LED Driver 14 Click Board™

How Does The LED Driver 14 Click Board™ Work?

The LED Driver 14 Click Board™ is based on the BD18337EFV-M, a four-channel constant current LED driver with built-in MOSFET ideal for LED rear lamps (turn/stop), fog lamps, and turn signals for automotive use from Rohm Semiconductor. The BD18337EFV-M incorporates a proprietary thermal dissipation circuit and individual LED control function to drive LED lamps with different specifications by one driver, allowing the possibility for up to 3 LEDs in series on its output OUTx pin. It also has integrated protection circuitry to guard against output-short, overvoltage, LED short-circuit protections, and overtemperature.

The LED Driver 14 Click Board™ provides an output current of 150mA per channel with an output current accuracy of ±5%, limited by two MCP4661 digital potentiometers from Microchip Technology, which establishes communication with the MCU via I2C serial interface. The MCP4661 also allows the choice of the least significant bit (LSB) of its I2C slave address by positioning SMD jumpers labelled as ADDR SEL to an appropriate position marked as 1 and 0. The MCP4661 also has a configurable Write Protection function labelled as WP routed on the RST pin of the mikroBUS™ socket, which protects the entire memory and all registers from write operations and must be set to a low logic state to inhibit all the write operations.

The BD18337EFV-M offers two ways to implement LED dimming: analog dimming and PWM dimming. Both methods control the average current flowing through the LEDs. The analog dimming can be achieved by adjusting the LED current by using an external voltage source on the VIN terminal, while the PWM dimming is implemented by direct control of the dimming control signal routed to the PWM pin on the mikroBUS™ socket. The selection can be made by positioning the SMD jumper labelled as CRT SEL to an appropriate position marked as PWM or VIN.

This board also has a two-channel switch labelled as MSET, which allows changing output channel operation mode based on detecting an LED error. It also uses the INT pin of the mikroBUS™ socket in two ways, used as a 'fault' indicator which immediately notifies the host when a fault condition occurs or as an input that disables the output current. The output channel operation mode is automatically selected according to a switch position. More information about these selectable modes can be found in the attached datasheet.

The LED Driver 14 Click Board™ supports an external power supply for the motor, which can be connected to the input terminal labelled as VIN and should be within the range of 5.5V to 20V (typically about 12V). This wide range can lead to significant device power consumption in applications where a high input voltage is applied to the device, and the output is relatively low. This amount of power can increase the BD18337EFV-M internal temperature to an unacceptable level depending on the package's thermal resistance. The BD18337EFV-M employs an Energy Sharing Control to solve this issue, which dissipates the extra power that can overheat the device in external resistors R2 and R3 (R3 is unpopulated by default configuration).

The LED Driver 14 Click Board™ can operate with both 3.3V and 5V logic voltage levels selected via the VCC SEL jumper. This way, it is allowed for both 3.3V and 5V capable MCUs to use the communication lines properly. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development.

SPECIFICATIONS

PINOUT DIAGRAM

This table shows how the pinout of the LED Driver 14 Click Board™ 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	PWM	PWM Signal
Digipot Write Protect	WP	2	RST	INT	15	INT	Interrupt
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	3.3V	7	3.3V	5V	10	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

ONBOARD SETTINGS AND INDICATORS

LED DRIVER 14 CLICK ELECTRICAL SPECIFICATIONS