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DC DC startup circuit question

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northeast1

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Hi, All
I have design the DC DC converter, In the simulation I find when I start up the circuit( power on), the current is large (10 A) at beginning, and then become normal(100mA), So I need to design current protection circuit or soft start up circuit, any one can provide some material or paper or books.


really appreciate.

Best regards
Ben
 

Areky_qin

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in general, there are a power on reset (POR) concept, when power reach level that you needed, then the circuit begin to work. this circuit can be detect by resistor divide or RC delay circuit.
 

engronger

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10A? oh my god , do you believe the start up circuit is no problem?

northeast1 said:
Hi, All
I have design the DC DC converter, In the simulation I find when I start up the circuit( power on), the current is large (10 A) at beginning, and then become normal(100mA), So I need to design current protection circuit or soft start up circuit, any one can provide some material or paper or books.


really appreciate.

Best regards
Ben
 

watersky

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10A? It is a too large current. Are you sure it is real? some times it is an algorithmic problem. If you use spectre, you can change options.
 

Mr.Cool

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you are probably charging a capacitor in your converter .. this is the 10A peak current.

if your cap is huge then you either design to accept 10Apeak or put in a soft start circuit.

google for: converter "soft start" schematic

Mr.Cool
 

northeast1

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Mr.Cool said:
you are probably charging a capacitor in your converter .. this is the 10A peak current.

if your cap is huge then you either design to accept 10Apeak or put in a soft start circuit.

google for: converter "soft start" schematic

Mr.Cool
got it , thanks very much
 

peterwang

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the solution for soft-start:

Use a ramp signal to replace the Vref for your PWM control, until the Vout is OK. Then switch the reference to constant Vref. By doing so, you won't see any overshoot at Vout any more.
 

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