Motorola M68HC08 Manual page 41

5.2.5 3-Phase H Bridge
DRM046 — Rev 0
MOTOROLA
Freescale Semiconductor, Inc.
consisting of R11 and R12. The values are chosen such that a 65-volt
maximum DC-Bus voltage corresponds to 5 volts at output V_DCBUS.
The output stage is configured as a 3-phase H-bridge with IGBT output
transistors. It is simplified considerably by a high-voltage integrated
3-phase gate driver that has a cycle-by-cycle current limit feature with
over-current detection and fault generation. A schematic that shows one
phase is illustrated in Figure 5-6. 3-Phase H Bridge (Phase A
Gate drive is supplied by an International Rectifier, IR2132. It is a high
voltage, high speed power MOSFET and IGBT driver with three
independent high and low side referenced output channels.
Under-voltage lockout and over-current protection are also provided by
the IR2132.
One of the more important design decisions in a motor drive is the
selection of gate drive impedance for the output transistors. In
5-6. 3-Phase H Bridge (Phase A
diode D8, and the IR2132's current source/sinking capability determine
gate drive impedance for the lower half-bridge transistor. A similar
network is used on the upper half-bridge. These networks set turn-on
gate drive impedance at approximately 24 ohms and turn-off gate
impedance to approximately 4 ohms. These values produce transition
times of approximately 200 nsec.
The gate of the MOSFETs is protected by 18V Zener diodes D18 and
D21 that eliminate possible dangerous peaks on the gate signals.
Discharge resistors R44 and R47 are placed in parallel.
Hardware Design
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Detailed Design Description
Shown), resistor R16, resistor R30,
Designer Reference Manual
Hardware Design
Shown).
Figure
41