B3603 DC/DC Buck Converter mini review and how the SET key could be fatal...

[PeterFW]

Since you are doing it without a DMM, you may be doing it wrong.

No worries, i have all the wires in the world hooked up to the thing :-)

Thank you for your reply about the calibration!
The part (F2) about the current reading i have figured out, i have a problem to understand the current regulation (F4).

I calibrate the unit (F2) as you explained, i put the DMM set to DC current across the output and fun through the loops.
The DMM practially "shorts" the output in this case and the power supply runs in constant current mode in wich i calibrate it.

But the F4 function (current regulation) has me a bit stumped, i mean, it worked but i do not know why since i can not adjust it just hit the "SET" button and the unit does... something.
In the F4 calibration i put a resistor on the output, 6.4Ohm/10W in this case, it was the next best one i found.
It shows a current reading and all i can do is to hit the "Set" key and the value changes, the UP/DOWN keys have no function.
This way i run though the loops with the OK key for the HIGH and LOW reading.

Greetings,
Peter

[JonyBC]

Hi Guys. I have some problem also with the Calibration, most problaly the Unit.

I was powering it with a step up Buck converter from 5v to 40v, and maybe i overvoltage it >40v, not really sure, and around the same time, I shorted the converter pins and now its getting hot and all, problaly dead.

But i tested the Voltage regulator on the side and it was fine.

the next day, it wake up all crazy, the Regulation itselft if i use a DMM is good. be it Voltage or Current i externally measure the exact set values.

But the readings on the unit are way off. always 10v and 0 amps (Even after factory reset)

But when i go to Calibrate the readings they read ok, maybe 0.1 off, in V and A, but never acepts the calibration. (Its  always the same offset)

When i Calibrate the Voltage regulation, and save it, it starts to Read the Voltage almost ok  (0.5 to 1V off)

But the Current calibration never changes, It always read my last input when calibrating, But 0 when using.

The Leds however  function OK and it trips the current and voltage at the set value(Measuring with external DMM)

As this ever happened to anyone?

Thanks

[Rick Law]

Hi Guys. I have some problem also with the Calibration, most problaly the Unit.

I was powering it with a step up Buck converter from 5v to 40v, and maybe i overvoltage it >40v, not really sure, and around the same time, I shorted the converter pins and now its getting hot and all, problaly dead.

But i tested the Voltage regulator on the side and it was fine.

the next day, it wake up all crazy, the Regulation itselft if i use a DMM is good. be it Voltage or Current i externally measure the exact set values.

But the readings on the unit are way off. always 10v and 0 amps (Even after factory reset)

But when i go to Calibrate the readings they read ok, maybe 0.1 off, in V and A, but never acepts the calibration. (Its  always the same offset)

When i Calibrate the Voltage regulation, and save it, it starts to Read the Voltage almost ok  (0.5 to 1V off)

But the Current calibration never changes, It always read my last input when calibrating, But 0 when using.

The Leds however  function OK and it trips the current and voltage at the set value(Measuring with external DMM)

As this ever happened to anyone?

Thanks

JonyBC,

I am no EE expert, but I am experienced with the B3603, so see if I can help here...

First, you make sure you are calibrating it right.  If your read-calibration is not correct (first volt/current calibration), the regulation-calibration (second calibration) is meaningless.  Focus on the read-calibration for both V and I first to make sure it is within 2%-ish.  If the B3603 is healthy, it should reach 2% accuracy without too much headache - do it no-load or very very light load (200mA).  If you are 0.5V off after careful calibration, you may have a hardware problem, so read on.


re: "I was powering it with a step up Buck converter from 5v to 40v, and maybe i overvoltage it >40v, not really sure"

Let me understand this, your input to the B3603 is a Buck converter, did I understand you right?  And you might have had input to the B3603>40V, right?

40V is the B3603 max input voltage limit.  Depending on how long and how much over, the B3603 might have been damaged.    The caps are only 50V cheap caps, so 40V is on the high side of the margin already.  Over 40V is not healthy at all!  The operating limit is 36V.

Powering it via a Buck converter is ok, but you are adding noise.  Also you need to watch the power drawn and oscillation.  I have power source that when above a certain current, it (when working with another boost/buck board) really really oscillates!


re: "I shorted the converter pins and now its getting hot and all, problaly dead"

What converter pins?  If you mean the B3603 output, the 3603 should handle it ok if it is brief.  We need to know what pins you mean, and what part got hot.

The B3603 should take the shorting for sub-seconds.  Within sub-second, the B3603 will sense the over-current and drive it down to the current limit.  More than sub-second, and depends on the current-limit setting, something bad might have happened.  It also depends on how you feed the B3603.  Your setup (buck feeding buck), your buck that feeds B3603 input might not have worked well.  When you shorted it, the B3603 draws a lot from your feeder buck circuit.  I may draw so much the feeder voltage collapsed - to a point that the 3603 is not getting enough voltage to operate the controlling electronics.  If so, it is no longer regulating and it would be outputting as much as the supply can give.  That means a lots of current and likely damage might have occurred.


