njm13775 New Japan Radio Co.,Ltd, njm13775 Datasheet - Page 5

• Manufacturer Part Number: njm13775
• Description: Dual Stepper Motor Driver
• Manufacturer: New Japan Radio Co.,Ltd

recirculation diodes, capable of driving up to 350mA continuous current to the motor winding, a logic section that controls
the output transistors, an S-R flip-flop, and a comparator. The clock-oscillator is common to both channels.
current through the winding via a current-sensing resistor R
the current increases, a voltage develops across the sensing resistor, which is fed back to the comparator. At the
predetermined level, defined by the voltage at the reference input V
the upper output transistor. The turn-off of one channel is independent of the other channel. The current decreases until
the clock oscillator triggers the flip-flops of both channels simultaneously, which turns on the output transistors again, and
the cycle is repeated.
oscillator provides a blanking pulse which is used for digital filtering of the voltage transient across the current sensing
resistor during turn-on.
Each channel of the NJM13775 consists of the following sections: an output H-bridge with four transistors and four
Constant current control is achieved by switching the output current to the windings. This is done by sensing the peak
To prevent erroneous switching due to switching transients at turn-on, the NJM13775 includes a digital filter. The clock
The current paths during turn-on, turn-off and phase shift are shown in figure 5.
FUNCTIONAL DESCRIPTION
Figure 5. Output stage with current paths during turn-on,
turn-off and phase shift.
S
, effectively connected in series with the motor winding. As
R
, the comparator resets the flip-flop, which turns off
NJM13775
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