Charge Pump Issue

[bootsytakes6]

Hello all, first time poster, long time effects DIYer. I've just recently got into doing circuit layouts in Eagle CAD and had a quick question about a charge pump/ voltage reg I've been working on for a Forumvibe project. I made this board from the Charge Pump schematic here: http://www.geofex.com/circuits/+9_to_33.htm and the Voltage Regulator in the Forum Vibe instructions here: http://www.lynx.bc.ca/~jc/ForumVibe.pdf

This is my first time building a board from the ground up, and I'm having some issues with it. I'm not getting the +17V out of the charge pump section when I test it with a 9.24V power source (PP2). Not sure what the problem is, maybe a trace out of place from the schematic, or C1 is oriented wrong, or the IC I chose (TC1044S) isn't a good replacement for the MAX1044. The TC1044 has the same pinout so I thought it may work, and I"ve been staring at the schematic hoping to find a silly mistake but haven't come across it yet. Anyways, here is the layout from Eagle:



Charge Pump Section:

IC1: TC1044S
C1/ C2: 10uF Polarized Electrolytic
D1/ D2: Schottky 1N5817 Diodes

ForumVibe Voltage Regulator Section:

IC2: LM78L15
C5: .33uF 50V Film Cap
C6: .01uF 50V Film Cap

I laid it out so that the +17V from the charge pump feeds right into C5 and the regulator, then exits to the main board via the two pads above C6.

The pads are as follows from left to right:

Ground / +9V IN / +Voltage out to FV board / -Voltage (?) out to FV board

I'm getting 4.78V at pin 2 of IC1, and that gets bumped up to 9.2V after C1. By the time it gets through the diodes I'm down to 8.82V feeding the regulator section :/ Any assistance out there from the gurus?

[.Mike]

I'm closer to a n00b than a guru, but...

I think you are right that C1 is backwards. On the datasheet for the 1044S, Figure 8 (Positive Voltage Multiplier), the negative side of C1 is facing pin 2. On yours, I believe that it is backwards.

Is that the fix? I have no clue... heh.



Mike

[WLS]

I'm closer to a n00b than a guru, but...

I think you are right that C1 is backwards. On the datasheet for the 1044S, Figure 8 (Positive Voltage Multiplier), the negative side of C1 is facing pin 2. On yours, I believe that it is backwards.

Is that the fix? I have no clue... heh.



Mike

Mike, you're right c1 is backwards.

As far as th TC-1044 in place of the Max-1044. I 'll think you'll find it as an excellent choice.

Bill

[bootsytakes6]

Thanks for the replies. I flipped C1 around and still getting the same voltages. hmmm. I'm stumped then unless my layout is incorrect. I've already completed a Neovibe for a buddy of mine which I used a toroidal transformer for the power. I wanted to try something a little different with this FV to keep it more compact and stray away from the wallwart. Sigh....

[ahermida]

Take IC2 out and measure the voltage at C2.  What does it read?

Alf

[Andi]

Shouldn't pin 5 be grounded? That's how the 7660 works.

[Ripthorn]

Is your regulator oriented correctly?  I tried checking a data sheet but it was thoroughly unhelpful.

[solderman]

Hello all, first time poster, long time effects DIYer. I've just recently got into doing circuit layouts in Eagle CAD and had a quick question about a charge pump/ voltage reg I've been working on for a Forumvibe project. I made this board from the Charge Pump schematic here: http://www.geofex.com/circuits/+9_to_33.htm and the Voltage Regulator in the Forum Vibe instructions here: http://www.lynx.bc.ca/~jc/ForumVibe.pdf

This is my first time building a board from the ground up, and I'm having some issues with it. I'm not getting the +17V out of the charge pump section when I test it with a 9.24V power source (PP2). Not sure what the problem is, maybe a trace out of place from the schematic, or C1 is oriented wrong, or the IC I chose (TC1044S) isn't a good replacement for the MAX1044. The TC1044 has the same pinout so I thought it may work, and I"ve been staring at the schematic hoping to find a silly mistake but haven't come across it yet. Anyways, here is the layout from Eagle:



Charge Pump Section:

IC1: TC1044S
C1/ C2: 10uF Polarized Electrolytic
D1/ D2: Schottky 1N5817 Diodes

ForumVibe Voltage Regulator Section:

IC2: LM78L15
C5: .33uF 50V Film Cap
C6: .01uF 50V Film Cap

I laid it out so that the +17V from the charge pump feeds right into C5 and the regulator, then exits to the main board via the two pads above C6.

