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The MCP73831 device is an advanced linear
charge management controllers for use in
space limited, cost-sensitive applications.
The MCP73831 is available in an 8-Lead, 2 mm x 3 mm
DFN package or a 5-Lead,
SOT23 package.
Along with their small physical size, the low number of
external components required make the MCP73831 ideally suited for
portable applications.
For applications charging from a USB
port, the MCP73831
adhere to all the specifications
governing the USB power bus.
The MCP73831 employ a constant-current and constant-voltage charge
algorithm with selectable preconditioning and charge
termination.
The constant voltage regulation is fixed
with four available options:
4.20V, 4.35V, 4.40V or 4.50V, to
accommodate new, emerging battery charging
requirements. The constant current value
is set with one
external resistor.
The MCP73831 device limit the charge
current based on die temperature during high power or high ambient
conditions.
This thermal regulation optimizes
the charge cycle time while maintaining device
reliability. Several options are available
for the preconditioning threshold, preconditioning current
value, charge termination value and automatic
recharge threshold.
The preconditioning value and charge termination
value are set as a ratio, or percentage,
of the programmed constant current
value.
The MCP73831 device is fully a specified
over the ambient temperature range of -40°C to +85°C.
The Circuit
The circuit is very simple and uses few external components which facilitates
the assembly and reduces the assembly cost, the standard charging voltage
regulation is normally set at 4.2V.
However, there are variations in the nomenclature of the last digit of the
IC that differentiate them from the standard charging voltage, such as:
- MCP73831-2 = 4.2V
- MCP73831-3 = 4.3V
- MCP73831-4 = 4.4V
- MCP73831-5 = 4.5V
The constant current charging value, is adjusted through resistor
2.2K ohms R3, which in our circuit is programmed for a
~450mA charge. Using a simple formula, we can vary this constant
charging current:
Rc = charging resistor
CC = charging current in mA
Formula:
Cc = 1000/Rc
Being our 2.2K resistor, we have:
Cc = 1000/2.2
Cc = ~ 450mA
Remembering that the minimum charging current for this device is
15mA and the maximum current is 500mA.
Lithium-ion Batteries have become popular in large scale in portable
electronic devices, due to them having higher energy density compared to
other batteries on the market.
Benefits include thousands of recharges and none of the old, well-known “memory effect” problems we had in the first rechargeable
NiCd battery cells.
However, lithium-ion batteries must be charged following a carefully
controlled constant current (CC) and constant voltage
(CV) pattern that is unique to this type of cell.
Overloading and careless handling of a Li-Ion cell can cause
permanent damage or instability and a potential danger of explosion.
In Figure 2 below, we have the
3.7V Li-Ion Battery Charger Circuit schematic diagram, with the
MCP73831 IC and we can follow and analyze the entire circuit, which
is a simple and easy-to-assemble circuit, with few external components.
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| Fig. 2 - 3.7V Li-Ion Battery Charger Circuit with IC MCP73831 |
You may be interested in:
Features
- Linear load management controller:
- Integrated pass-through transistor
- Integrated current direction
- Reverse Discharge Protection
- High precision preset voltage regulation: +0.75%
- Four voltage regulation options: 4.20V, 4.35V, 4.40V, 4.50V
- Programmable load current: 15 mA to 500 mA
- Selectable preconditioning: 10%, 20%, 40% or Disable
- Selectable end of charge control: 5%, 7.5%, 10% or 20%
- Three-state status output - MCP73831
- automatic shutdown
- Thermal regulation
- Temperature range: -40°C to +85°C
- Packaging: 5 derivations, SOT-23
- applications
- Lithium Ion / Lithium Polymer Battery Chargers
- Personal Data Assistants
- Mobile phones
- Digital cameras
- MP3 Players
- Bluetooth Headphones
- USB chargers
Components List
- U1 ...................... Integrated Circuit MCP73831
- LED1 ................. Light Emitting Diode - Red
- LED2 ................. Light Emitting Diode - Green
- R1, R2 ............... 240 Ohm Resistors
- R3 ...................... 2.2K Ohms Charging Program
-
Others ................ Wires, connectors, PCI, tin etc.
The PCB - Printed Circuit Board
We are offering the PCB, in GERBER, PDF and PNG files, for you who want to do the most
optimized assembly, either at home.
If you prefer in a company that develops the board, you can is downloading
and make the files in the Download option below.
Files to download, Direct Link:
Click on the link beside: GERBER, PDF and PNG files
If you have any questions, suggestions or corrections, please leave them in the comments and we will answer them soon.
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