pinoutpower supplyvoltage-regulator
So I just put my first complicated circuit together and of coarse it doesn't work, good news is I found the problem.
Given a LA5752 voltage regulator I assumed the hookup was pin1->Vin, pin3->GND and pin5->5 Volts. For some reason I'm only getting .8-1.1V on pin 5… Do I need any other pins hooked up? Could someone help me out?
Well it is obvious that when you have 4.7V V between pins 1 and 4 while the phone accepts 3.7V then you'll have problems.
The solution would be to step down the voltage to 3.7V using various different methods. A voltage regulator would do the job.
First things first. Grab yourself a copy of the BISS0001 datasheet.
To understand what was going on I traced the signal line from the microwave IC to the BISS
The comparator does following ..
But .. what the hell is wrong? Why does the output stay always high? The problem (in my oppinion is the output amplitude of the 2nd amplification stage which higher then expected, maybe due to some noice or whatever).
To understand what is going on the 2OUT I got my arduino and connected 2OUT to an analog input via 1megohm resistor.
The following picture already shows my modified circuit.
During the retrigger-inhib period the signal gets very eradic, even after replacing the amplification resistor (2nd Amplification stage) from 105 to a 150k (154). Before doing this the max signal would spike VH (0.7*VCC) and the output would instantly toggle again at the end of the inhibition period.. rendering the module useless.
EDIT: Try a variable resistor with maybe 200k Ohm to find the best value for your application
After replacing the amplification resistor I got the module working!
SOLUTION:
Some additional ideas that worked very very well for me:
My final solution I am currently using:
To do so I used the statistics library and had very good results with max/min/std-dev
Best Answer
You know it's a switching regulator, right? So it won't work without a suitable external inductor and diode? See the application circuit in the datasheet.
Pin 5 is the Soft Start input. Connect it to ground via a capacitor (the app circuit suggests 1 uf)