CHARGER 9 CLICK
PID: MIKROE-3568 Weight: 23 g
Charger 9 click is a Li-Ion (Li+, Li-Po) battery charger, capable of charging one, two or three battery
cells. It is based on the MAX1757, an integrated Li+ battery charger with many features that allow
safe and reliable charging. This IC has an internal switching-mode regulation with input current
limiting, allowing it to use an external power supply from a cheap wall adapter, rated up to 14V. An
extensive state machine of the MAX1757 IC with two additional timers regulates the charging
process, ensuring safe and reliable battery charging process. In the case of an error, the charging
process is stopped, and the fault is reported both over the LED and over the mikroBUS™ pin.
Charger 9 click is supported by a mikroSDK compliant library, which includes functions that simplify
software development. This Click board™ comes as a fully tested product, ready to be used on a
system equipped with the mikroBUS™ socket.
Charging of the Li+ battery cell is a demanding task that requires a very accurate
current and voltage monitoring and limiting. In addition, it also requires specific charging
conditions, depending on the battery level (constant current mode, constant voltage
mode). Li+ batteries contain flammable chemical compounds and can easily be ignited.
The MAX1757 IC closely monitors the battery voltage and current during the charging
process, ensuring safe and reliable operation. Charger 9 click is a perfect solution for
the development of multiple Li+ battery cell charging applications, offering a set of
connectors, pins, and LED indicators, allowing fast and easy prototyping.
HOW DOES IT WORK?
Charger 9 click is equipped with the MAX1757, a stand-alone, switch-mode Li+ battery
charger, from Maxim Integrated. It can be used to charge one to three lithium-ion (Li+,
Li-Po) batteries with up to 1.5A. The number of batteries can be selected by a set of
onboard jumpers. The battery regulation voltage (VBATTR) is set to 4.2V per cell on this
Click board™. High accuracy of the integrated voltage limiter ensures reliable charging
and prevents over-charging of the connected cell. The charging process is closely
monitored and regulated by the extensive state machine with the addition of two timers,
protecting the system if damaged battery cells are connected.
Charger 9 click requires an external power supply for its operation. To prevent an
undervoltage lockout, the input voltage of the external power supply (VIN) should be at
least 100mV larger than the voltage at the BT outputs (BAT pin of the MAX1757 IC).
This prevents discharging of the batteries if the power source voltage drops too low.
The maximum allowed voltage at the VIN terminal of the Charger 9 click is 14V, while
the input current limit is set to 2A.
As already mentioned, the MAX1757 uses an extensive state machine, which is
explained in great details within the datasheet. However, the following is a brief
summary of the description:
The battery voltage (VBATT) is monitored by the state machine. After the IC reset
(power-up, etc.), the MAX1757 IC (charger) enters the so-called Prequalification mode.
Based on the battery voltage level, as well as the voltage of the input power supply (VIN
> VBATT), the state machine decides to start the charging process. If the battery cell is
deeply discharged, the charger tries to restore it by using 1/10 of the full charging
current.
Once the battery level is restored above the battery undervoltage level, and when all the
other prerequisites are met, the charger starts the fast charging process, by switching to
the Constant Current (CC) mode (limited to 1.5A on this Click board™). This mode is
indicated by a yellow LED indicator labeled as FAST, as well as the LOW logic level at
the CHG pin of the Click board™.
When the battery charge level reaches 85% approx. (when the VBATT reaches the
VBATTR, set to 4.2V on this Click board™) the charger switches to the Constant
Voltage (CV) mode. This is indicated by a blue LED indicator labeled as FULL, as well
as the LOW logic level at the FUL pin of the Click board™. The charging current now
starts to drop.
When the battery charge reaches 95% approx. (charging current falls below 330mA) the
charger enters the Top-Off mode, turning off all the LED indicators (CHG and FUL pins
are at the HIGH logic level). The charger is still operated in the CV mode.
After a timer expires, the charging process is done, and all the charging operations are
stopped until the battery voltage drops under the recharge voltage threshold (VBATT =
95% of the VBATTR). When this happens, the IC gets reset and the state machine
cycle is repeated.
