tb62217afg TOSHIBA Semiconductor CORPORATION, tb62217afg Datasheet - Page 25

• 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

tBLANK (noise rejection dead band time)
as to prevent malfunction because of switching noise.
Digital tBLANK time
The TB62217FG incorporates two different dead band times (blanking times) for different motors to be driven so
(1) Analog tBLANK (for stepping motor mode)
(2) Digital tBLANK (for DC motor mode)
In the initial setup mode, the tBLANK time can be set to 4 different levels for A-B and C-D pairs as follows:
Caution: For #2.0 and after, tBLANK (0, 0)
(1)
(2)
within the IC. It is used mainly to avoid misjudging Irr (diode recovery time) when a stepping motor is
driven with constant current.
It is fixed within the IC; it cannot be altered.
generated digitally from an external chopping period. It is used mainly to avoid misjudging the varistor
recovery current that occurs when a DC motor is driven by PWM in the DC motor drive mode.
enabling only the analog tBLANK time provided within the IC.
OSC_M. (Note that altering the OSC_M also changes other items (motor chopping frequency, dead band time
at the time of starting).)
The noise rejection dead band time (analog tBLANK), defined by the motor's AC characteristics, is fixed
Unlike the analog tBLANK, this tBLANK time, specified when the initial setup mode is selected, is
If the Motor Select signal selects the stepping motor mode, the digital tBLANK is nullified (0 Ps), thus
Because the digital tBLANK is generated in reference to the OSC_M, it can be changed by altering the
Immediately after the PHASE has changed
If the PHASE changes, the following time is needed for synchronization with an OSC_M edge and
internal synchronization.
tBLANK time
internal processing time (OSC_M u 1)  synchronization time (below OSC_M u 1)  set time
Charging in constant-current operation (limiter operation)
tBLANK time
The set tBLANK time is as follows:
tBLANK AB (0, 1) & tBLANK CD (0, 1) :
0
0
1
1
0: OSC_M period u 5
1: OSC_M period u 2
0: OSC_M period u 3
1: OSC_M period u 4
time need for synchronization between OSC_M and PHASE  set tBLANK time
set tBLANK time
OSC_M period u 5.
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TB62217AFG
2004-11-12