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Small Constant current linear 10/20mA driver

Primarily designed for breadboard

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$2.79
pnoxi has 54 orders / 10 reviews
Ships from Banska Bystrica, Slovakia
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:

  • 1x - BCR421UW6-7
  • 1x - RC0603FR-0791RL or RC0603FR-0795R3L (depends on the internal LED driver resistor)

BCR420U:

  • 1x - BCR420UW6-7
  • 1x - RC0603FR-0791RL or RC0603FR-0795R3L (depends on the internal LED driver resistor)

  • More detailed information

    Pnoxi06/23/2019 at 07:20 0 comments

    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

    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))

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