I want to make a BLDC Driver circuit but i have studied that i need to have a dead signal during switching of high side to save my MOSFETs from burning up,
according to my research, atmega328P cannot generate a dead signal which is also known as complimentary signal.
should i use 74HC08 at my HIGH side driver because it has 8ns Typical propagation time which means my problem of dead signal can be solved there?
is propagation and dead signal same thingy?
Note: this cct. is for a different application.
A version similar to this might work.
The junction of the two transistors would be your output.
A and B are connected to two different Arduino output pins.
// P U L S E O U T P U T
//****************************************************************
//function sends pulses the Pulse Probe
//The pulse goes from Hi Z to 0V for 10uS to Hi Z for 10uS to +5V for 10uS then back to Hi Z
// 10uS ____
// Hi Z______ 0V ____| +5 |________ Hi Z
// |____|10uS 10uS
//
void pulseOutput(byte number)
{
for (int x = 0; x < number; x++)
{
// ***** WARNING ***** you must never have pulseB HIGH when pulse A is LOW ! ! !
digitalWrite(pulseB,HIGH); //Pulse Probe to 0V
delayMicroseconds(5); //Granularity is ~5uS so ~5uS + 5uS = ~10uS in reality
digitalWrite(pulseB,LOW); //Pulse Probe to Hi Z
delayMicroseconds(5); //Granularity is ~5uS so ~5uS + 5uS = ~10uS in reality
digitalWrite(pulseA,LOW); //Pulse Probe to +5V
delayMicroseconds(5); //Granularity is ~5uS so ~5uS + 5uS = ~10uS in reality
digitalWrite(pulseA,HIGH); //Pulse Probe to Hi Z
}
} // END of pulseOutput()
It cannot solve the dead time generation alone - it will "safely delay" turn on of its MOSFET but it will also delay turn off of the MOSFET - causing the problem you want to avoid. Let alone 8ns is too short anyway.
If you feel lucky you may generate the dead time in SW - I think in ATMega328p two channels of phase correct PWM may be configured to generate dead time. But you have to trust your software and KNOW the timer NEVER turn both channels at once. It is better to generate dead time in HW somehow.