TPS610985: TPS610985 + SuperCAP

Naig

Part Number: TPS610985
Other Parts Discussed in Thread: TPS61098

Hi,

We are using TPS610985 in our device and 1F supercapacitor parallel to the boost converter TPS610985 as output capacitor in order to handle the high load for RF transmission. Our device main supply is primary battery alkaline which cannot handle the RF load transmission of NB-IoT module. So we added boost converter and supercap in our design to maximize the energy of the battery as well.

Is there upper limit for the output capacitance value? Also, do you recommend to place the supercapacitor prior to boost converter or after, which is more efficient method?

Thank you.

over 4 years ago

0 Minqiu Xie over 4 years ago

TI__Mastermind 21565 points

Hi Naig:

What's the current capability of the battery? Will it drop a lot with large current?

May I know your loading condition? How long time will a pulse come, and the width of the loading pulse?

And with super cap, I afraid the startup will take a long time.

0 Minqiu Xie over 4 years ago in reply to Minqiu Xie

TI__Mastermind 21565 points

Hi Naig:

As long time no hear from your side, I assume the issue is solved. I'll close this post. If you have further question, just reply in below. Thank you!

0 Naig over 4 years ago in reply to Minqiu Xie

Prodigy 250 points

Hi,

What would be the result if we don't use Rin=400R at Vin of TPS61098? Is it really necessary? Thank you.

0 Minqiu Xie over 4 years ago in reply to Naig

TI__Mastermind 21565 points

Hi Naig:

For applications where line transient is expected, an input filter composed of 400-Ω resistor and 0.1-μF capacitor as shown in Figure 57 of datasheet is mandatory to avoid interference to internal pass-through threshold comparison circuitry.

I'm not sure if your input power is clean and stable all the time.

0 Naig over 4 years ago in reply to Minqiu Xie

Prodigy 250 points

My input power is +3v alkaline battery. The whole system is powered by the boost converter. So only the boost converter is connected to the main input power.

0 Minqiu Xie over 4 years ago in reply to Naig

TI__Mastermind 21565 points

Hi Naig:

If it's just a battery, I'll recommend you keep 400Ω to avoid the unexpected influence caused by load transient or ripple.

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TPS610985: TPS610985 + SuperCAP