BoopathiS
Member level 2
HI,
I'm controlling BLDC motor(Blower) using Half bridge driving circuitry. When running only blower during EMI testing, at 63MHz frequency more EMI noise is producing(6db more than limit).
Half bridge driver circuit switching frequency is 30kHz and Gate resistor is 100 ohm. Driver is controlled by microcontroller with 72MHz internal clock frequency.
Can you please clarify below points,
1. Whether 100ohm gate resistor is suitable for 30kHz switching frequency ? If i'm changing Gate resistor or Switching frequency can help me in EMI reduction?
2. 63Mhz is 2000 times the switching frequency. considering this switching circuit will create this much multiplied noise ?
3. Blower is the load. Is this one as EMI source ?
4. Without running the blower EMI is within limit(Standby condition, only microcontroller is in ON state), hope microcontroller internal oscillator will not create any EMI source. My assumption is correct ?
Parallely, I'm looking into wire routing, PCB layout and component placement.
Schematic:
I'm controlling BLDC motor(Blower) using Half bridge driving circuitry. When running only blower during EMI testing, at 63MHz frequency more EMI noise is producing(6db more than limit).
Half bridge driver circuit switching frequency is 30kHz and Gate resistor is 100 ohm. Driver is controlled by microcontroller with 72MHz internal clock frequency.
Can you please clarify below points,
1. Whether 100ohm gate resistor is suitable for 30kHz switching frequency ? If i'm changing Gate resistor or Switching frequency can help me in EMI reduction?
2. 63Mhz is 2000 times the switching frequency. considering this switching circuit will create this much multiplied noise ?
3. Blower is the load. Is this one as EMI source ?
4. Without running the blower EMI is within limit(Standby condition, only microcontroller is in ON state), hope microcontroller internal oscillator will not create any EMI source. My assumption is correct ?
Parallely, I'm looking into wire routing, PCB layout and component placement.
Schematic: