tb6641fg TOSHIBA Semiconductor CORPORATION, tb6641fg Datasheet - Page 14

• Manufacturer Part Number: tb6641fg
• Description: Full-bridge Dc Motor Driver Ic
• Manufacturer: TOSHIBA Semiconductor CORPORATION

Internal CLK
(3)
(4)
OSC
Internal CLK
Operation on change of predetermined current value (when in Discharge mode)
The TB6641FG enters Discharge mode as V
then transits to Charge mode after four internal clocks. However, if V
the TB6641FG goes back to Discharge mode. If V
then the TB6641FG enters Charge mode and stays until V
Operation on change of predetermined current value (when in Charge mode)
Even though VREF reaches the predetermined current value, Discharge mode continues for four
internal clocks after that. And then Charge mode is entered.
Due to the peak current detection technique, the average current value of the constant-current
operation shall be smaller than the predetermined value. Because this depends on characteristics of
used motor coils, precise identification of the used motor coils must be performed when determining
the current value.
When both the PWM constant-current control and the direct PWM control (applying the PWM input
on the PWM pin, or on the IN1 and IN2 pins), Short Brake mode is preferentially selected.
VREF/10
Coil current
V
VREF/10
RSGND
GND
OSC
GND
Discharge
Discharge
Coil current
2.4 s (typ.)
14
RSGND
Charge
RSGND
Charge
Discharge
reaches the predetermined voltage (VREF/10) and
 VREF/10 after another four internal clocks,
RSGND
reaches VREF/10.
Charge
RSGND
Discharge
 VREF/10 at the time,
TB6641FG
2011-06-21