1. Home
  2. Electronics Design
  3. Photovoltaic Mosfet Driver?

Photovoltaic Mosfet Driver?

Is there anyway (short of the obvious a $500 to $5k high Z differential probe) to measure the rise and fall times of the FET's? The cct is here.

formatting link

I'm just testing this out on LVAC supply, but I plan on using this to remotely turn on-off a 10W flyback.

The photovoltaic driver I'm using is the LH1262.

formatting link

Also is it practical to pulse the LED to say 100mA to improve the current drive capability. They don't show any curves for power dissipation vs. temp in the data sheet. If anyone has any experience with these some advice would be appreciated. I only have three to tinker with:)

I'm using the second cell to drive a small logic level FET (5nC gate charge) to discharge the main FET's. I tested this on a DC supply and I get the full open CCT voltage Vgs=12V.

Reply to
Hammy
Loading thread data ...

You could characterize the FETs before you put them in the circuit and then look at the current rise time with them in the circuit.

Yiu can pulse the current higher at the start. You have to watch the temperature rise of the active area of the LED. This most likely has a thermal time constant of many microseconds.

You can use a pulse generator and a resistor to try to find this time constant. Set the offset voltage of the generator so that the current about 1mA with the generator is low and watch the variation in forward drop just after the full current stops.

Reply to
MooseFET

2 channel add and Invert?

Cheers

Reply to
Martin Riddle

Thanks but a probe (particularily 2) even in ten times measuring such a high output Z circuit would be inaccurate.

Reply to
Hammy

Thanks I'll try that.

Would a high Z JFET instrumentation amp give me an accuarate measurment?

Reply to
Hammy

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.