work. Update: Tested two 20330'S in parallel driving a sst-50 at 5 amps. Works perfect with pwm.

Cost of driver (buy 3 or more) plus the other parts under $5.00 depends on were you shop. Time to build it, priceless!I was having fun! I found a electronic parts store online that sells all the parts cheap and ships here in the usa cheap. My order arrived 3 days later. I am in noway affiliated with them. Just trying to help everyone. If its not stepping on anybodys toes here, I will post the site if its okay. Just let me know. Thanks to all that keep this place running.

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