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TPS62130A-Q1 Switching frequency

tsuyoshi tokumoto
Expert 2630 points
Other Parts Discussed in Thread: TPS62130A-Q1, TPS62090-Q1, TPS62090, TPS62065

I'm disty in Japan.

I'd like to ask you about the switching frequency of TPS62130A-Q1.

My customer is considering using TPS62130A-Q1 to next model.

He likes TPS62130A-Q1 with high efficiency characteristic (specially, in the power save mode) very much.


He would like to know the switching frequency of this device.

The switching frequency must maintain over 1.8MHz in his application,
because the clock noise of under 1.8MHz influence other equipment.


Can the switching frequency of this device maintain over 1.8MHz
in consideration of temperature characteristics and process variance
under the following conditions?

 1)Vin= 5V, Vout=3.3V,Iout=3A

 2)Vin= 5V, Vout=1.5V,Iout=3A

  *We are concerned that the switching frequency suddenly drops
   at input voltage below 6V.
 


Additional information, he knows that TPS62090-Q1 may be better than TPS62130A-Q1
under conditions of above only.

However he is considering TPS62130A-Q1 preferentially to have possibilities
to be usable in not only next model but also other models,
because it has the characteristic of wide input voltage range.

 

Best regards.

Tsuyoshi Tokumoto

 

  • 0
    TI__Guru*** 142860 points
    Figure 7 shows data for the 3.3V output case. It should not be expected to remain above 1.8MHz at such a high duty cycle.

    The 1.5V case will be close to 1.8MHz as well.

    The TPS62090 or TPS62065 would be recommended for higher frequency operation.
  • 0 in reply to Chris Glaser
    Expert 2630 points

    Dear Chris-san,

      Thank you for your reply.


      I evaluated the switching frequency with TPS62130EVM.
        *Cf. attached file TPS62130EVM.xlsx

      It seems to me that the Toff time of switching signal
      was fixed approximately 160ns around Vin=6V,
      when I confirmed the switching frequency and the duty on
      the test of Vout=3.3V.

      In the evaluation results,I think that if the Vout is 1.5V,
      the switching frequency of this device will maintain above
      1.8MHz under the conditions of Vin=5V(Iout=3A).

     

      Since I have two questions as follows,
      would you please give me reply?

    (Q1) Can TPS62130A-Q1 use with the switching frequency which is above 2MHz
             under the conditions of Vout=1.5V and Vin=5V and Iout=3A?

    　　       The Toff_time(ns) is calculated by following equation.
                    Toff_time(ns)=(1-Vout/Vin)*(1/fsw(MHz))*1000

                 I calculated the Toff_time(ns) under the conditions of Vout=1.5V and
                 Vin=5V and fsw=2MHz.
                    Toff_time(ns)=(1-1.5/5)*(1/2)*1000=350(ns)

                 I think that the value of 350ns is enough larger than 160ns.

    　
    (Q2) If the switching frequency try to maintain above 1.8MHz under the
             conditions of Vout=3.3V and Iout=3A,how many voltages will the Vin need?


    Best regards.

    Tsuyoshi Tokumoto.

    tps62130EVM.xlsx

  • 0 in reply to tsuyoshi tokumoto
    TI__Guru*** 142860 points
    Again, a low Vin device would be more optimized for a 5V input. At this Vin, the Rdson is beginning to increase which means the on time variation over load to overcome losses will be stronger.

    But yes, for the 1.5V output, it should remain above 1.8MHz as your data shows.

    For the 3.3V, you are in the portion of operation where you are operating with the ~160 nsec off time you found. With 6Vin, you should be outside of this area.