TPS61099: tps61099

Hi Minglai:

Do you mean the output voltage ripple?

For a extra light load, TPS61099 will enter the burst mode. In Burst mode, the boost converter ramps up the output voltage with several switching cycles. Once the output voltage exceeds a setting threshold, the device stops switching. The ripple could reach to 3%(For 5V, the typical value is 0.15V)

Actually, IL<20mA is near the typical condition entering burst mode. If the converter does't enter into burst mode, the ripple will be much smaller. The value is mainly determined by Vout and inductance.

Minqiu:

Thanks for the information.

What DC2DC converter would you suggest for light load and very small output ripple?

Thanks

Minglai

Hi Minglai:

May I know what's your application? And the requirement of efficiency and Vout ripple?

We have device with fixed frequency switching all time (FPWM mode) like TPS61071, but the efficiency at the light load is not so good as PFM mode.

Hi Minqiu,

We use this to generate voltage to bias laser.

Ming

Hi Ming:

So how do you think about the efficiency? And what's your requirement of ripple？

If you could accept low efficiency at light load, I'll recommend some parts with Fore PWM. It means the converter will keep switching even with no load. It will bring much power loss at light load, but the ripple is smaller than PFM.

If you do care about the efficiency even at light load, it's better to add a low-pass filter at the Vout side.

TPS61071 : 90% is fine. the ripple 10mV pp is good except the spikes.

However the package size is big.

Preferably DSBGA or similar.

Thanks