shut down supply voltage comparator

[yassin.kraouch]

i have an external battery ( 12V) that supply a developpement board throught a DC-DC converter, i want that if the voltage of the battery is below 12V i force DC-DC chip to not work, have you an idea about this ?

 

[joseMiguel]

Hi,

you need to have an another reference(low power, commercial battery) and to compare it with your battery and then drive a MOS transistor to shut down the supply of the development board.
Or to use a chip with a shutdown integrated.
Hope it helps you.
joseMiguel

 

[yassin.kraouch]

is there any method to be used in without shut a reference ?

 

[ALERTLINKS]

You need a voltage monitor circuit, when it detects voltage below a certain level, it disable dc-dc converter through its enable input. A series transistor can also switch off power to dc-dc converter.

TL431 Battery Voltage Monitor - Storage

In this circuit disconnect R3 from +ve and connect to base of series pnp transistor to disconnect 12v supplying to converter circuit.

 

[yassin.kraouch]

You mean that i should connect the base of a transistor in Ve and the emitter to the cathod of LM431 ? and the collector to the input ?