TLV3012: Push pull output fix

Hi Ibrahim,

a schematic of your would be helpful, and some scope plots :-)

Kai

Hi Ibrahim,

I agree with Kai. Can you post your schematic and/or simulation so that we can troubleshoot your issue?

Thanks,

Joe

Sure thing,

I can only provide a schematic since I have no access to an oscilloscope at the moment due to covid measures:

I am connecting my battery to VBat and PGND of the comparator which is driving the enable pin of my 5 V regulator at the output. The regulator is also connected to VBat and PGND for power. The load would be attached to +5V and PGND. Any help would be greatly appreciated !

Hi Ibrahim,

I am having trouble understanding what you mean by a 1A load. Are you saying that when the comparator sources 1A to the load that there is an issue? Or are you saying that 1A of current through your resistor divider network causes issues? 

I am curious as to why you chose a 100kOhm pull-up resistor as well. It seems a little high.

May I see a simulation illustrating your issue? 

Also, do you need to use a window comparator? It seems like you can simplify your circuit and use a single-channel comparator since your are leaving OUTB disconnected.

Thanks,

Joe

Hey Joe,

I have not designed the EVM board from scratch, I am merely showing a schematic of both modules I am using. The only change between the TPS3700EVM-114 module and the one I am using is, I swapped out R1 for 604kOhm and the 100kOhm PU resistor was already included in the evaluation board and I have not touched it.

I suppose the issue may be with the latter since all the comparator is doing is that it is triggering the enable pin of my boost converter and when i disconnect the connection, I am able to discharge properly but with no overdischarge monitor. A voltage drop maybe causing my enable pin to somewhat malfunction since proper load operation only occurs when supplying at 3.9 V and above from my lab test bench.

In my application, I require my battery to discharge up to 1.5 A where 1 A is an intermittent smart device load to act as a phone charger and 0.5 A consistently to drive a MCU unit and some WS2812B serial addressable LEDS. It should be able to do so between 3.3V-4.2V and cutoff at 3.2V.

No I do not need to use a window comparator, it was just what was available from my supplier for testing which is why I am considering a push pull comparator.

I have attached a video of my converter running with and without the enable being connected into the OUTA of the comparator. Notice how my converter remains on but with a low current output due to the enable pin.

Ibrahim,

Until you use a comparator in your design, I think its best that I assign this thread to the group responsible for answering TPS3700 questions.

I hope they can resolve your issue.

Regards,

Joe