General
Description
The CM6800/A is a controller
for power factor corrected, switched mode power suppliers. Power
Factor Correction (PFC) allows the use of smaller, lower cost
bulk capacitors, reduces power line loading and stress on the
switching FETs, and results in a power supply that fully compiles
with IEC-1000-2-3 specifications. Intended as a BiCMOS version
of the industry-standard ML4824, CM6800/A includes circuits for
the implementation of leading edge, average current, "boost" type
power factor correction and a trailing edge, pulse width modulator
(PWM). Gate-driver with 1A capabilities minimizes the need for
external driver circuits. Low power requirements improve efficiency
and reduce component costs.
An over-voltage comparator
shuts down the PFC section in the event of a sudden decrease in
load. The PFC section also includes peak current limiting and
input voltage brownout protection. The PWM section can be operated
in current or voltage mode, at up to 250kHz, and includes an accurate
50% duty cycle limit to prevent transformer saturation.
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Features
- Pin to pin compatible
with ML4800 and FAN6800/A
- Additional folded-back
current limit for PWM section.u 23V Bi-CMOS process
- VIN OK
turn on PWM at 2.5V instead of 1.5V
- VIN OK
turn on PWM at 2.25V instead of 1.5V
- Internally synchronized
leading edge PFC and trailing edge PWM in one IC
- Slew rate enhanced
transconductance error amplifier for ultra-fast PFC response
- Low start-up current
(100ŁgA typ.)
- Low operating current
(3.0mA type.)
- Low total harmonic
distortion, high PF
- Reduces ripple
current in the storage capacitor between the PFC and PWM sections
- Average current,
continuous or discontinuous boost leading edge PFC
- VCC OVP Comparator,
Low Power Detect Comparator
- PWM configurable
for current mode or voltage mode operation
- Current fed gain
modulator for improved noise immunity
- Brown-out control,
over-voltage protection, UVLO, and soft start, and Reference
OK
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Applications
- Desktop PC Power
Supply
- Internet Server
Power Supply
- IPC Power Supply
- UPS
- Battery Charger
- DC Motor Power
Supply
- Monitor Power Supply
- Telecom System
Power Supply
- Distributed Power
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Packages
- CM6800IP:
16-PIN PDIP (P16)
- CM6800IS:
16-PIN Wide SOP (S16)
