Quank
New Member
Hi everybody!
I'm designing a circuit for providing power to a final load that needs 12 VDS and 600 mA aprox (ie, consuming about 7,2 W). The circuit's input is 12 VDS from a 250 W power supply that is unavailable for some hours everyday. The main function of the circuit is to switchover between this power supply when it is available and a LFP 40 AH Battery when power supply is unavailable. I've already designed the charger for charging the battery in few hours and now I'm trying to design the circuit for making the automatic switchover between main supply and battery supply to the load.
The premises are:
* When power supply is on, the power must supply directly the load and in parallel charge the battery (supply the charger)
* When power is off, the battery must supply the load and don't waste foolish energy.
* It is assumed that when power is on, can be two situations: battery is almost empty and we must spend a lot of power charging the battery while suppling the load; and battery is full and we dont must spend almost power charging, only suppling the load.
* I'm trying to get an economic circuit and not very big, because space is important
* Circuit must be reliable because it works every day
I'm trying to use MOSFETs and comparators, as the main components of the circuit, because they don't use a lot of space and they are cheap components. At the same time, they don't consume so much power knowing that It can be a lot of time in one of the two states (power on or power off).
From the next link, I found an idea for begining the automatic switchover circuit:
**broken link removed**
The circuit is attached as "4410Fig01.gif".
The first problem I have is that I want to put the charger anywhere in the circuit. Where I connect it? How I connect the battery? I need another switch?
The second problem is to find the correct MOSFETs that support a lot of current for charging the battery in few hours. At first I want to ensure 20 A!!
Thank you in advance
I'm designing a circuit for providing power to a final load that needs 12 VDS and 600 mA aprox (ie, consuming about 7,2 W). The circuit's input is 12 VDS from a 250 W power supply that is unavailable for some hours everyday. The main function of the circuit is to switchover between this power supply when it is available and a LFP 40 AH Battery when power supply is unavailable. I've already designed the charger for charging the battery in few hours and now I'm trying to design the circuit for making the automatic switchover between main supply and battery supply to the load.
The premises are:
* When power supply is on, the power must supply directly the load and in parallel charge the battery (supply the charger)
* When power is off, the battery must supply the load and don't waste foolish energy.
* It is assumed that when power is on, can be two situations: battery is almost empty and we must spend a lot of power charging the battery while suppling the load; and battery is full and we dont must spend almost power charging, only suppling the load.
* I'm trying to get an economic circuit and not very big, because space is important
* Circuit must be reliable because it works every day
I'm trying to use MOSFETs and comparators, as the main components of the circuit, because they don't use a lot of space and they are cheap components. At the same time, they don't consume so much power knowing that It can be a lot of time in one of the two states (power on or power off).
From the next link, I found an idea for begining the automatic switchover circuit:
**broken link removed**
The circuit is attached as "4410Fig01.gif".
The first problem I have is that I want to put the charger anywhere in the circuit. Where I connect it? How I connect the battery? I need another switch?
The second problem is to find the correct MOSFETs that support a lot of current for charging the battery in few hours. At first I want to ensure 20 A!!
Thank you in advance