TPS40170: frequency synchronization

As the datasheet describes, the TPS40170 can be synchronized in slave mode, slave controllers can be synchronized to an external clock within +/- 30% of the internal switching frequency.

also note:

When an external SYNC clock signal is used for synchronization, limit maximum slew rate of the clock signal to 10 V/µs to avoid potential PWM jittering and connect the SYNC pin to the external clock signal via a 5-kΩ resistor.

Hi,

We got a additional question from customer.
Could you help us?

[Question]

When external clock be inputed for SYNC pin, how much is the delay time changing from free run switching frequency to external clock frequency?
They would like to make sure that the switching frequency change immediately after inputting external clock.

Best Regards,
tateo

I am waiting on the board. In the meanwhile I checked the TPS40400 and it responds within 2-5us.  Typically it would take 2-3 clock cycles for frequency to lock in.

So for example a 500khz sync pulse (2us periode) would change the switching frequency within 5us. More details when I get the TPS40170 board.

Regards,

Mathew

Thank you for your support.
I would appreciate it if you could provide waveform.

Best Regards,
tateo