3xBuck click
PID: MIKROE‐3201
Weight: 30 g
3xBuck click is a triple step-down (buck) converter Click board™. It features
three independent output terminals that can provide 1.8V, 3.3V, and 5V with
the combined current output up to 3A. This specific selection of output
voltages makes this Click board™ a perfect choice for an embedded
application power supply, as these voltages are the most commonly used
values. The voltage at each output can be switched to a programmable
internal voltage divider, in cases when the output voltage fine-tuning is
required. This can be done over the industry-standard I2C interface.
The integrated triple buck converter on the Click board™ is labeled as the
TPS65263, and it also features overcurrent, overvoltage, thermal, and short
circuit protection, as well as other functions that allow safe and reliable
operation of the triple buck converter. The TPS65263 uses out-of-phase
PWM control, ensuring that no significant input current ripple appears. Two
modes of operation (continuous current and pulse-skipping mode) allow
optimal efficiency and good performance with any type of load. These
features make the 3xBuck click a perfect solution as a power supply for an
embedded application, but also as a flexible and reliable power supply for
various other types of devices, which require clean and regulated power.
How does it work?
3xBuck click relies on the TPS65263, a triple synchronous step-down
converter with programmable dynamic voltage scaling, from Texas
Instruments. This IC contains three independent switching sections, which
operate at a fixed frequency of 600kHz. One buck section uses the switching
clock which is 180˚ out-of-phase, with respect to other two sections. This
ensures low input current ripple, as well as the lowered EMI of the power
supply itself.
The TPS65263 IC has the I2C bus logic section, which allows the output
voltage of each converter to be programmed. Initially, the output voltage is
set with a pair of feedback voltage divider resistors on each section. The
output voltages of the sections are set to 5V, 3.3V, and 1.8V because these
values are the most commonly used in the embedded applications. As soon
as the command is sent via the I2C interface, the logic section of the
TPS65263 IC takes over the control, allowing to program the voltage at each
of the three outputs between 0.68V to 1.95V, with 10 mV steps. This allows
the desired output to be fine-tuned, according to specific needs of the
application which is powered by the 3xBuck click. The I2C interface is also
used to retrieve the Power Good status, as well as the overcurrent and the
die temperature warning for each buck section, independently.
There are three completely independent switching sections in the TPS65263
IC, which means that each has its own dedicated Enable pin, Soft-Start pin,
and loop compensation pin. The Enable pins for each section are routed to
mikroBUS™. EN1, EN2, and EN3 are routed to AN, PWM and INT pins of the
mikroBUS™, respectively. This allows the host MCU to control the operation
of the 3xBuck click.
Not all three sections share the same characteristics. The output of the
3xBuck click labeled as 1V8 (VOUT1) can withstand up to 3A of current,
while supplied with 12V across the input terminal. Other two outputs can
deliver up to 2A, keeping the output well regulated, well within the 1%
margin. However, it should be noted that this is the combined current rating,
so if multiple outputs are used, the summed current consumption should not
exceed these values. The input voltage should range between 4.5V and 18V
with a remark that it must be sufficiently higher than the selected output
voltage, in order to reach the specified voltage and current ratings.
The soft-start feature is implemented by using a 10nF capacitor at the
dedicated SS pin. Each channel has its own dedicated SS pin, so there are
three pins in total, used to set the soft-start of each channel. The soft-start
function prevents the high inrush current on power up, ramping up the
output current during the soft-start period, defined by the capacitor.
As mentioned before, the device features a set of protecting functions, that
allow reliable operation in events such as the short circuit protection, as well
as the overcurrent, overvoltage, and thermal protection. If the connected
load draws too much current, the cycle-by-cycle current limit will be
activated on both the high-side and low-side output MOSFETs. If the high
current condition persists after 0.5ms, the device will enter the hiccup mode,
shutting down completely, then restarting after 14ms. The whole startup
sequence will be repeated and if the fault condition persists on the output,
this cycle will be repeated. This prevents damage in a case of significant
loads connected at the output. The logic voltage level of the 3xBuck click can
be selected by switching the SMD jumper labeled as VCC SEL to an
appropriate position. This allows interfacing with both 3.3V and 5V MCUs,
expanding the interfacing options of the Click board™.
