Tool/software: WEBENCH® Design Tools
Dear Sirs,
I've an old design with the TPS54380 where:
- Vin = 5V
- Vout = 1.5V
- Iout = 2.5 A (Core FPGAs)
In this situation, during the start up I've measured an oscillation behaviour of the VOut.
I don't see a TPS54380 PSPICE model and also in the Webench there isn't a solution with TPS54380.
Is there a method to simulate the TPS54380 behaviour?
Thanks in adnvance.
Daniele
Hi Excel,
in the following images I send you:
- a section of schematic where there is the DC/DC implementation;
- an image of the start up waveforms (yellow is the 1.5V and blue is the 5V current);
Could yuo verify if the Type III filter is good?
Do you see other problems in the implementation?
If these info aren't enough I try to extract the info from the PCB.
Best Regards,
Daniele
Hello Excel,
in the following picture there is the schematic diagram of the DC/DC.
Best Regards,
Daniele
Hi Daniele,
The PCB layout is not fully optimized (see reference PCB layout below). However, it is not yet clear if it is the root cause of the unstable Vout at start-up. Can you send the start-up waveforms as the following the signals?
1. Vin, Vout, inductor current (L1) and PH pins of the IC
2. Vin, Vout, VBIAS and ENA pins of the IC
3. Vin, Vout, VSENSE and ENA pins of the IC
Best regards,
Excel
