Chipset controller for ISDN micropower PWM
The UCC3883/3885 micropower PWM chipset provides primary and secondary
control for isolated switching regulators that require high efficiencies
for loads as light as 25 mW. The UCC1883 peak-current-mode controller
provides inrush current limiting, high-impedance starting, and all of the
control and protection for the primary-side power switch. The UCC3885
generates feedback information and sends it to the UCC3883 via an
isolation pulse transformer. Additional features of the chipset include
pulse-by-pulse current limiting, automatic feed-forward, high-current
switch drive, operation to 500 kHz, leading-edge blanking, duty cycle
clamping, undervoltage lockout, and a 1% reference. The devices are
available in 14- (UCC3885) and 16-pin (UCC3883) DIPs and SO packages. (The
UCC3883/3885 are from $2.42 and $2.46 ea/1,000, respectively -available
now.) Unitrode Integrated Circuits Corp. Merrimack, NH Al Fuller
603-429-8595 Fax 603-424-3460
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