tb62217afg TOSHIBA Semiconductor CORPORATION, tb62217afg Datasheet - Page 46

• Manufacturer Part Number: tb62217afg
• Description: Pwm Drive Stepping Motor Driver / Brush Dc Motor Driver Selectable, Dc-dc Converter And Reset Function Ic
• Manufacturer: TOSHIBA Semiconductor CORPORATION

Calculating the Motor Setting Constant Current
Iout (max)
Assume, for example:
Producing Iout = 1.0 A requires R
The error of constant current setting is 5 % when excluding Vref and Rs .
Calculating the Oscillation Frequency
(chopping reference frequency) for the Motor and DC-DC Converter Blocks
The motor setting current value is determined by R
The Vref (gain) is fixed at 1/10 for stepping motors and selectable from 1/10 and 1/20 for DC motors.
Vref (gain)
Vref 2 (V)
Torque 100 (%)
(1) Calculating the OSC Reference Frequency for the Motor Block (typical)
(2) Calculating the OSC Frequency for the DC-DC Converter Block (typical)
Hence, the OSC frequency for the motor block is about 810 kHz when Cosc_M = 220 pF.
The chopping frequency for stepping motors is about 1/8 the above frequency, that is, 810/8 (= 101) kHz.
In addition, only the fast decay mode is available for DC motor drive.
Hence, the OSC frequency for the DC-DC converter block is about 100 kHz when Cosc_D = 120 pF.
Vref (gain) u Vref (V) u
1/10: The attenuation ratio is typically 1/10 when Vref = 1/10.
fosc_M 61820 u C (pF) ^  0.8043 (kHz)
f OSCD
5315.3 u C (pF) ^  0.8341 (kHz)
RS
= 0.20 : (at least 0.2 W).
Torque
(Torque
RS
100,
46
and Vref as follows:
R
RS
85,
(
:
70,
)
u
50%
100%
:
input serial data
‡
ˆ »
)
TB62217AFG
2004-11-12