Hola,
I'm using LM27313 as new project design as below circuit：
USBVCC is the power supply from NB, but the newest NB USB specification is 5V/1000mA and that will causes the output power increased from 6V/400mA
to 6V/1000mA so the LM27131's temperature will rising to 70'！
My question is that how can I limited the output current fixed at 500mA with this circuit？Can I use LM317 to limited the output current？if yes, how can I integrated
them？
Hi Jacky,
As far as I understand your system , you are charging 6V battery (probably PbAcid) using LM27313 with USB at its input . If that is the case , the better solution is to use single stage LM27313 Boost in Constant current ,Constant Voltage application(CC/CV) .
The idea is to use something like this at the output and modify the feedback :
This was done for 12 Volt battery . You can see there are two loops here one through R1 (the current sense resistance) as CC and other through Zener D3,R4,R3 as CV .The offset in Feedback is added through Shunt regulator TL431 for reducing the looses across the current sense R1 . You might want to go through below reference design for more details
Also you can refer to below application notes for more details on above described circuit :
These examples are made on buck converter but you can use the same concept to modify your feedback circuit in boost converter .
With Regards
Ambreesh
Hola Ambreesh,
Very clearly and helpful, thank you. Below figures are our thermal test result, can you give some advice for reduce temperature？
Or you can advice another device with lower temperature which can meet our application. Thank you ～
Brs