Specifications
Type
Buck
Applications
A regulated power source with three independent outputs, well
suited for a wide range of embedded applications, single board
systems, general points of load, and similar applications which
can benefit from having three most commonly used regulated
outputs on a single device
On-board
modules
TPS65263, a triple synchronous step-down converter with
programmable dynamic voltage scaling, from Texas Instruments
Key Features
Low power dissipation due to high efficiency, three independent
converters on a same die, overcurrent, overvoltage and thermal
protection, output voltage adjustment over the industry-standard
I2C interface, reasonably high current
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 3xBuck click corresponds to the pinout on
the mikroBUS™ socket (the latter shown in the two middle columns).
Notes
Pin
Channel 1
Enable
Pin
Notes
EN1
1
AN
PWM
16
EN2
Channel 2 Enable
NC
2
RST
INT
15
EN3
Channel 3 Enable
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
Ground
GND
8
GND
GND
9
GND
Power supply
Ground
Onboard settings and indicators
Label
Name
Default
Description
LD1
PWR
-
Power LED indicator
TB1
5V
-
Regulated 5V voltage output connector
TB2
3V3
-
Regulated 3.3V voltage output connector
TB3
1V8
-
Regulated 1.8V voltage output connector
TB4
VIN
External power supply input connector
Software support
We provide a library for the 3xBuck 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 initializes and defines the I2C bus driver and drivers that offer a
choice for writing data in registers and reading data from registers. The
library includes functions for set output voltage, enable and disable buck,
configuration buck and read buck status.
Key functions:
void c3xbuck_enableBuck(uint8_t buck) - Function for enable Buck
void c3xbuck_setVoltage(uint8_t buck, uint8_t voltage) - Function for set output
voltage
void c3xbuck_configurationBuck(uint8_t buck, uint8_t config) - Function for
configuration buck
Examples description
The application is composed of the three sections :
System Initialization - Initializes I2C module and set INT pin, PWM pin and AN pin as OUTPUT
Application Initialization - Initializes the driver init, enable and configuration Buck 1, Buck 2 and
Buck 3c
Application Task - (code snippet) - Sets variable output voltage and default output voltage
note: Default output voltage on Buck 1 is 1800mV, Buck 2 is 3300mV and Buck 3 is 5000mV
Variable output voltage on all Bucks from 680mV to 1950mV
void applicationTask()
{
c3xbuck_setVoltage(_C3XBUCK_SELECT_BUCK_1, _C3XBUCK_OUTPUT_VOLTAGE_1000mV);
c3xbuck_setVoltage(_C3XBUCK_SELECT_BUCK_2, _C3XBUCK_OUTPUT_VOLTAGE_1250mV);
c3xbuck_setVoltage(_C3XBUCK_SELECT_BUCK_3, _C3XBUCK_OUTPUT_VOLTAGE_1500mV);
Delay_ms( 5000 );
c3xbuck_setVoltage(_C3XBUCK_SELECT_BUCK_1, _C3XBUCK_BUCK_DEFAULT_OUTPUT_VOLTAGE);
c3xbuck_setVoltage(_C3XBUCK_SELECT_BUCK_2, _C3XBUCK_BUCK_DEFAULT_OUTPUT_VOLTAGE);
c3xbuck_setVoltage(_C3XBUCK_SELECT_BUCK_3, _C3XBUCK_BUCK_DEFAULT_OUTPUT_VOLTAGE);
Delay_ms( 5000 );
}
The full application code, and ready to use projects can be found on
our LibStock page.
Other mikroE Libraries used in the example:
I2C
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 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/3xbuck‐click 10‐30‐18