LB1871M 查看數據表（PDF） - SANYO -> Panasonic

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LB1871M

Three-Phase Brushless Motor Driver

SANYO -> Panasonic 

LB1871, 1871M

5. External interface pins

• LD pin

Output type: open collector

Breakdown voltage: 30 V absolute maximum

Saturation voltage manufacturing variation reference value (ILD = 10 mA): 0.10 to 0.15 V

• FGS pin

Output type: open collector

Breakdown voltage: 30 V absolute maximum

Saturation voltage manufacturing variation reference value (IFGS = 4 mA): 0.15 to 0.30 V

A hysteresis comparator converts the FG amplifier output to a pulse signal to create the FGS output, which is used

for speed monitoring. The pull-up resistor is not required if this pin is not used.

• S/S pin (start/stop pin)

Input type: A pnp transistor whose base is pulled up to the internal 6.3 V power supply through a 23 kΩ

resistor, and is pulled down to ground through a 40 kΩ resistor.

Threshold level (low → high): about 2.8 V

Threshold level (high → low): about 2.4 V

The LB1871 goes to stop mode with this pin in the open state.

• CLK input pin

Input type: A pnp transistor whose base is pulled up to the internal 6.3 V power supply through a 23 kΩ resistor,

and is pulled down to ground through a 40 kΩ resistor.

Threshold level (low → high): about 2.8 V

Threshold level (high → low): about 2.4 V

• N1 pin

Input type: A pnp transistor whose base is pulled up to the internal 6.3 V power supply through a 23 kΩ resistor,

and is pulled down to ground through a 40 kΩ resistor.

Threshold level (typical): about 2.6 V

• N2 pin

Input type: The base of a pnp transistor is pulled up to the internal 6.3 V power supply through a 23 kΩ resistor,

and is pulled down to ground through a 40 kΩ resistor.

Threshold level (low → high): about 1.5 V

Threshold level (high → low): about 3.6 V

6. FG amplifier

R1 and R2 determine the FG amplifier gain, with the DC gain G being R2/R1. C2 and C3 determine the FG amplifier

frequency characteristics, with R1 and C2 forming a high-pass filter and R2 and C3 forming a low-pass filter. Since a

Schmitt comparator follows the FG amplifier directly, R1, R2, C2, and C3 must be chosen so that the FG amplifier

output is at least 400 mVp-p. (It is desirable for the FG amplifier output to be set up to be between 1 and 3 V during

steady state rotation.) The FG amplifier is often the cause when capacity becomes a problem in noise evaluation. One

solution to that problem is to insert a capacitor of between 1000 pF and 0.1 µF between FG OUT pin and ground.

7. External capacitors

• C1

C1 is the AGC (automatic gain control) pin smoothing capacitor. This pin is an automatic gain control pin for

holding the hall amplifier output amplitude fixed. This pin outputs the three-phase hall signal envelope, and is

smoothed with a capacitor (about 0.1 µF) since it has ripple. When the hall input amplitude is small, the AGC pin

potential will rise, and when the input amplitude is large, the AGC pin potential will fall.

• C10

C10 is required for fixed voltage power supply stability. Since the output from the 6.3 V fixed voltage power

supply is supplied to all circuits within the IC, noise on this signal must be avoided. This power supply must be

adequately stabilized so that malfunctions due to noise do not occur.

• C11

C11 is required for VCC stabilization. Since, just as with C10, noise must be avoided, this capacitor is provided to

adequately stabilize the power supply. The length of the pattern lines used to connect capacitors C1, C10, and C11

between their respective pins and GND2 must be kept as short as possible. C10 and C11 require special care, since

the pattern line length can easily influence their characteristics.

No. 4849-8/10

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