The use of CCS in HT power supplies is well known, however generally misunderstood why it can be a good addition to some circuits. There is an excellent article from Gary Pimm which has been lost and luckily I found it on my archive. Here it is in case you haven’t read it. Worth it as a refresher or for anyone who is new to the subject:
Continue reading “CCS in power supplies”Tag: VR
СГ2С Russian voltage regulator test
Here is a quick test of a russian СГ2С (SG2S) 75V voltage valve regulator:
The CCS is a classic cascoded DN2540 MOSFET. A russian PIO capacitor is bypassing the regulator and the input impedance is the Pete Millet’s interface impedance. HT is a well regulated variable power supply.
When near maximum bias current is achieved (circa 30mA), the noise floor is surprisingly low: -85.5dB / 53uV.
Need to capture input of power supply at the CCS input 🙂
Edit: after measuring the power supply noise level and finding that is near -90dB, came up to the conclusion that the above noise level is the VR noise. Quite good for a simple (but effective) voltage regulator. Gary Pimms used this configuration many times on his designs…
Update
Upon request from Vyacheslav, here is the noise analysis for different current points:
As you can see it’s very linear. There is a 4dB difference between 5mA and 40mA.
Also tested ripple attenuation using a poor-regulated HT power supply. Here are the interesting results:
- 62dB @50Hz
- 80dB @100Hz
