a lot of switching mode power supply design questions

[MooseFET]

1 ohm is the load or in series with coil?

The 1 Ohm is where th eload would go. I was showing the sort of
topology not the full circuit.


If you change where the diode hooks to connect to the drain of the
MOSFET it may do a little better.

Did you look at the ripple current in the R1.

 

[Paul E. Schoen]

1 ohm is the load or in series with coil?
today I tried to drive a power laser diode but failed. is there a
chip to do this work? 0-10A current source, ripple as low as possible?

Read the FAQs and detailed information about laser diodes I posted:
http://www.repairfaq.org/sam/laserdio.htm

There are other links if you check the Wiki article.

Your laser diode is probably toast.

Paul

 

[[email protected]]

I modified it and deleted the C-L on the right side. If a 400khz, 22
uF of C2 are applied,ripple will be very low. however, I did a deadbug
of this circuits, the transistor got hot at 400kHz! at 100 kHz it's
okay. Is't caused by the switching power consumed on transistor?


Version 4
SHEET 1 880 680
WIRE -192 48 -624 48
WIRE -32 48 -192 48
WIRE 176 48 32 48
WIRE -192 96 -192 48
WIRE -624 208 -624 48
WIRE -592 208 -624 208
WIRE -448 208 -512 208
WIRE -288 208 -368 208
WIRE -192 208 -192 160
WIRE -192 208 -208 208
WIRE -16 208 -192 208
WIRE 176 208 176 48
WIRE 176 208 64 208
WIRE -624 288 -624 208
WIRE 176 352 176 208
WIRE -624 416 -624 368
WIRE 128 432 -16 432
WIRE 176 464 176 448
WIRE -16 528 -16 512
FLAG -16 528 0
FLAG 176 464 0
FLAG -624 416 0
SYMBOL ind2 -32 224 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 5 56 VBottom 0
SYMATTR InstName L1
SYMATTR Value 1000?
SYMATTR Type ind
SYMBOL schottky 32 32 R90
WINDOW 0 0 32 VBottom 0
WINDOW 3 41 34 VTop 0
SYMATTR InstName D1
SYMATTR Value MBRB2545CT
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL nmos 128 352 R0
SYMATTR InstName M1
SYMATTR Value IRF530
SYMBOL voltage -16 416 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value PULSE(0 11.5 0 500n 500n 5?10?
SYMBOL res -192 192 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 30 55 VTop 0
SYMATTR InstName R1
SYMATTR Value 1
SYMBOL voltage -624 272 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value 11.8
SYMBOL res -496 192 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R2
SYMATTR Value 0.015
SYMBOL cap -208 96 R0
SYMATTR InstName C1
SYMATTR Value 100n
SYMBOL ind -464 224 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 -1 52 VBottom 0
SYMATTR InstName L2
SYMATTR Value 3.9?
TEXT -656 552 Left 0 !.tran 0 50ms 0ms 5ms
TEXT -656 600 Left 0 ;k1 l1 l2 1.0

 

[MooseFET]

I modified it and deleted the C-L on the right side.

Did you understand what those two parts did?

They allowed you to have zero ripple current in the LED.

 

[legg]

Did you understand what those two parts did?

They allowed you to have zero ripple current in the LED.

You might want to recheck this circuit, boss. Your capacitors are in
Farads, and your inductors are in Henries. You won't see much
happening in the simulator's 100mSec time frame.

RL

 

[MooseFET]

You might want to recheck this circuit, boss. Your capacitors are in
Farads, and your inductors are in Henries. You won't see much
happening in the simulator's 100mSec time frame.

I just checked:
C1 = C2 = 100uF

L1 = 12.2uH

L2 = 10uH

K1 = 0.9

 

[legg]

I just checked:
C1 = C2 = 100uF

L1 = 12.2uH

L2 = 10uH

K1 = 0.9

This ia the file you posted.

Begin led.asc ****************
Version 4
SHEET 1 880 680
WIRE -208 48 -480 48
WIRE 128 48 -208 48
WIRE 384 48 192 48
WIRE -208 96 -208 48
WIRE -480 208 -480 48
WIRE -480 208 -624 208
WIRE -384 208 -480 208
WIRE -208 208 -208 160
WIRE -208 208 -304 208
WIRE -16 208 -208 208
WIRE 176 208 64 208
WIRE 256 208 176 208
WIRE 384 208 384 48
WIRE 384 208 320 208
WIRE 384 272 384 208
WIRE -624 288 -624 208
WIRE 176 352 176 208
WIRE 384 384 384 352
WIRE -624 416 -624 368
WIRE 128 432 -16 432
WIRE 176 464 176 448
WIRE -16 528 -16 512
FLAG -16 528 0
FLAG 176 464 0
FLAG 384 384 0
FLAG -624 416 0
SYMBOL ind2 -32 224 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 5 56 VBottom 0
SYMATTR InstName L1
SYMATTR Value 12
SYMATTR Type ind
SYMBOL ind2 400 368 R180
WINDOW 0 36 80 Left 0
WINDOW 3 36 40 Left 0
SYMATTR InstName L2
SYMATTR Value 10
SYMATTR Type ind
SYMBOL schottky 192 32 R90
WINDOW 0 0 32 VBottom 0
WINDOW 3 32 32 VTop 0
SYMATTR InstName D1
SYMATTR Value MBRB2545CT
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL nmos 128 352 R0
SYMATTR InstName M1
SYMATTR Value HAT2160H
SYMBOL voltage -16 416 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value PULSE(0 12 100u 100n 100n 8u 10u)
SYMBOL cap 320 192 R90
WINDOW 0 0 32 VBottom 0
WINDOW 3 32 32 VTop 0
SYMATTR InstName C1
SYMATTR Value 100
SYMBOL res -288 192 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R1
SYMATTR Value 1
SYMBOL voltage -624 272 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value 12
SYMBOL cap -224 96 R0
SYMATTR InstName C2
SYMATTR Value 100
TEXT 536 248 Left 0 !k1 l1 l2 0.9
TEXT -658 552 Left 0 !.tran 0.1
end led.asc ***********************************

value C1 = 100
value C2 =100
value L1 = 12
value L2 = 10

I already know that adding E-6 to these values gives ~ functional
units in the simulation time frame.

 

[MooseFET]

This ia the file you posted.

You are absolutely right. In LTSpice the mu symbols are there. When
I copy and paste from the text file they aren't.