Need help in ELM9748CAA CMOS voltage detector IC for battery

[NicholasTok]

hello everyone,

Currently I am looking for a IC chip which enable me to monitor the voltage of a battery of 9V, when the voltage of the battery falls below 4.8V ~ 4.9V it will trigger and activate a either a buzzer or vibrator.

After some goggle on the net I came across ELM9748CAA - CMOS voltage detector IC for battery.

can anyone show me how it can be connected from a 9V battery going into the ELM9748CAA IC then to a load?

Thanks in advance

Best regards,
Nicholas Tok

 

[mister_rf]

Re: Need help in ELM9748CAA CMOS voltage detector IC for bat

I think one solution is like that:

 

[laktronics]

Re: Need help in ELM9748CAA CMOS voltage detector IC for bat

Hi Nicholas,
As mister_rf has shown, the circuit can be used up to 6V battery, the maximum voltage specified for the IC. You can see if they offer other models specified for 9 to 12 V operation. If you want, you can use National's LPM7300 as shown in the circuit below, but it requires more compnents and it is an 8pin SMD IC, which can be hand soldered also.
Regards,
Laktronics

 

[NicholasTok]

Re: Need help in ELM9748CAA CMOS voltage detector IC for bat

Hi Laktronics,

Thanks for the alternative advice, i will go download the datasheet of LMP7300 to understand more of it.

Regards,
Nicholas Tok

 

[mister_rf]

Re: Need help in ELM9748CAA CMOS voltage detector IC for bat

Are you looking for a 9V-LR22 type battery monitor, low stand-by current or else?
You can use also LTC1440.

Other ideas
https://www.analog.com/UploadedFiles/Application_Notes/783694550AN139.pdf

 

[laktronics]

Re: Need help in ELM9748CAA CMOS voltage detector IC for bat

Hi Nicholas,
As suggested by mister_rf, LTC1440 is aslo an equally good choice. You can just see the price difference and decide. For LTC 1440, go for DIP package, if you want. If you decide on LTC, some component values will change which I can give you.
By the way, do you think that a 9V battery can work down to 5V?, I doubt. Please check on this aspect.
Regards,
Laktronics

 

[mister_rf]

Re: Need help in ELM9748CAA CMOS voltage detector IC for bat

But, threshold voltage is
V=1.18x(R1+R2)/R2
So keep R1- fixed and you need to modify only R2 in order to obtain as threshold voltage 4.8V.
R2=1.18R1/(V-1.18 )
For V=4.8, R1=4.7M
R2=1.5M

 

[NicholasTok]

Re: Need help in ELM9748CAA CMOS voltage detector IC for bat

Hi mister_rf and laktronics

Thank you so much for the help on giving me such informative advice. For the price for LMP7300 cheaper by S$0.9 as compared to LTC1440. according to **broken link removed**.

Think I will get both the IC chips to test.

mister_rf, yap I will be using the 9V/LR22 battery

Regards,
Nicholas Tok