LR7843 Mosfet Module

LR7843 Mosfet Driver Module

Optocoupler isolation 30V 110A 140W Pwm Speed Control Motor Solenoid Valve Led

Note: The screw terminals and pin header are shipped as separate parts, not soldered to the board. Depending on your needs you can solder the terminals or solder the cables directly to the board.

     The LR7843 Mosfet Module is a single channel, optocoupler isolated DC load switching board. The IRLR7843 N channel MOSFET on the board is driven by a 3.3V or 5V logic signal and switches DC loads up to 30V on and off; with a PWM signal, led brightness and motor speed can be adjusted. Because the control input drives the MOSFET through an optocoupler, the controller board and the load circuit are isolated from each other.

     The on resistance of the MOSFET is very low at 3.3mΩ, so it heats little at medium currents. The 161A value in the MOSFET datasheet is the limit of the transistor itself; this small 33mm x 16mm board is suitable for about 15A continuous current at 12V without a heatsink. Compared with a relay it is silent, has no contact wear and can switch fast enough for PWM. It is not suitable for controlling AC loads.

     It is used to switch DC loads such as motors, pumps, solenoid valves, fans, led strips and heaters from a controller board or to adjust them with PWM.

Key features:

     Optocoupler isolation: The control input (PWM, GND) is connected to the MOSFET circuit through an optocoupler; the control ground is not connected to the load ground on the board.

     Low on resistance: The IRLR7843 MOSFET has 3.3mΩ on resistance; voltage drop and heating on the MOSFET under load are low.

     PWM adjustment: Led brightness, motor and fan speed and heater power are adjusted with a PWM signal; the load runs when the PWM pin is HIGH.

     Wide control voltage: The control input works with 3.3V and 5V logic outputs and accepts a 2.5V-20V control signal.

     Small board: 33mm x 16mm in size; fixed in an enclosure with two mounting holes, connected with screw terminals or direct wiring.

Features:

• Product type: Single channel, optocoupler isolated N channel MOSFET switching module
• MOSFET: IRLR7843 (LR7843), N channel, TO-252 (D-PAK) package
• Control signal: 3.3V / 5V logic, load on while the PWM pin is HIGH
• Control input voltage range: 2.5V-20V
• Load voltage: 6V-28V DC recommended, max 30V (MOSFET limit)
• Load current: about 15A continuous at 12V without heatsink; higher for short periods with PWM
• MOSFET limit values (datasheet): 30V, 161A; these are limits of the transistor, not of the board
• On resistance (RDS(on)): 3.3mΩ (datasheet, maximum, at 10V gate voltage)
• PWM: Can be driven with PWM for led brightness, motor and fan speed control
• Isolation: Optocoupler; control ground and load ground are not connected on the board
• Switching type: Low side (load negative line) switching
• Gate drive: From the load supply through a voltage divider (about half of the supply)
• Control connection: PWM and GND; via 2 pin screw terminal or pin header
• Supply and load connection: 3 pin screw terminal position (+ / LOAD / -; terminals shipped unsoldered)
• Flyback diode: Not on the board; an external diode is required for inductive loads
• Current type: DC only; not suitable for AC loads
• Mounting: 2 mounting holes, 2mm
• Material and colour: Black PCB
• Dimensions: 33mm x 16mm
• Weight: 5gr (board without terminals)

Usage information:

• Connect the PWM or digital output of the controller board to the PWM pin of the module, and the controller GND to the GND pin of the module.
• On the 3 pin terminal, connect the load supply + to + and - to -; connect the load + to + and the load - to LOAD. The MOSFET switches the negative line of the load.
• The terminals and pin header come unsoldered; solder the terminals as needed or solder wire thick enough for the current directly to the board.
• For inductive loads such as motors, solenoid valves and relay coils, connect a flyback diode in reverse across the two leads of the load.

Areas of use:

•  Led strip dimmer and brightness control
•  DC motor speed control
•  Aquarium and irrigation pump control
•  Solenoid valve control
•  Fan speed control and ventilation
•  Incubator and heater resistor control
•  Electric door lock and lock coil control
•  Greenhouse ventilation and irrigation control
•  Caravan and boat 12V lighting control
•  Silent and fast DC switching instead of a relay
   

Precautions:

•  The board is for DC loads only; do not control AC (230V mains) loads with this board.
•  The load voltage must not exceed 28V (max 30V).
•  Do not take the MOSFET datasheet value of 161A as the board current; the small board is suitable for about 15A without a heatsink. Check the MOSFET temperature at high current and use a heatsink if needed.
•  The gate voltage is about half of the load supply; with supplies below 9V the MOSFET may not turn fully on above a few amperes and may heat up.
•  There is no flyback diode on the board; without an external diode on inductive loads the MOSFET may be damaged.

Package contents:

•  1 Piece LR7843 Mosfet Module
•  1 Piece 3 pin screw terminal (unsoldered)
•  1 Piece 2 pin screw terminal (unsoldered)
•  1 Piece male pin header (unsoldered)