I am using MCP73213 IC for charging my 2S Li Ion battery. I want to use this IC for 1 ampere charging during constant current charge cycle. My specifications are as follows. Input source voltage : 9 volts(10 % accurate) charge current : 1 ampere during constant charging cycle Max power dissipation for such application is as follows : (9.9 volts -6 volts)* 1 ampere = 3.9 W Thermal resistance of IC : 62 C/W So rise of temperature during max power dissipation : 62*3.9 = 241 centigrade. But according to datasheet, IC will die at 150 centigrade. Datasheet of MCP73213 : http://ww1.microchip.com/downloads/en/DeviceDoc/20002190C.pdf I would like to place PCB heat sink below MCP73213 IC to allow power dissipation. What should be the dimension of PCB heat sink. I am really confused. Please help me in this regard.
Electronic – How to decide dimensions of PCB heatsink
battery-chargingheatsinkpcbpower-dissipation
Related Solutions
Do I need to limit the current progressively as the charge progresses? Yes. My understanding is that the battery will 'accept' lower and lower current as it nears the end of charge. You will need to be able to recognize that and then choose a value at which the battery is full. For example when charging current becomes 10% of original charging current then battery is full. For a faster charge, some people might choose a larger percentage as a cutoff.
Do I cutoff charging when voltage reaches 25.2 volts? As you can tell from the answer to number 1, no. To charge the lithium chemistry you start with a constant CURRENT until the battery reaches final voltage (25.2) then you charge at constant VOLTAGE allowing the current to slow down as the battery fills up, terminating charge as described in question 1.
Any IC to build charger around? Yes, lots. You do need to know how to build a charger around the IC but look here for an example. http://www.ti.com/product/bq24616. I am sending this via my phone so please excuse me if this link doesn't work. Just go to the TI.com website and search under power management and you will find around 200 to choose from.
Finally, the BMS that you are going to use could technically control the termination of the charging of the battery and it will in fact provide the all important balance charging that your battery will require, but most people recommend using it only as a backup to a proper battery charger and not to rely on the BMS as a battery charger.
Good luck.
I do not think so, because the documentation does not list any special string with that content.
.Application_BuildNumber - the version of Altium Designer that the PCB is currently loaded in. When generating Gerber output, this string will record the software build that the design was created on
.Arc_Count - the number of arcs on the PCB
.Comment - the comment string for a component (used in designing component footprints)
.Component_Count - the number of components on the PCB
.ComputerName - The name of the machine that the PCB is currently loaded in
.Designator - the designator string for a component (used in designing component footprints)
.Fill_Count - the number of fills on the PCB
.Hole_Count - the number of drill holes on the PCB
.Layer_Name - the name of the layer the string is placed on
.Legend - a symbol legend for mechanical drill plots. This string is only valid when placed on the Drill Drawing layer
.Net_Count - the total number of different nets on the PCB
.Net_Names_On_Layer - the names of all nets on the specific layer. This string is only valid when placed on an internal plane layer
.Pad_Count - the number of pads on the PCB
.Pattern - the names of the component footprints used on the PCB
.Pcb_File_Name - the path and file name of the PCB document
.Pcb_File_Name_No_Path - the file name of the PCB document
.Plot_File_Name - When generating Gerber output, this string identifies the file name of the Gerber plot file. When generating printed output, this string identifies the layer depicted within the output. When generating ODB++ output, this string identifies the name of the parent folder in which the files are stored
.Poly_Count - the number of polygons on the PCB (consisting of polygon pours, internal planes and split planes)
.Print_Date - the date of printing/plotting
.Print_Scale - the printing/plot scale factor
.Print_Time - the time of printing/plotting
.Printout_Name - the name of the printout
.SlotHole_Count - the number of slotted holes on the PCB
.SquareHole_Count - the number of square holes on the PCB
.String_Count - the number of strings on the PCB
.Track_Count - the number of tracks on the PCB
.VersionControl_RevNumber - the current revision number of the document. Version control must be used for this string to contain any information
.Via_Count - the number of vias on the PCB.
Or am I missing your point?
Best Answer
Texas Instruments has this handy guide for PCB heatsinks. AN-2020 Thermal Design By Insight, Not Hindsight