D4184 MOSFET switch module

A dual MOSFET switch board: two logic-level AOD4184A in parallel switch a motor, a pump or an LED strip from a board pin. Aliases: D4184 module, XY-MOS.

It is sold as the D4184 module, the XY-MOS, or the "15 A 400 W MOS FET trigger switch", and it is the board to reach for when a 3.3 V or 5 V pin has to switch amps.

Pins

Pin	What it does
TRIG	The input: a logic level or PWM, 3.3 V to 20 V.
GND	The input's ground. It is VIN- on the board.
VIN+	The load supply's +. It is joined to OUT+.
VIN-	The load supply's -: both MOSFETs' sources.
OUT+	The load's +, the same as VIN+.
OUT-	The load's -: both MOSFETs' drains.

While it runs

The readout is the load current. The red LED lights while TRIG is high.

What the model gets right

The board as its schematic draws it: 10 kΩ from the gates to ground, the LED with 1.8 kΩ from the gates to ground, and two AOD4184A on the MOSFET part's card for that sheet, 9.5 mΩ each at 4.5 V. Both are fully on from a 3.3 V or 5 V pin, which is the point of the board: 12 V into a 1 Ω load passes about 11.5 A with a tenth of a volt across the board. There is no flyback diode, so a motor or a solenoid on it needs one across it.

What it does not model

The 100 Ω gate resistor. On the board TRIG reaches the gates through 100 Ω; here the gates are on TRIG itself, because the board brings the gate node out on no pin. At DC that resistor carries only the pull-down's and the LED's current, about 2.3 mA from a 5 V trigger, so the real gates sit about 0.23 V lower and the pair is about 4.3 mΩ where the model has 3.9 mΩ. Heat, and the thermal limit, as on the MOSFET part. Some boards sold under the same name have an optocoupler on the input instead; this is the common one without.

See it in action

The 12 V lamp dimmer with a MOSFET module dims a 12 V lamp with PWM from pin 9 and a knob on A0.