TPS564247: High Quiecent Current with no load

You need to remove inductor , r34,r35,c17, force FB=0.65V. 

Shuai

couldn't understand why you suggest of removing this parts, i want the converter to work not to make it stop working.

what are your intentions ?

The definition of quiecent current is the current when converter stop switching. It is a spec to show the consumption of non-power circuit. If you let the converter run, the input current will contain the consumption of inductor, output capacitor and resistor.

Shuai

Ok, let me rephrase my question.

there is unexplained current consumption with no load.

9-12 mA is unacceptable in no laod situation somethign is clearly wrong here

exactly, i do not understand where this extra current comsumption is coming from.

Output capacitor has parasitic leakage, FB resistor is also a load between VOUT and GND. 

the rsistors can cause 0.6 mA leakage. i tried tp replace the to ceramic ones, but no change 

every kind of capacitor all have parasitic leakage. As long as there is load in output, the converter will switch. The switch will cause consumption because of switching loss and conducting loss, these loos are higher than the parasitic leakage.

i do not follow, you just showed me a table which implies that when there is no load there is 400 uA current sonsumption, and now you are justifying 9-12 mA power consumption on the output capacitor.

so TI measurement was without external capacitors at all??? that can't be right 

can someone in TI please help with that issue !?!! i am just getting frustrating comment by you.

Yes, we measured Iq without inductor and output cap. And force FB with 0.65V, let it be in non-switch state. We already mentioned 400uA is in non-switching state.

Hi, Sagy

   About the 9~12mA you mentioned, it was measured when the part is switching but no load on output side, right?

   TPS564247 is a FCCM mode part, it has fixed switching frequency to get lower ripple on output at light load condition, but the cost is higher input current consumption even there is no load on output side. If your application care about light load efficiency, you can try TPS564242, hope it helps. Thanks.

this is missleading information. instead of telling what is the switching controller power consumption, especially when this is an FCCM which maintain the same frequency.

i am very dissapointed as this switching regulator right now draws more power than my full IoT system.

my system in low powe mode draws 5 mA.

this is absolutley rediculous.

Hi Sagy,

My colleague will give you reply later.

BRs

Zixu

Still waiting, thanks