MPS5922 EN to ON signal delay

DC-DC Power Converters
1

In our design we are using MP5991 and MP5922.

MP5922 is driving 10nos. of MP5991 e-fuses connected in parallel on Loop1.

A delay of 2.6s is observed from assertion of EN1 of 5922 to ON1 signal of MP5922.

Different values were written to TON_DELAY register.It is observed that when the TON_DELAY value is above 2.6 seconds, the delay between the EN and ON signals in the captured waveform matches the value programmed in the TON_DELAY (0x60h) register. However, for TON_DELAY values below 2.6 seconds, the delay does not vary and remains approximately constant at around 2.6 seconds.

The GOK signal is not asserted. EN is pulled high by the VDD33 of MP5991 (shorted for all 10 fuses)

Please assist to find out what is the cause of the 2.6 s delay.

2

Hi @sonalit ,

Are you referring to the TON_DELAY (60h) register from the MP5990 device?

Thanks, Will

3

Yes William. That is correct.Rregister TON_DELAY [60h] . But the device is MP5922.

4

I see, are you able to assert & de-assert the EN pin on the MP5922? Or is it shorted to VDD33 of MP5991?

VDD33 is used for powering internal circuitry. I recommend triggering EN on the MP5922 with an external source.

Please provide EN and ON waveforms showing the 2.6 second TON_DELAY.

Thanks, Will