Re: "But the readings on the unit are way off. always 10v and 0 amps (Even after factory reset" & "The Leds however  function OK and it trips the current and voltage at the set value(Measuring with external DMM)"
I understand as "The B3603's LED reads 10V 0mA which is not what you set, but your DMM get around the set voltage/current" Do I understand correctly?  If so, and you have redone your calibration carefully, you have a Hardware problem somewhere... Read on, check the stuff explained below.  You may have killed the XL1509 part and it went on to do some damage.


Some info that may help you debug and see if something is wrong:


Before we start, a quick overview:  (First) The input caps are rated only 50V, much over 40V, you are toasted.  (Second) The B3603 has two voltage regulators connected to the Vin: the LM2596s for the B3603's output and the other one is a XL1509-adj powering the internal electronics.  One or both could be damaged.  If you have a scope (and DMM), look at both the B3603 output and the internal voltage.  To look at the internal, connect to pin12 as negative and pin13 as positive (for pin numbers definition, look at reply#21). The XL1509 output should be 5V.  I would look at that with and without connecting the top board.  A third one is on the bottom-side of the top-board.  This one does not connect to the Vin but instead it draws from the XL1509. 

Since you said the LEDs are not showing the right values, lets see if it is lying or something is passing it bad info.  If it is getting bad info, your ADC part of the circuit may be shot.  The voltages-to-measure (which translates to readings on the LEDs) are amplified by an MCP6002 rail-to-rail Op-Amp.  That op-amp will blow at 6V.  The MCU which does the ADC gets its power after another voltage regulator.  That part should also be checked.  The ADC input (ie: the MCP6002 output) has mapped voltage (the B3603 output volt/current translates to certain voltage as ADC input.)  It should be fairly linear.  Check against that.  Get a few data points and see if it is really linear.  It should approximate:
  Real output voltage = ADCinputVolt*slope + intercept
  Real output current = ADCinputVolt*slope + intercept

Doesn't matter what the slope and intercepts are, you can check for if it is linear.  An output increase of 1V say from 5volt to 6volt; that) should show a delta in voltage for ADC input, that ADC input change for 1volt output change should be very very close to the same delta when you increase output from 6volt to 7volt and very very close to if you increase output from 7 to 8volt.


So, test 1:

Look up the pin definitions (described above) and test to see if the OpAmp is feeding something linear to the MCU's ADC.  Test both the volt and current's translated voltage.   For the right pin to tests, look up the reply with the pin definition described above.

If that linear relationship (described above)  is not holding, your OpAmp part of the circuit is not well.  If your XL1509 is feeding it right (ie: good and clean output at pin12 & pin13, read on for more details), your  OpAmp needs a replacement.


Test 2, is the XL1509 (part of the circuit) healthy:

If you see the B3603 output with noise level like the one I posted in the OP, you are at best marginal.  If you see the internal 5V with noise like reply#173, your XL1509 (part of the circuit) is not well.  If you don't have a scope, may be you can catch that with the DMM reading jittering.  A scope would show the info much better.  When I did the OP, I did not realize my XL1509 was probably marginal.  It later blew the display LED so I begun debugging.  It was then I realized the bad XL1509 (part of the circuit).  Post repair, the Vout noise dropped by 1/3.  If you see internal electronic noise level that high, and the internal voltage is NOT below 5% of 5V (preferrably within 1-2%), you need to look at that part of the board.

Note: I said  "XL1509 (part of the circuit)" because it may not be the XL1509 itself.  In my case described in reply 173, it was the inductor!

See what we get so far.  Make sure proper calibration then see if both the B3603 and the XL1509's output are well.

Good luck.  Keep us posted.

Rick

[JonyBC]

Hi Rick Law.

First of all thanks for your detailed Reply 


- - Let me understand this, your input to the B3603 is a Buck converter, did I understand you right?  And you might have had input to the B3603>40V, right?

Yes Exactly that, The more i think about it. I´m Almost sure  i overvoltage it, Somehow i had the idead of 40v tops and not 36v, and then i gave it even more...


- Powering it via a Buck converter is ok, but you are adding noise.  Also you need to watch the power drawn and oscillation.  I have power source that when above a certain current, it (when working with another boost/buck board) really really oscillates!

I was doing it for some time also. And was perfectly fine for me. I was mostly using it to Charge Car battery with a powerbank, And triggering all shorts off automotive stuff, with great sucess, Until i got greedy i mean.

- What converter pins?  If you mean the B3603 output, the 3603 should handle it ok if it is brief.  We need to know what pins you mean, and what part got hot.


