DESCRIPTION
The PBL3717A is a monolithic IC which controls and drives one phase of a bipolar stepper motor with chopper control of the phase current. Current levels may be selected in three steps by means of two logic inputs which select one of three current comparators. When both of these inputs are high the device is disabled. A separate logic input controls the direction of current flow.
A monostable, programmed by an external RC network, sets the current decay time.
The power section is a full H-bridge driver with four internal clamp diodes for current recirculation. An external connection to the lower emitters is available for the insertion of a sensing resistor. Two PBL3717As and few external components form a complete stepper motor drive subsystem.
The raccomended operating ambient temperature ranges is from 0 to 70 °C.
The PBL3717A is supplied in a 12 + 2 + 2 lead Powerdip package.

■ FULL STEP - HALF STEP - QUARTER STEP OPERATING MODE
■ BIPOLAR OUTPUT CURRENT UP TO 1 A
■ FROM 10 V UP TO 46 V MOTOR SUPPLY VOLTAGE
■ LOW SATURATION VOLTAGE WITH INTEGRATED BOOTSTRAP
■ BUILT IN FAST PROTECTION DIODES
■ EXTERNALLY SELECTABLE CURRENT LEVEL
■ OUTPUT CURRENT LEVEL DIGITALLY OR ANALOGUE CONTROLLED
■ THERMAL PROTECTION WITH SOFT INTERVENTION