19

SLA7024M, SLA7026M, SLA7027MU, SLA7022MU, SLA7029M,

SMA7022MU, SMA7029M, SLA7020M, SLA7021M and SDK03M

Application Note

s Determining the chopper frequency

SDK03M are self-excited choppers. The chopping OFF

Td.

22

Rn(1–

Rn(1–

)

recommended.

µs

= 47 K

Ω

= 500 pF

=5 V

s Thermal design

An outline on the method of computing heat dissipation is

shown below.

put current lo”.

(2) The power dissipation Pdiss is obtained through the

following formula.

• SLA7000M and SMA7000M series

2-phase excitation

3

1-2 phase excitation : Pdiss =

2

• SDK03M

2-phase excitation

3

1-2 phase excitation : Pdiss =

4

(3) Obtain the temperature rise that corresponds to the

computed Pdiss from Fig. 12 “Temperature rise curve.”

Fig. 10 Chopper frequency vs. Motor coil resistance

.

.

.

.

.

.

.

.

.

.

Typ.

Motor : 23LM-C004

Holding mode

=44V

36V

24V

15V

SLA7024M, SLA7029M, SMA7029M and SLA7020M

0

0.2

0.4

0.6

0.8

1.0

1.2

1.0

0.8

0.6

0.4

0.2

0

60

50

40

30

20

10

0

02468

10

12

14

16

15

20

25

30

35

40

Motor coil resistance Rm (

Ω)

=24V

=36V

Ω

=1~3ms

=

=

47k

Ω

500PF

µ

Typ.

Motor : 23PM-C503

Rm=1.16

Ω/

Lm=2.9mA/

Holding mode

φ

φ

36V

15V

24V

SLA7026M and SLA7021M

4.0

3.0

2.0

1.0

0

0

1.0

2.0

3.0

1.4

1.2

1

0.8

0.6

0.4

0.2

0

0

0.2

0.4

0.6

0.8

1

36V

24V

15V

=44V

SLA7022MU, SLA7027MU, SMA7022MU and SDK03M

Typ.

Motor : 23LM-C202

Holding mode