UNISONIC TECHNOLOGIES CO., LTD
UC3846
LINEAR INTEGRATED CIRCUIT
LOW COST POWER-SAVING
MODE PWM CONTROLLER
FOR FLYBACK CONVERTERS
DESCRIPTION
The UTC UC3846 is a high performance current mode PWM
controller ideally suited for low standby power and cost effective
off-line flyback converter.
DIP-8
Low VDD startup current make the power reliable in startup
design and a large value resistor could be used in the startup
circuit to minimize the standby power. At no load condition, the
IC operates in burst mode for lower standby power and in
decreasing frequency for higher conversion efficiency at light
load condition. The PWM switching frequency is programmable
externally at normal operation.
The UTC UC3846 contains protection coverage with
automatic self-recovery including OCP (cycle-by-cycle current
limiting), OTP (over temperature protection), UVLO (VDD over
voltage clamp and under voltage lockout).To protect the power
MOSFET, Gate-drive output is fixed up to 15V max.
The internal slope compensation improves system stability at
high PWM duty cycle output. Leading-edge blanking on current
sense (CS) input removes the signal glitch that offers minimal
reqnirement of external component and lower system cost.
Excellent EMI performance is achieved by UTC proprietary
frequency hopping technique together with soft driver control.
Audio noise is eliminated because switch frequency is more
than 20kHz during operation.
FEATURES
* UTC proprietary frequency hopping technology
for Improved EMI
* performance.
* Power-saving mode for high light-load efficiency
* Burst mode for minimum standby power
* Dynamic peak current limiting for constant output
power
* Built-in synchronized slope compensation
* OTP,OVP and VDD clamp for higher security
* Programmable PWM Frequency
* Gate output voltage clamped at 15V
* Low start-up current
The UTC UC3846 can be used in the applications, such as
battery charger, power adaptor, set-top box power supplies, ink
jet printers open-frame SMPS
* Cycle-by-cycle Current Limiting
* Under voltage lockout (UVLO)
* Few external components required
ORDERING INFORMATION
Ordering Number
Lead Free
Package
DIP-8
Packing
Tube
Halogen Free
UC3846G-D08-T
UC3846L-D08-T
UC3846L-D08-T
(1) T: Tube
(1)Packing Type
(2)Package Type
(3)Lead Free
(2) D08: DIP-8
(3) G: Halogen Free, L: Lead Free
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