tb62214ftg TOSHIBA Semiconductor CORPORATION, tb62214ftg Datasheet - Page 15

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

Calculation of the Predefined Output Current
output current can be set via the current-sensing resistor (R
OFF
ON
U1
L1
For PWM constant-current control, the TB62214FG/FTG uses a clock generated by the CR oscillator. The peak
where, 1/5 is the V
For example, when Vref = 3 V, to generate an output current (I
Output Transistor Operating Modes
Note: This table shows an example of when the current flows as indicated by the arrows in the figures shown above.
constant-current control.
purposes.
Output Transistor Operating Modes
Slow-decay Mode
Slow-decay Mode
Fast-decay Mode
Fast-decay Mode
I
OUT
The TB62214FG/FGT switches among Charge, Slow-Decay and Fast-Decay modes automatically for
The equivalent circuit diagrams may be simplified or some parts of them may be omitted for explanatory
A current flows into the motor
coil.
Charge
Charge
CLK
CLK
If the current flows in the opposite direction, refer to the following table.
= V
R
RS
Charge Mode
ref
R
= (V
RS
R
/5
Load
S
V
M
÷
Pin
ref
PGND
R
ref
S
/5) ÷ I
(Ω)
decay rate, V
OFF
OFF
OFF
OFF
ON
ON
U1
U1
OUT
OFF
ON
U2
L2
= (3/5) ÷ 0.8 = 0.75Ω. (≥ 0.5 W)
ref (GAIN)
OFF
OFF
OFF
OFF
ON
ON
U2
U2
OFF
ON
U1
L1
A current circulates around the
motor coil and this device.
. For the value of V
Slow-Decay Mode
R
OFF
OFF
ON
ON
ON
ON
L1
L1
RS
R
Load
S
V
M
15
Pin
PGND
RS
) and the reference voltage (V
OUT
OFF
OFF
ref (GAIN)
ON
ON
ON
ON
L2
L2
) of 0.8 A, R
OFF
ON
U2
L2
, see the Electrical Characteristics table.
OFF
ON
RS
U1
L1
is calculated as:
The energy of the motor coil
is fed back to the power
Fast-Decay Mode
TB62214FG/FTG
ref
R
), as follows:
Load
S
V
M
Pin
R
PGND
RS
2010-06-10
OFF
ON
U2
L2