To verify the startup behavior, connect the
oscilloscope to the evaluation module:
- Channel 1 - Input Voltage (Test Point Label VIN)
- Channel 2 - A pin Voltage (Test Point Label VA)
- Channel 3 - DGATE Voltage (Test Point Label DGATE)
- Channel 4 - HGATE Voltage (Test Point Label HGATE)
Set the load to 200 mA, trigger to Channel 1 rising and turn ON the power
supply. Start-up behavior of LM74800EVM-CS is captured in
Figure 5-2.
Figure 5-2 Power Up 12 V: HGATE and Output Figure 5-4 Power Up 12 V: Charge Pump VCAP Figure 5-3 Power Up 12 V: DGATE and A Figure 5-5 Power Up 12 V: DGATE and HGATE