tb62214ftg TOSHIBA Semiconductor CORPORATION, tb62214ftg Datasheet - Page 19

• Manufacturer Part Number: tb62214ftg
• Description: Bicd Constant-current Two-phase Bipolar Stepping Motor Driver Ic
• Manufacturer: TOSHIBA Semiconductor CORPORATION

Overcurrent Shutdown (ISD) Circuitry
Calculating OSCM Oscillating Frequency
The OSCM oscillating frequency can be approximated using the following equation:
Where:
C = Capacitor capacity
R1= Resistance
Assigning C = 270 × 10
f
f
OSCM
OSCM
ISD Masking Time and ISD On-Time
switching from erroneously tripping the ISD circuitry. The masking time is a function of the chopper
frequency obtained by CR:
them are:
manner. The ISD circuitry might not work, depending on the control timing of the output transistors.
optimal fuse capacitance varies with usage conditions, and one that does not adversely affect the motor
operation or exceed the power dissipation rating of the TB62214FG/FTG should be selected.
An overcurrent starts flowing into the output transistors
The overcurrent shutdown (ISD) circuitry has a masking time to prevent current spikes during Irr and
The minimum and maximum times taken to turn off the output transistors since an overcurrent flows into
It should be noted that these values assume a case in which an overcurrent condition is detected in an ideal
Therefore, a protection fuse must always be added to the VM power supply as a safety precaution. The
(chopper waveform)
OSC_M oscillation
= 1.61 × 10
ISD masking time
=
masking_time = 4 × CR_frequency
Min: 4 × CR_frequency
Max: 8 × CR_frequency
0
.
56
×
C
6
×
⇒ 1.6 MHz
1
R (
1
+
−12
500
[F], R1= 3600 [Ω] to get:
)
min
min
ISD on-time
Disabled (reset state)
max
19
max
1 chopping cycle
TB62214FG/FTG
2010-06-10