Sorry for the confusion. I shorted the Output of the Step up converter while connected to the input of the B3603, And now the Step up converter it works ok for a minute, But then starts jumping the temperature and consumption until it stops working.

I checked no Fault in the B3603 at that time, All seem normal, only a day after it went crazy.

-  The B3603 should take the shorting for sub-seconds.  Within sub-second, the B3603 will sense the over-current and drive it down to the current limit.  More than sub-second, and depends on the current-limit setting, something bad might have happened.  It also depends on how you feed the B3603.  Your setup (buck feeding buck), your buck that feeds B3603 input might not have worked well.  When you shorted it, the B3603 draws a lot from your feeder buck circuit.  I may draw so much the feeder voltage collapsed - to a point that the 3603 is not getting enough voltage to operate the controlling electronics.  If so, it is no longer regulating and it would be outputting as much as the supply can give.  That means a lots of current and likely damage might have occurred.



So its not really a good idea to power it only with 5v? it may work but if i shorted and it come down to 3 volts it may get to that condition right? I think the powerbank circuit cuts off before, but its always good to know, Thanks. I have use this before, for fooling a control unit into thinking the B3603 was a Sensor output.  and it worked great, No considerable current in this situation.

- I understand as "The B3603's LED reads 10V 0mA which is not what you set, but your DMM get around the set voltage/current" Do I understand correctly?  If so, and you have redone your calibration carefully, you have a Hardware problem somewhere... Read on, check the stuff explained below.  You may have killed the XL1509 part and it went on to do some damage.

Yes Exactly Everytime i do a Factory Reset, The readings are always the same 10v 0mA it doenst matter the settings or output current.

But if i forget about the readings and use external reading, Everything works fine.

No matter how many times i try to do the Read (V and A) calibration Its always Off a little and it nevers changes. But strange think is while calibrathing the Read function, The B3603 Manage to Read  and not while normal operating.

 Anyway. If i do the Voltage Regulation Calibration (That by the way  its Way off like 20v off) I have do do it maybe 4 times. Then the Voltage reading starts working almost normal (0.5 V off)

Now the current Regulation, its strange, Let me try to explain. I start the calibration.

- It starts with the low setting 200 mA, on the external DMM its ok but on the B3606 it says 2 AMPS
 and then i press down like a milion times(Normal for this unit i guess) and i get to 200 mA and set it.

- After it starts the high setting (Not sure now if its 2Amp or 1 but i will say 2) on the external DMM it read  ok
 But now on the B3606 it says 200mA or the set value that i input before for the low set, So milion clicks after i get to 2Amp and set it.

-It comes again to the low Setting. Once Again  the external DMM reads 200 mA but the B3606 as 2Amps on screen.

And I think this cycle never stops. I have tried 3 cycles and always the same.

I will try to do the test´s that you said.

Once again Rick thanks for your reply 

[iglesigu]

Hi, very good review of the B3603.
I have received one, the last week,but when I tried to adjust the output voltage below 1 volt , it return to 2.16 Volt.
Somebody have the same problem. I need voltage below 1 volt but I can't get it.
Thank you for any advice

[Rick Law]

Hi Rick Law.

First of all thanks for your detailed Reply 


- - Let me understand this, your input to the B3603 is a Buck converter, did I understand you right?  And you might have had input to the B3603>40V, right?

Yes Exactly that, The more i think about it. I´m Almost sure  i overvoltage it, Somehow i had the idead of 40v tops and not 36v, and then i gave it even more...


- Powering it via a Buck converter is ok, but you are adding noise.  Also you need to watch the power drawn and oscillation.  I have power source that when above a certain current, it (when working with another boost/buck board) really really oscillates!

I was doing it for some time also. And was perfectly fine for me. I was mostly using it to Charge Car battery with a powerbank, And triggering all shorts off automotive stuff, with great sucess, Until i got greedy i mean.

- What converter pins?  If you mean the B3603 output, the 3603 should handle it ok if it is brief.  We need to know what pins you mean, and what part got hot.


Sorry for the confusion. I shorted the Output of the Step up converter while connected to the input of the B3603, And now the Step up converter it works ok for a minute, But then starts jumping the temperature and consumption until it stops working.

I checked no Fault in the B3603 at that time, All seem normal, only a day after it went crazy.

-  The B3603 should take the shorting for sub-seconds.  Within sub-second, the B3603 will sense the over-current and drive it down to the current limit.  More than sub-second, and depends on the current-limit setting, something bad might have happened.  It also depends on how you feed the B3603.  Your setup (buck feeding buck), your buck that feeds B3603 input might not have worked well.  When you shorted it, the B3603 draws a lot from your feeder buck circuit.  I may draw so much the feeder voltage collapsed - to a point that the 3603 is not getting enough voltage to operate the controlling electronics.  If so, it is no longer regulating and it would be outputting as much as the supply can give.  That means a lots of current and likely damage might have occurred.



