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IP4001

5-CH MOTOR DRIVE IC

APPLICATION SUMMARY (Continued)

- Thermal shutdown

The IP4001 has a thermal protection against the abnormal operation, and the detailed operation

of the TSD circuit is as follows

Temperature

mute

on

off

- BTL drive part (Focus, Tracking, Spindle, Sled drive part)

BTL drive part is composed of V-I converter, level shifter and output power amp.

All Output

Driver Bias

VCC2

Q4

I

TSD

Hysteresis

10.6k

Pref

10k

Level

Shift

23

10

3

19

25

24

4

2

11

18

26

1

12

17

27

10.6k

As shown in figure 3,

TSD circuit controls the base of the TR Q4.

TR Q4 will be turned on, and the bias current

of the output drive circuit will be shut down

(because of the negative temperature characteristic

of the NPN transistor).

be turned off.

Fig3. Thermal shut down

Hysteresis

Fig4. BTL drive part

- V-I converter converts voltage of the input pin into current,

* Vin = input voltage of the input pin (pin3, 10, 19, 25)

*Vref = reference voltage (pin23)

10k

Vref

-

Vin

=

Iconv

Iconv

Ra

Ra

Pamp1

Pamp2

-Va

Va