Charger 2 click
PID: MIKROE‐3049 Weight: 24 g
Charger 2 click is a LiPo/Li‐Ion battery charger with the additional monitoring IC
onboard. This Click board™ as a whole, offers unpreceded battery charging and monitoring
solution for 3.7V LiPo/Li‐Ion batteries, with the capacity measurement/gas gauge function,
for up to 7000 mAh. It provides measurement data via the I2C interface and two signaling
LEDs on the Click board™ itself. It features two dedicated ICs ‐ one for charging the battery
and one for monitoring its status. The charging function is performed by the
STBC08, a standalone linear battery charger IC, while the monitoring of the critical battery
parameters is done by the STC3100, a battery monitor IC with Coulomb counter/gas gauge.
Featuring an independent charging IC with the user adjustable charge current,
undervoltage protection, automatic recharge, charge termination, thermal protection, soft
start function, as well as the the specialized battery gauge IC, used to provide battery
depletion data via the I2C interface, Charger 2 click can be used to charge and
monitorLiPo/Li‐Ion batteries for a wide range of applications that can benefit from reliable
and efficient LiPo/Li‐Ion battery charger.
How does it work?
As already mentioned, Charger 2 click features two dedicated ICs, which are used to
manage LiPo/Li‐Ion battery charging process and to provide monitoring data. Charging
itself is done by the STBC08, an 800 mA standalone linear Li‐Ion battery charger with
thermal regulation, from STMicroelectronics. This IC features a lot of protection and
charging functions that minimize the battery degradation while charging.
The nominal charging voltage is set to 4.2V. The STBC08 IC maintains constant
current/voltage, providing maximum charging rates while avoiding overheating of the IC.
The charging current is limited to about 450 mA with the onboard resistor connected to the
PROG pin of the IC. It can be further adjusted down to 80mA by the onboard potentiometer,
which is connected in series with the PROG pin resistor. When the battery is nearly fully
charged, and the charging current drops to 10% of the programmed value, the charging is
terminated. The device automatically restarts the charge cycle when the battery
voltage drops below 4.05 V, maintaining the battery capacity value above 80%.
Two LEDs are used to signalize status of the STBC08 IC: red LED is used to signalize the
ongoing charge process. The green LED signalizes if the charging conditions are nominal
and within the specs. It signalizes the validity of the charging voltage value.
The battery connector is supplied with the regulated power from the STBC08 IC via the
BAT pin. This pin outputs the current and voltage for the battery charging. This connector
is mounted on the Click board™ PCB and it is a standard 2.54mm pitch male pin battery
connector, used on most of MikroElektronika products for connecting LiPo/Li‐Ion
batteries. With its lock‐on feature, it provides a secure and reliable connection.
For monitoring purposes, Charger 2 click uses the STC3100, a battery monitor IC with
Coulomb counter/gas gauge, also from STMicroelectronics. It monitors voltage and current
of the charging battery. It also includes hardware functions to implement a gas gauge for
battery charge monitoring, based on a programmable A/D converter. This IC can measure
the battery capacity up to 7000mAh.
Gas gauge utilizes a sensing resistor of 50mΩ, and the voltage drop on this resistor is
sampled by an internal 12‐14 bit ADC. These measurements are integrated and stored into
an internal register. The host MCU can read this data via the I2C interface, with its lines
routed to the appropriate I2C pins of the mikroBUS™. The resolution of the gas gauge
measurement is 0.2 mAh
Battery voltage is measured and converted by a separate ADC, providing readings which
are independent of the readings made by the gauge section. The battery output voltage is
routed to the VIN pin of the STC3100 and can be read via the I2C interface. In a case when
the battery voltage drops under the defined threshold, the IC shuts down and no current is
drawn from the connected battery. The measurement resolution is 2.44 mV for the battery
voltage and 0.125° C for the temperature.
STC3100 also features an additional 32 volatile RAM memory locations for storing various
application relevant data. The status of this memory is retained as long as there is the
power supply to the IC itself. When the power supply is cut off, the content of this memory
is lost.
The Click board™ is equipped with the SMD jumper labeled as VCCIO SEL, used to choose
between 3.3V or 5V operation. However, this Click board™ requires 5V to be present on its
5V mikroBUS™ rail, because it is used as the power source for the battery charging IC.
