STEP UP CLICK
PID: MIKROE-3709
Weight: 21 g
Step Up Click is a fixed frequency DC-DC step-up (boost) regulator, which can be
obtained from any low voltage input - such as NiCd, NiMH or one cell Li-Po/Li-Ion
batteries. This click features very high efficiency, low noise and anti-ringing voltage
output and inrush current limiting with the internal soft-start, as well as true disconnect
option for minimized power drain, when in shutdown mode. These features allow this
device to be used as the power source for various battery-operated devices, such as
microcontrollers, various portable embedded electronic devices, handheld instruments,
GPS modules, or various battery-operated USB emergency backup chargers. Very
good switching efficiency factor ensures prolonged battery life for any application this
device is used in.
Step Up click board™ 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.
Step Up click carries the MCP1665, a high-voltage, 3.6A, integrated switch PFM/PWM
boost regulator, available in a 2mm x 2mm VQFN® package, from Microchip. Boost
click provides an adjustable output voltage through the onboard DAC that drives the FB
pin of the MCP1665 to set desired output voltage. The input voltage can be in range
from 2.9V to 5V V from an external DC source connected to VIN screw terminal. The
output voltage can be set up to 32V.
HOW DOES IT WORK?
Step Up click utilizes the MCP1665, a 500 kHz, compact, high-efficiency, fixedfrequency, nonsynchronous step-up DC-DC converter that integrates a 36V, 100 mΩ
NMOS switch, from Microchip. This IC is targeted towards boosting the voltage
from NiCd, NiMH, Li-Po/Li-Ion batteries and as such it has a great efficiency factor, that
allows for prolonged battery life. The MCP1665 IC uses the fixed switching frequency of
500 kHz and has the overvoltage protection to ensure safe operation.
Thanks to the undervoltage lockout feature, the voltage step-up process starts with the
input voltage as low as 2.7V. MCP1665 features an UVLO that prevents fault operation
below 2.7V, which corresponds to the value of three discharged primary Ni-Cd cells.
The device starts its normal operation at 2.85V (typical) input. For the optimal efficiency,
the device should be powered with at least 2.85V at the input terminal. Output current
depends on the input and desired output voltageFor example, when powered with 4V at
the input, Step Up click will be able to deliver about 1A @ 12V to the connected load. As
with the most step-up regulators, the input voltage should always be less than the
voltage at the output to maintain the proper regulation. On the diagram below, the
dependence of the maximum output current (Iout) on the input and typical output
voltages is given.
The MCP1665 step-up regulator actively damps the oscillations typically found at the
switch node of a boost converter. This removes the high-frequency radiated noise,
ensuring low noise operation.
Besides the MCP1665, Step Up 2 click also contains the D/A converter (DAC) labeled
as MCP4921, 12-Bit DACs with the SPI Interface by Microchip, which is used in
feedback loop. The DACs is connected to the feedback loop of the boost converter and
therefore, the DAC signal which commonly ranges from 0 to +VREF, influences the
voltage on the feedback midpoint. That way, the output voltage can be set to a desired
value, up to 30V. The mentioned DAC uses SPI communication so the SDI, SDO, SCK,
and CS pin of the mikroBUS™ are used for communication with the main MCU.
The device also features the mode pin, labeled as MOD, which is constructed as the
open-drain output, that is pulled HIGH by the onboard 10K resistor. This allows an easy
interfacing with the MCU and a simple solution to have the control over the switching
mode. When the MOD pin is set to logic high level, the device is switching in PFM for
light load. The MOD pin is routed to the mikroBUS™ RST pin
Besides the mode pin, the EN pin used to enable the device is routed to the
mikroBUS™ CS pin. When pulled LOW, this pin will engage the true disconnect of the
output load option, resulting in very low quintessential currents, suitable for the batteryoperated devices. This pin is also pulled HIGH by the onboard resistor.
SPECIFICATIONS
PINOUT DIAGRAM
This table shows how the pinout on Step Up click corresponds to the pinout on the
mikroBUS™ socket (the latter shown in the two middle columns).
Notes
Pin
Pin
NC
1
AN
PWM
16
EN
MOD
2
RST
INT
15
NC
CS
3
CS
RX
14
NC
SPI Clock
SCK
4
SCK
TX
13
NC
SPI Data Out
SDO
5
MISO
SCL
12
NC
SPI Data In
SDI
6
MOSI
SDA
11
NC
NC
7
3.3V
5V
10
5V
GND
8
GND
GND
9
GND
Mode input
SPI Chip Select
Ground
Notes
Enable Input
Power Supply
Ground
ONBOARD SETTINGS AND INDICATORS
Label
Name
Default
Description
LD1
PWR
-
Power LED Indicator
TB1
VIN
-
Input voltage terminal
TB2
VOUT
-
Output voltage terminal
SOFTWARE SUPPORT
We provide a library for the Step Up 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
Library contains functions for setting states of RST and PWM pins Library contains
function for setting configuratoin word Library contains function for setting output value
Library contains function for calculating output value expressed in percent Library
contains function for device initialization.
Key functions:
uint8_t stepup_setConfig( uint16_t config ) - sets first 4 bits in command word.
uint8_t stepup_setOut( uint16_t out_value ) - sets output value.
void stepup_init(void) - initializes the device.
Examples description
The application is composed of three sections :
System Initialization - Initializes SPI, LOG, RST, CS and PWM pins
Application Initialization - Initializes SPI driver, sets config word, initializes the device, sets and log
output value
Application Task - Checks for user input in UART terminal, if user enters + or - output value is
increased or decreased respectively
void applicationTask( )
{
if (UART_Data_Ready( ) == 1)
{
uart_char = UART_Read( );
switch ( uart_char )
{
case '‐' :
{
if (out_value 0)
{
out_value‐‐;
}
stepup_setOut( out_value );
stepup_logPercent( out_value );
break;
}
default :
{
mikrobus_logWrite( "error : invalid command", _LOG_LINE );
break;
}
}
}
}
Additional Functions :
stepup_logPercent() - calls 'stepup_getPercent()' function to get output value in expressed as
percentage and logs that value
The full application code, and ready to use projects can be found on our LibStock page.
Other mikroE Libraries used in the example:
SPI
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/step‐up‐click/8‐20‐19