TPS71501 minimum load current

Timothy Friend

Other Parts Discussed in Thread: TPS715

The data sheet for the TPS71501 does not specify a minimum load current necessary to maintain regulation. But the specification for load regulation gives a value for an output current range from 100uA to 50mA. What happens with this regulator if the load current falls below 100uA? Note 2 on page 3 of the data sheet implies that load current can be less than 5uA, but what happens to regulation in this region?

Thanks

~Tim

over 15 years ago

0 Bill Stokes over 15 years ago

TI__Expert 8890 points

Hello Tim,

I don't know why TPS715xx data sheet was written this way. I am hunting down the writer and I'll get back to you as soon as I have an answer for you.

Bill

0 Kurt Schmidt over 15 years ago in reply to Bill Stokes

TI__Genius 11125 points

Bill - did you ever resolve this issue? In a battery powered application where the load is about 5uA, one of the engineers wants to add an external resistive load, claiming the output will float up if this isn't done. But this is killing the battery life. What is the minimum required current for regulation, if any? Figure 3 in the data sheet suggests it can go all the way down to zero load.

0 Bill Stokes over 15 years ago in reply to Kurt Schmidt

TI__Expert 8890 points

Hello Kurt,

There are no reported problems found to date concerning the TPS715 at very light loads. In fact, the internal leakage null circuit is specifically designed as a secondary precaution for high voltage, high temperature cases where the pass FET leakage current might cause the output voltage to rise due to high load impedance.

I just tested a TPS71533 in the lab. At 5-22Vin to 3.3Vout with no load the quiescent current was 3.4-4.4uA and the output voltage was stable.

The only provision for current "loading" that I am aware is that for the divider current. The Application Information recommends that the divider current be 1.5uA minimum.

Bill