Technologies

News information

BA6247FP-Y, BA6238A are two motor / motion / ignition controllers and drivers

Release on : Aug 2, 2019

The BA6247FP-Y, BA6238A reversible motor drive for output of 1.0A or higher for two motors drives a brushed motor and includes a semi-motor reversible motor drive circuit. In addition, since the output portion can control the voltage voltage setting pin applied to the motor by the output high, the torque at the time of driving the motor can be changed.

 

Features:

 

1) Reversible motor driver with one half circuit built in

2) Minimal external components

3) The output voltage can be selected by the reference voltage setting pin

4) Built-in thermal shutdown circuit

 

application:

 

 

Audio-visual equipment; PC peripheral equipment; car audio; car navigation system; OA equipment

BA6247FP-Y block diagram and pin configuration diagram

 

BA6247FP-Y

 

BA6247FP-Y_1

 

BA6238A Block Diagram and Pin Configuration Diagram

 

BA6238A

 

BA6238A_1

 

External application component:

 

 

1) Current limited resistor R1 This is a current limiting resistor used to reduce the collector loss and current limit when the output is shorted. This depends on the power supply voltage used, etc., but the selection resistor is approximately 5 to 10 Ω. In addition, care must be taken to set the voltage drop caused by the surge current flowing through the motor when it starts.

2) Resistors and Zener diodes for output high voltage settings, R2, R3 and ZD These are resistors and Zener diodes used when setting the output high voltage. It is recommended to use Zener diode ZD instead of resistor R3 when the power supply voltage is unstable.

3) Stable capacitance of power line C1

Connect a 1μF to 100μF capacitor to stabilize the power cord and confirm motor operation.

4) Phase compensation capacitor, C2, C3, C4, C5 output pin produces noise or oscillation results in accordance with the set installation state (such as power supply) circuit, motor.

 

Output high voltage setting:

 

This function selects the output voltage through the VR pin and controls the motor speed. However, when the output high voltage is set to a low level, the consumption of the IC increases. With sufficient margin for thermal design combined with power consumption (Pd) under practical application conditions. Please do not exceed the VCC1 and VCC2 voltages to force the VR pin voltage.

 

The circuit diagram associated with the BA6247FP-Y output high voltage setting VR pin is shown below.

The output high voltage and low voltage VOH and VOL are expressed as:

VOH = VR +(VF(Q5)+ VF(Q4)) - (VF(Q2)+ VF(Q3))

VOH≈VR

VOL = VSAT(Q7)+ VF(Q6) (reference value; VSAT≈0.2V, VF≈0.7V)

In addition, the relationship between VREF voltage and output voltage

Expressed as:

VR <VCC1 - VSAT(Q1) - VF(Q4) - VF(Q5)

VR <VCC2 - VSAT(Q3)+(VF(Q2)+ VF(Q3)) - (VF(Q4)+ VF(Q5))

Therefore, when the VR voltage condition is as follows, the output high voltage is limited.

VR> VCC1 - VSAT(Q1) - VF(Q4) - VF(Q5)

VR> VCC2 - VSAT(Q3)+(VF(Q2)+ VF(Q3)) - (VF(Q4)+ VF(Q5))

VOH = VCC1 - VSAT(Q1) - VF(Q2) - VF(Q3)

VOH = VCC2 - VSAT (Q3)

 

BA6247FP-Y_2

 

BA6238A

The circuit diagram associated with outputting the high voltage setting VR pin is shown below.

The output high voltage and low voltage VOH and VOL are expressed as:

VOH = VR +(VF(Q5)+ VF(Q4)) - (VF(Q2)+ VF(Q3))

VOH≈VR

VOL = VSAT(Q7)+ VF(Q6) (reference value; VSAT≈0.1V, VF≈0.7V)

In addition, the relationship between the VREF voltage and the output voltage is expressed as:

VR <VCC1 - VSAT(Q1) - VF(Q4) - VF(Q5)

VR <VCC2 - (VSAT(Q2)+ VF(Q3))+(VF(Q2)+ VF(Q3)) - (VF(Q4)+ VF(Q5)

Therefore, when the VREF voltage condition is as follows, the output high level voltage is limited.

