Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

Hardware Design

Low-Voltage Hardware Set Components

The LV BLDC power stage has both a printed circuit board and a power substrate. The printed circuit board contains MOSFET gate drive circuits, analog signal conditioning, low-voltage power supplies, and some of the large passive power components. This board also has a 68HC705JJ7 microcontroller used for board configuration and identification. All of the power electronics that need to dissipate heat are mounted on the power substrate. This substrate includes the power MOSFETs, brake resistors, current-sensing resistors, bus capacitors, and temperature sensing diodes. Figure 4-5shows a block diagram.

POWER

BIAS

 

INPUT

BRAKE

 

POWER

 

 

 

 

MOSFET

SIGNALS

 

POWER MODULE

 

 

TO/FROM

GATE

TO

CONTROL

DRIVERS

MOTOR

BOARD

 

PHASE CURRENT

 

 

PHASE VOLTAGE

 

 

BUS CURRENT

 

 

BUS VOLTAGE

 

 

MONITOR

 

BOARD

 

 

ID BLOCK

 

 

 

ZERO CROSS

 

 

BACK-EMF SENSE

Figure 4-6. Block Diagram

4.6.1.1 Electrical Characteristics of the 3-Ph BLDC Low Voltage Power Stage

The electrical characteristics in Table 4-6apply to operation at 25°C with a 12-Vdc supply voltage.

DRM028 — Rev 0

 

Designer Reference Manual

 

 

 

MOTOROLA

Hardware Design

73

 

For More Information On This Product,

 

 

Go to: www.freescale.com

 

Page 73
Image 73
Motorola M68HC08 manual Block Diagram