CM6805(A;B)/CM6806A
10-PIN Green-Mode PFC/PWM Combo CONTROLLER for High Density AC Adapter
GENERAL DESCRIPTION
The CM6805A and CM6806A are the Green-Mode
PFC/PWM Combo controller for High Density AC Adapter.
For the power supply, its input current shaping PFC
performance could be very close to the performance of the
CM6800 or ML4800 leading edge modulation average
current topology.
CM6805A/CM6806A offers the use of smaller, lower cost
bulk capacitors, reduces power line loading and stress on
the switching FETs, and results in a power supply fully
compliant to IEC1000-3-2 specifications. The CM6805A /
CM6806A includes circuits for the implementation of a
leading edge, input current shaping technique “boost” type
PFC and a trailing edge, PWM.
The CM6805A’s PFC and PWM operate at the same
frequency, 67.5kHz. A PFC OVP comparator shuts down
the PFC section in the event of a sudden decrease in load.
The PFC section also includes peak current limiting for
enhanced system reliability.
Both PFC and PWM have the Green Mode Functions.
When the load is below GMth, Green Mode Threshold,
PFCOUT is turned off. The GMth can be programmed by
the designer. PWM Green Mode will happen when the
PWMCMP (PWM Comparator) Duty Cycle is less than ~
6%, in the next cycle, the PWMOUT pulse will be removed
until PWMCMP Duty Cycle is greater than 6%, then the
next cycle, PWMOUT pulse appears.
PWM has a PWMtrifault pin which can sense the PWM
short and determine the GMth to turn off PFC.
FEATURES
Both PFC and PWM have the Green Mode to meet blue
angel and energy star spec.
10-Pin SOIC package
PWM pulse skipping for the green mode
Use RAC as the Startup resistor around 5 Mega Ohm at
IAC pin
It can use the HV bipolar to start up the chip and it helps
green mode.
Easy to configure into Boost Follower
Enable lowest BOM for power supply with PFC
Internally synchronized PFC and PWM in one IC
Patented slew rate enhanced voltage error amplifier with
advanced input current shaping technique
Universal Line Input Voltage
CCM boost or DCM boost with leading edge modulation
PFC using Input Current Shaping Technique
Feedforward IAC pin to do the automatic slope
compensation
PFCOVP, VCCOVP, Precision -1V PFC ILIMIT, PFC
Tri-Fault Detect comparator to meet UL1950
Low supply currents; start-up: 100uA typical, operating
current: 2mA typical.
Synchronized leading PFC and trailing edge modulation
PWM to reduce ripple current in the storage capacitor
between the PFC and PWM sections and to reduce
switching noise in the system
VINOK Comparator to guarantee to enable PWM when
PFC reach steady state
High efficiency trailing-edge current mode PWM
Exact 50% PWM maximum duty cycle
UVLO, REFOK, and brownout protection
Digital PFC and PWM soft start, ~10mS
Precision PWM 1.5V current limit for current mode
operation
PWMtrifault to sense DC to DC short and Turn off PFC at
GMth
PWMtrifault also can be programmed to do the Thermal
Protection
2006/10/11
Rev1.0
Champion Microelectronic Corporation
Page 1
模拟电子
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