I have two inverters, driven by two IRF530 mosfets. I need to drive them with a specific phase shift. What is the simplest, most basic way to do it, for simple prototyping? (I am neglecting PWM modulation for first prototype, I just want to make circuit work)

I am currently trying with LM5046, but it seems too time-consuming for initial version. Size of circuit doesn't matter.

  • \$\begingroup\$ How precise, how repeatable, what resolution must you have? \$\endgroup\$ – analogsystemsrf Apr 22 '18 at 1:50
  • \$\begingroup\$ This is what I know: Second MOSFET should start with 0.083us delay. Repetition should continue until the input power is cut off. \$\endgroup\$ – DenR Apr 25 '18 at 0:14

The simplest is to use is an RC network and (just to be safe) a Schmitt trigger.


simulate this circuit – Schematic created using CircuitLab

This will have a few problems. The biggest is that, for an arbitrary fixed trigger level, it will provide different phase shifts for rising and falling edges. This can be fixed by taking the natural hysteresis found in simple Schitt triggers and setting the rising trigger level at about 63% of the input logic swing, and the falling trigger level at about 37%. If you do this, the delay (ignoring the propagation delay of the trigger) will be equal to the product of R and C. If R is ohms and C is in Farads, the delay will be expressed in seconds.

However, as long as the two trigger levels are symmetric around the average of the high and low logic levels the delays will be equal, just a bit harder to calculate.

  • \$\begingroup\$ So a suggestion is to connect a clock directly to a first MOSFET's gate, and use the shown circuit for the second? \$\endgroup\$ – DenR Apr 25 '18 at 0:15
  • \$\begingroup\$ Yes. Also keep in mind that the inverter adds another 180 degrees of phase shift. If your clock is a fixed square wave, that's not a problem, but if you're looking at an arbitrary (random) pulse train you'll need to be careful. \$\endgroup\$ – WhatRoughBeast Apr 25 '18 at 15:59
  • \$\begingroup\$ I see. Any recommendation about what is the simplest clock implementation? \$\endgroup\$ – DenR Apr 28 '18 at 14:17
  • \$\begingroup\$ @DenR - That's the subject of a different question. When you ask it, you'll need to specify voltage levels, frequencies, duty cycle, rise/fall times, available power supply voltage, and anything else you can think of. \$\endgroup\$ – WhatRoughBeast Apr 28 '18 at 19:16

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