So its not really a good idea to power it only with 5v? it may work but if i shorted and it come down to 3 volts it may get to that condition right? I think the powerbank circuit cuts off before, but its always good to know, Thanks. I have use this before, for fooling a control unit into thinking the B3603 was a Sensor output.  and it worked great, No considerable current in this situation.

- I understand as "The B3603's LED reads 10V 0mA which is not what you set, but your DMM get around the set voltage/current" Do I understand correctly?  If so, and you have redone your calibration carefully, you have a Hardware problem somewhere... Read on, check the stuff explained below.  You may have killed the XL1509 part and it went on to do some damage.

Yes Exactly Everytime i do a Factory Reset, The readings are always the same 10v 0mA it doenst matter the settings or output current.

But if i forget about the readings and use external reading, Everything works fine.

No matter how many times i try to do the Read (V and A) calibration Its always Off a little and it nevers changes. But strange think is while calibrathing the Read function, The B3603 Manage to Read  and not while normal operating.

 Anyway. If i do the Voltage Regulation Calibration (That by the way  its Way off like 20v off) I have do do it maybe 4 times. Then the Voltage reading starts working almost normal (0.5 V off)

Now the current Regulation, its strange, Let me try to explain. I start the calibration.

- It starts with the low setting 200 mA, on the external DMM its ok but on the B3606 it says 2 AMPS
 and then i press down like a milion times(Normal for this unit i guess) and i get to 200 mA and set it.

- After it starts the high setting (Not sure now if its 2Amp or 1 but i will say 2) on the external DMM it read  ok
 But now on the B3606 it says 200mA or the set value that i input before for the low set, So milion clicks after i get to 2Amp and set it.

-It comes again to the low Setting. Once Again  the external DMM reads 200 mA but the B3606 as 2Amps on screen.

And I think this cycle never stops. I have tried 3 cycles and always the same.

I will try to do the test´s that you said.

Once again Rick thanks for your reply 

(1)  The input is rated for 6V to 40V.  The over 40V could be the cause of your problems.

(2)  Supplying the B3603 with 5V is marginal.  The XL1509 cannot give out 5V when the input is 5V, so your on board electronics are under-powered.  Best to follow the designed minimum of >=6V.

(3)  The "condition" is load-caused Vin drop is not related to 5V in per-se.  It could happen even if Vin is >6V.  Some power supply just drop the voltage if the current draw is exceeded, and it doesn't care that the B3603 needs 6V.  Once when say it drops to well below the B3603's needs to operate, it is "temporary brain dead" and just let whatever can flow through the system go through.

(4)  You said "Now the current Regulation, its strange, ... and then i press down like a milion times(Normal for this unit i guess) and i get to 200 mA and set it. ..."

Yeah it is hard to operate.  During regulation calibration, it display the "real" current.  Once you press up/down to change, it display your "modified" current.  Then, a short time later, it go back to "show real current."  And it also seem to purposely ignore your key press.  I think there is a timed-ignore in there to stabilize the regulation/display.  It is very frustrating.  You have to press up/down long enough for the B3603 to see it, and not so long that it goes to "auto repeat" and it goes up tens of clicks instead of just the one click you might have intended.

(5) You said "...setting 200 mA, on the external DMM its ok but on the B3606 it says 2 AMPS..."
The calibration current for LOW is 0.200A and for HIGH is 1.200A.  If you see 2A, your calibration for the current-display is not right or the ADC/opAmp is not well.

(6) You said "Yes Exactly Everytime i do a Factory Reset, The readings are always the same 10v 0mA it doenst matter the settings or output current."

Make sure you save (F5) your new (hopefully correct) calibrated reading.  Once you saved it, it will start with your calibrated reading.  That it doesn't have a good factory-reset reading is annoying, but the factory-reset value really doesn't matter if you saved your better calibration.

[Rick Law]

Hi, very good review of the B3603.
I have received one, the last week,but when I tried to adjust the output voltage below 1 volt , it return to 2.16 Volt.
Somebody have the same problem. I need voltage below 1 volt but I can't get it.
Thank you for any advice

I can regulate down to 0.09V.  At that low count, the accuracy is not great (next click is not 0.10 but 0.12) but it does regulate down to that low.

Since you just received your unit, perhaps it is operator error.

There are two ways to set Voltage regulation:
1. HOT - while voltage is already being output
   While the voltage is being output and being displayed on the LED,
   Pressing UP/DOWN changes the regulated output voltage.
   This method does not save the setting.  It lasts only until you power-off.
2. COLD - voltage is not ON (no volt out)
   While voltage is is on, press SET, now it goes COLD with no voltage coming out.
   Press UP/DOWN to set a voltage, [edit: I missed a step here]
   Press SET to accept this voltage, the display should show 4 dashes.[end edit]
   Press OK to save and being output.
   This method saves the setting.  This voltage setting survives the power off[/b].

