An RC network (R to VCC, C to ground) connected to this terminal determines the chopper rate. A voltage applied to this pin determines the peak load current. Input for load current sense voltage from power stages of phases A and B. Input for load current sense voltage from power stages of phases C and D. When low chopper acts on INH1 and INH2 when high chopper acts on phase lines ABCD. Control input that defines action of chopper. When low (inactive) B, C and D are brought low. Motor phase D drive signal for power stage.
Active low inhibit control for drive stages of C and D phases. Motor phase C drive signal for power stage. Motor phase B drive signal for power stage. Also used by chopper to regulate load current if CONTROL input is low. When a bipolar bridge is used this signal can be used to ensure fast decay of load current when a winding is de-energized. Active low inhibit control for driver stage of A and B phases. Motor phase A drive signal for power stage. The transistor is open when this signal is active. Open collector output that indicates when the is in its initial state (ABCD = 0101).
If an external clock source is used it is injected at this terminal. The SYNC connections The SYNC connections of all to be synchronized are connected together and the oscillator components are omitted on all but one. N° 1 NAME SYNC FUNCTION Output of the on-chip chopper oscillator. TWO PHASE BIPOLAR STEPPER MOTOR CONTROL CIRCUIT Mounted in DIP20 and SO20 packages, the L297 can be used with monolithic bridge drives such as the L293E, or with discrete transistors and darlingtons. Since the phase are generated internally the burden on the microprocessor, and the programmer, is greatly reduced. This device is that it requires only clock, direction and mode input signals. Symbol Vs Vi Ptot Tstg, Tj Supply voltage Input signals Total power dissipation (Tamb = 70☌) Storage and junction temperature Parameter
The motor can be driven in half step, normal and wawe drive modes and onchip PWM chopper circuits permit switch-mode control of the current in the windings. NORMAL/WAVE DRIVE HALF/FULL STEP MODES CLOCKWISE/ANTICLOCKWISE DIRECTION SWITCHMODE LOAD CURRENT REGULATION PROGRAMMABLE LOAD CURRENT FEW EXTERNAL COMPONENTS RESET INPUT & HOME OUTPUT ENABLE INPUT DESCRIPTION The L297 Stepper Motor Controller IC generates four phase drive signals for two phase bipolar and four phase unipolar step motors in microcomputercontrolled applications.
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