EDIT: I used to boost circuit to provide 10V to the driver IC (which is within its spec and the MOSFET spec) and that fixed it. I guess the 4.7 volts was just too low for the driver circuit.

Okay so long story short, I'm trying to switch an LED load powered through a MOSFET, which is controlled by a MOSFET driver (see attached spec sheet), which is signaled by an Arduino Nano. The power is a USB port from my PC, about 4.7V, I have the ground and VCC connected directly to the Nano's ground and 5V pin, I'm using the TimerOne library to get a 25khz signal to the logic A (also tried logic B) pin on the driver. I've tested the signal with my oscilloscope and a load, it is fine all the way up to the logic side of the driver, but I'm getting no consistent signal on the output and getting no apparent throughput with the MOSFET. My DMM is measuring about 100mV on the output side. After looking at the data sheet a little more I'm wondering if I'm missing some resistors or capacitors somewhere, but I'm not enough of a hobbyist to figure all that out, nor do I have electrical engineering experience. If anyone's willing to help me out, it would be greatly appreciated!

 

Hi Like,
Please post a diagram showing the connections.

E

 

Hi Like,
Please post a diagram showing the connections.

E

Updated the original post with a schematic. I know it's bad, hopefully it's good enough, but let me know if it's not.

 

Hi Like,
Please post a diagram showing the connections.

E

I edited the initial post also, I got it working.

 

Hi Like,
Well done!
Post your final diagram, it may help other users.

E

 

For clarity this is your circuit:

Personal observations: The resistor (1KΩ) is a bit high for a 4.7V source. Your edited statement says you boosted it to 10V. At 4.7V you were getting roughly 4.7mA through the LED. That may be too low for the LED you used. We don't know what type LED you used or what the forward voltage is. At 10V your current through the LED should be roughly 10mA. That should be enough to be seen. If you want to eliminate the booster you can go with a lower resistance. It depends on the forward voltage of the LED and the desired current you want it operating at. Since you're happy with 10mA I'd suggest a 470Ω resistor. That should give you roughly the same current through the LED.
Observation #2: The FET ? ? ? What FET did you use?

 

Followup on the potential forward voltage (Vf) of the LED: IF it's 3Vf then (4.7V - 3Vf) ÷ 1000 = 1.7mA. That's way low. You'd need a spotlight just to see if the LED was lit. IF it was lit. Using a 470Ω resistor and a 3Vf LED your current would be 3.6mA. That's low too. So to get 10mA through your LED you'd need (4.7V - 3Vf) ÷ 10mA = 170Ω.

Of course this is assuming your LED has a 3Vf. As yet we don't know what you have. So your results will vary depending on the LED. As for the FET - - - that too is an unknown. It may require a higher voltage differential in order to switch it on. 4.7V might not be sufficient. As you said, when boosted to 10V you got the results you wanted. If you're happy enough with a working model then there is no need for further modifications. But if you desire to have it operate the way you originally hoped for, you may need a different FET as well. It's all in the numbers and the parts used. You wouldn't put a Briggs & Stratton engine in a Chevy Van and expect it to drive down the road at 70 MPH. For that you need the right parts.

 

Here is an appropriate TO-92-package Logic-Level-FET for your project.
Other numbers are available if You are using SMD-components.
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For clarity this is your circuit:
View attachment 339081
Personal observations: The resistor (1KΩ) is a bit high for a 4.7V source. Your edited statement says you boosted it to 10V. At 4.7V you were getting roughly 4.7mA through the LED. That may be too low for the LED you used. We don't know what type LED you used or what the forward voltage is. At 10V your current through the LED should be roughly 10mA. That should be enough to be seen. If you want to eliminate the booster you can go with a lower resistance. It depends on the forward voltage of the LED and the desired current you want it operating at. Since you're happy with 10mA I'd suggest a 470Ω resistor. That should give you roughly the same current through the LED.
Observation #2: The FET ? ? ? What FET did you use?

I tested the LED with the 1k, it works fine. The output voltage from the MOSFET driver IC was too low, about 100mV. After increasing the Vcc to the driver to 10V everything worked fine.

 

everything worked fine.

OK. Glad to hear it. Happy New Year.

 

OK. Glad to hear it. Happy New Year.

Thanks!