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???
02/13/06 09:42
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#109827 - issues
Responding to: ???'s previous message
Kai Klaas said:

Q4 provides a soft-start, means a slow turn on of LM338.

I think its due to the RC network connected to the base of Q4. Hence the impedence of the adj terminal towards ground decreases with increase in cap charge.Is it so.

kai klaas said:

by the help of suited feedback, the voltage at output of U2B also appears as voltage drop across R12. This voltage drop is caused by the current of constant current source. Output of U2A controls Q2 and by this Q3, so that the voltage drop across R12 always equals the potential at non-inverting input of U2B.

Is this power dissipation in R12 needed or can i remove it.

Also in the regulator part,
The adj current is equal to the current flowing through the current set resistor - R7(120E). How the power rating could be calculated for this resistor.
The presently running one has a R7=120E/.25W and is working well.

For instance let me assume that the regulator delivers 2A at 6V to the load. for this voltage value, how the power rating of R7 will be calculated.
Terry Lingle said:

(this lacks solution temperature feedback for example)

The temperature of the plating bath will be at 65 degree celsius.
Will this need to be taken into account for setting the current. will the load experience any additional current due to this temperature effect.

Terry Lingle said:

all the 338 circuit does is remove most of the ripple on the input supply and thus improve the current regulation. It also shares the power dissapation with the mje3055.
it dissapates most of its power across the regulators rather than the load.

Is the buck regulator proving main cause of power dissipation?
I would like to know how, more power is being dissipated in the regulators and mje3055 referring to my circuit.

-suresh.

List of 21 messages in thread
TopicAuthorDate
3A constant current source            01/01/70 00:00      
   Where did you find it?            01/01/70 00:00      
   Ripple            01/01/70 00:00      
      plating purpose            01/01/70 00:00      
         I got it from a person known to me            01/01/70 00:00      
            replies            01/01/70 00:00      
               plating circuit            01/01/70 00:00      
                  Compliance of source            01/01/70 00:00      
                     yes            01/01/70 00:00      
         Think about that            01/01/70 00:00      
   Component Purposes            01/01/70 00:00      
   This circuit will never work!            01/01/70 00:00      
      Could it be?            01/01/70 00:00      
         Function            01/01/70 00:00      
            issues            01/01/70 00:00      
                plating quality control.            01/01/70 00:00      
               Answers            01/01/70 00:00      
                  followups            01/01/70 00:00      
                     Answers II            01/01/70 00:00      
                        followups & Back EMF's?            01/01/70 00:00      
                           Floating regulator            01/01/70 00:00      

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