SG1731/SG2731/SG3731

4/90 Rev 1.3 9/99

Microelectronics

Inc.

Copyright

 1999

11861

Western

Avenue

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Garden

Grove,

CA

92841

1

(714) 898-8121

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FAX: (714) 893-2570

DC MOTOR PULSE WIDTH MODULATOR

FEATURES

••••• ±±±±±3.5V to ±±±±±15V control supply

••••• ±±±±±2.5V to ±±±±±22V driver supply

••••• Dual 100mA source/sink output

drivers

••••• 5KHz to 350KHz oscillator range

••••• High slew rate error amplifier

••••• Adjustable deadband operation

••••• Digital SHUTDOWN input

HIGH RELIABILITY FEATURES

- SG1731

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♦ Available to MIL-STD-883

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♦ LMI level “S” processing available

BLOCK DIAGRAM

DESCRIPTION

The SG1731 is a pulse width modulator circuit designed specifically for DC motor

control. It provides a bi-directional pulse train output in response to the magnitude

and polarity of an analog error signal input. The device is useful as the control

element in motor-driven servo systems for precision positioning and speed control,

as well as in audio modulators and amplifiers using carrier frequencies to 350 KHz.

The circuit contains a triangle waveform oscillator, a wideband operational amplifier

for error voltage generation, a summing/scaling network for level-shifting the

triangle waveform, externally programmable PWM comparators and dual

±100mA,

±22V totem pole drivers with commutation diodes for full bridge output. A

SHUTDOWN terminal forces the drivers into a floating high-impedance state when

driven LOW. Supply voltage to the control circuitry and to the output drivers may be

from either dual positive and negative supplies, or single-ended.