CURRENT MODE PWM CONTROLLER

FEATURES

••••• Automatic feed forward compensation

••••• Programmable pulse by pulse current limiting

••••• Automatic symmetry correction in push-pull

configuration

••••• Enhanced load response characteristics

••••• Parallel operation capability for modular power

systems

••••• Differential current sense amplifier with wide

common mode range

••••• Double pulse suppression

••••• 200mA totem-pole outputs

••••• ± 1% bandgap reference

••••• Under-voltage lockout

••••• Soft-start capability

••••• Shutdown capability

••••• 500KHz operation

HIGH RELIABILITY FEATURES - SG1846

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♦ Available to MIL-STD - 883

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♦ Radiation data available

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♦ LMI level "S" processing available

DESCRIPTION

The SG1846 family of control ICs provides all of the necessary

features to implement fixed frequency, current mode control

schemes while maintaining a minimum external parts count. The

superior performance of this technique can be measured in im-

proved line regulation, enhanced load response characteristics,

and a simpler, easier-to-design control loop. Topological advan-

tages include inherent pulse-by-pulse current limiting capability,

automatic symmetry correction for push-pull converters, and the

ability to parallel “power modules” while maintaining equal current

sharing.

Protection circuitry includes built-in under-voltage lockout and

programmable current limit in addition to soft start capability. A

shutdown function is also available which can initiate either a

complete shutdown with automatic restart or latch the supply off.

Other features include fully latched operation, double pulse sup-

pression, deadtime adjust capability, and a ±1% trimmed bandgap

reference.

BLOCK DIAGRAM

SG1846/SG2846/SG3846

Rev 1.1a 3.21.2005

Microsemi Inc.

Copyright

© 1994

11861 Western Avenue

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