LED Driver 5 click
PID: MIKROE‐3297
Weight: 25 g
LED Driver 5 click is a Click board™ capable of driving an array of high-power
LEDs with constant current, up to 1.5A. This Click board™ features the
TPS54200, a highly integrated LED driver IC, with many useful features. It
consists of a synchronous, fixed-frequency buck converter which operates at
600kHz, providing an excellent size/efficiency ratio. LED Driver 5 click can
use both analog and PWM control signal for dimming the connected LED
array.
It comes in the package which also includes the mikroSDK™ software and a
library with all the functions. The Click board™ comes as a fully tested and
approved prototype, making it a reliable device ready to use on the
development board.
The TPS54200 supports analog and PWM dimming mode. In analog dimming
mode, the internal reference voltage is scaled in the range from 1% to
100%. In the PWM dimming mode, the LED output is synchronized with the
PWM control signal at the input. The smart signal-switching logic
automatically selects the dimming mode by examining the signal applied to
the PWM pin. LED Driver 5 click is an ideal solution for driving a single or
multi-stream LED arrays, including monochrome, white, and IR LED arrays,
providing up to 28V at the output.
How does it work?
The main component of the LED Driver 5 click is the TPS54200, a
synchronous buck converter designed to drive monochrome, color, and IR
LED arrays made by Texas Instruments. The Click board™ is very flexible
regarding the input voltage choice, allowing any voltage in the range from
4.5V up to 28V to be used. This is possible thanks to the TPS54200 driver
IC, which integrates a buck converter IC, and supports an LED dimming by
using the pulse width of the PWM signal on the control input. This IC has a
mode selection logic circuitry which is used to select one of two dimming
modes, depending on the incoming PWM control signal level.
The PWM pin is used to control more than just one function. Besides
choosing the dimming mode (analog or PWM), this pin is also used to enable
or disable the IC. If the signal at the PWM pin rises above the threshold
value (0.56V typically) the IC will be enabled. Keeping the voltage at the
PWM pin lower than 0.56V for at least 40 ms will effectively disable the IC.
After the device is enabled, the magnitude of the PWM signal is detected and
stored by an internal peak detector. The voltage of the peak detector is then
compared with two threshold values, VADIM and VPDIM, after 300 µs. If the peak
detector output is at a higher voltage than 2.07V, analog dimming mode will
be selected and locked. If the peak detector voltage is in the range between
1V and 2.07V, the PWM dimming mode will be selected and locked. If the
voltage is less than 1V, the whole detection process will be repeated after
300 µs, until one of two operating modes is selected and locked. Once
locked, the dimming mode can only be changed by cycling the VIN voltage
or re-enabling the IC. The PWM pin is routed to the PWM pin of the
mikroBUS™, allowing it to be controlled by the host microcontroller (MCU).
When the analog dimming mode is selected (the magnitude of the control
PWM signal is above 2.06V during the boot-up sequence of the TPS54200),
the internal reference voltage (VREF) is scaled down according to the duty
cycle of the PWM signal applied to the PWM pin. The internal reference
voltage for this mode is 200 mV at full-scale (duty-cycle at 100%). As the
duty cycle decreases, the reference voltage is scaled down to 1% of its
value. This will cause the current through the LED to be scaled as well,
effectively dimming the LED. This type of dimming, where the LED intensity
is dimmed to a very low-level invisible to the eye, is sometimes referred to
as deep‐dimming. The PWM control signal at the PWM pin should stay within
the range of 10 kHz, to reduce the output voltage ripple.
If the PWM dimming mode is selected (the magnitude of the control PWM
signal is between 1V and 2.06V during the boot-up sequence of the
TPS54200), the internal reference voltage is fixed at 100mA. In this mode,
the LED dimming is performed by using the PWM signal applied to the PWM
pin, modulating the LED output. Holding the internal reference voltage fixed,
the LED at the output will only be switched ON or OFF, according to the duty
cycle of the control PWM signal.
