Hai all..
I am using LPC1769 to generate PWM with dead time using MCPWM peripheral. The problem is normal PWM is max duty cycle is 48% , inverted PWM should be max duty cycle 48%. But inverted PWM is getting minimum 52% duty cycle. Dead time is 2usec. Can any one help me?
Skew occurs when Ciss rises with lower RdsOn for each stage.
I assume lpc1769 output RdsOn is 25 Ohm from recollection of Vol/Iol. See end of spec for actual values, and show schematic and waveforms with load ESR.
I am not using any drivers, just absorbed wave forms in scope. see the attached image.
pwm switching frequency = 10khz
dead time = 2usec
yellow color = PWM
Blue color = Inverted PWM
Good, now show output pins and how this complementary output is generated with load/no load.
Asymmetric delays are often created with series R and //diode to input Ciss for asymmetric delays to enhance deadtime. Driver Chips do this internally with single ended inputs.
Oh , ok, but they don't satisfy your need for deadtime, so try something else and contact OEM, your purchasing and/or Distributor support with an Incident Report.
Consider a bridge driver chip after you define the load specs.