
SG1731/SG2731/SG3731
4/90 Rev 1.3 9/99
Copyright
1999
L
IN
F
IN
ITY
Microelectronics Inc.
Garden
Grove,
FAX: (714) 893-2570
11861 Western Avenue
∞
CA
92841
1
(714) 898-8121
∞
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
Available to MIL-STD-883
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.