The buck converter itself is a very feature-rich circuitry, a synchronous buck
converter, operating at the fixed frequency of 600kHz. This offers an
excellent size/efficiency ratio, keeping the footprint of the TPS54200 IC very
small. Features such as the open LED or shorted LED detection, overvoltage,
and under-voltage protection, over-current and open loop protection,
thermal shutdown, soft start function that prevents the inrush current, allow the
Click board™ to be a very reliable and safe solution for driving high current
LEDs or LED arrays.
The Click board™ contains four SMD jumpers used to select the current
through the LED array. They are grouped together and labeled as IOUT. There
are four different settings: 0.35A, 0.7A, 1A, and 1.5A. Switching the current
selection SMD jumper to the ON position will connect a respective sensing
resistor (RS)to the circuit. The value of each RS is calculated using a very
simple formula, given in the datasheet of the TPS54200 IC:
ILED = VREF/RS
Note that switching two SMD jumpers to the ON position simultaneously will
cause them to form a parallel connection with its equivalent resistance.
However, this is not recommended since almost all the resistor combinations
will result with the value too low to be used (the LED current will be set to
above 1.5A, thus triggering the protection circuit)
Specifications
Type
Buck
Applications
LED Driver 5 click is an ideal solution for a reliable and efficient
driving of a single or multi-stream LED arrays, including
monochrome LED, white LED, and IR LED arrays, providing up to
28V at the output
On-board
modules
TPS54200, a synchronous buck converter for driving
monochrome, color, and IR LED arrays
Key Features
Highly regulated, selectable LED current, can use a wide range of
power supply voltages, open LED or shorted LED detection,
overvoltage and undervoltage protection, over-current and openloop protection, thermal shutdown, soft start function prevents
the inrush current
Interface
PWM
Input Voltage
3.3V or 5V
Compatibility
mikroBUS
Click board
size
M (42.9 x 25.4 mm)
Pinout diagram
This table shows how the pinout on LED Driver 5 click corresponds to the
pinout on the mikroBUS™ socket (the latter shown in the two middle
columns).
Notes
Pin
Pin
Notes
PWM
Control PWM
Signal
10
5V
Power supply
9
GND
NC
1
AN
PWM
16
NC
2
RST
INT
15
EN
3
CS
RX
14
NC
4
SCK
TX
13
NC
5
MISO
SCL
12
NC
6
MOSI
SDA
11
Power supply
3.3V
7
3.3V
5V
Ground
GND
8
GND
GND
Onboard settings and indicators
Label
Name
Default
Description
PWR1
PWR
-
Power LED indicator
TB2
Vin
-
Power supply input terminal
Ground
TB1
Vout
-
LED output terminal
JP1JP3
1.5A, 1A, 0.7A
OFF
LED current selection: left position ON, right
position OFF
JP4
0.35A
ON
LED current selection: left position ON, right
position OFF
Software support
We provide a library for the LED Driver 5 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
You can find all the functions for controlling LED lighting in the file
Click_LED_Driver5_pwm
Key functions:
uint32_t leddriver5_pwmInit(uint16_t freq) - PWM init function
void leddriver5_pwmSetDuty(uint16_t duty) - PWM set duty function
void leddriver5_pwmStart() - PWM start function
void leddriver5_pwmStop() - PWM stop function
Examples description
The application is composed of the three sections :
System Initialization - Sets PWM pin as OUTPUT
Application Initialization - Initialization driver init and pwm init
Application Task - (code snippet) - Controls the brightness of the LED using PWM
void applicationTask()
{
_dutyCycle += 250;
leddriver5_pwmSetDuty(_dutyCycle);
if (_dutyCycle > 10000 )
{
_dutyCycle = 0;
leddriver5_pwmSetDuty(_dutyCycle);
Delay_ms(2000);
}
Delay_ms( 100 );
}
The full application code, and ready to use projects can be found on
our LibStock page.
Other mikroE Libraries used in the example:
PWM
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/led‐driver‐5‐click/1‐9‐19