View BA6446FM_209580.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

Motor driver ICs
3-phase motor driver
BA6446FP / BA6446FM
The BA6446FP and BA6446FM are 3-phase, full-wave, pseudo-linear motor drivers suited for VCR capstan motors. The IC has a torque ripple cancellation circuit to reduce wow and flutter, a forced brake circuit that allows abrupt change of operational mode, and an output transistor saturation prevention circuit that provides superb motor control over a wide range of currents. The IC also contains FG and hysteresis amplifiers. FApplications VCR and DAT capstan motors FFeatures 1) 3-phase, full-wave, pseudo-linear drive system. 2) Torque ripple cancellation circuit. (cancellation ratio adjustable) 3) Forced brake circuit. FAbsolute maximum ratings (Ta = 25_C)
4) High- and low-side output transistor saturation prevention circuit. 5) FG and hysteresis amplifiers. 6) Thermal shutdown circuit.
FRecommended operating conditions (Ta = 25_C)
645
Motor driver ICs
FBlock diagram
BA6446FP / BA6446FM
646
Motor driver ICs
FPin descriptions
BA6446FP / BA6446FM
647
Motor driver ICs
FInput / output circuits (1) RCC pin (1 pin)
BA6446FP / BA6446FM
(2)
ED / S pin (2 pin)
(3)
BRK pin (3 pin)
(4)
Motor output (A1, 5 pin; A2, 6 pin; A3, 9 pin)
(5)
EC and ECR pins (10 pin, 11 pin)
(6)
TL pin (12 pin)
(7)
Hall signal input pins (H1) : 27 pin, H1* : 26 pin, H2) : 25 pin, H2* : 24 pin, H3) : 23 pin, H3* : 22 pin)
648
Motor driver ICs
BA6446FP / BA6446FM
(8)
Schmitt trigger amplifier I / O pins (17 pin, 16 pin)
(9)
Amplifier I / O pins (20 pin, 19 pin, 18 pin)
649
Motor driver ICs
BA6446FP / BA6446FM
FElectrical characteristics (unless otherwise noted, Ta = 25_C, VCC = 5V, VM = 12V)
650
Motor driver ICs
FCircuit operation (1) Pseudo-linear output and torque ripple cancellation The IC generates a trapezoidal (pseudo-linear) output current, whose waveform phase is 30 degrees ahead of that of the hall input voltage (Fig. 1).
BA6446FP / BA6446FM
Reverse when the voltage is above 2.8V. (5) Output transistor saturation prevention circuit This circuit monitors the output voltage and maintains the operation of the output transistors below their saturation levels. Operating the transistors in the linear characteristic range provides good control over a wide range of current and good torque characteristics even during overloading.
(2) Torque control The output current can be controlled by adjusting the voltage applied to the torque control pins.
The pins are the inputs to a differential amplifier. A reference voltage between 2. 3-3. 0V (2.5 V recommended) is applied to pin 11. A brake is applied to the motor when the brake pin (3 pin) is put to LOW. The brake mode is activated when the brake pin voltage is 0.7V or less and deactivated when the voltage is 2.0V or more. (3) Output current sensing and torque limitation The RNF pin (7 pin) is the ground pin for the output stage. To sense the output current, a resistor (0.5 recommended) is connected between pin 7 and the ground. The output current is sensed by applying the voltage developed across this resistor to the TL amplifier input as a feedback. The output current can be limited by adjusting the voltage applied to pin 12. The current is limited when pin 12 reaches the same potential as pin 7. The output current (IMAX.) under this condition is given by : VTL*(TL*RNF offset) IMAX.= RRNF where RRNF is the value of the resistor connected between the RNF pin and the ground, and VTL is the voltage applied to the TL pin. (4) Motor direction control (ED / S pin) The motor mode is : Forward when the ED / S-pin voltage is less than 2.2V,
(6) Ripple cancellation circuit The torque ripple cancellation ratio can be adjusted by an external resistor connected to pin 1. Select a suitable value by taking wow and flutter into consideration. (7) Brake pin The brake pin threshold depends on the chip temperature as shown in Fig. 5. Make sure that your application will work properly when using the IC at low or high temperatures.
651
Motor driver ICs
FApplication example
BA6446FP / BA6446FM
652
Motor driver ICs
FOperation notes (1) Thermal shutdown circuit The BA6446FP / FM has a thermal shutdown circuit to protect the IC. The shutdown temperatures is 175_C (typical) with a hysteresis width of 45_C (typical). When the circuit is activated due to an increase in the chip temperature, the output pins (pins 5, 6, and 9) are set to the open state. The circuit is functional against excessive power dissipation, output short-circuiting, and other irregularities in the output current, but does not work against overheating caused by high internal currents due to externally caused IC damage or pin-to-pin short-circuiting. (2) Brake circuit The brake circuit has temperature-dependent thresholds as shown in Fig. 5. Make sure that your application will work properly when using the IC at low or high temperatures. (3) Be sure to connect the radiation fins to the ground.
BA6446FP / BA6446FM
(4) Hall input The Hall input circuit is described in (7) of "I / O equivalent circuits." Hall devices can be connected in either series or parallel. Be sure to keep the Hall input within the range of 1.5V to (VCC*1.8V).
(5) FG amplifier Note that unpredictable outputs may occur when the FG amplifier input is outside the recommended range. (6) ECGND pin (4 pin) Pin 4, a torque amplifier ground pin, should be connected to the ground. By connecting this pin to a point close to the motor ground, you can prevent the effect of GND common impedance on the current-sensing resistor (0.5 recommended) connected between RNF (pin 7) and the motor ground pin.
653
Motor driver ICs
FElectrical characteristic curves
BA6446FP / BA6446FM
FExternal dimensions (Units: mm)
654

▲Up To Search▲

Price & Availability of BA6446FM

	To Download BA6446FM Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .