TB62202AFG Datasheet, PDF (71/84 Pages) Toshiba Semiconductor – Dual-Stepping Motor Driver IC for OA Equipment Using PWM Chopper Type

TB62202AFG
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
[%]
100
Constant-
current
control
10
0
−10
Charge
Output off
period
−100
Constant-
current
control
Diode parasite
Non-flyback diode mode
[%]
100
Constant-
current
control
Charge
10
0
−10
Constant-
current
control
−100
Specifies a level of 10%,
either side of 0.
Constant-
current
control
Charge
R_RS
To V_M power supply
The coil’s energy returns through
the parasitic diodes.
R_S pin
Because V_DS < V_F, the power
U₁
U₂
dissipation is large.
OFF
OFF
L₁
Load
L₂
OFF
OFF
Forced Off mode
PGND
R_RS
To V_M
The coil’s energy returns through
the MOS, which is turned on.
Then the coil is charged to a level
of 10%.
R_S pin
The power dissipation is smaller
U₁
U_{2 than when the energy is returned}
ON
OFF _{via the parasitic diode.}
(However, the longer the ±10%
rated current control time, the
Load
OFF
longer the period of current
ON _{dissipation.)}
L₁
L₂
Charge mode
PGND
71
2005-04-04