LM73100EVM: Power Good signal not working properly

suraj pardeshi

Part Number: LM73100EVM

Tool/software:

Hi,

In one the custom board I am using LM73100 as the oring device for 2 USB inputs. The problem is the Power good output signal, Normally it works properly as per design. But sometimes the PG signal goes low even if the input is 5.03V and output is 5.02V. Dont know the reason. After couple of times, we remove the USB cables and then it starts working normally. Any idea what can be the issue. I have attached schematic section of LM73100.

3 months ago

0 suraj pardeshi 3 months ago

Prodigy 40 points

0 Arush Gupta 3 months ago in reply to suraj pardeshi

TI__Mastermind 38845 points

Hi Suraj,

Most likely reason for PG going low in this scenario (ORing) is Reverse current blocking. Are you probing very close to the device pins? Can you try tip and barrel measurements.

Best regards,
Arush

0 suraj pardeshi 3 months ago in reply to Arush Gupta

Prodigy 40 points

Hi Arush,

The PG signal is routed to the microcontroller to know the status of USB cable being connected or not, through a 22Ohm series resistor. So I am measuring near the controller. Do you see any problem in schematic.

0 Arush Gupta 3 months ago in reply to suraj pardeshi

TI__Mastermind 38845 points

Hi Suraj,

When I mentioned probing near the device, I meant probing Vin and Vout near the device.

suraj pardeshi said:
But sometimes the PG signal goes low even if the input is 5.03V and output is 5.02V

Best Regards,
Arush

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LM73100EVM: Power Good signal not working properly