I've constructed the following circuit...(I think everything is drawn correctly)
Using the following components...
IR Receiver
P-chan MOSFET
LED
Resistor is 0.1 Ohm.
The circuit works quite well in the sense that I can turn it on with 56 kHz pulsed IR and it draws around 750 mA -- just what I want. My problem is when plugging in the battery. When doing so, the LED flashes on and off multiple times (same thing when unplugging). This is not good for my application, but far worse is that sometimes it goes on and stays on just from plugging it in.
After doing some research, I think this may be referred to as MOSFET latch-on. I'm not entirely clear on how to fix it though. I've seen a couple circuits that add a resistor from gate to ground, but those are n-type and I'm not sure if it will solve my issues. Alternatively, a series resistor from IR out to gate to keep Vgate lower than Vsource. Or a capacitor somewhere to limit transients. Or a diode somewhere...
I've been fiddling with this circuit for a long time, trying different parts and configurations to get this thing to switch ~750 mA for an LED and in a package that's ~ 7mm x 8mm. Now that I've finally got that, I just need some help with this one (hopefully simple) issue to perfect it.
Using the following components...
IR Receiver
P-chan MOSFET
LED
Resistor is 0.1 Ohm.
The circuit works quite well in the sense that I can turn it on with 56 kHz pulsed IR and it draws around 750 mA -- just what I want. My problem is when plugging in the battery. When doing so, the LED flashes on and off multiple times (same thing when unplugging). This is not good for my application, but far worse is that sometimes it goes on and stays on just from plugging it in.
After doing some research, I think this may be referred to as MOSFET latch-on. I'm not entirely clear on how to fix it though. I've seen a couple circuits that add a resistor from gate to ground, but those are n-type and I'm not sure if it will solve my issues. Alternatively, a series resistor from IR out to gate to keep Vgate lower than Vsource. Or a capacitor somewhere to limit transients. Or a diode somewhere...
I've been fiddling with this circuit for a long time, trying different parts and configurations to get this thing to switch ~750 mA for an LED and in a package that's ~ 7mm x 8mm. Now that I've finally got that, I just need some help with this one (hopefully simple) issue to perfect it.