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The project presented here enables users to switch all kinds of resistive, inductive and capacitive loads, limited by clamping energy (EAS) and maximum current requirement. The user may interface 2 x inductive, resistive, and capacitive loads such as solenoid, dc motor, high current contact switch, high current relay, LEDs, lamps, and piezo etc. The project is most suitable for inductive loads as well as loads with inrush current. The project has been designed using BTF3050TE IC which is a 50 mΩ single-channel Smart Low-Side Power Switch in a PG-TO252-5 package providing embedded protective functions. The power transistor is built by a N-channel vertical power MOSFET. The device is monolithically integrated. The BTF3050TE is automotive qualified and is optimized for 12V automotive and industrial applications. Two loads can be controlled using Arduino UNO. IC has a thermal-restart function. The device will turn on again, if input is still high, after the measured temperature has dropped below the thermal hysteresis.

In order to optimize electromagnetic emission, the switching speed of the MOSFETs is set to 5 us ON time and 5 us OFF time approx. but this can be adjusted by R6, and R7, refer to the datasheet of the chip for more information. This allows balancing between electromagnetic emissions and power dissipation. Shorting the SRP pin to GND represents the fastest switching speed. Open SRP pin represents the slowest switching speed. It is recommended to put a high ohmic resistor like 200kΩ on this SRP pin to GND. The accuracy of the switching speed adjustment is dependent on the precision of the external resistor used. It’s recommended to use accurate resistors. It is advisable to change capacitor C1 to 470uF if the full load current is in use.

- Operates 2 x Loads (Nominal Load Current Each Channel 3A – 6A both)
- Maximum on State Resistance 100mOhms Each Channel
- Operating Voltage Range 12V-24V for Load ( 3V to 28V Operating Range)
- Operating Supply Voltage Range VCC 3 to 5.5V (Connected to 5V of Arduino Uno)
- Input Signal Maximum 5.5V
- The project can drive Inductive, Resistive, Capacitive Loads
- Arduino Digital pin D3 drives Load-1, and D5 drives Load-2
- BTF3050TE Input PWM < 20Khz or TTL Input (Arduino D3 and D5)
- SW1 and SW2 Resets switch when a Fault condition occurs
- Over-temperature shutdown with auto-restart
- Active clamp over voltage protection of the output
- Enhanced short circuit protection
- Active clamp over voltage protection of the output
- 2 additional LEDs On Arduino D11 and D12 provided for operation indication.
- PCB dimensions: 61.91 x 50.64 mm”

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