LM51561: Maximum Comp Clamp Voltage

Kuramochi Tadahiko

Guru 28715 points

Part Number: LM51561

Hi,

How is the device work when comp pin voltage hits the maximum comp clamp voltage?

Best Regards,

Kuramochi

over 5 years ago

0 Julian Hagedorn over 5 years ago

TI__Mastermind 20900 points

Hi Kuramochi-san,

i will double check the behavior, but I think the device will clamp the voltage and falls out of regulation.

regards,

Julian

+1 Julian Hagedorn over 5 years ago in reply to Julian Hagedorn

TI__Mastermind 20900 points

Hi Kuramochi-san,

The comp dynamic range is 1.2V to 2.4V, if comp hits the clamp, the part will not be able to regulate.

In flyback we allow comp to have an external resistor to VCC to pull up on it. The clamp sinks any current needed to prevent the comp pin from going too high but we limit the pull up resistor value such that the max current the clamp runs is 1.6mA. This is mentioned in the comments below the abs max table.

regards,

Julian

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LM51561: Maximum Comp Clamp Voltage