It's a small size (5x10mm) linear constant current source for LEDs. Supports pulse-width modulated (PWM) by a microcontroller for LED dimming. Selectable current 10-20mA via SMD jumper (default 10mA).

There are two options.

• BCR421U - Maximum input voltage 5V. Recommended for low voltage applications, single LED.
• BCR420U - Maximum input voltage 40V. Recommended for serial LED connection.

Details:

• Small size (5x10mm)
• Fully assembled
• Negative temperature coefficient (NTC) reduces current with increasing temperature (0.2 %/K of the LED driver)
• The set current has a tolerance of +/- 3mA, depending on the input voltage, temperature, and component tolerance
• Parallel connection possible to increase regulated current
• Voltage drop 0.95V

BCR421U

• Input voltage up to 5V (Above 5V possible up to 18V but with 0.1W power dissipation!)
• Maximum power dissipation 0.2W (25°C, up to 5V) (established safe value) (Due to the small size of the PCB)
• Maximum power dissipation 0.1W (25°C, from 5V up to 18V - because it has its own power consumption of 10mA above 5V) (established safe value) (Due to the small size of the PCB)
• Supports dimming through PWM up to 25kHz
• Reverse polarity protection is not officially supported, but it works

BCR420U

• Input voltage up to 40V
• Maximum power dissipation 0.2W (25°C) (established safe value) (Due to the small size of the PCB)
• Dimming is not officially supported but works up to a 29V voltage drop on LED driver
• Reverse polarity protection is not officially supported, but it works

Included based on the chosen option (as photo):

BCR421U - Assembled PCB:

• 1x - fully assembled LED driver without any cables and LED (photo with description - "Assembled")

BCR421U - White LED, Breadboard (Assembled):

• 1x - fully assembled LED driver with 2pin header and white LED (photo with description - "White LED, Breadboard")

BCR421U - White LED, 15cm Cable (Assembled):

• 1x - fully assembled LED driver with 15cm cables and white LED (photo with description - "White LED, 15cm Cable")

BCR420U - Assembled PCB:

• 1x - fully assembled LED driver without any cables and LED (photo with description - "Assembled")

Read this before ordering!

Maximum power dissipation (Pd) 0.2W (25°C)! It has no officially polarity reversal protection

Example of calculation BCR421U:

• Input voltage (VCC): 5V
• LED forward voltage (Lfv): 3V
• LED current (Lc): 0.01A/0.02A (10mA/20mA)

• (VCC - Lfv) * Lc = Pd
• (5 - 3) * 0.01 = 0.02W (0.02 <= 0.2 (OK))
• (5 - 3) * 0.02 = 0.04W (0.04 <= 0.2 (OK))

• Input voltage (VCC): 12V/18V
• LED forward voltage (Lfv): 3V
• LED current (Lc): 0.01A/0.02A (10mA/20mA)

• (VCC - Lfv) * Lc = Pd
• (12 - 3) * 0.01 = 0.09W (0.09 <= 0.1 (OK))
• (12 - 3) * 0.02 = 0.18W (0.18 <= 0.1 (BAD))
• (18 - 3) * 0.01 = 0.15W (0.15 <= 0.1 (BAD))
• (18 - 3) * 0.02 = 0.3W (0.3 >= 0.1 (BAD))

Example of calculation BCR420U:

• Input voltage (VCC): 24V/40V
• LED forward voltage (Lfv): 3 x 3V (9V)/10 x 3V (30V)
• LED current (Lc): 0.01A/0.02A (10mA/20mA)

• (VCC - Lfv) * Lc = Pd
• (24 - 9) * 0.01 = 0.15W (0.15 <= 0.2 (OK))
• (24 - 9) * 0.02 = 0.3W (0.3 >= 0.2 (BAD))
• (40 - 30) * 0.01 = 0.1W (0.1 <= 0.2 (OK))
• (40 - 30) * 0.02 = 0.2W (0.2 <= 0.2 (OK))

Return Policy:

Never underestimate electrostatic discharge (ESD)! The return does not apply to mechanical damage. If you exceed the maximum power dissipation 0.2W, voltage and driver burns, there is no return or refund.