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I want to set my 2 BP 2.1s to output 14 or so VDC at about 250mA on both to power up some active boards. My question is when testing the shunt points, it is nowhere near the specified 50 to 60mA mentioned in the manual. If someone can post up a better set up procedure that is to the point with a few pics, it would be greatly appreciated.
Thank You
Jack
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Rank: Member
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Set up the modules
Before the first use, the modules need to be adjusted. Do not attach the transformer yet. If you are setting up the Placid BP remember to perform each step at each of the two sides.
1. Adjust VR1 (i.e. VR1A and VR1B for a Placid BP) so the resistance across it is around 500 Ω. This is a safe starting point.
2. If you are using the variable resistors for VR2, adjust VR2 to around 1K Ω.
3. Attach the transformer but do not attach the load yet.
4. Apply power
5. If required adjust the output voltage (VR2) as needed for your application.
6. Adjust VR1A and VR1B to set the CSS current.
7. Power off and connect the load.
8. Apply power
9. Check the output voltage and the shunt current. If the voltage is too low it’s likely the CSS current is too low.
10. Adjust the CSS current so the shunt current is round 50-60mA.
Measuring CSS and shunt current
To measure CCS current measure the voltage between TP-VIN and TP-CCS. The measured voltage is the same as the current being sourced. Example: 250mV means 250mA is being sourced.
To measure the current being shunted measure the voltage between TP-OUT and TP-SHUNT. The measured voltage is the same as the current being sourced. Example: 50mV means 50mA is being shunted.
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This is the correct procedure so lets work with that.
Without load apply power and do:
1. Check Vout equals the desired voltage, if not adjust VR2. Adjust VR2 until you see 14V.
2. Check CSS current by measuring between TP-VIN and TP-CCS. If your load consumes say 200mA you aim is to measure about 250mV (equals 250mA). That leaves 50mA to be shunted.
Power off, connect (dummy) load, power on.
3. Measure Vout. Are you getting less than 14V, DON'T touch VR2. Remember, it's already set for 14V. Instead increase CSS current by trimming VR1 (measure between TP-VIN and TP-CCS) until you see Vout=14V. 2 DMM's comes in handy.
4. When seeing the desired Vout move your test point from TP-VIN and TP-CCS to TP-OUT and TP-SHUNT. Adjust VR1 until you have 50mV.
5. Check Vout.
6. Let it warm up.
7. Check voltages and current.
8. Done.
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 1 user thanked avr300 for this useful post.
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Rank: Member
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Joined: 4/22/2016(UTC) Posts: 11 Location: Sudbury Thanks: 4 times
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Thank You for the reply. With VDC set at 14 and mA at 250 loaded, VDC on all 4 taps is 14 and mA is 250. Testing for shunt, it is at 120mA. When I set the shunt to 50mA, the CSS is down to 180mA with VDC at 14. Is this correct ? I'm supplying 5 dual op amps per BP that consume 150mA or so. Edited by user Saturday, June 18, 2016 4:39:27 PM(UTC)
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Lets see if I can follow you.
With load attached you have 14V out ?
With load attached you have 180mA CSS and 50mA shunted current ?
Correct ?
If yes, then your consumer(s) (the load) consumes 180mA-50mA=130mA
And it looks ok to me.
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1 user thanked avr300 for this useful post.
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Rank: Member
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Joined: 4/22/2016(UTC) Posts: 11 Location: Sudbury Thanks: 4 times
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Thank you for your replies. I have the BP setup down pat now thanks to you avr300. I was lost on how the shunting was done via the manual. It is a rather foolproof way to get the proper juice inline to get the fun stuff cooking. Now to get permanent resistors soldered in. Thanks again Jack Edited by moderator Thursday, July 7, 2016 6:12:30 PM(UTC)
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