NJU7333 データシートの表示（PDF） - Japan Radio Corporation

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コンポーネント説明

メーカー

NJU7333

Single-phaseDC Brushless Motor Driver IC

Japan Radio Corporation  

Lock detection time (Ton) is given by:

NJU7333

Preliminary

[ ] TON

= C 2 VCL − VID

ICHG

sec

Where C2 is 0.47uF:

TON

=

0.47

×10

−

6

×

2.6 − 0.6

1.5 ×10−6

= 0.62[sec]

Auto Resume Time (Toff) is given by:

[ ] TOFF

= C 2 VCL − VID

IDCHG

sec

Where C2 is 0.47uF:

TOFF

=

0.47

×10

−6

×

2.6 − 0.6

0.5 ×10−6

= 1.88[sec]

In actual application, Lock detection time (Ton) is affected by the mechanical time constant of a motor. Therefore,

constant start up must be confirmed in actual evaluation taking operating variations (i.e.Temperature, Voltage change

and so on) in consideration.

A typical value of C2 is either 0.47uF or 1uF depending on a motor.

Hall input

Motor output

Ct Terminal voltage

Toff

Ton

Motor Lock protection period

Motor Locked

Returns to normal operation

3. Design of hall element bias resistance (R1 and R2)

Hall amplifier is a differential amplifier with hysteresis characteristics (24mV typical).

The common-mode input voltage is between 0.4V and VDD-1V and the input signal must be within the

range.Non-excitation hall bias voltage is to be set at a half of VDD for effective use of common-mode input voltage

range. Therefore the same value of hall bias resistors is selected for R1 and R2.

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