Try both and see if that is the confusion.  By the way, HOT and COLD are my words.  You wont find that in manual.  I just find HOT/COLD being good words to describe and highlight the differences with the two modes.  Amperage setting also have the exact HOT/COLD change modes.

[iglesigu]

Thank you rick,
I tried what you say, but when I fixed in "Hot" the display go down but after a sec, it increase at a minimun of 2.7 volt. In "cold" i did the same, but when the voltage go out the voltage increase again.
Y have already both two of this, but I have the same problem. Could be another problem?
thank you again

[Rick Law]

Thank you rick,
I tried what you say, but when I fixed in "Hot" the display go down but after a sec, it increase at a minimun of 2.7 volt. In "cold" i did the same, but when the voltage go out the voltage increase again.
Y have already both two of this, but I have the same problem. Could be another problem?
thank you again

Sorry, I missed a step.  (I also edited the post prior so it doesn't confuse others)

Try COLD again:

2. COLD - voltage is not ON (no volt out)
   While voltage is is on, press SET, now it goes COLD with no voltage coming out.
   Press UP/DOWN to set a voltage, [edit: I missed a step here]
   Press SET to accept this voltage, the display should show 4 dashes.[end edit]
   Press OK to save and being output.
   This method saves the setting.  This voltage setting survives the power off[/b].

[iglesigu]

Thank you again Rick,

I did as you said. In both devices (i have bought two) .I saved the voltage (ie, 1 Volt), but when the voltage come out (switch ok), the display goes up to 2.71 v. (and also the voltage, I could measure it with a voltimeter) Then,  when I click set (the voltage output is off, the display show the initial value 1 .00 v again.
It happened with two device and thus is the doubt I have?. Two device are wrong? or I am making a mistake. May be the microcontroller can not have a feedback of the output?
One thing, when I connect a resistor, ie 1000 ohm, the voltage and the display show the preset voltage.
thank in advance.

[Rick Law]

Thank you again Rick,

I did as you said. In both devices (i have bought two) .I saved the voltage (ie, 1 Volt), but when the voltage come out (switch ok), the display goes up to 2.71 v. (and also the voltage, I could measure it with a voltimeter) Then,  when I click set (the voltage output is off, the display show the initial value 1 .00 v again.
It happened with two device and thus is the doubt I have?. Two device are wrong? or I am making a mistake. May be the microcontroller can not have a feedback of the output?
One thing, when I connect a resistor, ie 1000 ohm, the voltage and the display show the preset voltage.
thank in advance.

I wonder if it is different board version.  I have another B3603 that is of a different board layout.

Stay tuned.  I will check all my B3603's - I got two of one board layout and one of another layout.

I am busy with another project at the moment, so I can't mess around with my "bench" setup for now.  I will try tomorrow and update you.

[Rick Law]

Ok, I can confirm that all three of my B3603 units regulated down to 0.1 volt quite well.  Two of my units are of the same board design while my first one (unit 3) is of a different board design.

For a look at how those units looks different, refer to reply #180 here:
https://www.eevblog.com/forum/reviews/b3603-dcdc-buck-converter-mini-review-and-how-the-set-key-could-be-fatal/msg654541/#msg654541

Unit 1 and unit 2 are presumed later (numerically larger) serial number, and within 10 of each other.  They have black inductor and green capacitors.   Unit 3 is the one with white inductor and black capacitors.  It is presumed older serial number (numerically smaller) but it was my first purchase.

iglesigu, try this exact process and see what you get.  If you do not have 0.1ohm and 500ohm pot, just use a resistor 100ohm to 500ohm, anywhere around there.  See if the output volt is around 100mV.  Also, look at my pictures in reply 180, see if your board looks different.  Let me know...

Test Details:

I connected the B3603 to a 0.1ohm current sense resister in serial with a 500ohm VR.  The 500ohm pot allows me to alter the current.  A DMM is connected to the 0.1ohm (1mv=10mA) to monitor the current so I have a reading outside the B3603's own sensor, and my UT61E measuring the output voltage.

Load:

Omitting wire and connection point resistance, at minimum load, it is 500ohm+0.1ohm and maximum load is 0.1ohm.

B3603:
All three units are set up the same way.
- Connect Unit to power supply, turn on without output connection
- Press SET to change voltage, press UP/DOWN to 00.10 (Volt) and
   then Press SET again to save the voltage setting at 00.10
- After a brief four dashes [----] display, now voltage is saved (to survive power off)
  and the unit displays 00.10.
- Press SET again now it display X.XXX (note decimal position).  X.XXX is my current,
  If it is between 500mA to 1.000A, it is low enough, I just press OK and just begin.
- If it was > 1A, I just lower it to between 0.500 to 1.000, press SET again to accept.
- Now press OK for it to go HOT (ie: output the voltage), connect that to my resister+vr in serial.

