LS7362

Features:

• Speed Control by Pulse Width Modulation (PWM) of low-side drivers only.
• Open or closed loop motor speed control.
• +5 to +28 Volt operation (V_ss - V_DD).
• 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.
• Overcurrent Sensing.
• Six outputs drive switching bridge directly.
• LS7362 (DIP); LS7362-S (SOIC); LS7362-TS (TSSOP) - See Connection Diagram


Pinout




Specifications

PARAMETER	SYMBOL	VALUE	UNIT
Storage Temperature	TSTG	-65 to +150
Operating Temperature	TA	-25 to +70
1. Plastic	TA	-55 to +125
2. Ceramic	VMAX	-30 to +.5	Volts
Voltage (any pin to Vss)

Description

The LS7362 is a monolithic, ion implanted MOS 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 circuit responds 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 either the ENABLE input or through the V TRIP input (Analog Speed control) in conjunction with the OSCILLATOR input. Overcurrent circuitry is provided to protect the windings, associated drivers and power supply.

The LS7362 circuitry causes the external output drivers to switch off immediately upon sensing the overcurrent condition, and on again only when the overcurrent condition disappears and the positive edge of either the ENABLE input or the sawtooth OSCILLATOR occurs. This limits the overcurrent sense cycling to the chopping rate of the ENABLE input or the sawtooth OSCILLATOR. A positive braking feature is provided to effect rapid deceleration. The LS7362 is designed for driving Bipolar and Field Effect Transistors. Because only low-side drivers are pulse width modulated, the LS7362 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. Figure 1 indicates how the level conversion is accomplished.The COMMON, Pin 5, is tied to the positive supply rail and LS7362 Outputs 1, 2, and 3 are used to drive level converters Q101, Q102 and Q103 respectively. Only the motor top side drivers consisting of Q107, Q108 and Q109 which are connected to the motor power supply, VM, will be subject to the high speed switching currents that flow through the motor. The level converters are turned on and off at the slower commutation rate.