PCB Heaven

General Category => Digital discussion => Topic started by: cheerio on January 24, 2013, 03:57:53 AM

Title: lipo protection circuit question
Post by: cheerio on January 24, 2013, 03:57:53 AM
hi guys. i am a little bit confused by a circuit using this ic: http://www.ic-fortune.com/upload/Download/DW01-P_DataSheet_V10.pdf (http://www.ic-fortune.com/upload/Download/DW01-P_DataSheet_V10.pdf)

check out page 3 and have a look at the typical application circuit. in my opinion one of the diodes will always produce a voltage drop. But there is no voltage drop when i measure it. can you point me on my mistake?
Title: Re: lipo protection circuit question
Post by: kam on January 24, 2013, 09:02:46 AM
i suppose you talk about the body diode of the mosfet, right? If so, it will indeed have a voltage drop which will be visible when current flows, but it is typical less than normal diodes, about 0.4V. Depending on the type of the fet, it can be as low as 0.2V at low currents. So you wanna add a resistor to the output to have some current and then measure across the fet at the scale of mV
Title: Re: lipo protection circuit question
Post by: cheerio on January 24, 2013, 14:03:33 PM
ah that's why! thx kam
i think i will use a ~0.1 schottky across because voltage drop really sucks