NJM3775E3 NJR, NJM3775E3 Datasheet - Page 3

• Manufacturer Part Number: NJM3775E3
• Description: Motor / Motion / Ignition Controllers & Drivers Dual Stepper
• Manufacturer: NJR
• Type: Stepper Motor Controller/Driverr

Specifications of NJM3775E3

• Product: Stepper Motor Controllers / Drivers
• Operating Supply Voltage: 10 V to 45 V
• Supply Current: 50 mA to 70 mA
• Mounting Style: SMD/SMT
• Package / Case: EMP-24
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Each channel of the NJM3775 consists of the following sections: an output H-bridge with four transistors and four
recirculation diodes, capable of driving up to 750 mA continuous current to the motor winding,
a logic section that controls the output transistors, an S-R flip-flop, and a com- parator. The clock-oscillator is
common
to both channels.
peak current through the winding via a current-sensing resistor R
winding. As the current increases, a voltage develops across the sensing resistor, which is fed back to the compa-
rator. At the predetermined level, defined by the voltage at the reference input V
flop, which turns off 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.
NJM3775 includes a digital filter. The clock oscillator provides a blanking pulse which is used for digital filtering of
the voltage transient across the current sensing resistor during turn-on.
Constant current control is achieved by switching the output current to the windings. This is done by sensing the
To prevent erroneous switching due to switching transients at turn-on, the
The current paths during turn-on, turn-off and phase shift are shown in figure 3.
FUNCTIONAL DESCRIPTION
Figure 3. Output stage with current paths
during turn-on, turn-off and phase shift.
Motor Current
3
1
Fast Current Decay
Slow Current Decay
1
2
2
V
R
MM
S
S
, effectively connected in series with the motor
3
Time
R
, the comparator resets the flip-
NJM3775