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NJM3717E2 Dataheets PDF



Part Number NJM3717E2
Manufacturers New Japan Radio
Logo New Japan Radio
Description STEPPER MOTOR DRIVER
Datasheet NJM3717E2 DatasheetNJM3717E2 Datasheet (PDF)

NJM3717 STEPPER MOTOR DRIVER ■ GENERAL DESCRIPTION The NJM3717 is a stepper motor diver, which consists of a LS-TTL compatible logic input stage, a current sensor, a monostable multivibrator and a high power H-bridge output stage with built-in protection diodes. The output current is up to 1200mA. Two NJM3717 and a small number of external components form a complete control and drive unit for stepper motor systems. ■ PACKAGE OUTLINE ■ FEATURES ● Half-step and full-step modes ● Switched mod.

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NJM3717 STEPPER MOTOR DRIVER ■ GENERAL DESCRIPTION The NJM3717 is a stepper motor diver, which consists of a LS-TTL compatible logic input stage, a current sensor, a monostable multivibrator and a high power H-bridge output stage with built-in protection diodes. The output current is up to 1200mA. Two NJM3717 and a small number of external components form a complete control and drive unit for stepper motor systems. ■ PACKAGE OUTLINE ■ FEATURES ● Half-step and full-step modes ● Switched mode bipolar constant current drive ● Wide range of current control 5 to 1200mA ● Wide voltage range 10 to 50V ● Thermal overload protection ● Packages DIP16-D2 / PLCC28-M2 SOP20 JEDEC 300mil NJM3717D2 ( DIP16 ) NJM3717E2 ( SOP20 ) NJM3717FM2 ( PLCC28-M2 ) ■ BLOCK DIAGRAM Figure 1. Block diagram Ver.2011-12-08 -1- NJM3717 ■ PIN CONFIGURATIONS Figure 2. Pin configurations ■ PIN DESCRIPTION DIP SOP 1 1 2 2 PLCC 10 11 3,14 4,5,12,13 6 7 3,18 4,5,6,7,14, 15,16,17 8 9 12,4, 1,2,3,9,13, 14,15,16, 17,28 18 19 8 10 20 9 11 21 10 12 23 11 13 24 15 19 6 16 20 8 Symbol MB T VMM GND VCC I1 Phase I0 C VR MA E Description Motor output B, Motor current flows from MA to MB when Phase is high. Clock oscillator. Timing pin connect a 56 kΩ resistor and a 820 pF in parallel between T and Ground. Motor supply voltage, 10 to 45 V. VMM pins should be wired together on PCB. Ground and negative supply. Note these pins are used for heatsinking. Make sure that all ground pins are soldered onto a suitable large copper ground plane for efficient heat sinking. Logic voltage supply normally +5 V. Logic input, it controls, together with the I0 input, the current level in the output stage. The controllable levels are fixed to 100, 60, 20, 0%. Controls the direction of the motor current of MA and MB outputs. Motor current flows from MA to MB when the phase input is high. Logic input, it controls, together with the I1 input, the current level in the output stage. The controlable levels are fixed to 100, 60, 20, 0%. Comparator input. This input senses the instantaneous voltage across the sensing resistor, filtered through a RC Network. Reference voltage. Controls the threshold voltage of the comparator and hence the output current. Input resistance: typically 6.8kΩ±20%. Motor output A, Motor current flows from MA to MB when Phase is high. Common emitter. Connect the sense resistor between this pin and ground. -2- Ver.2011-12-08 NJM3717 Figure 3. Definition of terms ■ FUNCTIONAL DESCRIPTION The NJM3717 is intended to drive a bipolar constant current through one motor winding of a 2-phase stepper motor. Current control is achieved through switched-mode regulation, see figure 4 and 5. Three different current levels and zero current can be selected by the input logic. The circuit contains the following functional blocks: ● Input logic ● Current sense ● Single-pulse generator ● Output stage Input logic Phase input. The phase input determines the direction of the current in the motor winding. High input forces the current from terminal MA to MB and low input from terminal MB to MA. A Schmitt trigger provides noise immunity and a delay circuit eliminates the risk of cross conduction in the output stage during a phase shift. Half- and full-step operation is possible. Current level selection. The status of I0 and I1 inputs determines the current level in the motor winding. Three fixed current levels can be selected according to the table below. Motor current High level I0 I1 100% L L Medium level 60% H L Low level 20% L H Zero current 0% H H The specific values of the different current levels are determined by the reference voltage VR together with the value of the sensing resistor RS. The peak motor current can be calculated as follows: im = (VR • 0.083) / RS [A], at 100% level im = (VR • 0.050) / RS [A], at 60% level im = (VR • 0.016) / RS [A], at 20% level The motor current can also be continuously varied by modulating the voltage reference input. Ver.2011-12-08 -3- NJM3717 Current sensor The current sensor contains a reference voltage divider and three comparators for measuring each of the selectable current levels. The motor current is sensed as a voltage drop across the current sensing resistor, RS, and compared with one of the voltage references from the divider. When the two voltages are equal, the comparator triggers the single-pulse generator. Only one comparator at a time is activated by the input logic. Single-pulse generator The pulse generator is a monostable multivibrator triggered on the positive edge of the comparator output. The multivibrator output is high during the pulse time, toff , which is determined by the timing components RT and CT. toff = 0.69 • RT • CT The single pulse switches off the power feed to the motor winding, causing the winding to decrease during toff. If a new trigger signal should occur during to.


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