TPS3700: TPS3700 negative voltage monitoring application

Geethanjali Srinivasan

Part Number: TPS3700

We are using the attached design for -5V , +/-10% Over voltage and under voltage monitoring.

We are not getting proper Pgood indication in the LEDs. . Can you please suggest, is there any

mistakes in the resistor (R1,R2,R3) calculations ?

Our understanding as follows

1. For normal -5V, the OUTA and OUTB pins are at High (+5V)

2. For UV(-5.5V) or OV(-4.5V) OUT A or OUT B will be pulled Low.

0 Abhinav.Sharma over 4 years ago

Hi Geethanjali,

Did you use the guide in this app note for your design? http://www.ti.com/lit/an/slva600/slva600.pdf

This should allow you to design your resistors seemingly, in addition to using the calculator linked in the guide.

Thanks,
Abhinav.

0 Trailokya Rai over 4 years ago in reply to Abhinav.Sharma

Hi Geetanzali

The diode is not turning on in your case, when it is trying to assert low signal at the output.

Use R336 and R335 = 100k

and R358 and R359 = 5k { in case your UV and OV is 4.5 to 5.5V}. it will work.

You can refer to section 4.2 of app note http://www.ti.com/lit/an/sbva062/sbva062.pdf for details of calculation.

Regards

Trailokya

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