Hi guys!
I'm relatively new to designing circuits and I would like to have some input from someone who is knowledgeable about it.
I'm trying to get a board with some regulators and a PIC on it work even when main power goes out and switches to battery. For that, I'm using an icl7673 chip to perform the automatic switch between main power to battery when needed. The main source would be coming from a 12V adapter and the secondary source (9v rechargeable battery) would be the secondary source. I connected it such as shown in figure 8 of the datasheet attached ..except that I added a 220ohm resistor with an LED between pins 1 and 6 so I could actually see which source it's being used. I checked through the other thread of a person also using this chip in the forum and followed same suggested procedure for calculating what value Rc should be and I ended up using a 680 ohm resistor.
I've put the chip on the breadboard and I do see that it switches between sources. However I'm having problems now with the battery that I'm wondering if I ruined it or something and would like someone more knowledgeable of this to point out where I went wrong. What I see happening is that after the battery is charged ( I measured it with multimeter and got 8.5 volts or so), I connect it and turn on the main power so the board is being powered by the 12 volt..the program on the PIC works fine and everything is well, but when I turn off the main power, so battery works, the system does not work at all and it all just shuts off despite the battery being "charged". I unplugged the battery and checked it again with multimeter and then I read that it was 1.8 volts. What am I doing wrong? Any suggestions?
The battery that I am using is this one from Radioshack:
http://support.radioshack.com/support_tutorials/batteries/bt-nicd-hicap-9V.htm
Thank you very much in advance for any input. I know you guys are busy I read so many interesting questions some people are having. I'm doing this for a hobby so I don't need immediate response, but I would appreciate some help
I'm relatively new to designing circuits and I would like to have some input from someone who is knowledgeable about it.
I'm trying to get a board with some regulators and a PIC on it work even when main power goes out and switches to battery. For that, I'm using an icl7673 chip to perform the automatic switch between main power to battery when needed. The main source would be coming from a 12V adapter and the secondary source (9v rechargeable battery) would be the secondary source. I connected it such as shown in figure 8 of the datasheet attached ..except that I added a 220ohm resistor with an LED between pins 1 and 6 so I could actually see which source it's being used. I checked through the other thread of a person also using this chip in the forum and followed same suggested procedure for calculating what value Rc should be and I ended up using a 680 ohm resistor.
I've put the chip on the breadboard and I do see that it switches between sources. However I'm having problems now with the battery that I'm wondering if I ruined it or something and would like someone more knowledgeable of this to point out where I went wrong. What I see happening is that after the battery is charged ( I measured it with multimeter and got 8.5 volts or so), I connect it and turn on the main power so the board is being powered by the 12 volt..the program on the PIC works fine and everything is well, but when I turn off the main power, so battery works, the system does not work at all and it all just shuts off despite the battery being "charged". I unplugged the battery and checked it again with multimeter and then I read that it was 1.8 volts. What am I doing wrong? Any suggestions?
The battery that I am using is this one from Radioshack:
http://support.radioshack.com/support_tutorials/batteries/bt-nicd-hicap-9V.htm
Thank you very much in advance for any input. I know you guys are busy I read so many interesting questions some people are having. I'm doing this for a hobby so I don't need immediate response, but I would appreciate some help
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