TLV2171: How to decrease TLV2171 Iq

Hi Robert,

Very appreciate your quick reply. it's a good idea to use a device with built in shutdown capability, nice~ i will recommend it to my customer

Btw, you are totally right, the Amps output to ADC, and customer use TLV2171 with 5V power supply.

Now i recommend TLV9042IDR  Iq=10μA  and TLV9151SIDBVR  to customer.

Lastly, i have a question, Does the devices Iq parameter is fixed regardless peripheral circuit design changed? 

Looking forward to your reply.

Have a nice day.

Hi Robert,

update.

My customer test the TLV9042IDR & OPA2244, and they found that there is no large difference of battery quiescent current consumption, comparing with TLV2171 in off-work status.

The amp circuit shows as below

And they want to identify if the input back to back diode will affect the Iq consumption.

Could you please help to check the reason why this is no more difference between TLV2171 and TLV9042?

And they want to identify if TLV9151 is useful to reduce battery quiescent current consumption.

Thx

add.

Customer didn't test TLV2171 & TLV9042 Iq, just test the battery quiescent current consumption, which show no much difference.

In this battery voltage sensing application, customer want to know if the low Iq amp could reduce the battery quiescent consumption?

Thx, looking forward to your reply.

Hey Chen, 

Can you provide what voltages are expected at BAT+ and BAT-? 
Additionally what are the resistor and capacitor values that are missing? Specifically what are the values for R5, R6, R7, R8, R9, and C1? 

From the customer's description it seems that testing between the two op amps, there is not a difference in the system's Iq? 
If this interpretation is correct, the op amps Iq must be so low to the overall Iq of the system. I would focus on lowering the overall system Iq. 

All the best,
Carolina

Carolina,

Sorry for the mix expression. Customer want to reduce the battery 12V quiescent current consumption in the machine off status, in which the power of amp is off.

But the quiescent current consumption is about 200uA with TLV2171, and after replacing TLV9042 the quiescent current is 190uA.

So, customer want to get the support of reducing the quiescent current, and i recommend to increase the R1~R4，and R8, to decrease the current. And add RC to eliminate noise caused by increased resistance.

Do you have another good advices? thx

Hey Chen, 

Can you please provide the values of R5, R6, R7, R8, R9, and C1? 

I need to double check with their values

Do you have better solution about this case? Thx 

Hey Chen, 

The Iq seems really high to me, therefore I would like to know the values to see if I get the same results. 
Implying that there is something else going on here that is not just the op amps. 

The only obvious solution to dramatically decrease the Iq is what Robert already suggested which is to use shutdown devices. The TLV904X family is also available in shutdown. 

All the best,
Carolina

Hey Caro,

I have to notice that in this situation, the power of amp is off. But the battery quiescent current consumption is very high.

I don't think it's the op amps effect, may be the R1 R2 R3 R4 is too small , which cause a high current consumption?

In this way, does the shutdown would works to reduce the current, even though no power supply for amp?

Hi Robert,

Customer want to decrease the battery quiescent consumption in the shutdown state, in this state, customer found that the battery output current is 200μA;

After increasing the circuit resisters with 5x, the current decrease to 34μA; but it's still too big.

So customer want to identify if the TLV2171 input protect back to back diode cause the big current?

Robert,

Impressive, thx for your explain.

I notice that the TLV9151 stand high impedance state when shunt down.

So i want to know if TLV9151 will still cause quiescent consumption when shunt down?

Thx