Hi P-A,
I have started populating the SSR01 board that I bought from you and I have some questions that I think you can answer in a second (I know that it would take me hours to figure it out myself.......).
1) On the silkscreen there are two different indications (thin and fat line) for the position of the Vref and I assume they are there because of the different pinnings of the LM431 and LM329. Which go where?
2) Which are the resistors corresponding to R8, R9 and R7 on the JSR03/05? (question taken from our e-mail communication).
Your reply:
R7 -> R12
R8 -> R7, R8, P1
R9 -> R10, R11
The best thing you can do is to print out both of the schematic and compare.
3) From the BOM for the 5V supply I understand that the voltage is set by R8 and R11 (both 1k). R7 is shorted and P1 and R10 open.
If I want to fine tune the output voltage using a pot at P1 I should/could:
a) Leave R7 and R8 open and mount a pot at P1.
b) Leave R8 open and use a a fixed resistor (R7) and a pot (P1) in parallel to set the desired voltage.
c) as in a and b, but shorting R8 in stead of leaving it open?
Did I get something right here or am I entirely off?
Thanks for a very nice layout,
Nic
1 the figure is the LM431 of the VR1.
2, 3) I have both schematic and BOM's for 12 variants but not published yet. You can get these working copies for the time being.
a) R8 must be shorted!
b) R8 must be shorted!
c) ...
The feedback is a voltage divider and you must make sure current can flow from output of the regulator via the feedback network down to ground. The net FB (see the schematic) MUST have a resistance to ground AND to the regulator output. R8 may never be omitted.
If you want to trim the voltage:
1) R7 + P1, R8(wire)
2) R7 + P1, R8(resistor)
3) P1, R8(resistor)
I'll recommend you to avoid having R8 = wire since the gain then can be near 1 which is not good. The gain should be 1.5 or more but max 10.
Finally I found the time to build the SSR01 supply. To avoid problems I followed precisely the BOM for a 5V supply (BOM-ssr01r0(5V, LM431)).
However, in stead of the expected 5V I get 3.02V....
I have checked and double-checked all component values and placing. All in full accordance with the BOM.
The red LED's lit up (DZ1 somewhat brighter than H1).
Any help would be appreciated.
Thanks,
Nic
What is your input voltage?
What is the voltage across the LM431?
Do you have the J1, J2, the sense connections shorted?
Any results?
Sorry for the late reply. I did not solve the problem but got a JSR03 to do the work :)
The sense connections are shorted.
9-18V input voltage (tried various, but it makes no difference).
1.23V over LM431.
Thanks,
Nic
Voltage at:
pin 7, 6?
pin 2, 3?
I have now a very detailed picture over the board in various output voltages and 5 V is one of them. I will publish them next week.
pin 7, 6 = 4.19V
pin 2, 3 = 0.26V
I hope it means more to you than to me :?
Thanks,
Nic
Measure these voltages with repect to ground. I want also to know the voltage across collector emitter of D44H11. Should be 2.5 V if the LM317 is working properly. You are sure the both the sense shorted to output and ground?
Pin2 = 1.51V
Pin 3 = 1.23V
Pin 7 = 5.33V
Pin 6 = 1.13V
col/emi = 2.52V
Both sense pads on PCB shorted with solder blob.
Any idea?
Nic
Pin 2 voltage should be less than pin 3, otherwise the regulator won't start. Do you have the LM431 mounted in the right position, the fat outline? How have you connected the REF pin to the CATHODE?
The LM is mounted correctly.
Having a look it seems that the ref connects to R15 under the underside of the PCB (in accordance with the BOM). The cathode connects to R14 (47R). The other end of R14 connects to R15, R16 and R17, but none of these are present (again in accordance with the BOM). In fact, it looks a little bit unconnected.........
Nic
Is the REF really connected via 47 ohms the cathode? What is the voltage at REF and the cathode?
The voltage vs. GND is the same at REF and cathode (1.23V if I recall). I measure 75R between REF and cathode so it would appear they are connected like that. Are you suggesting that I may have a short somewhere?
The reference is a LMV431IZ (Farnell code 9486259).
