ta8435h TOSHIBA Semiconductor CORPORATION, ta8435h Datasheet - Page 21

• Manufacturer Part Number: ta8435h
• Description: Pwm Chopper-type Bipolar Stepping Motor Driver.
• Manufacturer: TOSHIBA Semiconductor CORPORATION

When using TA8435H/HQ
0.
1.
2.
The TA8435H/HQ controls the PWM to set the stepping motor winding current to a constant current. The
device is a micro-step driver IC used to drive the stepping motor efficiently at low vibration.
The TA8435H/HQ drives the stepping motor in micro steps with a maximum resolution of 1/8 of the 2-phase
stepping angle (in 2W1-2-phase mode).
size and the rotation angle are even. Just inputting clock signals rotates the stepping motor in micro steps.
In micro step operation, A-phase and B-phase current levels are set inside the IC so that the composite vector
(1)
(2)
Introduction
Micro-step drive
PWM control and output current setting
The TA8435H/HQ controls the PWM by turning the upper power transistor on and off.
Here, current flows as shown in the figure below.
Output current path (PWM control)
Setting of output current by REF-IN input and current detection resistor
The motor current (maximum current for micro-step drive) I
equation, using REF-IN input and the external current detection resistor R
I
O
where,
= V
REF−IN = High,
REF−IN = Low,
REF
/ R
NF
V
V
REF
REF
= 0.8 V
= 0.5 V
21
O
is set as shown in the following
NF
.
TA8435H/HQ
2006-3-2