AN8480NSB Datasheet, PDF (5/6 Pages) Panasonic Semiconductor – 3-phase full-wave motor driver IC

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AN8480NSB
s Application Notes (continued)
• Phase conditions between Hall input and output current
Phase of Hall pin
H1+ H2+ H3+
H1
H3
H2
H1
H2
A
H
M
L
B
H
L
M
C
M
L
H
H3
0
D
L
M
H
E
L
H
M
F
M
H
L
ECR
EC
A3
A2
A1
Emit
A2 A3
A1
0
Output current
0
Sink
ABCDE F
• Power consumption calculation method
You can find a rough value of electric power to be consumed in the IC in the following method and the use of EXCEL
(computer soft ware) will enable you to put it on a graph.
Calculating formula:
1. Let an induced voltage generated in each phase as below:
(Reference to a motor center point)
E_A1 = E_O × sin (X) · · · (1)
E_A3 = E_O × sin (X+240) · · · (3)
E_A2 = E_O × sin (X+120) · · · (2)
X: Phase angle
2. Let a current flowing in each phase as below:
I_A1 = I_O × sin (X) · · · (4)
I_A3 = I_O × sin (X+240) · · · (6)
I_A2 = I_O × sin (X+120) · · · (5)
3. The voltages generated by a wire-wound resistance of a motor are:
V_R1 = I_A1 × R · · · (7)
V_R2 = I_A2 × R · · · (8)
V_R3 = I_A3 × R · · · (9)
4. In each phase, add the voltage generated by an induced voltage and that by a wire-wound resistance.
V_A1' = (1) + (4)
V_A2' = (2) + (5)
V_A3' = (3) + (6)
5. As the lowest voltage in each phase angle must be 0 V, you can get the voltage to be generated in each phase by
means of subtracting the lowest voltage from the voltage of the remaining two phases.
V_A1 = V_A1' − MIN (V_A1', V_A2', V_A3') · · · (10)
V_A2 = V_A2' − MIN (V_A1', V_A2', V_A3') · · · (11)
V_A3 = V_A3' − MIN (V_A1', V_A2', V_A3') · · · (12)
6. Subtract the supply voltage from each phase's voltage found in item 5 and then multiply it by each phase's current,
so that you can get the power consumption.
3
Σ P = (12 − VAn ) × IAn
n=1
5