LM5066IEVM-626:LM5066I Problems with the test

Hi Joaquin Celma,

Thanks for reaching out.

The device starts timer when load current exceeds 1.5A and allows the load current till fault timer expires. Can you share the test waveform of Vout, GATE, input current and Timer voltage to check.

Best Regards, 

Rakesh

Hi Joaquin Celma,

How did you set the overcurrent limit to 1.5A? Have you changed the Rsense on the EVM ?

Best Regards, 

Rakesh

Hi Rakesh

Hi Rakesh

I have the limitation seen in image 1.0682A (Input Overcurrent Warning).

The Rsense has not been changed.

I have the limitation seen in image 1.0682A (Input Overcurrent Warning).

The Rsense has not been changed.

I have the limitation seen in image 1.0682A (Input Overcurrent Warning).

The Rsense has not been changed.

Hi,

The current limit on the EVM is set at 25A. Overcurrent warning limit can be changed on GUI but the device cuts off the path only when the load current exceeds 25A as per the EVM setting.

To modify the current limit, please adjust the Rsense resistor on the EVM

Best regards, Rakesh

I thought the current limit setting was by application.

I have changed the RSENSE = 10mOHM.

1. I increase the current little by little by lowering the load resistance.
2. At 2.5A it cuts the output.
3. I raise the resistance but the output remains at 0 until I remove the Load (It does not start).
4. When putting the Load back (1.45A) If it starts.
5. Without removing the Load Does not start with the ON / OFF switch.

Now it doesn't even start without load.

It's broken?

Hi Joaquin Celma,

There is a limit on the load value where the device can startup. It depends on the power limit setting, dvdt slew-rate.

Please verify using LM5066i design calculator for your circuit configuration values. The design calculator is available at https://www.ti.com/product/LM5066I#design-development##design-tools-simulation 

Now it doesn't even start without load. It's broken?

Rakesh-> please check impedances of each pin with respect to the ground. Check VDD, VREF voltages and verify whether hot-swap MOSFETs are fine or not.

Best Regards, 

Rakesh

I have checked with another board (LM5066IEVM-626) the following:

1. With RNS = 10mOhm (VCL = 26mV) -> 2.5A current limit -> Cut the output.

2. For it to start, the load must be removed.

Conclusion: LM5066I DOES NOT START WITH CHARGE

Question: Is there a way for the system to boot under load?