1998 Oct 27

13

Philips Semiconductors

Product specification

Brushless DC motor drive circuit

TDA5145TS

If the chosen value of CAP-TI is too small oscillations can occur in certain positions of a blocked rotor. If the chosen value is too large, then it is possible

that the motor may run in the reverse direction (synchronously with little torque).

handbook, full pagewidth

MGH318

VMOT 1

voltage

on CAP-TI

Other design aspects

There are other design aspects concerning the application

of the TDA5145TS besides the commutation function.

They are:

• Direction function

• Brake function

• Reliability.

If the voltage at pin 9 is less than 0.8 V, the motor is

running in one direction (depending on the motor

connections). If the voltage at pin 9 is greater than 2.0 V,

the motor is running in the opposite direction.

If the voltage at pin 8 is greater than 2.0 V, the motor

brakes. In that condition, the 3 outputs MOT1, MOT2 and

MOT3 are forced to a LOW voltage level and the current

limitation is performed internally by the sink drivers.

If the voltage at pin 18 is greater than 2.0 V, the output

states are shown in Table 2.

Table 2

Note

1. Z = high-impedance OFF-state; L = LOW state;

H = HIGH state.

DRIVER OUTPUT

MOT1

Z

MOT2

L

MOT3

H