The pads are as follows from left to right:

Ground / +9V IN / +Voltage out to FV board / -Voltage (?) out to FV board

I'm getting 4.78V at pin 2 of IC1, and that gets bumped up to 9.2V after C1. By the time it gets through the diodes I'm down to 8.82V feeding the regulator section :/ Any assistance out there from the gurus?

Check the layout at the bottom of the PDF. If you follow the layout its gonna Work I have built and verified it.
http://solderman.fatabur.se/TT/TT.pdf
Red=+ V
Yellow=+ 2x V
Green = GND


//Solderman

[solderman]

Hello all, first time poster, long time effects DIYer. I've just recently got into doing circuit layouts in Eagle CAD and had a quick question about a charge pump/ voltage reg I've been working on for a Forumvibe project. I made this board from the Charge Pump schematic here: http://www.geofex.com/circuits/+9_to_33.htm and the Voltage Regulator in the Forum Vibe instructions here: http://www.lynx.bc.ca/~jc/ForumVibe.pdf

This is my first time building a board from the ground up, and I'm having some issues with it. I'm not getting the +17V out of the charge pump section when I test it with a 9.24V power source (PP2). Not sure what the problem is, maybe a trace out of place from the schematic, or C1 is oriented wrong, or the IC I chose (TC1044S) isn't a good replacement for the MAX1044. The TC1044 has the same pinout so I thought it may work, and I"ve been staring at the schematic hoping to find a silly mistake but haven't come across it yet. Anyways, here is the layout from Eagle:



Charge Pump Section:

IC1: TC1044S
C1/ C2: 10uF Polarized Electrolytic
D1/ D2: Schottky 1N5817 Diodes

ForumVibe Voltage Regulator Section:

IC2: LM78L15
C5: .33uF 50V Film Cap
C6: .01uF 50V Film Cap

I laid it out so that the +17V from the charge pump feeds right into C5 and the regulator, then exits to the main board via the two pads above C6.

The pads are as follows from left to right:

Ground / +9V IN / +Voltage out to FV board / -Voltage (?) out to FV board

I'm getting 4.78V at pin 2 of IC1, and that gets bumped up to 9.2V after C1. By the time it gets through the diodes I'm down to 8.82V feeding the regulator section :/ Any assistance out there from the gurus?

Check the layout at the bottom of the PDF. If you follow the layout its gonna Work I have built and verified it.
http://solderman.fatabur.se/TT/TT.pdf
Red=+ V
Yellow=+ 2x V
Green = GND
Square pad is + on Caps and diodes etc Round dot on IC is pin 1



//Solderman
[/quote]

[.Mike]

Shouldn't pin 5 be grounded? That's how the 7660 works.

That's what I was thinking too, but the layout posted by solderman doesn't have it grounded either.

bootsytakes6: I'm wondering, did you just pull C1, flip it around, and fire it up? Or did you replace C1 with a new capacitor? It would seem to me that putting an electrolytic in backwards and then pumping it would destroy the capacitor. My research indicates that it could happen very fast, and could possibly make it a short circuit.

I'm particularly interested in this because I plan on building a few 1044S supplies for submini projects at some point down the road, so I would love to see the solution to this.



Mike

[frequencycentral]

Using a charge pump as a -ve voltage supply, pin 5 is the -ve output and has a cap to ground. But as a voltage multiplier pin 5 in not connected.

http://www.geofex.com/circuits/+9_to_33.htm

http://www.diystompboxes.com/smfforum/index.php?topic=74729.0

[bootsytakes6]

Thanks a mil for all the replies, you folks are great. It was actually something extremely simple and stupid...I got sidetracked last night after I desoldered C1. I turned it around but forgot to solder it back in place, sooooo when I got back to it and tested my voltages the cap was just loose in the hole Can't believe I didn't notice that..Doh! It's always something silly.

