• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 62 subscribers
  • Views 688 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

FPGA Design using 5 simple switcher modules LMZ family and want to synch the clocks so the power modules all run at the same frequency

Timothy Darling
Prodigy 120 points
Other Parts Discussed in Thread: LMZ31506, LMZ31520

The power supply input is 5V

LMZ3710 is generating 1.8V and 3.3V. The LMZ31506 is generating 1.5V and 2.5V, The LMZ31520 at 1V.

I want to use synch out of an LMZ3710 to drive the RT/CLK inputs of the other LMZ3710 and the two LMZ31506. In looking at the data sheet of the LMZ31520 I will not be able to synch to that part?

In looking at page 26 of the 3710 data sheet you get the resistor values for a given Vout for Rset and R(RT). In my application each part will have a unique R(RT) based on the Vout and switching frequency.. The synch out from the LMZ3710 will connect to the RT_CLK pins to the other LMZ3710 and the two LMZ31606 to make the power control module clock frequencies all the same.

My question is when I synch the three parts to one synch out signal will this synch out clock over ride the internal set frequency (set by R(RT))? Is there a schematic showing how to connect multiple LMZ parts to one clock frequency?

Each part needs to have a resistor from RT_CLK pin to ground that sets the output voltage. T

  • 0
    TI__Mastermind 28020 points

    The clock frequency on the RT_CLK pin will override the switching frequency set by Rrt. I recommend placing a Rrt resistor at each device. The value of Rrt should be selected to set the switching frequency close to the synchronization frequency. (The Rrt resistor does not set the output voltage. Rset sets the output voltage.)

    LMZ31520 cannot be synchronized to an external clock.

    Contact me directly at jarrigo@ti.com with other questions.

    Thanks, Jason