4 channel Knight rider circuit with high power outputs (12V 10A)

I never thought to make old, well known knight rider circuit with 555 and 4017 ICs in this age, but some students from Medical Faculty of University of Sri Jayawardhanapura asked to make it again....

They need simple LED running circuit to animate their something for the exhibition, and I proposed simple kinght rider LED runner to achieve the task. But, their design has fairly large number of LEDs and hence the output current capacity per channel must be large.

In the design time, I have no idea about the number of LEDs to be connected per channnel. So, I decided to make the circuit with high power outputs, make it enable for at least 10A load from each channel.

As traditional practice, I thought to setup with some BJT for output stage, but then I need to setup output current buffer amplifiers for 4017. Next option is to setup with power darlington transistors. But, one such high power darlington transistor is costs more than 100 rupees......

It is very simple idea to use MOSFETs for the output stage to do this. Here, I selected cheap IRFZ44N, which can handle fairly large load current with extremely low ON resistance. One FET costs less than Rs. 50 and have extreme boost on output current. Because MOSFETs are voltage operated devices.  Any MOSFET with low ON resistance, will work for this design.

I checked this circuit with 12V 8A load per channel without having heat sinks for MOSFETs..But, it is not recommended to use this circuit with low supply voltages below 9V, because, it might be having problems to keep required gate voltage across the MOSFET to keep it fully ON.

I used vero board to make the circuit, but special care must be pay for the ground connection of the MOSFETs. They operate with high currents and have a chance to burn vero board traces or, they might get heat up. Apply a layer of lead alone the trace to make it thicker, will solve the problem.

Since, SMPS modules are so popular, I advised them to use 12V 10A Switch Mode Power Supply with this, to power up the LED system.

Here is the circuit diagram of the knight rider circuit. It can be extend up to 10 channels, by following the same design, without any problem.