AN1627 Freescale Semiconductor / Motorola, AN1627 Datasheet - Page 22

• Manufacturer Part Number: AN1627
• Description: Low Cost High Efficiency Sensorless Drive for Brushless dc Motor Using MC68HC (7)05MC4
• Manufacturer: Freescale Semiconductor / Motorola

6.2
The MC68HC(7)05MC4 is a low cost
fact, the board schematic is very simple.
There are no special requirements as long as common rules for microcontroller design are followed.
6.3
The rectified line voltage is filtered by a 100
(harmonic) filter are used to meet the new EMC regulation (IEC555-1).
Any type of power supply system (e.g. SMPS or classical centre-taped transformer) can be used to
produce the auxiliary voltage levels (+15V, -15V and +5V).
This solution does have one limitation. The DC-Bus voltage can be 260V - 350V (the best case) which
might not be sufficient for very large required speed range. The DC-Bus voltage should be three times
higher (in star connection) than the phase Back-EMF voltage at maximal speed.
6.3.1
The application was designed to meet this regulation. The cheapest way often is to use one RF filter
and one LF filter to improve the line current shape. The value of the inductance in the LF filter is a trade-
off between power factor and current shape. It must be also kept in mind that any inductance before or
after the mains rectifier decreases the DC-Bus voltage. This reduces the speed range this application
can be used for.
MOTOROLA
22
50uF
MUX command PhA
MUX command PhB
MUX command PhC
+
VCC
SW2
RESET
100nF


Power Supply Board
Meeting European Community Regulation IEC555-1
AD_Voltage
C 68HC(7)05MC4 Board
47k
PWM - A bottom
VCC
~230V AC
PWM - B top
PWM - A top
GND
100nF
START/STOP
Freescale Semiconductor, Inc.
RXD
SW1
18pF
18pF
2M2
Figure 6-4.
Fuse
100nF
For More Information On This Product,
Figure 6-5.
HF Filter
2×1 mH
0,1 F (X2)
2×2500 pF (Y)

47k
m icrocontroller especially dedicated for motor control. Due to this
10
11
12
13
14
Go to: www.freescale.com
1
2
3
5
7
8
9
PA4/PWMB2
PA5/PWMA3
PA6/PWMB3
PA7
OSC2
OSC1
RESET
IRQ/VPP
PC0/AD0
PC1/AD1
PC2/AD2
PC3/AD3
MC68HC(7)05MC4
Microcontroller Board Schematic
VCC
Main Power Supply Filters
F (400V) capacitor. The RFI filter and the Low-frequency
PD6/TCMP/TCAP1
0,75 mH
0,75 mH
PA2/PWMB1
PA3/PWMA2
PA1/PWMA1
PC6/VREFH
PD7/TCAP2
PC7/VREFL
PB4/TDO
PC5/AD5
PC4/AD4
PB5/RDI
VCC
PA0
PB7
PB6
28
27
26
25
24
23
22
21
20
19
18
17
16
15
4×1N5404RL
47k
Analog (GND)
390
390
DIRECTION
AD Current
VCC
10uF
SW3
PWM - B bottom
PWM - C top
PWM - C bottom
+
100nF
100nF
Fault (Over-current)
TX
RXD
Analog (GND)
LED
VCC
Zero cross. det.
VCC
10k
REV 0.2
AN1627