B3603 - unit 1 (Serial ending 72)

Minimum load 0.1V unit display: 0.09V/0mA, DMM displays: 94mV/0mA
Maximum load 0.1V unit display: 0.09V/47mA, DMM displays: 86mV/47mA
** Power off and restart
0.1V is saved properly, unit with 0.09V display
Vout is +- 2mV Current is +- 2mA of DMM.

B3603 - unit 2 (Serial ending 60)

Minimum load 0.1V unit display: 0.10V/0mA, DMM displays: 97mV/0mA
Maximum load 0.1V unit display: 0.10V/52mA, DMM displays: 96mV/55mA
** Power off and restart
0.1V is saved properly, unit with 0.10V display
Vout is +- 1mV
Current is +- 1mA of DMM.

B3603 - unit 3 (Serial ending 58)

Minimum load 0.1V unit display: 0.09V/0mA, DMM displays: 104mV/0mA
Maximum load 0.1V unit display: 0.09V/53mA, DMM displays: 97mV/54mA
** Power off and restart
0.1V is saved properly, unit with 0.10V display
Vout is +- 1mV
Current is +- 1mA of DMM.

[iglesigu]

Thank you,
I did all step. The two b3603 have white inductor as you can see in the picture.
I have tested with two resistor only, 470 ohm and 3.3 ohm

B3603 - unit 1

Minimum load (470 ohm)0.1V unit display: 0.12V  /0 A, DMM displays: 71 to 79 mV(oscillating) / 0.15 mA
Maximum load (3.3 ohm) 0.1V unit display: 0.14V/0.011 A, DMM displays: 130 to 139 (oscillating)mV/ 12.33 to 12.54 (oscillating mA

B3603 - unit 2

Minimum load (470 ohm)0.1V unit display: 0.13V  /0 A, DMM displays: 65.2 to 70 mV(oscillating) / 0.14 mA
Maximum load (3.3 ohm) 0.1V unit display: 0.14V/0.012 A,    DMM displays: 60 to 103 (oscillating)mV/ 11.90 to 13.87 (oscillating mA


thank you

[Rick Law]

Great!  It looks like the procedure got your units pass the 2.71V you were stuck on and they regulate down to 0.1V.

I would not worry about that small oscillation when the voltage is that low.  The noise you pick up from the environment is a larger factor when you are measuring that low.

How is the DMM verses B3603 readout for higher voltage?  Good enough?  Looking at your readings, hard to tell at that very low voltage (hence expected high error), but it does look like you could get some benefit out of carefully re-calibrating the darn things.

Even while the 4-button 4-led UI is awful, the B3603 is a nice little job!

[iglesigu]

Thank you RicK,

I just tested in a friend´s device (b3608) more current. But when I fix the voltage in 0.1 V (100 mV), and press out (ok) without charge (resistor) the display of the unit keep the voltage on 0.1 and not 2.7 V like the others b3603) I have, that is ok?

[Rick Law]

Thank you RicK,

I just tested in a friend´s device (b3608) more current. But when I fix the voltage in 0.1 V (100 mV), and press out (ok) without charge (resistor) the display of the unit keep the voltage on 0.1 and not 2.7 V like the others b3603) I have, that is ok?

(Bold added to pin point specific words in quote)

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Wait..  From your post quoted above [May 10, second reply after my test], you are saying that your unit displays 2.7V, where as, from this May 9 post quoted below [first reply after my test], you have the voltage display in the 0.1V range.  (I added the bold+underline)

Is it displaying 2.7V or 0.1V (about)?

Your first (May 9) reply quoted below are in the 0.1V range and agrees with your DMM.  So it indicates all is well.   If it is like your second reply above, DMM has around 0.1V and your unit has 2.7V, your unit needs re-calibration.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Thank you,
I did all step. The two b3603 have white inductor as you can see in the picture.
I have tested with two resistor only, 470 ohm and 3.3 ohm

B3603 - unit 1

Minimum load (470 ohm)0.1V unit display: 0.12V  /0 A, DMM displays: 71 to 79 mV(oscillating) / 0.15 mA
Maximum load (3.3 ohm) 0.1V unit display: 0.14V/0.011 A, DMM displays: 130 to 139 (oscillating)mV/ 12.33 to 12.54 (oscillating mA

B3603 - unit 2

Minimum load (470 ohm)0.1V unit display: 0.13V  /0 A, DMM displays: 65.2 to 70 mV(oscillating) / 0.14 mA
Maximum load (3.3 ohm) 0.1V unit display: 0.14V/0.012 A,    DMM displays: 60 to 103 (oscillating)mV/ 11.90 to 13.87 (oscillating mA


thank you

[iglesigu]

Thank,
to summarize, I am  a little muddled.
 
