AN1857 Freescale Semiconductor / Motorola, AN1857 Datasheet - Page 22

• Manufacturer Part Number: AN1857
• Description: A 3-Phase ac Induction Motor Control System Based on the MC68HC908MR32
• Manufacturer: Freescale Semiconductor / Motorola

Application Note
dc Bus Signal
Conditioning
22
PWM_AB
PWM_AT
C419
1 nF
10 k
R403
GND
10 k
R404
Shut_Down
C420
1 nF
Phase currents and dc bus are measured by sensing the voltage drop
across sensing shunt resistors located on the power module.
is a schematic diagram of the design of the dc bus analog signal
conditioning circuit. The output voltage of the amplifier is proportional to
the sensed currents. The input to the circuit in
across a 0.075- shunt resistor connected in series with the particular
current being measured. The input signal to the amplifier is multiplied
times 7.5 and then the output of the amplifier is shifted up by a 1.65-volt
reference. The final output of the circuit is 1.65 volts with an input
current of 2.93 amps passing through the 0.075- shunt resistor.
DM74ALS1034M
Freescale Semiconductor, Inc.
U404A
3
1
For More Information On This Product,
U404B
10 k
DM74ALS1034M
R414
Figure 12. IGBT Driver Circuit
2
4
100 nF
C401
+5V_D
+5V_D
Go to: www.freescale.com
100
R413
GND
4.7 F/16V
C402
8.2 pf
C413
10
11
12
13
14
15
16
9
IR2112S
n/c
n/c
VDD
HIN
SD
LIN
VSS
n/c
U401
+5V_D
COM
VCC
HO
VB
VS
n/c
n/c
LO
8
7
6
5
4
3
2
1
C403
C404
MURS160T3
470 nF/
470 nF/
50 V
50 V
D401
Figure 13
GND
+
C416
33 mF/
25 V
+15V_D
MMSZ5251BT1
MMSZ5251BT1
MBRS130LT3
MBRS130LT3
is derived
120
120
D402
R401
D404
R402
D403
D405
MOTOROLA
Figure 13
Source_AB
Source_AT
AN1857
Gate_AB
Gate_AT