TPS61120: TPS61120PWG4

Hi it's not good and bad. The difference is because the load varies. Guess the bad unit load is lighter, so the device enters Power save mode.

Both units are running the same load current (about 110mA)

Can you also provide the inductor current and sw

I do not know how I would measure the inductor and switch current. How do I determine when the device goes into power saving mode? At what current level does it do that or at what voltage level???

How do I email you ?  What address? 

Power save mode IS enabled.
What is the threshold for power saving mode?
What external components affect this threshold??

Since we have built over 150,000 of these units and the powe save has been enabled for all of them, I need to determine what other factors would cause these failed units to be in hiccup mode. All units idle at about 110mA so load is not different between good units and bad units. Please advise on how to narrow down the reason for this discrepancy. 

Hi I need to see the inductor current and SW bus waveforms to debug. Can you provide this?

Please link to method of measuring inductor current.  

Can Sw bus be measured directly with a scope (10x probe) ?

Can inductor current for this device be measured simply by putting a sense resistor in the supply line or must it be separated from Vbatt current??

No you can't do this because the sense resistor is much larger than LS MOSFET Rdson. The actual input voltage will degrade as well

What factors would cause one device to power save and another not to power save.
These are production units.
We are building 100s at a time.

I need solutions to isolate the cause.

R27 and R28 are 1% tolerance

Normally only when the load is light enough the device will enter power save mode. You can contact me through e-mail. 

nini-zhong@ti.com