without pressed ok (no voltage output) the unit display show any value. (i.e 1 v). But when I press ok button (output voltage) without any load, its going from 1 v to 2.7 v and stay there ( problem only if the fixed voltage is below 2.7 v)  The DMM display the real final voltage (2.7 v).
This not happen when I put a load as I said in previous test with R=480 ohm and lower.
The unit and DMM display the correct value.
thank

[Rick Law]

Thank,
to summarize, I am  a little muddled.
 
without pressed ok (no voltage output) the unit display show any value. (i.e 1 v). But when I press ok button (output voltage) without any load, its going from 1 v to 2.7 v and stay there ( problem only if the fixed voltage is below 2.7 v)  The DMM display the real final voltage (2.7 v).
This not happen when I put a load as I said in previous test with R=480 ohm and lower.
The unit and DMM display the correct value.
thank

Since you tried it on your friend's B3603 and it did 1V properly, so your unit is failing in someway.  Interesting that it only fail when it is without external load and it appears to work with external load.  I would however not trust that to regulate properly without thoroughly testing it first.

It may be interesting to know at what external load does it begin failing, but that would be just for curiosity as fixing it would not be a simple tasks.

[iglesigu]

Thank Rick,
By the way my units have black botton while my friend unit is red. My be it have a different chip?
I will try to do an scanning  of some value of load and post it.
thank again

[Rick Law]

Thank Rick,
By the way my units have black botton while my friend unit is red. My be it have a different chip?
I will try to do an scanning  of some value of load and post it.
thank again

New thought: Your calibration for regulation is way way way way off.  It is possible that the offset is so far off what it should be so when it asks for 1V, it is actual 2.7V.  It looks like your sensing/display calibration is ok since it matches your DMM.  See what it generates when you regulate it to 30V, 20V, 10V, 7.5V, 5V, 3V.  If your regulation is way way way off, you should see it particularly when you hit 7.5V down to 3V.

If so, try recalibrating.  You need a 36V power source. 33V-ish will do, but nearer to 35V-36V is better.  40V is max, but I would not go that near the limit.

Good luck!

By the way, a new chip is possible, but I rather doubt it.

[hobby16]

Hi all,
Thank you all for the thread and the good read that helped my work a lot.
Coming a bit late to this thread but I have finished a new user interface for the B3603. I've been able to squeeze into the module's STM8S003FS all the necessary functionnalities :
- use of a rotary encoder as input interface (no pushbutton), with acceleration sensing
- floating point calculation
- conversion ADC -> volt, amp using degree 3 polynomials (of course, an affine conversion is also possible with x^3 & x^2 coefficent = 0)
- floating point first degree filters
- calculation & display of power (AxI), mAh & Wh
- uart interface for data logging with Tx at 9600 bds
- sampling period for logging from 1s to 100s
- datalogging of input voltage also
- a console with Rx to accept basic commands : voltage & amp setpoint setting, polynomials coefficient change for calibration, output enable/disable
- the unused pin 8/con1 is used as an output for controlling an external fan when current is above a (changeable) threshold
- setpoint values, Wh & mAh and parameters are store in eeprom and restored automatically at power-up

With datalogging, the B3603 module is not only a PC controllable power supply, it can also be used to datalog voltage and current of an external supply.
The performance is as stated by other users above, amazingly good (when you set the output voltage to 10.00V, the real voltage will be 10.00 !). With a good user interface (which the original version does NOT have), the module is now really usable. I've used it to test leds, motors, charging battery...
The nice thing is that since it can be recalibrated by the end user using an ascii console (a process that can be automated by scripting), you can essentially get the best accuracy in the interval you wish.

I will post a video to show how the rotary encoder has made the user interface really really user-friendly. More documentation and pictures will come. I'll keep the firmware proprietary for the moment.

About the weird wiring of the pushbuttons in the original schematics, it is a multiplexing scheme to scan 4 buttons using only 2 I/O. Here is how it works, for forumers who want to get back to programming the STM8S :
button OK : PC7 = in pullup, PD1= out 0V, read PC7=0 => pressed
button UP : PC7 = out 0V,    PD1 = in pullup, read PD1=0 => pressed
button SET: PC7 = in pullup, PD1 = in pullup, read PC7=0 => pressed
button DN : PC7 = in pullup, PD1 = in pullup, read PD1=0 => pressed

I have connected the rotary encoder to the button and used sucessfully the same scanning scheme to read the encoder (see wiring diagram). The scanning is fast enough to manage the encoder acceleration (if it is turned fast enough, each step will be +- 10 instead of +-1). With acceleration sensing, it's much easier and faster (and imho funnier) to make big changes, for example from 3.30V to 25.00V.

About the voltage surge at power-on mentionned above, I was very concerned but I personnaly have NOT seen it. I've order 5 more modules, I'll check it again to be sure it won't ever be a problem.

