NJM2640

- 5 -

Lock detection time (Ton) is given by:

Where C2 is 0.47uF:

Auto Resume Time (Toff) is given by:

Where C2 is 0.47uF:

In actual application, Lock detection time (Ton) is affected by the mechanical time constant of a motor.

Therefore, constant start up must be confirmed in actual evaluation taking operating variations

(i.e.Temperature, Voltage change and so on) in consideration.

A typical value of C2 is either 0.47uF or 1uF depending on a motor.

Lock Protection

Lock Alert Out (LA: Pin 3) is a open collector output and R3 is a pull up resister. A typical value of R3 is

10k

Ω.

It must be noted that Lock Alert Out stays a H state during few hundred milliseconds from power up as

shown in the picture below.

[]

sec

2

Ic

Vcl

Vch

C

T

ON

−

=

[]

sec

22

.

0

10

8

.

3

7

.

0

5

.

2

10

47

.

0

6

6

=

×

−

×

×

=

−

−

ON

T

[]

sec

13

.

1

10

75

.

0

7

.

0

5

.

2

10

47

.

0

6

6

=

×

−

×

×

=

−

−

OFF

T

[]

sec

2

Idc

Vcl

Vch

C

T

OFF

−

=

High

Hall input

Motor output

Ct Teminal voltage

LATeminal voltage

Returns to normal operation

Motor Lock protection period

Motor Locked

Power supply

LA terminal output

Hundreds of millimeter second