The board works great now, I'm getting 13.49V at the + side of C1, 17.89V feeding the regulator section, and a regulated 15.04V to feed the ForumVibe! Maybe I can get it up and running today 

Here's a shot of the completed board for your enjoyment:

[Andi]

Using a charge pump as a -ve voltage supply, pin 5 is the -ve output and has a cap to ground. But as a voltage multiplier pin 5 in not connected.

Must just be the 7660S that needs that then. Don't mind me.

[orangetones]

Have you read this thread?  IT appears that using a chargepump is not wise with the Neovibe/ForumVibe.

Is the TC1044S any different than the Max1044?

http://www.diystompboxes.com/smfforum/index.php?topic=42888.0

[frequencycentral]

Using a charge pump as a -ve voltage supply, pin 5 is the -ve output and has a cap to ground. But as a voltage multiplier pin 5 in not connected.

Must just be the 7660S that needs that then. Don't mind me.

Actually, .Mike pointed out to me by PM that the datasheet shows pins 5 and 6 grounded for voltage doubling. I'm going off R.G.'s schematic, which shows no connection to these pins. I've built quite a few charge pumps now, using multiple doubling stages putting out ~80 volts, I've never grounded those pins. Interesting though, I'm curious about this issue, I'll do a bit of investigation.

[.Mike]

Using a charge pump as a -ve voltage supply, pin 5 is the -ve output and has a cap to ground. But as a voltage multiplier pin 5 in not connected.

Must just be the 7660S that needs that then. Don't mind me.

Actually, .Mike pointed out to me by PM that the datasheet shows pins 5 and 6 grounded for voltage doubling. I'm going off R.G.'s schematic, which shows no connection to these pins. I've built quite a few charge pumps now, using multiple doubling stages putting out ~80 volts, I've never grounded those pins. Interesting though, I'm curious about this issue, I'll do a bit of investigation.

Looking at the datasheets for the MAX and the TC, pin 6 is labeled as "LV." The TC1044S datasheet says it stands for Low Voltage. It apparently should be connected to ground when V+ is < 3.5V:

To improve low-voltage operation, the "LV" pin should be connected to GND, disabling the regulator. For supply voltages greater than 3.5V, the LV terminal must be left open to ensure latch-up-proof operation and prevent device damage.

I would assume it is the same for the MAX IC.



Mike

[frequencycentral]

Looking at the datasheets for the MAX and the TC, pin 6 is labeled as "LV." The TC1044S datasheet says it stands for Low Voltage. It apparently should be connected to ground when V+ is < 3.5V:

Thanks Mike, great info. 

So thats pin 6, but what about pin 5? 

[bootsytakes6]

Have you read this thread?  IT appears that using a chargepump is not wise with the Neovibe/ForumVibe.

Is the TC1044S any different than the Max1044?

http://www.diystompboxes.com/smfforum/index.php?topic=42888.0

I've read it now....never considered that. I didn't notice any differences on the datasheets, but I was mainly looking at the pinouts for the IC to see if they matched up.

So, basically the pump doesn't put out enough current to run the 12V-60mA incandescent bulb in the center of my board? I have a 12V-40mA bulb lying around, but that's too much current too it seems from reading that post.

[frequencycentral]

Have you read this thread?  IT appears that using a chargepump is not wise with the Neovibe/ForumVibe.

Is the TC1044S any different than the Max1044?

http://www.diystompboxes.com/smfforum/index.php?topic=42888.0

I've read it now....never considered that. I didn't notice any differences on the datasheets, but I was mainly looking at the pinouts for the IC to see if they matched up.

So, basically the pump doesn't put out enough current to run the 12V-60mA incandescent bulb in the center of my board? I have a 12V-40mA bulb lying around, but that's too much current too it seems from reading that post.

The LT1054 does the same job as the TC or the MAX, and have the same pinout (I believe), but it puts out 100ma, that should do the job for you. A bit more expensive though.

[orangetones]

The LT1054 does the same job as the TC or the MAX, and have the same pinout (I believe), but it puts out 100ma, that should do the job for you. A bit more expensive though.

Smallbear has the lt1054 for $1.70 and the MAX1044 for $3.50.  So that one is cheaper there!