They do have a current path to ground always, its their shunt element. As long as the sinking is plenty enough to take all the Wattage (CCS current*Vout) during standby without any load to share it, all will be well. As a rule of thumb don't have >65C long term on the output sink in any circumstances. If you got a DMM with K thermocouple or some thermogun do check out the fins temperature during standby. To evaluate the thermals and decide if some reg needs any more sinking area.
If you are going to utilize two wire connection use 16 AWG. If you are going to utilize four wire connection you can use 20 AWG for the force pair and shielded coax like RG174 or twisted UTP for the sense pair (to utilize two wire connection you need to short F+ to S+ and F0 to S0 right at the output connector)
I did not know of the calculator. Found it and ran some number through it.
I should be good with a a 4k resistor and trimpot of at least 3k, so I'll go with 5k.
Thanks for pointing me to the calculator, nice tool!
The calculator is attached to post1 of this design Thread.
But be careful. It is not protected at this time.
Salas,
could you unprotect the data entry cells and then protect each of the sheets, making the "select unprotected cells" option active.
For normal operation that leaves the whole sheet protected from damaged formulae. Particularly useful for users not familiar with speadsheets.
If you leave the passwork blank (no entry), then each user can turn the protection off if they need access to the cells.
But be careful. It is not protected at this time.
Salas,
could you unprotect the data entry cells and then protect each of the sheets, making the "select unprotected cells" option active.
For normal operation that leaves the whole sheet protected from damaged formulae. Particularly useful for users not familiar with speadsheets.
If you leave the passwork blank (no entry), then each user can turn the protection off if they need access to the cells.
Had a proper look at the sslv calcultor.
Nicely done.
It makes all my hand calculation so much easier.
There is an error in D101 voltage. The calculation ignores a non zero value for the Zener.
I would like to suggest an "improvement".
At the power dissipation we see Q101 and Q106, when there is a load current still passing.
How about a third display showing the required heatsink for a combined sink on the two transistors?
And an option to reset the output current to zero to see the worst case combined dissipation (or add a note suggesting that the output current be set to zero to see this worst case condition).
This worst case condition should not damage the regulator (q106 runs very hot) and when the load is reconnected all should cool and return to normal.
There is another worst case condition:
Output shorted.
Again this can be set up manually by changing the appropriate input fields. The CCS Q101 will run very hot. Again it would be nice to see the worst case temperature and know that the CCS remains undamaged and survives until the short is removed.
Nicely done.
It makes all my hand calculation so much easier.
There is an error in D101 voltage. The calculation ignores a non zero value for the Zener.
I would like to suggest an "improvement".
At the power dissipation we see Q101 and Q106, when there is a load current still passing.
How about a third display showing the required heatsink for a combined sink on the two transistors?
And an option to reset the output current to zero to see the worst case combined dissipation (or add a note suggesting that the output current be set to zero to see this worst case condition).
This worst case condition should not damage the regulator (q106 runs very hot) and when the load is reconnected all should cool and return to normal.
There is another worst case condition:
Output shorted.
Again this can be set up manually by changing the appropriate input fields. The CCS Q101 will run very hot. Again it would be nice to see the worst case temperature and know that the CCS remains undamaged and survives until the short is removed.
Shoot....
Ordered the SSLV half a year ago, and since then it´s at home lying there, and me always on the run coz of job. At the moment in Saudi, but comin home at weekend. DI ordered then the minikit for 5-45V.
Does anybody have a BOM for +-15V and 350mA target current (for the Twisted pear legato) ? Would be great!!!
Ordered the SSLV half a year ago, and since then it´s at home lying there, and me always on the run coz of job. At the moment in Saudi, but comin home at weekend. DI ordered then the minikit for 5-45V.
Does anybody have a BOM for +-15V and 350mA target current (for the Twisted pear legato) ? Would be great!!!
The BOM would be individually diversified for transformer choice, R101/201 choice, and voltage trimmer value mainly.
In your situation I would get a 18+18V (two+two wire secondaries) 50VA transformer. I would have the four green CCS Leds all stuffed, start with 6.8R 5W R101 R201 (have 5.6R 5W R201 also because non matched IRF610 can present higher Vgs than IRF9610, you confirm CCS current by measuring voltage drop across the setting resistors and dividing by their value). I would also choose 1K R103/203 and 5K VR105/205. Good luck finishing it.