PBL3770A

February 1999 PBL 3770A High Performance Stepper Motor Drive Circuit Description PBL 3770A is a bipolar monolithic circuit intended to control and drive the current in one winding of a stepper motor. It is a high power version of PBL 3717 and special care has been taken to optimize the power handling capability without suffering in reliability. The circuit consists of a LS-TTL compatible logic input stage, a current sensor, a monostable multivibrator and a high power H-bridge output stage. The circuit is pin-compatible with the PBL 3717 industry-standard driver. Two PBL 3770A and a small number of external components form a complete control and drive unit for LS-TTL or microprocessor-controlled stepper motor systems. Key Features Half-step and full-step operation. Switched mode bipolar constant current drive Wide range of current control 5 -1800 mA. Wide voltage range 10 - 45 V. Designed for unstabilized motor supply voltage. Current levels can be selected in steps or varied continuously. Thermal overload protection. VCC Schmitt Trigger Time Delay VMM VMM Phase I 1 1 ≥1 ≥1 P B L B A P 70 37 MA I0 V R MB & + – + – + – GND & & & ≥1 ≥1 L Monostable t off = 0.69 RT CT Current Sensor 37 PBL 3770A C T E 16-pin plastic batwing DIP 28-pin plastic PLCC package 20-pin SO Figure 1. Block diagram. 1 P B L 37 Output Stage 70 A 70 A PBL 3770A Maximum Ratings Parameter Pin no. [DIL package] Symbol Min Max Unit Voltage Logic supply Motor sup...