LB1922 查看數據表（PDF） - SANYO -> Panasonic

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LB1922

Three-Phase Brushless Motor Driver for Office Automation Applications

SANYO -> Panasonic 

LB1922

D2, and D3 are for through current prevention, use Schottky diodes with a small Vf. This will prevent the potential

difference between the output pins and VCC from becoming a problem. Although normal rectifying diodes can be

used for D4, D5, and D6, design the ground lines carefully as described in item 6, “Ground leading”, so that parasitic

effects do not occur.

8. External interface pins

• LD pin

Output type: open collector

Voltage handling capacity: 20 V (absolute maximum)

Saturation voltage sample-to-sample variation reference value (ILD = 10 mA)

0.0 to 0.5 V

• FGS pin

Output type: open collector

Voltage handling capacity: 20 V (absolute maximum)

Saturation voltage sample-to-sample variation reference value (IFGS = 2 mA)

0.12 to 0.18 V

The FGS pin output is the FG amplifier output converted to a pulse output by a hysteresis comparator. It is used

as a speed monitor. If the FGS pin is not used, the pull-up resistor is not required.

• Start/Stop pin

Input type: PNP transistor base with a 50-kΩ pull-down resistor connected to ground

Threshold level (typical): About 2.6 V

The 4-V, 5-V, and 7-V fixed-voltage supplies are turned off in stop mode.

• F/R pin

Input type: PNP transistor base with a 50-kΩ pull-down resistor connected to ground

Threshold level (typical): About 2.2 V (high → low), about 2.7 V (low → high)

Hysteresis: about 0.5 V

F/R switching must only be performed in stop mode when the motor is stopped.

9. Fixed-voltage supply temperature characteristics

• 4-V supply: about –0.5 mV/°C

• 5-V supply: about –0.6 mV/°C

• 7-V supply: about –2.5 mV/°C

10. FG amplifier

The FG amplifier gain is determined by R1 and R2, and the DC gain, G, will be R2/21. The FG amplifier frequency

characteristics are determined by C4 and C5. (R1 and C4 form a high-pass filter and R2 and C5 form a low-pass

filter.) Since the FG amplifier output is input to a Schmitt comparator, set up values for R1, R2, C4, and C5 so that

the FG amplifier output has an amplitude of at least 250 mV p-p. (It is desirable to set up the FG amplifier so that its

output has an amplitude of between 1 and 3 V p-p during steady state motor operation.)

11. External capacitors

• C3

C3 is required to stabilize the FGIN+ pin fixed-voltage supply and to generate the initial reset pulse for the IC

internal logic. Although a relatively small capacitance suffices for power supply stabilization, a larger capacitance

(about 4.7 µF) is required to generate the reset pulse. The reset pulse is generated at the time when the FGIN+ pin

goes from 0 V to about 1.3 V. If the reset function does not operate, the LD pin may go on briefly at startup. If this

phenomenon is not a problem, a capacitance of around 0.1 µF can be used for C3. After C3 is charged to 4 V, if

VCC is turned off (or the IC is set to stop mode), the capacitor will be discharged by an IC-internal load of about

10 kΩ that is connected to this capacitor.

• C1 and C2

C1 and C2 are required for fixed-voltage supply stabilization. Since this IC adopts a direct PWM technique and

switches large currents in the outputs, it is extremely easy for noise to be generated. Therefore, adequate power-

supply stabilization is required to prevent that noise from causing incorrect circuit operation. C1 through C3 must

be connected to GND1 with lines that are as short as possible. In particular, C1 can easily influence system

characteristics and requires care.

No. 5679-6/10

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