Rainbow-electronics BA6287F Manual de usuario descargar pdf (Pagina 3)

441

Motor driver ICs BA6287F

Electrical characteristics (unless otherwise noted, Ta = 25C, VCC = 9V, VM=9V, VREF = 9V)

Circuit operation

(1) Input section

The four output modes are controlled by two logic inputs.

Current flows from OUT1 to OUT2 when F

IN is HIGH and

IN is LOW, and from OUT2 to OUT1 when RIN is HIGH

and F

IN is LOW (refer to the truth table). The input circuit

can be operated by a logic circuit with a current capacity

of 120  170µA.

Input / output truth table

(2) Output section

Current flows from OUT1 to OUT2 during forward rota-

tion, and from OUT2 to OUT1 during reverse rotation.

The output voltages V

OH and VOL are given by :

OH [V]=VREFVCE (sat) (PNP)VBE (NPN)

OL [V]=VCE (sat) (NPN)

CE and VBE are functions of the output current (see elec-

trical characteristic curves). The output current can be

set with the V

REF pin.

(3) Power saving circuit

All circuits are turned OFF when the F

IN and RIN input pins

are both put to LOW level. This circuit saves power dur-

ing standby mode by leaving the outputs OPEN.

(4) Thermal shutdown circuit

When the thermal shutdown circuit is activated at the

chip temperature of about 175C (typical), the outputs

are left OPEN. The temperature difference between the

activation and deactivation settings is about 15C. When

the thermal shutdown circuit is deactivated, the outputs

revert to the status determined by input mode.

Application example

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Rainbow-electronics BA6287F Manual de usuario Pagina 3