Hi Could anyone please provide a schematic with component specs/values for a Low voltage switch / cut off using a n channel mosfet.
I have a power supply consisting of a 5S lithium battery pack and its powering a 35 watt LED via a constant current driver.
I want the circuit to latch when the battery is connected and unlatch/disconnect when the supply voltage drops to 15 volts.
I have seen some examples using a FQP47P06 and FQP30N06L and understand the concept but I don't know where to begin to set the correct disconnect threshold.
Could anyone please help with a schemtaic?
OK here is a little more.....
here is a basic schematic. (constant current circuit omitted for clarity)
Source: 5S Lipo @ 18.5v
Load: Cree Xhp 70 ~ 12v @ 1050 mA, max 12.8V @ 2400mA
Mosfet :FQP30N06L or similar
What I Know:
he Mosfet allows power flow through the drain and source pins when the gate pin receives a voltage between 1v & 2.5V and higher.
When the gate pin receives a voltage below 1v the flow between drain and source stops.
What I Need to Know:
Using minimal components and keeping generated heat to a minimum, I want the mosfet gate pin to disconnect when the battery voltage drops to 15v.
So I need the line to the gate to drop from above 2.5v to below 1v when the battery voltage falls below 15v.
Other requirements:
Mosfet to be active when battery is connected.
Mosfet to cut power when battery voltage drops to 15v.
Kept as simple as possible.
No buttons to turn it on or off.
No audible or visual indicator. Easy to obtain components.
I have seen similar circuits but they use p channel mosfets, I hear that its better to have the n channel as its easier to pull it to ground when the circuit fails than it is to try and supply +5v when the circuit fails.
I like the simplicity of this circuit http://forum.allaboutcircuits.com/threads/request-guidance-nimh-low-voltage-cut-off.91806/ but not sure if it'll work for my application or if it can be tweaked for it and it is a p channel type.
Any help you can give would be appreciated.
I have a power supply consisting of a 5S lithium battery pack and its powering a 35 watt LED via a constant current driver.
I want the circuit to latch when the battery is connected and unlatch/disconnect when the supply voltage drops to 15 volts.
I have seen some examples using a FQP47P06 and FQP30N06L and understand the concept but I don't know where to begin to set the correct disconnect threshold.
Could anyone please help with a schemtaic?
OK here is a little more.....
here is a basic schematic. (constant current circuit omitted for clarity)
Source: 5S Lipo @ 18.5v
Load: Cree Xhp 70 ~ 12v @ 1050 mA, max 12.8V @ 2400mA
Mosfet :FQP30N06L or similar
What I Know:
he Mosfet allows power flow through the drain and source pins when the gate pin receives a voltage between 1v & 2.5V and higher.
When the gate pin receives a voltage below 1v the flow between drain and source stops.
What I Need to Know:
Using minimal components and keeping generated heat to a minimum, I want the mosfet gate pin to disconnect when the battery voltage drops to 15v.
So I need the line to the gate to drop from above 2.5v to below 1v when the battery voltage falls below 15v.
Other requirements:
Mosfet to be active when battery is connected.
Mosfet to cut power when battery voltage drops to 15v.
Kept as simple as possible.
No buttons to turn it on or off.
No audible or visual indicator. Easy to obtain components.
I have seen similar circuits but they use p channel mosfets, I hear that its better to have the n channel as its easier to pull it to ground when the circuit fails than it is to try and supply +5v when the circuit fails.
I like the simplicity of this circuit http://forum.allaboutcircuits.com/threads/request-guidance-nimh-low-voltage-cut-off.91806/ but not sure if it'll work for my application or if it can be tweaked for it and it is a p channel type.
Any help you can give would be appreciated.