BA6247FP-Y , BA6238A reversible motor driver for output of 1.0A or higher for two motors drives brushed motors and contains a half-motor reversible motor drive circuit. In addition, since the output section can control the voltage applied to the motor voltage setting pin by outputting high, the torque when driving the motor can be changed.

Features

1) Built-in one and a half circuit reversible motor driver

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 Peripherals; Car Audio; Car Navigation Systems; OA Equipment

BA6247FP-Y block diagram and pinout diagram

BA6238A block diagram and pinout diagram

External application components

1) Resistor R1 for Current Limiting This is a current limiting resistor to reduce collector losses and current limiting when the output is shorted. It depends on the supply voltage used etc., but choose a resistor around 5 to 10Ω. Also, special care must be taken to set the resistance to the voltage drop caused by the inrush current that flows when the motor is started.

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

3) Stabilizing capacitor C1 of the power line

Please connect a 1μF to 100 μF capacitor to stabilize the power line and confirm motor operation.

4) Phase compensation capacitors, C2, C3, C4, C5 output pins produce noise or oscillation results consistent with the set installation state (such as power supply) circuit, motor.

Output high voltage setting

This function optionally sets the output voltage and controls the motor speed through the VR pin. However, when the output high voltage is set to a low level, the consumption of the IC increases. Thermal design with sufficient margin combined with power dissipation (Pd) under actual application conditions. Please do not force more than the VCC1 and VCC2 voltages to the VR pin voltage.

The circuit diagram of BA6247FP-Y related to the output high voltage setting VR pin is shown in the figure 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

VR

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)

BA6238A

The circuit diagram related to the output high voltage setting VR pin is shown in the figure 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 VREF voltage and output voltage is expressed as:

VR

VR

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)

Precautions for use

1) Absolute Maximum Ratings

The device may be damaged when the supply voltage or operating temperature exceeds the Absolute Maximum Ratings. Because the cause of this damage cannot be identified as, for example, a short or open circuit, it is important to consider circuit protection measures - such as adding fuses - if any value exceeding the Absolute Maximum Ratings will be performed.

2) Connect the power connector backwards

Connecting the power supply with reversed polarity will damage the IC. Take precautions to prevent reverse polarity when connecting power lines, such as adding external directional diodes.

3) Power cord

The return current generated by the back EMF of the motor requires countermeasures such as providing a return current path and inserting a capacitor between the power supply and GND (10µF, ceramic capacitor is recommended). In this case, it's important to be sure that no electrolytic capacitors sometimes have any negative effects - including capacitance drops at low temperatures - occur. In addition, the connected power source must have sufficient current sink capability. Otherwise, regenerative current will increase the voltage on the power supply line which in turn may cause problems with 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 supplying voltage clamping diodes between the power supply and GND.

4) Potential of GND

Keep the GND terminal potential at the minimum potential under any operating conditions. Also, check to see if any terminals supply voltages below GND, including voltage phenomena during transients. When there is a small signal GND and a high current GND, a single point ground (at the device) is recommended as a reference point in order to separate the small signal and high current GND and ensure that voltage changes due to wiring resistance and high current do not affect the small signal GND voltage. Inside again, care must be taken to avoid any variation in the GND line pattern in the externally connected components.

5) Thermal Design

Using thermal design allows sufficient headroom conditions depending on the power dissipation (Pd) in actual operation.

6) Short circuit between pins and wrong installation

Be careful when mounting ICs on printed circuit boards. If there is an IC, it may be damaged if the IC is connected incorrectly, or the pins are shorted together.

7) Operation in strong electromagnetic fields

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

8) ASO - Safe Operating Area

When using an IC, set the output transistors to not exceed Absolute Maximum Ratings or ASO.

9) Built-in Thermal Shutdown (TSD) circuit The TSD circuit is only used to shut down the IC - when the BA6238A driver outputs a low level - to prevent thermal runaway. It is not designed to protect the IC or guarantee its operation under extreme heat. Do not continue to use the IC after the TSD circuit is activated, and do not operate the IC in an environment where the circuit is activated.

10) Capacitance between output and GND

If you connect a large capacitor between the output and GND, if VCC and VIN are shorted to 0V or 0 to GND for any reason, the current charged in the capacitor flows into the output and can damage the IC. Use a capacitor with less than 1µF of current between the output and GND.

11) Test on application board

When testing the IC on an application board, connecting a capacitor to a low impedance pin will stress the IC. Therefore, always discharge the capacitor after each process or step. Always turn off the power to the IC before connecting it to or removing it from the test fixture during inspection. Ground the IC during the assembly step as an antistatic measure. Use similar precautions when shipping or storing ICs.

12) Rotation direction switching (FWD/REV)

When the rotation state of the motor switches 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 it takes for the output L terminal to reach the potential below GND when the brake is activated.)

13) About the input pins of the IC

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

When GND>pin A and GND>pin B, the PN junction acts as a parasitic diode.

When GND > pin B, the PN junction acts as a parasitic transistor.

Parasitic diodes inevitably appear in the structure of ICs. The operation of parasitic diodes can lead to interference between interacting circuits, as well as operational failures and physical damage. So don't use methods which parasitic diodes work, such as applying a voltage lower than the GND (P substrate) voltage to the input pins.