Each charging phase has a time-out period: if the time-out period is exceeded, an error
will be indicated by a red LED labeled as FAULT, as well as the LOW logic level at the
FLT pin of the Click board™. An ongoing charging operation will be terminated to
prevent any damage.
HOW TO PROPERLY SET THE NUMBER OF BATTERY CELLS ?
The number of battery cells can be set by moving the SMD jumper labeled as CELL
NUMBER to an appropriate position (1 or 3). To select two cells, the SMD jumper
should be unpopulated. The number of physically connected cell batteries must
correspond to the number of cells set by the CELL NUMBER jumper.
The CELL NUMBER jumper must be used in conjunction with two additional SMD
jumpers, labeled as JP2 and JP3. These two jumpers are used to override unused
connectors in the case when the number of battery cells is less than 3. If an unused
connector is not overridden by a jumper, the GND path will be cut off from the
connected battery (the battery cells are connected in series). By default, the number of
battery cells is set to 3, so JP2 and JP3 should remain unpopulated. Charger 9 click
offers XH type connectors as well as 2-pole terminal screw connectors, allowing to
connect various types of Li+ batteries.
SPECIFICATIONS
Type
Battery charger
Applications
Charger 9 click is a perfect solution for the development of multiple Li+ battery
cell charging applications, offering a set of connectors, pins, and LED
indicators, allowing fast and easy prototyping.
On-board
modules
MAX1757, a stand-alone, switch-mode Li+ battery charger, from Maxim
Integrated
Key Features
Designed for a safe and efficient charging of up to 3 Li-Po / Li-ion battery cells
(selectable), an extensive state machine for reliable charging process, two
types of battery connectors, charging state indicators over LEDs and
mikroBUS™ pins, etc.
Interface
GPIO
Input Voltage
3.3V
Click board
size
M (42.9 x 25.4 mm)
PINOUT DIAGRAM
This table shows how the pinout on Charger 9 click corresponds to the pinout on the
mikroBUS™ socket (the latter shown in the two middle columns).
Notes
Pin
Pin
Notes
Fault Indicator
FLT
1
AN
PWM
16
CHG
Fast charge state indicator
Charger IC
Shutdown
SHD
2
RST
INT
15
FUL
Full charge state indicator
NC
3
CS
RX
14
NC
NC
4
SCK
TX
13
NC
NC
5
MISO
SCL
12
NC
NC
6
MOSI
SDA
11
NC
Power Supply
3.3V
7
3.3V
5V
10
NC
Ground
GND
8
GND
GND
9
GND
Ground
ONBOARD SETTINGS AND INDICATORS
Label
Name
Default
Description
LD1
PWR
-
Power LED Indicator
LD2
FAULT
-
Charger FAULT LED indicator
LD3
FULL
-
Charger FULL status LED indicator
LD4
FAST
-
Charger FAST status LED indicator
BT1 BT3
BT1 - BT3
-
Li-Ion battery cell connection terminals
J1 - J3
BT1 - BT3
-
Li-Ion battery cell XH connectors
JP1
JP2 JP3
Left
Number of battery cells: left position for 3 battery
cells, right position for 1 battery cell, unpopulated
for 2 battery cells
Unpopulated
Override jumpers: unpopulated for a used battery
cell connector, populated for an unused battery
connector
CELL NUMBER
JP2 - JP3
CHARGER 8 CLICK ELECTRICAL SPECIFICATIONS
Description
Min
Typ
6
-
Battery voltage regulation (per cell)
4.167
Full-scale charging current
1.35
Input Voltage (at VIN terminal)
Max
Unit
14
V
4.2
4.233
V
1.5
1.65
A
SOFTWARE SUPPORT
We provide a library for the Charger 9 click on our LibStock page, as well as a demo
application (example), developed using MikroElektronika compilers. The demo can run
on all the main MikroElektronika development boards.
Library Description
This library allows user to perform a control of the Charger 9 Click board. Also user can
check the indication status from the charger to get charging state. Fault condition also
can be checked. For more details check documentation.
