TPS54340 use for "Synchronizes to External Clock"

Dear John

OK!! I double check again

You mean

The resister close to IC is 50 ohm for termination

The resister close to CLK source is 162K for 600KHz

The cap is 10pF

Is it right? 

Yes you are correct if you are driving the RT pin form a 50 ohm source clock.  Other wise you should change to the appropriate load termination for your clock.  Hi-Z clock can drive just the RT pin with RT resistor directly.

Dear Sirs,

I designed 4-phase DC/DC which employ TPS54340. My problem is, the chips are not loaded at the same level, small difference in circuit and inside chip  are reasons in my opinion.

How do it better? 

Best regards.

KWT

Can you post your schematic?

There are 4 channels, but only one have veedback resistors mounted. Clock is 5Vpp, 500kHz, 0,90,180 and 270 deg.

As far as synchronization is OK, the circuit works well. Ton time for every channel is slight different, waht brings to not the same load level for every channel.

I think to add small seriall resistor on output and to give fidback resistor for every channel, but I didn't try it yet.

Best regards

So you have the outputs of all four converters tied together?  And three are running open loop?

Or do you have all 4 converters connected together at VFB?

the outputs of all four conventers are tied together.

all 4 chips are connected together at VFB, (res 0R) andy via resitor puted to output voltage

I don't think you can reliably force current share with TPS54340.  You can synchronize the clock frequencies of multiple converters with independent outputs.  You might try tying the COMP pins together.

We do have other devices that are designed to work as multiphase converters.  You might take a look at them.

I would like to convert 24V to 6V, around 15A. Becaouse EMC and few athers reasons, I would like to have at least 4 phase supply.

Could you please advise an chip suitable to thi job?

Best regards.