TA8401F View Datasheet(PDF) - Toshiba

Part Name

Description

Manufacturer

TA8401F

Functional Bridge Driver

Toshiba 

TA8401F/FG

Notes on Using the TA8401F/FG

The TA8401F/FG functionable bridge driver is an IC specifically developed to control rotation switching in brush motors.

This IC has been carefully designed and strengthened to withstand counter-electromotive force or startup rush current,

which are problems often associated with driving brush motors.

However, as with other power ICs, application circuits must be designed not to apply surge voltage or excess current that

exceeds the standard values. In addition, when designing PCBs, make sure the wiring pattern does not cause oscillation,

which can result in equipment malfunction or destruction of the IC.

The following are notes on use of the TA8401F/FG. These should be reflected at the design stage.

(1) Power supply voltage

To avoid the motor current affecting the TA8401F/FG control-side power supply, we recommend you use two power

supplies: an external transistor power supply, and a TA8401F/FG control-side power supply. However, when using

a single power supply, connect as in the diagram below.

(2) Maximum voltage and current

The maximum supply voltage (pin 1) for the TA8401F/FG is 18 V. The operating supply voltage is in the range of

1.8~15 V. No voltage exceeding this range should be applied to pin 1.

The maximum current is 0.5 A (ave.) or 1.5 A (peak). The circuit should be designed so that rush current at startup

does not exceed peak current, and average current during steady operation does not exceed 0.5 A.

(3) External diodes

As the block diagram shows, the TA8401F/FG has internal diodes.

The lower two diodes, which are the IC’s internal parasitic diodes, have a relatively large capacitance. However,

when a motor with a large reactance such as a core motor is driven, the upper two diodes may be damaged by the

motor’s counter-electromotive force. In such a case, connect external diodes in parallel. The lower diodes should

not be subjected to high current. For brake operation, therefore, external diodes should be connected.

(4) PCB design

The following points concern the TA8401F/FG pattern design around the power supply line (pin 1) and the pattern

design of the GND (pin 8, pin 12 / 13).

a) Ensure that the bypass capacitor between pin 1 and GND does not share impedance with other lines.

b) The GND line should not be shared by other circuits.

c) The capacitance of the bypass capacitor should be as large as possible.

(5) Oscillation remedies

To prevent noise from sparks when using brush motors, a capacitor may be connected between both pins.

When using the TA8401F/FG, the capacitor is connected between outputs (pins 10 / 11 and pins 14 / 15. This

may cause oscillation. Therefore avoid connecting the capacitor where possible. If connection is necessary to

overcome noise, connect resistors in series as shown in the technical data.

The values for the capacitor and resistors must be determined according to the motor.

Note: Particular care is necessary in the design of the output, VCC and GND lines since the IC may be destroyed

due to short circuits between outputs, air contamination faults, or faults caused by improper grounding.

6

2006-3-2

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