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Dear Sir:
If LM5176 shall be enable/disable by another enable signal from Microcontroller, how do I use it?
Now the EN/UVLO of LM5176 is on/off by mosfet 2N7002 with 1.5Kohm.
If no 1.5Kohm, the comp of LM5176 is damaged. (impedance is around 30ohm to GND). Finally, I found it shall be current limit resistor for EN/UVLO.
But it is not robust. It is damaged again during enable signal on/off rapidly.
Thanks.
Aska
Hi Aska Lee,
Thanks for reaching out with your question and for using the LM5176 in your design.
The best way to enable and disable the LM5176 is to use the EN/UVLO pin as mentioned in your original post. Can you please show how the EN/UVLO pin connected in your schematic?
Thanks,
Garrett
Hi Aska,
The schematic looks fine to me. If the 1.5kOhm resistor is not present is the UVLO pin getting pulled below -300mV? If so, this is outside the absolute maximum voltage rating and could damage the device.
Thanks,
Garrett
Dear Garrett:
Thanks for your reply.
It shall be damaged by the over stress on EN/UVLO, but not sure which one (<-0.3V or >60V). The input voltage is only 52V from Chroma DC source, so I think it shall be <-0.3V.
BTW, I am going to find another damaged reason while LM5176 power up with external constant current circuit.
BR,
Aska