Race Technology

I want to use the PWM output to control some heaters. So I could configure their power/heat level in the D2P. This would work perfectly, but of course the D2P can only sink up to 0.5A and I need it to be switching up to 4A. So I need to replicate what the D2P output is doing, but actually controlling a bigger supply.

Anyone got any suggestions as to how I can do this?

I control a 10A waterpump from my ECU PWM (a spare injector pin) using a Solid State Relay with a thermal pad and old PC cpu heat-sink attached. Can't remember what make the relay was but it is about the size of a box of matches and was approx £30. Wiring is simple - wire to battery, wire to ECU pin, and then two wires to the water pump.

Would have thought 4A driven by 0.5A should be easy and may not need a heat-sink.

Paul

I've been thinking along the same lines, but as I only need to actually switch 2A, I could just use a single transistor as the switch. I'm trying to power 2 heaters which take 2A each so a pair of 2A transistors would handle that and provide the 4A total I need.

I need to carefully select a suitable transistor so that it is being driven between its Saturation and Cut off areas and this would be very efficient and not generate much heat. Also the relatively low required gain means a single transistor should suffice to get the 2A while keeping the sink current through the D2P acceptably low.

I just need to confirm how I apply the PWM output to the transistor's Gate and also select a suitable transistor. If anyone can help with either/both of the above it would be much appreciated.

Since I want to control this output according to the Ambient Air Temperature, which is being calculated as °C from one of the input voltages (from a table), can I set the PWM % values to be in the calculated °C rather than the raw voltages?

Easier to fine tune if it's by ° than having to relate back to the voltage every time.