32

SI-7300A and SI-7330A

Application Note

s Thermal design

The procedures for the thermal design of the SI-7300A are

as follows:

the output current lo are measured at the maximum

in holding mode at the 2-phase excitation.

(2) From the above measurements, the internal power dis-

sipation (2 phases) of the hybrid IC can be obtained

through the following formula.

Shown in the lower graphs are sample calculations of

Pdiss vs. Io.

(3) The heatsink area corresponding to the ambient tem-

perature can be obtained from the SI-7300A derating

curve shown in the lower right.

(4) Verify that the temperature of the aluminum base plate

of the hybrid IC or adjacent heatsinks is below 85

°C

(equivalent to max. ambient temperature) when operat-

ing under actual conditions.

*

For details on thermal design, refer to the technical

data.

80

60

40

20

0

Ambient temperature Ta (°C)

0

4

8

12

16

20

24

28

SI-7300A Derating curve

No heatsink

100

×50

×2

100

×100

×2

SI-7300A

Aluminium heatsink

Using silicone grease

Unit : mm

SI-7330A Derating curve

SI-7300A

Aluminium heatsink

Using silicone grease

Unit : mm

0

5

10

15

20

25

30

80

60

40

20

0

Ambient temperature Ta (°C)

100

×

100

×

2

100

×50

×2

No heatsink

Excitation

signal input

(Active low)

TD62302P

(Toshiba)

(Open collector)

PD

2.2 F

10V

+

1

2

3

4

16

15

14

13

10k

Ω

Rx

2SC2002

9

8

510

Ω×4

A

B

A

B

114

4

10

6

12

2

8

15

5

7

17

9

11

18 16

3 13

ZD

100 F

50V

A

B

A

B

SPM

+

SI-7300A

Method for measuring current SI-7300A

A

A

µ

µ

0

0.2 0.4 0.6 0.8

1.0 1.2 1.4

9

8

7

6

5

4

3

2

1

0

SI-7300A Heat dissipation per phase

vs. output current

Output current Io (A/ )

1

2

3

VCC1

1 40V

2 30V

3 20V

Motor

3.6

Ω/

9.0mH/

No load

Excitation signal

1-phase, holding

mode

16

14

12

10

8

6

4

2

0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

SI-7330A Heat dissipation per phase

vs. output current

Condition

1-phase, holding

mode

Motor

Rm=0.85

Ω/

Lm=1.45mH/

Output current Io (A/ )

φ

φ

φ

φ

φ

φ