Low battery voltage - automatic shutdown
Low battery voltage - automatic shutdown
(OP)
4.8-5.2Vdc, 150mAh device is powered by 4-AA nimh batteries in series.
Looking for a simple (few extra components needed) i/c component to regulate voltage in the range of 4.8-5.2Vdc (fully charged, 4-AA nimh can be 6.0Vdc, which might be too much for the device), and, to shutoff device (open the 5.0Vdc 150mAh circuit) when voltage drops below 4.8Vdc (3.3 min. to 4.5 range),
I found LDO linear regulators with integrated reset (e.g. http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3494) and http:/ /focus.ti. com/docs/p rod/folder s/print/tp s7325.html
But, I didn't see an application diagram for my situation.
Mick
Looking for a simple (few extra components needed) i/c component to regulate voltage in the range of 4.8-5.2Vdc (fully charged, 4-AA nimh can be 6.0Vdc, which might be too much for the device), and, to shutoff device (open the 5.0Vdc 150mAh circuit) when voltage drops below 4.8Vdc (3.3 min. to 4.5 range),
I found LDO linear regulators with integrated reset (e.g. http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3494) and http:/
But, I didn't see an application diagram for my situation.
Mick





RE: Low battery voltage - automatic shutdown
http:/
They have a truck load - run thru their parametric search.
Linear Technology also has these devices as does National. However National's web site has gone from very good to supreme suckedness in recent months.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Low battery voltage - automatic shutdown
I looked and read, but I still don't get it. I don't have enough electronics savy.
Linear Technologies LM1121 series shows some circuit diagrams in their pdf data sheet (1121fc.pdf) showing how to connect pins. but:
In the case of adjustable regulator, what value of resistors will give output of 4.8 volts? Input is 4-AA nimh. maybe 6.0 volts when fully charged.
I see automatic shutdown pin SHTDN, but I don't know what to connect to this pin, to cause the input to shutdown when battery voltage drops below 4.8V.
RE: Low battery voltage - automatic shutdown
Dan - Owner
http://www.Hi-TecDesigns.com
RE: Low battery voltage - automatic shutdown
h
Undervoltage shutdown is something that laptops have to have.
TTFN
RE: Low battery voltage - automatic shutdown
RE: Low battery voltage - automatic shutdown
I agree with Keith, something has gone wrong with National's website. I wonder what machines or what software their web developers are using, but it shows really bad on my Opera browser.
RE: Low battery voltage - automatic shutdown
Thanks for your suggestion. I may try to figure how to use LP2986 and LM3701 if this (below) doesn't work.
Couple of days ago, I found a simple low battery cutoff circuit at <http://www.edn.com/archives/1998/091198/19di.htm>
It uses a Panasonic MN13812-Q-ND (TO92) voltage detector IC set to trip at 3.8 volt and an Internal Rectifier IRLZ14S-ND (D3PAK) MOFSET to open and close the circuit.
I will add a Microchip MCP1700-5002E (TO92) 5V LDO voltage regulator with 1mfd ceramic capicators in Vin and Vout.
Does this combination seem ok?
Mickey
RE: Low battery voltage - automatic shutdown