UTC UC3863L-AG6, UC3863L-S08 Schematic [ru]

UNISONIC TECHNOLOGIES CO., LTD

UC3863

LINEAR INTEGRATED CIRCUIT

LOW COST POWER-SAVING
MODE PWM CONTROLLER
FOR FLYBACK CONVERTERS

 DESCRIPTION

The UC3863 is a high performance current mode PWM

controller ideally suited for low standby power. The PWM switching
frequency is programmable externally at normal operation. Low
V

startup current make the power reliable on startup design and

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a large value resistor could be used in the startup circuit to
minimize the standby power. At no load condition, the IC operates
in power-saving mode for lower standby power, decreasing
frequency for Higher conversion efficiency at light load condition.

The UC3863 contains protection with automatic recovery

including OLP (over load protection), OTP (over temperature
protection), OVP (over voltage protection), UVLO (V
clamp and under voltage lockout).To protect the power MOSFET,

Gate-drive output is fixed up to 15V max. The UC3863 contains

protection OCP (cycle-by-cycle current limiting).

The internal slope compensation improves system stability at
high PWM duty cycle output. Leading-edge blanking on current
sense input removes the signal glitch, which offering minimal
external component count in the design. Excellent EMI
performance is achieved with UTC proprietary frequency hopping
technique (ZL201020615247.1) together with soft driver control.
Audio noise is eliminated due to switch frequency more than 20kHz
during operation.

The UC3863 has such applications as: battery charger, power

adaptor, set-top box power supplies, ink jet printers, open-frame
SMPS

over voltage

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 FEATURES

* UTC proprietary frequency hopping technology for Improved EMI

performance.
* Power-saving mode for high light-load and standby efficiency
* Dynamic peak current limiting for constant output power
* Built-in synchronized slope compensation
* OTP,OLP,OVP and V
* Programmable PWM Frequency
* Gate output voltage clamped at 15V
* Low start-up current
* Cycle-by-cycle Current Limiting
* Under voltage lockout (UVLO)
* Few external components required

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clamp for higher security

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UC3863 LINEAR INTEGRATED CIRCUIT

 ORDERING INFORMATION

Ordering Number

Lead Free Halogen Free

UC3863L-AG6-R UC3863G-AG6-R SOT-26 Tape Reel

UC3863L-S08-T UC3863G-S08-T SOP-8 Tube
UC3863L-S08-R UC3863G-S08-R SOP-8 Tape Reel

Note: xx: Output Voltage, refer to Marking Information.

Package Packing

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UC3863 LINEAR INTEGRATED CIRCUIT

 MARKING INFORMATION(For SOT-26)

 PIN CONFIGURATION

SOT-26 SOP-8

 PIN DESCRIPTION

PIN NO.

SOT-26 SOP-8

1 8 GND P Ground.

2 7 FB I

3 5 RI I

4 4 SENSE I

5 2 VDD P Power supply.
6 1 GATE O The totem-pole output driver for driving the power MOSFET.

- 3, 6 NC - No Connection

PIN NAME PIN TYPE DESCRIPTION

Feedback input pin. The PWM duty cycle is determined by
voltage level into this pin and SENSE pin input.
A resistor connected between RI and GND sets switching
frequency. A 100kΩ resistor RI results in a 65KHz switching
frequency.
Current sense input pin. Connected to MOSFET current sensing
resistor node.

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UC3863 LINEAR INTEGRATED CIRCUIT

 BLOCK DIAGRAM

V

5/2

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RI

3/5

FB

2/7

Reference voltage

OVP

Logic

Control

OTP

Slope Compensation

1/8

GND

UVLO

Frequency

Burstmode

PWM COMP

Hopping

Constant Power Limit

Oscillator

Latch

S

R

Driver

6/1

GATE

Q

Q

OCP

4/4

LEB

SENSE

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