UNISONIC TECHNOLOGIES CO., LTD
UC2843B
Preliminary
LINEAR INTEGRATED CIRCUIT
HIGH-PERFORMANCE
CURRENT-MODE PWM
CONTROLLERS
DESCRIPTION
The UTC
UC2843B
provides off-line or DC-DC fixed-frequency
current-mode control design with minimum external components.
Internally-implemented circuits include an under-voltage lockout
(UVLO) and a precision reference with accuracy at the error amplifier
input. The UTC
UC2843B
also contain internal circuits which include
a pulse width modulation (PWM) comparator providing current-limit
control, logic ensuring latched operation, and a totem-pole output
stage designed to source or sink high-peak current. The output
stage is low when it is in off-state condition and suitable for
N-channel MOSFETs driving.
The UTC
UC2843B
also has following advantages: the start-up
current lower than 0.5mA while the oscillator discharge current is
specified to 8.3mA (Typ.). In UVLO conditions, the output has a
maximum saturation voltage of 1.2V when sinking 10mA@V
CC
= 5V.
The typical UVLO threshold of the UTC
UC2843B
is 8.4V (on)
and 7.6V (off) and can operate to duty cycles approximately 100%.
FEATURES
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Current mode operation:500 kHz
Low start-up current value<0.5mA
Latching PWM for cycle-by-cycle current limiting
Trimmed oscillator discharge current
Automatic feed-forward compensation
Internally trimmed reference with UVLO
High-current totem-pole output UVLO with hysteresis
Double-pulse suppression
Halogen free
ORDERING INFORMATION
Ordering Number
UC2843BG-S08-R
Package
SOP-8
Packing
Tape Reel
www.unisonic.com.tw
Copyright © 2009 Unisonic Technologies Co., Ltd
1 of 9
QW-R103-048.a
UTC-IC [ UNISONIC TECHNOLOGIES ]
