What is the right way to use TPS3839 for power monitoring

Thread Starter

sairfan1

Joined May 24, 2012
97
I'm planning to use TPS3839 in 3.3v battery operated project. As per attached datasheet it says I will be connecting power supply for IC GND, VCC and it will activate RESET' pin when power is below the required level.

Here I do not understand its working, looks like when battery is low it will stuck into a loop, it will send a signal to reset MCU, after reset signal, MCU will again power up and that will cause another reset.

What I understand, every reset will reduce the load which will reset the circuit and power up the uC and it will continuously reapting. I have SMD component can't try it before design and assemble a PCB, I need help how it will work in a circuit.
 

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Last edited:

crutschow

Joined Mar 14, 2008
33,983
The Reset output can do anything you want it to do, not just reset your micro.
So what do you want it to do when the battery voltage becomes too low?
In other words, what was the purpose for adding this low voltage monitor to the system?
 
Last edited:

ericgibbs

Joined Jan 29, 2010
18,625
Hi s1
The way I read the datasheet, is when Vsupply falls and stays below the threshold, the Reset will remain active Low.
It will only remove the Reset when the Vsupply rises above the threshold, after a short delay.

E
Clip
Both devices initiate an active-low reset
• Push-Pull RESET Output signal whenever the VDD supply voltage drops below
• Factory-Trimmed Reset Threshold Voltages
the factory-trimmed reset threshold voltage. The reset output remains low for 200 ms (typical) after the VDD • Temperature Range: –40°C to 85°C voltage rises above the threshold voltage and

EG57_ 1259.png
 

Thread Starter

sairfan1

Joined May 24, 2012
97
My objective is to keep uC off (shutdown) when battery is low.
@ericgibbs what do you mean by Push/Pull RESET. please note that I'm using three pin package and I do not have MR' pin.
 

ericgibbs

Joined Jan 29, 2010
18,625
when battery is low it will stuck into a loop, it will send a signal to reset MCU, after reset signal,
Hi sair,

I refer to the Push/Pull RESET, note in the datasheet clip.
Please post a digram showing how the device is connected to the MCU and power source.

E
 

Thread Starter

sairfan1

Joined May 24, 2012
97
I'm getting help from TI datasheet/application notes, please refer to attached image. I did not develop any schematic yet, I wanted better understanding to power management module first.


PowerManagement.png
 
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