TPS61094: Coin cell with coulomb counter?

Dave Pulvermacher

Part Number: TPS61094
Other Parts Discussed in Thread: BQ35100

I would like to use the TPS61094 with a coin cell to power my project. We are using a 1F, 2.7v, cap on the EVM and achieving positive results. Is it possible, though, to use a coulomb counter in series with the TPS61094?

over 2 years ago

0 Zack Liu over 2 years ago

TI__Mastermind 34201 points

Hi Dave,

The application engineer supporting this device is out of office. He will reply you as soon as he is back.

0 Wenhao Wu over 2 years ago in reply to Zack Liu

TI__Genius 9046 points

Hi Dave,

I have no idea about the coulomb counter and how it works. Do you have P/N or any material of the coulomb counter you are going to use?

-Wenhao

0 Dave Pulvermacher over 2 years ago in reply to Wenhao Wu

Intellectual 870 points

it would be something like

BQ35100

0 Wenhao Wu over 2 years ago in reply to Dave Pulvermacher

TI__Genius 9046 points

Hi Dave,

According to block diagram of BQ35100, I draw below simplified chart. Is this how you are going to use for BQ35100+TPS61094?

-Wenhao

0 Dave Pulvermacher over 2 years ago in reply to Wenhao Wu

Intellectual 870 points

Yes, that is the plan.

0 Wenhao Wu over 2 years ago in reply to Dave Pulvermacher

TI__Genius 9046 points

Hi Dave,

I think it would be fine but please note the resistance can act like battery's internal resistance. So when current from battery increases, voltage that TPS61094 sees decreases. This can influence TPS61094's work some time. What is your sense resistance, battery voltage, VCHG, ICHG and OSEL setting?

0 Dave Pulvermacher over 2 years ago in reply to Wenhao Wu

Intellectual 870 points

I don't have the fuel gauge in series yet - that part isn't designed yet. I am still trying to get the TPS61094 to work reliably.

Vbat = 3v (coin cell)

Vchg = 2.2v

Ichg = 2.5mA

OSEL = 2.8v

Cap is 1F, 2.7v

The TPS61094 seems to be in bypass (or pass through) made all the time.

0 Dave Pulvermacher over 2 years ago in reply to Zack Liu

Intellectual 870 points

Hi Zack, one major question we have: can the TPS61094 be used with a coin cell battery? If our supercap is depleted (Vsup = 0.6v) and our battery is dead, what happens when we install a fresh coin cell? The datasheet would lead me to believe that 300mA is fed into the supercap until the output voltage is above 0.5v. That is waaaaaaay too much current for a coin cell.

0 Wenhao Wu over 2 years ago in reply to Dave Pulvermacher

TI__Genius 9046 points

Hi Dave,

Yes, TPS61094 can be used with a coin cell battery. I see why you want to use the solution. TPS61094 can help decrease power stress to coin battery when there is a heavy load to increase power density. See my blog how to utilize TPS61094 in this kind of application:

e2e.ti.com/.../3-benefits-of-using-a-low-iq-buck-boost-converter-to-extend-battery-life-in-flow-meters

When Vin is below OSEL+100mV, it enters supplement mode so supercapacitor is not charged. In you case TPS61094 should be able to charge supercap. Are you using current meter in series of input line? Current meter has internal resistance and can influence TPS61094 charge function.

-Wenhao

0 Wenhao Wu over 2 years ago in reply to Wenhao Wu

TI__Genius 9046 points

Hi Dave,

I closed the thread and if you have more questions you can post below.

-Wenhao

Power management

Power management forum

TPS61094: Coin cell with coulomb counter?

BQ35100