This is the wrong type. It's a low voltage type, 1.24 V but you can still use it. Take 10k + 10 k as feedback, then you'll get 2.5 V from it. You may also check the datasheet for the IC. Did I suggest this reference or have I written the wrong article number?
I will try to find out the origin of this component. I don't think it is a problem in your end as I did not have to buy any new components for this build (the component list is pretty much identical to the one for the JSR03). However, I don't even remember having ever bought this particular reference.....
Thanks.
Nic
This part will work if you set the reference voltage to 2.5 volts.
Ok. Your BOM is correct.
I changed the 1.24V reference with a pin compatible 2.5V ref (TL431CLP) and now everything works (I think). It is still a mystery why I have LMV431 v-ref's around and it might explain a few JSR03 that I never got to work!
Thanks for the support that lead to the solution.
Nic
P.S. I'm not sure exactly how to change the reference to 2.5V so I tried the swap first.
You can change the reference voltage by help from a voltage divider between the REF and anode and REF and cathode. This written in the text for JSR01 and also at the of the datasheet of LM431. There is also some other difference between the regular 431 and the low voltage type. I don't remember what but I think it was the current range.
Sorry P-A, but I had to re-register to get in.
What is the recommended pre-regulation before the JSR and SSR super regulators? Just rectification or maybe something more sophisticated like high-frequency filters etc? Schematics for a (semi)Newbie would be welcome.
Thanks Nic
User Monello is deleted. /Admin
What was the trouble to log in? Both of "you" have been logged in today. I'll prefer one user per person.
The super regulators need 2-3 V more in than the output voltage and with a preregulator you'll need 4-5 V at least. Examples how the circuits can look like can be found in the QRV08, JSR04, JSR06 and QSXPS.
What these 2.2k (R1...R13) & 10k (R5...R14) values (http://ekke.kapsi.fi/temp/.superregu.jpg) are? Schematic have only 1k & 47R for those? Have I missed some documentation? I deleted C14 & C15, won't be using sense, so it's ok?
EDIT: 5V version...
I must fix this. This is something when you create the BOM. I'll get back to you.
Ignore the "LibRef" column.
Thanks, makes sense with the schematic. :-)
Is there any option for bc556c? Or a source for those? Can't find those from Digikey/Farnell/Elfa/eBay.. :|
Is bc557c ok? Same but lower voltage rating?
BC557C is OK if you have max 30 V in. "B" is also OK.
well, I must say these are great little regs, using them to feed a PCM1794A dac and sound seems to have quite noticeably blacker background. 5v reg is stable under load at 4.975 and that is to be expected duie to using a couple of 5% resistors instead of 1%. this means nothing anyway as it is stable and quiet. so at the moment sense wires are shorted under the board, but i'm going to wire them up tomorrow, should the ground and u sense wires shield be grounded at both ends or just floating at the target? obviously the wires should be the same wire used for the load correct?
using silmic II, nichicon FG and vishay MKS, opamp is 825, red LEDs etc. everything pretty much stock on these 2
will I kill the regs using them without a sink at low voltages? the dac is in a cardboard box at the moment for a few more days and I have some slabs of copper coming for the RFB03, but at the moment running with 9vdc in and 5vdc out. not going to be running it much until its cased anyway, but thought I should check in case I kill them while I wait for these bits to arrive. will be using the case for the regs and the slab for the rectifier. going to do something similar to the low noise/low power modified one for preamp
You will kill the regulator if it gets too hot. It's as simple as that. Too hot is above 110-120 degrees C. It's also about life time. High temperature will shorten the life time.
Any replacement for D44H11?
I'm sure there are but the transistor is easy to get. I have those if you are interested.
It should be rather fast, fT=50-100 MHz, 3-5 A, 80-100 V
Quote from: peranders on April 26, 2010, 02:50:35 PM
I'm sure there are but the transistor is easy to get. I have those if you are interested.
It should be rather fast, fT=50-100 MHz, 3-5 A, 80-100 V
Ok, Digikey is out of stock, 1 week lead time, but I'm not in a hurry. Didn't find those from Elfa nor local shop. Farnell and some other places have those, but +7â,¬ postage is quite much for 1â,¬ part.. :)
EDIT: Ahh.. They have other brand in stock.. :)