I would like to make some suggested changes to the circuit although I bet they have already been suggested,
What do you think of lm329?
A lot of pages to get through, hopefully not repeating anything here.
You can't say from Vgs(ON) what will be the Vgs at working drain current in your configuration, but you can use close Vgs(ON) samples that will tend to show close Vgs at other higher Id too. The exact LEDS VF is a matter of predicting the Rset value exactly which is of little practical use. Just have same VF total with ~same Vgs(ON) semis so to have same CCS current.
Ok thanks. I'm dry on 2,1 Vf leds, all my green and yellow go up to max 2,05. Will I be fine with that or do I have to go shop?
Ok. I just noticed that I have 4 led seatings instead of 3 in the paper. Dx02 has an a and a b. Shall I populate them to? With greenies?
At the end of the paper says there was a revision with four places on the second batch so you can use all four or jumper one position and use three. By using all four you get more voltage across Rset so you can find more standard power resistors values in higher CCS settings. The flip side is more dissipation on the Rset but almost everybody uses sturdier Rset than strictly necessary anyway.
Salas do you have a pcb for any of these curcuits?
If not I'll bread board it.
The original circuit with minor tweaks is extremely good.
If not I'll bread board it.
The original circuit with minor tweaks is extremely good.
Must have an old print in my hand. Mine says Dont obsess over matching and selecting LEDS and JFETS. 😀
There are only the 1.1 and the Reflektor-D pcbs from time to time on GB by Tea-Bag. I only got very few personal samples.
There is a Rev2 uploaded for looong time now. About the don't obsess advice, well I should have put an asterisk *skip that line if you can't help it 😀
Hello,
I have a quick question about Salas shunts with intermediate voltage output for a power amplifier input stage. Around 55 Volts (at 20 mA) are neccessary here.
The BiB version doesn´t go high enough (45 V max), the SSHV2 version doesn´t go low enough (100 V min.). Is there a recommended solution for these intermediate voltages (45-60 V) in the Salas-range of regulators?
I already did a search but apparently this voltage range is rarely needed.
Thanks...
I have a quick question about Salas shunts with intermediate voltage output for a power amplifier input stage. Around 55 Volts (at 20 mA) are neccessary here.
The BiB version doesn´t go high enough (45 V max), the SSHV2 version doesn´t go low enough (100 V min.). Is there a recommended solution for these intermediate voltages (45-60 V) in the Salas-range of regulators?
I already did a search but apparently this voltage range is rarely needed.
Thanks...
You can easily increase the voltage of the Salas Shunt reg.
Increase the component voltage ratings.
Check the dissipations of the components.
And increase the reference voltage that gets compared to the output voltage.
60V mosFETs and 63V capacitors will easily do a 50Vdc supply
A 60V supply would probably need to go to 80V, or 100V, components, irf5x0 are 100V rated.
Have a look at Roender's shunt reg for an alternative. There are others.
Increase the component voltage ratings.
Check the dissipations of the components.
And increase the reference voltage that gets compared to the output voltage.
60V mosFETs and 63V capacitors will easily do a 50Vdc supply
A 60V supply would probably need to go to 80V, or 100V, components, irf5x0 are 100V rated.
Have a look at Roender's shunt reg for an alternative. There are others.
The simplest to change its scale is the SSHV2. You just use smaller values for R9 & R10. Say 15K 1W each in your case. Its also a good type for your mA requirements. Bib can be changed also but its a more involved mod.
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