VCCIO SEL jumper only allows logic voltage level to be selected, in order to interface the
Click board™ with both 3.3V and 5V MCUs.
Specifications
Type
Applications
On-board
modules
Key Features
Battery charger
It can be used for applications that require optimal and reliable
charging of 3.7 V Li-Po batteries.
STBC08, an 800 mA standalone linear Li-Ion battery charger with
thermal regulation; STC3100, a battery monitor IC with Coulomb
counter/gas gauge, both from STMicroelectronics.
A wide range of different monitoring and charging features, which
provide optimal charging characteristics, gas gauge measurement
of the remaining battery capacity, manual regulation of the
charging current limit.
Interface
I2C
Input Voltage
3.3V,5V
Click board
size
M (42.9 x 25.4 mm)
Pinout diagram
This table shows how the pinout on Charger 2 click corresponds to the pinout on the
mikroBUS™ socket (the latter shown in the two middle columns).
Notes
Pin
Pin
Notes
NC
1
AN
PWM
16
NC
NC
2
RST
INT
15
NC
NC
3
CS
RX
14
NC
NC
4
SCK
TX
13
NC
NC
5
MISO
SCL
12
SCL
I2C Clock
NC
6
MOSI
SDA
11
SDA
I2C Data
Power Supply
+3V3
7
3.3V
5V
10
+5V
Power Supply
Ground
GND
8
GND
GND
9
GND
Ground
Onboard settings and indicators
Label
Name
Default
LD1
PWR
-
CHRG
Red LED
-
Description
Power LED indicator
Indicates charging status of the battery:
lights/blinks while the charging is ongoing
Indicates validity of the charging
PWRON
Green LED
-
conditions: lights/blinks when the
charging conditions are within limits
Logic voltage level selection: left position
JP5
VCCIO SEL
Left
VR1
CURRENT ADJ
-
Charging current limiting potentiometer
BAT CON
BAT CON
-
LiPo/Li-Ion battery connector
3.3V, right position 5V
Software support
We provide a library for Charger 2 click on our Libstock page, as well as a demo application
(example), developed using MikroElektronika compilers and mikroSDK. The provided click
library is mikroSDK standard compliant. The demo application can run on all the main
MikroElektronika development boards.
Library Description
This library provides generic functions for working with the Click board™.
Key functions:
uint8_t charger2_writeReg( uint8_t register_address, uint8_t transfer_data ) - The
uint8_t charger2_readReg( uint8_t register_address, uint8_t *valueOut, uint8_t nBytes
) - The function reads the desired number of data bytes.
function writes one-byte data to the register.
uint8_t charger2_readData( uint8_t dataMode, uint32_t *dataOut ) - The function reads
the desired data from data registers and converts this data to the appropriate unit.
Examples Description
The application is composed of three sections:
System Initialization - Initializes peripherals and pins.
Application Initialization - Initializes I2C driver, performs the counter and accumulator reset and
puts the device in operating mode with the 14-bit ADC resolution.
Application Task - (code snippet) - Reads the all necessary information for the battery charging
status and logs this results on UART. Repeats operation every second. The LED diodes are
used to indicate the Vcc presence when this voltage is in operating range, and to show the
charging status.
void applicationTask()
{
charger2_readData( _CHARGER2_GAS_GAUGE_CHARGE_DATA, &batteryData );
resultsLogger();
charger2_readData( _CHARGER2_CONV_NUMBER, &batteryData );
resultsLogger();
charger2_readData( _CHARGER2_SHUNT_VOLTAGE, &batteryData );
resultsLogger();
charger2_readData( _CHARGER2_BATTERY_VOLTAGE, &batteryData );
resultsLogger();
charger2_readData( _CHARGER2_TEMPERATURE, &batteryData );
resultsLogger();
charger2_readData( _CHARGER2_BATTERY_CURRENT, &batteryData );
resultsLogger();
mikrobus_logWrite( "", _LOG_LINE );
Delay_ms( 1000 );
}
Additional Functions:
void resultsLogger() - Logs the desired data for the battery charging status.
The full application code, and ready to use projects can be found on our Libstock page.
Other mikroE Libraries used in the example:
Conversions
I2C
UART
Additional notes and information
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 by 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‐2‐click 6‐19‐18