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Old 1st February 2013, 09:25 AM   #151
dadod is offline dadod  Croatia
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Quote:
Originally Posted by keantoken View Post
The BC3x7 has a much larger die, so more thermal inertia and less thermal modulation. This is the theoretical basis for its improvement on quality. However it is much slower than the BC560C and while either of these will probably keep measured distortion pretty low, it was my experience in listening tests that the speed of the BC5xx is more important for a small-signal circuit.

At frequencies where R3 and R12 are bypassed, the effectiveness of the J1 CCS will not matter. At DC it will however.

For transient performance, compare the AC current through Q1 and Q2. Lower is always better. Multiply this current by the output impedance and you have a metric for the quality of regulator load response. With this metric you'd find that many regulators have fantastic output impedance but poor transient load response.

You need to consider inductance in absolute terms. Viewing output inductance against the backdrop of output resistance will just show you the proportion of the two. Compare the actual output inductance value to the real inductance of a cm of wire; how many virtual cm of wire does your regulator have?

Same for output resistance. How does it compare to the resistance of the PCB traces? How does the output resistance compare to the standard trace size used for carrying currents of this magnitude?
Kean, we are no dealing with rocket science here, this looks to me to mutch to go so dip in to PCB traces resistance/inductance.
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Old 1st February 2013, 12:45 PM   #152
smms73 is offline smms73  Portugal
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.model BC327-40 PNP(IS=2.077E-13 NF=1.005 ISE=1.411E-14 NE=1.3 BF=449.8 IKF=0.36 VAF=29 NR=1.002 ISC=2.963E-13 NC=1.25 BR=20.92 IKR=0.104 VAR=10 RB=40 IRB=1.00E-05 RBM=5.3 RE=0.14 RC=0.32 XTB=0 EG=1.11 XTI=3 CJE=5E-11 VJE=0.9296 MJE=0.456 TF=7E-10 XTF=3.25 VTF=2.5 ITF=0.79 PTF=80 CJC=2.675E-11 VJC=0.8956 MJC=0.4638 XCJC=0.459 TR=3.50E-08 CJS=0 VJS=0.75 MJS=0.333 FC=0.935 Vceo=45 Icrating=500m mfg=Philips)

.model BC337-40 NPN(IS=7.809E-14 NF=0.9916 ISE=2.069E-15 NE=1.4 BF=436.8 IKF=0.8 VAF=103.6 NR=0.991 ISC=6.66E-14 NC=1.2 BR=44.14 IKR=0.09 VAR=14 RB=70 IRB=2.00E-04 RBM=8 RE=0.12 RC=0.24 XTB=0 EG=1.11 XTI=3 CJE=3.579E-11 VJE=0.6657 MJE=0.3596 TF=5E-10 XTF=2.5 VTF=2 ITF=0.5 PTF=88 CJC=1.306E-11 VJC=0.3647 MJC=0.3658 XCJC=0.455 TR=2.50E-08 CJS=0 VJS=0.75 MJS=0.333 FC=0.843 Vceo=45 Icrating=500m mfg=Philips)


Thanks for the files.
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Old 1st February 2013, 03:12 PM   #153
smms73 is offline smms73  Portugal
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Dado, I gave a quick look at your power supply and it has a very low output impedance indeed, I have to look better, congratulations.
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Old 1st February 2013, 03:31 PM   #154
dadod is offline dadod  Croatia
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Originally Posted by smms73 View Post
Dado, I gave a quick look at your power supply and it has a very low output impedance indeed, I have to look better, congratulations.
Thanks, but what I did is just to change a bit Borbely(and Salas) shunt regulator.
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Old 1st February 2013, 04:13 PM   #155
bcarso is offline bcarso  United States
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It is simple to get that graph, but my question was about practical experience. I think that 2SK170 should be of GR type.
My point in showing the graph: you can use its data (derive the slope of the curve at your particular operating point) to validate or invalidate your sim model.

If the impedance of the real 170 is too low, one option is to run with two of them, that is, two I generators, with each off of the opposing rail. Make sure to clamp each base-emitter junction with a diode to prevent excessive reverse voltage under a fault condition.

Or, short of that, you could use DMOS parts with a few volts of threshold in place of the bipolars. Unfortunately the low frequency noise will usually be higher, and the transconductance lower, compared to the bipolars. Candidates if used might be the ZVN3306 and ZPN3306.
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Old 1st February 2013, 07:39 PM   #156
smms73 is offline smms73  Portugal
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Default Mirror bjt

This is the my circuit with mirrors , the distortion (10khz)is :
0,000029% at 4V p-p out.
0,000069% at 8V p-p
0.000219% at 16V p-p.

I must say i never have made a circuit with mirrors with distortion that low.
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Old 1st February 2013, 07:57 PM   #157
smms73 is offline smms73  Portugal
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Default Mirror FET

this is with fets at the input

0.000223% at 4v p-p out
0.000447% at 8v p-p out
0.000897% at 16v p-p out

S
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Old 1st February 2013, 08:07 PM   #158
smms73 is offline smms73  Portugal
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this is the frequency response. It seems very stable

The gain is 12db
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Old 1st February 2013, 08:17 PM   #159
smms73 is offline smms73  Portugal
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Using the "B" type of current mirror gives 0.000029%
The "A" type give 0.000125%

A good improvement.
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Old 1st February 2013, 08:20 PM   #160
dadod is offline dadod  Croatia
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Nice circuits, but with 20(19) transistors and you need output buffer too.
Could you post spice files for both(with all models you used), I would like to make some simulation with.
By the way, I am still playing with the shuntreg to see if I can make it better without more transistor added.
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