Chip-Rail CR6853 Manual

Novel Low Cost Green-Power PWM Controller
Feature
Low Cost, PWM&PFM&CRM (Cycle
Reset Mode)
Low Start-up Current (about 1.5µA)
Low Operating Current (about 1.4mA)
Current Mode Operation
Under Voltage Lockout (UVLO)
Built-in Synchronized Slope
Compensation
Built-in Low EMI Technique
Programmable PWM Frequency
Audio Noise Free Operation
Leading edge Blanking on Sense input
Constant output power limiting for
universal AC input Range
SOT-23-6L 、SOP8 and DIP-8 Pb-Free
Applications
Switching AC/DC Adaptor
Battery Charger
Open Frame Switching Power Supply
General Description
The CR6853 is a highly integrated low cost
current mode PWM controller, which is ideal
for small power current mode of offline
AC-DC fly-back converter
Making use of external resistors, the IC
changes the operating frequency and
automatically enters the PFM/CRM (Cycle
Reset Mode) under light-load/zero-load
conditions. This can minimize standby
power consumption and achieve power-
saving functions. With a very low start-up
current, the CR6853 could use a large value
start-up resistor (2M ).
Built-in synchronized slope compensation
enhances the stability of the system and
avoids sub-harmonic oscillation. Dynamic
peak current limiting circuit minimizes output
power change caused by delay time of the
system over a universal AC input range.
Leading edge blanking circuit on current
Dec, 2007 V1.1
Chengdu Chip-Rail Tech. Co., Ltd.
With Low EMI Technique
sense input could remove the signal glitch
due to snubber circuit diode reverse
recovery and thus greatly reduces the
applications. external component count and system cost
in
limiting ensures safe operation even during
short-circuit.
Excellent EMI performance is achieved
built-in soft driver and low EMI technique.
The CR6853 offers perfect protection like
OVP(Over Voltage Protection)、OLP(Over
Load
protection)、OTP、Sense Fault Protection
and OCP(Over current protection). The
CR6853's output driver is soft clamped to
maximum 18.0V to protect the power
MOSFET. CR6853 is offered in SOT-23-6L,
SOT-8 and DIP-8 packages.
Packaging
Compatible with SG6848 (6849) /
SG5701/SG5848/LD7535 (7550) /
OB2262 (2263)/OB2278（ （ （ （ 2279） ） ） ）
Complete Protection with
Soft Clamped GATE output voltage
18.0V
VDD over voltage protect 34.0V
Cycle-by-cycle current limiting
Sense Fault Protection
OTP (Over Temperature Protection)
Output SCP (Short circuit Protection)
Output OLP (Over Load Protection)
Latch mode After OLP&SCP
High-Voltage CMOS Process with ESD
Standby Power Supplies
Set-Top Box Power Supplies
384X Replacement
the design. Cycle-by-Cycle
Protection) 、 SCP(Short
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CR6853
current
circuit
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