[dc2]

Hi hobby16,

thats really great news 
I have been following this thread for a while now, hoping that somebody could complete a new, fully functional firmware.

Are you planning to release the firmware somewhere? I'm really keen on trying it out myself 

[flywheelz]

Great review and amazing details about the product and a schematic  .  I went with the bigger brother B3606 and its the same design.  What is different is it uses the XL4016 instead of LM2596 and TI 272C op amp in place of one MCP6002. 

Few days ago I needed to test 30v zener.  Stupidly  I supplied 48v to the device and saw the LCD flash for a second and that was the last of it.

What I've found so far:
bottom board

• XL4016 - DEAD - VIN shorted to SW OUT - cost $1.71 for 1
• XL1509 - DEAD - SW OUT shorted to GND - cost $1.68 for 5
• MCP6002 - DEAD - VCC shorted to GND - cost $2.13 for 10
• TI 272C - no shorts, unknown if works - cost $1.08 for 1

top board

• 2 x 74HC595 - DEAD - VDD shorted to GNDD - cost $0.50 for 10

Surprisingly the 3.3v regulator and stm8s003f3 on the top board I think survived.  I see 1.93khz signals on pin 4 and 5 of connector and it changes duty cycle on both.  The OK and CC leds turn on as well.

This mistake costed me $7.10 so far.  Hopefully parts from various aliexpress sellers arrive and functional.  I will give an update in time.

Update:

• 09/05/16 - Changed both 74HC595's on the top board and the LCD started working now.  Waiting for more parts to arrive for the bottom board.
   
• 09/21/16 - Replaced XL4016. Ordered the wrong XL1509-5.0E1 instead of XL1509-ADJ.  I did end up using the XL1509-5.0E1 (had to remove r16/r17 and short r17 pads) to get 4.98volts.  Ti 272c hasn't showed up yet so I installed MCP6002 in its place and replaced the other MCP6002.  The unit is back to life .  However the display is showing ~10mA more that actual.  Perhaps need calibration but I will wait for Ti 272c first.  I was lucky the MCU survive the over voltage since the original firmware is not available.
   

[dan_bitsy]

never mind fgot it,

[Rick Law]

Great review and amazing details about the product and a schematic  .  I went with the bigger brother B3606 and its the same design.  What is different is it uses the XL4016 instead of LM2596 and TI 272C op amp in place of one MCP6002. 

Few days ago I needed to test 30v zener.  Stupidly  I supplied 48v to the device and saw the LCD flash for a second and that was the last of it.

What I've found so far:
bottom board

• XL4016 - DEAD - VIN shorted to SW OUT - cost $1.71 for 1
• XL1509 - DEAD - SW OUT shorted to GND - cost $1.68 for 5
• MCP6002 - DEAD - VCC shorted to GND - cost $2.13 for 10
• TI 272C - no shorts, unknown if works - cost $1.08 for 1

top board

• 2 x 74HC595 - DEAD - VDD shorted to GNDD - cost $0.50 for 10

Surprisingly the 3.3v regulator and stm8s003f3 on the top board I think survived.  I see 1.93khz signals on pin 4 and 5 of connector and it changes duty cycle on both.  The OK and CC leds turn on as well.

This mistake costed me $7.10 so far.  Hopefully parts from various aliexpress sellers arrive and functional.  I will give an update in time.

Update:

• 09/05/16 - Changed both 74HC595's on the top board and the LCD started working now.  Waiting for more parts to arrive for the bottom board.
   
• 09/21/16 - Replaced XL4016. Ordered the wrong XL1509-5.0E1 instead of XL1509-ADJ.  I did end up using the XL1509-5.0E1 (had to remove r16/r17 and short r17 pads) to get 4.98volts.  Ti 272c hasn't showed up yet so I installed MCP6002 in its place and replaced the other MCP6002.  The unit is back to life .  However the display is showing ~10mA more that actual.  Perhaps need calibration but I will wait for Ti 272c first.  I was lucky the MCU survive the over voltage since the original firmware is not available.
   

(Something must be wrong with notification)  I just got to read this today!

The 10mA extra seems like something re-calibration can easily deal with.  If you have to play with that part of the circuit, perhaps it is a good idea to swap out the current sense resister with a better one?  I changed mine with better temp-co.  Not worth doing it just for the slight improvement, but if you are already messing around there...

Did you check the noise?

That darn thing is pretty robust.  I too had to change out the guts (due to shorting) of the one of my 3603.  XL1905, the inductor and capacity for the XL1905, pair of 74HC595, pair of MCP6002.  Initially, I did not change the caps with the XL1905.  It fired back up and needed a re-calibration before the reading reads correctly.  I suppose variation with the mcp6002 is to blame.

It also came back to life with a bit more noise.  After changing the caps and inductor, the noise went back down to similar to my other two units.