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TPS61088: Vin 9.5V, Vout 10V, Iout 1A condition

Hirokazu Takahashi
Expert 8420 points
Part Number: TPS61088
Other Parts Discussed in Thread: TPS61089,

Hello Support team,

Is it possible to support below condition with TPS61088 and TPS61089?
* Vin : 4.5~9.5V
* Vout : 10V, Iout=1A@max
* Peripheral parts accuracy : +/-1%

If there are other products supporting this condition, please let me know.

Best Regards,
Hirokazu Takahashi

  • 0
    TI__Mastermind 40080 points

    Dear Sir,

    u can choose TPS61089. But make sure the operation frequency fsw is not higher than 400kHz because of the minimum Ton limit, or it will enter into the PFM mode even in the full load when Vin is high(near 9.5V)

  • 0 in reply to Helen chen
    TI__Expert 8420 points

    Hello Helen-san

    Tnanks for your support.
    I have some question below.

    Why we can't choice TPS61088?
    Could you let me know how you calculated max fsw as 400kHz?
    How does TPS61089 automatically change PFM and PWM?

    Best Regards,
    Hirokazu Takahashi

  • 0 in reply to Hirokazu Takahashi
    TI__Mastermind 40080 points

    Dear Sir,

    Of course you can choose TPS61088. But it is a little bit over design.

    When Vin close to Vo and met minimum Ton, then if Vin further increases, it will enter into PFM mode.

    when fsw=400kHz, Ts=2.5us, D(9.5Vin10Vo)=0.05, Ton=125ns, considering the efficiency, the real Ton will be higher than 125ns.  For the IC,   Tomin_typ=90ns,  Tomin_max=180ns. so fsw=400kHz is at the corner of can or cannot.

    If possible, please choose fsw=300kHz, thus Ton=166ns, considering the efficiency, the real Ton will be around 180-200ns. So ti will be OK.