MC33937 Datasheet, PDF (43/48 Pages) Freescale Semiconductor, Inc – Three Phase Field Effect Transistor Pre-driver

TYPICAL APPLICATIONS
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Supply Voltage (V)
Figure 24. Power Dissipation Profile of Application Using Charge Pump
Reference application with:
• Pump capacitor: 1.0 F MLC
• Pump filter capacitor: 47 F low ESR aluminum electrolytic
• Pump diodes: MUR120
• Output FET gate charge: 240 nC @ 10 V
• PWM Frequency: 20 kHz
• Switching Single Phase
Below approximately 17 V the charge pump is actively regulating V_PWR. The increased power dissipation is due to the charge
pump losses. Above this voltage the charge pump oscillator shuts down and V_SYS is passed through the pump diodes directly to
V_PWR.
Analog Integrated Circuit Device Data
Freescale Semiconductor
33937A
43