tb62202afg TOSHIBA Semiconductor CORPORATION, tb62202afg Datasheet - Page 71

• Manufacturer Part Number: tb62202afg
• Description: Dual-stepping Motor Driver Ic For Oa Equipment Using Pwm Chopper Type
• Manufacturer: TOSHIBA Semiconductor CORPORATION

Points for Control that Includes Current of 0%
In modes other than 2-Phase Excitation mode (from 1-2 Phase Excitation mode to 4W1-2 Phase Excitation mode),
when the current is controlled to 0%, the TB62201F’s output transistors are all turned off.
At the time, the coil's energy returns to the power supply through the parasitic diodes. If the same current is
applied several times and is within the rated current, then : the power consumed by the on-resistance when current
flows to the output MOS will be less than the power consumed when current is applied to the parasitic diodes.
Therefore, when controlling the current, rather than setting 0%, set the current to the next step beyond 0% (the
minimum step in the reverse direction) for better power dissipation results.
However, if the 0% (actually 10%) current cycle is long, the power dissipation may be greater than in Off mode
because of the need for constant-current control.
Therefore, Toshiba recommend setting the current according to the actual operating pattern. (1-2 Phase Excitation
mode is the most effective.)
Flyback diode mode
Non-flyback diode mode
−100
−100
100
−10
100
−10
[%]
[%]
10
10
0
0
Specifies a level of 10%,
either side of 0.
Constant-
Constant-
current
control
current
control
Diode parasite
Charge
Output off
Constant-
current
control
period
Charge
Charge
Constant-
Constant-
current
control
current
control
OFF
OFF
U
L
1
1
ON
OFF
U
L
1
1
71
R
RS
R
R
Load
S
RS
R
pin
Load
S
PGND
pin
Forced Off mode
To V
PGND
Charge mode
To V
M
power supply
M
OFF
OFF
U
L
2
2
OFF
L
ON
U
2
2
The coil’s energy returns through
the parasitic diodes.
Because V
dissipation is large.
The coil’s energy returns through
the MOS, which is turned on.
Then the coil is charged to a level
of 10%.
The power dissipation is smaller
than when the energy is returned
via the parasitic diode.
(However, the longer the ± 10%
rated current control time, the
longer the period of current
dissipation.)
DS
TB62202AFG
< V
F
, the power
2005-04-04