Key functions:
void charger9_gpioDriverInit(T_CHARGER9_P gpioObj) - Convert ADC value to Pressure data in
mBar.
T_CHARGER9_RETVAL charger9_enable( T_CHARGER9_STATE pwr_state ) - Convert ADC value to
Voltage in mV.
T_CHARGER9_RETVAL charger9_faultInd( void ) - Sets max output voltage on the AN pin.
Examples description
The application is composed of three sections :
System Initialization - Initializes peripherals and pins.
Application Initialization - Initializes GPIO driver and turns OFF the charger as initial state.
Application Task - (code snippet) - Checks which command was sent by user and performs the
selected command. Also checks the fault condition, and when fault condition is detected sends a
report message to the uart terminal and turns OFF the charger. Note: When user sends a desired
command to the charger, a report message will be sent to the uart terminal as indication to the user.
The possible commands, for Charger 9 control, will be written to the uart terminal. The alarm sound
will be generated on the determined commands: enable, disable and fault condition detecting.
void applicationTask()
{
rx_dat = UART_Rdy_Ptr();
if (rx_dat != 0)
{
rx_dat = UART_Rd_Ptr();
switch (rx_dat)
{
case 'e' :
{
if (en_flag == _CHARGER9_DISABLE)
{
charger9_enable( _CHARGER9_ENABLE );
en_flag = _CHARGER9_ENABLE;
_LOG_LINE );
mikrobus_logWrite( "** Charger 9 is enabled **",
alarmOn();
}
else
{
led **", _LOG_LINE );
}
break;
}
case 'd' :
{
if (en_flag == _CHARGER9_ENABLE)
{
charger9_enable( _CHARGER9_DISABLE );
en_flag = _CHARGER9_DISABLE;
, _LOG_LINE );
mikrobus_logWrite( "** Charger 9 is disabled **"
alarmOff();
}
else
{
bled **", _LOG_LINE );
}
break;
}
case 's' :
{
charge_state = charger9_fullChargeInd();
if (charge_state == _CHARGER9_IND_ACTIVE)
{
OG_LINE );
}
charge_state = charger9_fastChargeInd();
if (charge_state == _CHARGER9_IND_ACTIVE)
{
mikrobus_logWrite( "** Charger 9 is already enab
mikrobus_logWrite( "** Charger 9 is already disa
mikrobus_logWrite( "** Full‐Charge state **", _L
OG_LINE );
mikrobus_logWrite( "** Fast‐Charge state **", _L
}
break;
}
case 'l' :
{
break;
}
default :
{
mikrobus_logWrite( "** Invalid command **", _LOG_LINE );
writeLegend();
break;
}
}
}
charge_state = charger9_faultInd();
if (charge_state == _CHARGER9_IND_ACTIVE)
{
charger9_enable( _CHARGER9_DISABLE );
en_flag = _CHARGER9_DISABLE;
mikrobus_logWrite( "** Fault condition! **", _LOG_LINE );
mikrobus_logWrite( "** Charger 9 is disabled **", _LOG_LINE );
alarmFault();
}
writeLegend();
}
Additional Functions :
alarmOn - Generates an alarm sound for charger power ON.
alarmOff - Generates an alarm sound for charger power OFF.
alarmFault - Generates an alarm sound for fault condition.
writeLegend - Writes possible valid commands to the uart terminal.
The full application code, and ready to use projects can be found on our LibStock page.
Other mikroE Libraries used in the example:
Sound
UART
Additional notes and informations
Depending on the development board you are using, you may need USB UART
click, USB UART 2 click or RS232 click to connect to your PC, for development systems
with no UART to USB interface available on the board. The terminal available in all
MikroElektronika compilers, or any other terminal application of your choice, can be
used to read the message.
MIKROSDK
This click board is supported with mikroSDK - MikroElektronika Software Development
Kit. To ensure proper operation of mikroSDK compliant click board demo applications,
mikroSDK should be downloaded from the LibStock and installed for the compiler you
are using.
For more information about mikroSDK, visit the official page.
https://www.mikroe.com/charger‐9‐click/6‐5‐19