IC-SP-06027 R1
1-4. Motor drive system
Three-phase inverters generally fall into two categories according to the method of commutation of the six output-stage
devices: 120-degree energization and 180-degree energization. The method of 120-degree energization is such that
the device on the top arm and that on the bottom arm are controlled to set the energization period between phases to
120 degrees, thus transferring the current from phase U to V to W, thus driving the motor. Hitachi Single-chip Inverter
ICs (VSP-input series) are based on 120-degree energization and receive position signals from hall ICs and VSP
signals that constitute speed instructions, thus conducting PWM control by the chopping action of the lower arm. For
uses of 180-degree energization, a six-input series are provided where six output stage devices can be controlled by
each input signal.
1-5. Block Diagram of Inverter IC
Fig. 1-4 shows a block diagram of ECN30206 for receiving 230V AC, as an example of inverter IC. Its main function is
to receive input signals from the three phases of hall ICs of the brushless DC motor, turns on and off the particular
IGBTs with the three-phase distribution circuit, and to drive the motor. Other components include a charge pump circuit
as a power self-supply circuit, a triangular wave oscillator and a comparator-based PWM generation circuit as rpm
control circuits, an over current detection circuit which provides a current trip function at motor startup, and an under
voltage detection circuit that detects power drops in the drive circuit and turns off the output.
RU
VCC(15V)
C0
CB
VCC
VB
RV
RW
D2
C2
+ -
HU
HV
HW
C+
C-
D1
+
C1
-
CL
VS1
VS2
VS
VB supply
VCC
Clock
VB
Charge Pump
FG
FG
DM
Motor Rotating
Direction
Filter Circuit
MicroController
Top Arm
Driver
3-Phase
Distributor
All off
+
CMP
Bottom
arm off
Hall ICs
MU
MV
MW
VSP
PWM Comparator
+
CMP
Bottom Arm
Driver
Over Current Sense
Motor
SAW wave
Generator
VCC
Clock
LVSD
GL
+
Vref
GH1
GH2
CR
VTR
RTR
CTR
RS
Note : Inside of bold line
shows ECN30206
RS
Fig.1-4. Block diagram of ECN30206
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