VR> VCC1 - VSAT(Q1) - VF(Q4) - VF(Q5)

VR> VCC2 - (VSAT(Q2)+ VF(Q3))+(VF(Q2)+ VF(Q3)) - (VF(Q4)+ VF(Q5)

VOH = VCC1 - VSAT(Q1) - VF(Q2) - VF(Q3)

VOH = VCC2 - VSAT(Q2) - VF(Q3)

 

BA6238A_2

 

Precautions for use:

 

 

1) Absolute maximum rating

When the power supply voltage or operating temperature exceeds the absolute maximum rating, the device may be damaged. Since the cause of this damage cannot be identified as, for example, a short circuit or an open circuit, it is important to consider circuit protection measures - such as adding a fuse - if any value exceeding the absolute maximum rating is to be performed.

2) Connect the power connector backwards

Connecting the power supply in reverse polarity will damage the IC. Take precautions against reverse polarity by connecting the power cord, such as adding an external directional diode.

3) Power cord

The return current generated by the back EMF of the motor requires countermeasures, such as providing a return current path to insert a capacitor between the power supply and GND (10μF, ceramic capacitor is recommended). In this case, it is important to make sure that no electrolytic capacitors sometimes have any negative effects - including a drop in capacitance at low temperatures - occur. In addition, the connected power supply must have sufficient current sink capability. Otherwise, the regenerative current will increase the voltage on the power line, which in turn may cause problems in the product, including peripheral circuits that exceed the absolute maximum ratings. To help prevent damage or degradation, physical safety measures should be taken, such as providing a clamp diode between the power supply and GND.

4) Potential of GND

Keep the GND terminal potential at the minimum potential under any operating conditions. In addition, a check is made to determine if any of the terminals provide a voltage below GND, including a voltage phenomenon during transients. When there is a small signal GND and a high current GND, a single point ground (at the device) is recommended to separate the small signal and high current GND, and ensure that the voltage change due to wiring resistance and high current does not affect the small signal GND. Voltage. Also inside, care must be taken to avoid variations in the GND line pattern in any externally connected components.

5) Thermal design

Depending on the power consumption (Pd) in actual operation, the use of thermal design allows for sufficient margin conditions.

6) Short circuit between pins and installation error

Be careful when installing the IC on a printed circuit board. If there is an IC, it may damage the IC connection error or the pins are shorted together.

7) Operating in a strong electromagnetic field

Using this product in a strong electromagnetic field may cause IC malfunction. Use extreme caution with electromagnetic fields.

8) ASO - Safe Operating Area

When using the IC, set the output transistor to no more than the absolute maximum rating or ASO.

9) Built-in thermal shutdown (TSD) circuit The TSD circuit is only used to turn off the IC - when the BA6238A driver outputs low - to prevent thermal runaway. It is not designed to protect the IC or to ensure its operation at extreme temperatures. Do not continue to use the IC after the TSD circuit is activated, and do not operate the IC assumptions in a circuit-activated environment.

10) Capacitance between output and GND

If a large capacitor is connected between the output and GND, if VCC and VIN are shorted to 0V or 0 GND, the charge current in the capacitor flows into the output and may damage the IC for any reason. Use a current between the capacitor output and GND that is less than 1μF.

11) Test on the application board

When testing an IC on an application board, connecting the capacitor to a low-impedance pin puts the IC under pressure. Therefore, the capacitor is always discharged after each process or step. Always turn off the power to the IC before connecting it to the test unit or removing it from the test unit. Grounding the IC as an antistatic measure during the assembly process. Use similar precautions when transporting or storing ICs.

12) Rotation direction switching (FWD / REV)

When the motor rotation state changes the rotation direction, the direction after switching the motor temporarily enters the braking state or the opening state. It is recommended to keep the relevant conditions as

as follows:

By braking: longer than braking time.

(The time required for the output L terminal to reach the potential below GND when the brake is started.)

13) About the input pin of the IC

The monolithic IC contains P+ isolation and P substrate layers between adjacent elements to keep them isolated. A P-N junction is formed at the intersection of these P layers and other elements of the N layer to form a parasitic diode or transistor. For example, the relationship between each potential is as follows:

When GND > Pin A and GND > Pin B, the P-N junction acts as a parasitic diode.

When GND > pin B, the P-N junction acts as a parasitic transistor.

Parasitic diodes inevitably appear in the structure of the IC. Operation of the parasitic diode can cause interference between the interacting circuits, as well as operational and physical damage. Therefore, do not use methods to work with parasitic diodes, such as applying a voltage below the GND (P substrate) voltage to the input pins.