help on LM2576 with minus (-12v)

help needed.

i use the exact circuit (figure 10) in the manual of LM2576, but cant get the output of -12v the power supply is 24v with the max amp of 5amp, when it turns on the chip get hot and the power supply get overloade with a high amp of about 3.5amp.

is there any one can help on this? THanks.

Reply to
xuzhenxz
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Did you think to mount the device on an adequate heatsink? What kind of inductor are you using? It might be saturating when your load draws over 3.5A.

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Dave M
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Reply to
DaveM

As replied in sec, this kind of circuit can have a very high startup current. His power supply may be limiting at 5A and preventing the SMPS from properly starting.

Best regards, Spehro Pefhany

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Reply to
Spehro Pefhany

On page 17 of the datasheet, one small item in reference to Figure

10:"For an input voltage of 12V or more, the maximum available output current in this configuration is approximately 700 mA."
Reply to
Fred Bloggs

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