Description

The LS7362C is a MOS integrated circuit designed to generate the signals necessary to control a three phase or four phase brushless DC motor. It is the basic building block of a brushless DC motor controller. The circuits respond to changes at the SENSE inputs, originating at the motor position sensors, to provide electronic commutation of the motor windings. Pulse width modulation (PWM) of low-side drivers for motor speed control is accomplished through the VTRIP input (Analog speed control) in conjunction with the OSCILLATOR input. Over-current circuitry is provided to protect the windings, associated drivers, and power supply. The LS7362C circuitry causes the external output drivers to switch off immediately upon sensing the over-current condition, and on again only when the over-current condition disappears and the positive edge of the saw-tooth OSCILLATOR occurs. This limits the over-current sense cycling to the chopping rate of the saw-tooth OSCILLATOR. A positive braking feature is provided to effect rapid deceleration. The LS7362C is designed for driving Bipolar and Field Effect Transistors. Because only low-side drivers are pulse-width modulated, the LS7362C is ideally suited in situations where the integrated circuit interfaces with level converters to drive high voltage brushless DC motors. By pulse width modulating the low-side drivers only, the switch losses in the level conversion circuitry for the high-side drivers is minimized.

Features:

• Speed control by Pulse Width Modulating (PWM) only the low-side drivers reduces switching losses in level converter circuitry for high voltage motors
• Open or closed loop motor speed control
• +5V to +28V operation (VSS–VDD)
• Externally selectable input to output code for 60°, 120°, 240°, or 300°electrical sensor spacing
• Three or four phase operation
• Analog speed control
• Forward/Reverse control
• Output enable control
• Positive static braking
• Over-current sensing
• Six outputs drive switching bridge directly