BUCK 11 CLICK
PID: MIKROE-3438 Weight: 25 g
Buck 11 click is a high-efficiency step-down converter which provides 3.3V on its
output, derived from the connected power supply voltage, in the range from 4.2V to
60V. Buck 11 click is based on the LMR36015, a highly efficient DC-DC step-down
converter. In addition, Buck 11 click offers monitoring the stability of the output voltage
by employing an additional A/D converter circuit. Due to its high efficiency, LMR36015
allows the Click board™ to easily deliver up to 1.5A of current. The efficiency for lighter
loads is optimized by using the PFM mode. It features a HotRod™ package which
enables a low noise performance, high efficiency, and very compact size.
Buck 11 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.
The LMR36015 has a wide voltage input range, which is one of its key features. It can
sustain transients up to 66V at its input, making it compliant with the surge immunity
requirements of IEC 61000-4-5. It also features a set of standard protection options,
found on many similar devices: undervoltage lockout, short circuit protection, thermal
shutdown, etc. The Click board™ can be used for a wide range of applications that
require 3.3V, including field embedded applications, sensors, PLC modules, video
surveillance systems, and similar applications that require step-down conversion to
3.3V.
HOW DOES IT WORK?
Buck 11 click is equipped with the LMR36015, a synchronous step-down converter,
from Texas Instruments. This is an advanced integrated step-down converter, which
requires a minimum number of external components, readily available on the market. It
utilizes a peak-current-mode control architecture, which along with the automatic
PFM/PWM mode switching, ensures a very good efficiency. The LMR36015 buck
converter features over-current, under-voltage, and thermal protection, making Buck 11
click a robust and reliable power supply solution.
The output voltage is determined by the feedback voltage on the FB pin. The output
voltage is set to 3.3V making it usable with most embedded applications, allowing them
to be powered from the same source, like the rest of the application, which may use a
higher voltage for its operation. This is a common-case scenario in various field
applications where a relatively high voltage is required i.e. for servos, step motors,
displays, etc.
When there is overload at the output, the low-side MOSFET will allow the inductor
current to drop. It will remain open until the current through the inductor falls below the
limit. If the FB voltage drops too much during the overload, the device enters the hiccup
mode, in which the device attempts to periodically restarts itself.
The LMR36015 is able to automatically switch between PWM and PFM modes,
depending on the current through the load. At very light loads, the device is operated in
PFM mode. In this mode, the high-side MOSFET is operated in bursts, after which the
LMR36015 waits for the current through the inductor to drop below the limit. This way,
the device is in an idle state, while the light load consumes energy stored within the coil.
This greatly improves the efficiency when a light load is used.
While operated in PWM mode, the output MOSFETs are driven with the constant PWM
frequency of 400kHz, using the pulse width modulation to control the output voltage.
This provides very good voltage regulation and a low output voltage ripple.
Featuring the HotRod™ technology, the LMR36015 occupies a very small area on the
PCB. Combined with the low count of external components it requires, the LMR36015
leaves enough space for an additional IC to be used. This click uses the MCP3221, a
12-bit A/D converter (ADC) which uses the I2C interface, from Microchip. It allows
monitoring the output voltage over the I2C interface. This ADC is powered from the +5V
mikroBUS™ power rail. The same voltage is used as a reference. The Click board™
itself requires an external power supply to be connected at the input terminal, labeled as
VIN. The VOUT terminal provides the connected load with the regulated 3.3V voltage.
SPECIFICATIONS
Type
Buck
Applications
It can be used for a wide range of applications that require 3.3V,
including field embedded applications, sensors, PLC modules,
video surveillance systems, and similar applications that require
step-down voltage conversion.
On-board
modules
LMR36015, a synchronous step-down converter, from Texas
Instruments; MCP3221, a 12-bit A/D converter (ADC) which uses
the I2C interface, from Microchip.
Key Features
Low power dissipation due to high efficiency, over-current, undervoltage, and thermal protection, wide range for the input supply
voltage, ADC for measuring the output voltage accuracy, etc.
Interface
I2C
Input Voltage
5V
Click board
size
M (42.9 x 25.4 mm)
PINOUT DIAGRAM
This table shows how the pinout on Buck 11 click corresponds to the pinout on the
mikroBUS™ socket (the latter shown in the two middle columns).
Notes
Ground
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
NC
7
3.3V
5V
10
5V
GND
8
GND
GND
9
GND
Power Supply
Ground
BUCK 11 CLICK ELECTRICAL SPECIFICATIONS
Description
Min
Typ
Max
Unit
Efficiency (5V at VIN, 0.1A to 1.5A)
83.15
-
92.52
%
Efficiency (30V at VIN, 0.1A to 1.5A)
68.67
-
79.52
%
Output voltage (VOUT)
-
3.3V
-
V
Output current (continuous)
0
-
1.5
A
ONBOARD SETTINGS AND INDICATORS
Label
Name
Default
Description
PWR
PWR
-
Power indication LED
VIN
VIN
-
External PSU input connector
VOUT
VOUT
-
Output connector
SOFTWARE SUPPORT
We provide a library for the Buck 11 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
The library allows user to perform the VOUT measurement of the Buck 11 Click board.
One measurement cycle can consist a one conversion or more averaged conversions.
This library also allows user to enter a real measured reference voltage for the AD
conversion (VDD). For more details check documentation.
Key functions:
void buck11_set_vdd_value( float vdd_volts ) - This function allows user to set VDD voltage to
the desired (measured) value.
uint16_t buck11_read_adc( void ) - This function reads the results of the AD conversion from the
MCP3221A5T 12-bit converter.
float buck11_get_vout( uint8_t vout_resolution ) - This function allows user to get VOUT
voltage value in the desired unit resolution, volts or millivolts.
Examples description
The application is composed of the three sections :
System Initialization - Initializes peripherals and pins.
Application Initialization - Initializes I2C serial interface and selects the desired VDD voltage value
and VOUT value resolution (to get VOUT value in Volts). Note : The user should measure the VDD
voltage value and enter this measured value to the function as VDD value to get more accurate
measurement. This VDD voltage is used as reference voltage for the AD conversion.
Application Task - (code snippet) - Reads the averaged VOUT voltage calculated to Volts by
performing a 30 conversions in one measurement cycle. The measured results will be showed on
the uart terminal every 300 milliseconds. Note : The input voltage (VIN) range is from 4.2V to 60V.
The output current (IOUT) value should not be greater than 1.5A.
void applicationTask()
{
vout_value = buck11_get_averaged_vout( vout_resol, 30 );
FloatToStr( vout_value, text );
floatCut();
mikrobus_logWrite( "** VOUT : ", _LOG_TEXT );
mikrobus_logWrite( text, _LOG_TEXT );
if (vout_resol == _BUCK11_VOUT_VOLTS)
{
mikrobus_logWrite( " V", _LOG_LINE );
}
else
{
mikrobus_logWrite( " mV", _LOG_LINE );
}
mikrobus_logWrite( "*************************************", _LOG_LINE );
Delay_ms( 300 );
}
Additional Functions :
floatCut - Allows to real values be rounded on two decimal places.
The full application code, and ready to use projects can be found on our LibStock page.
Other mikroE Libraries used in the example:
I2C
UART
Conversions
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/proximity‐8‐click//4‐9‐19