Tool/software:
Hello,
I want to confirm how I_LIM works in TPS1641(16412 and 16416).
The datasheet says that
when the output current is within ILIM< IOUT<IOCP, The device provides current up to IOCP for a duration of IDLY and then limits current to ILIM for a maximum duration of tILIM-DUR in Table 8-1.
But as far as my customer and I tested, it didn’t start the limit operation until reaching to ILIM+a few 10~100mA (depending on the ILIM setting value).
When (ILIM+a few 10m~100mA)< IOUT < IOCP for duration of IDLY, then the output current is limited to ILIM. I can’t find any description about this behavior in the datasheet.
Is this expected behavior?
For example I tested on the below 3 cases with our TPS1641 EVM.
When I_LIM is set at 30mA, when the output current reaches at 40mA, it limits the current to 30mA after IDLY duration. If it is under 40mA, it never limits the current.
When I_LIM is set at 1.0A, when the output current reaches at 1.18A, it limits the current to 1.0A after IDLY duration. If it is under 1.18A, it never limits the current
When I_LIM is set to 1.8A, when the output current reaches at 2.17A, it limits the current to 1.8A after IDLY duration. If it is under 2.17A, it never limits the current.
The below is the waveforms I took for this test for 1.0A and 1.8A configuration
<1.0A configuration>
CH1(Yellow): VOUT, CH2(Blue):FLT, CH4(Green) IOUT}
I used a manual variable resitance for this test. Not using a electric load.
<1.8A configuration>
(please ignore ch3)
Regards,
Oba
