Features: Internally synchronized leading-edge modulated PFC and trailing-edge modulated PWM in one IC
TriFault DetectTM for UL1950 compliance and enhanced safety
VCCOVP provides additonal PFC fault protection
Slew rate enhanced transconductance error amplifier for ultra-fast PFC response
Low power: 200µA startup current, 5.5mA operating current
Low total harmonic distortion, high PF
Reduces ripple current in the storage capacitor between the PFC and PWM sections
Average current, continuous boost leading edge PFC
PWM configurable for current-mode or voltage mode operation
Overvoltage and brown-out protection, UVLO, and soft start
Pinout
SpecificationsVCC ............................................................................... 18V
ISENSE Voltage .................................................. -5V to 0.7V
Voltage on Any Other Pin ...........GND - 0.3V to VCCZ + 0.3V
IREF .............................................................................10mA
IAC Input Current ........................................................10mA
Peak PFC OUT Current, Source or Sink ............................ 1A
Peak PWM OUT Current, Source or Sink .......................... 1A
PFC OUT, PWM OUT Energy Per Cycle ......................... 1.5µJ
Junction Temperature ................................................ 150°C
Storage Temperature Range ....................... -65°C to 150°C
Lead Temperature (Soldering, 10 sec) ....................... 260°C
Thermal Resistance (JA)
Plastic DIP .................................................................80°C/W
Plastic SOIC ............................................................ 105°C/WDescriptionThe ML4804 is a controller for power factor corrected, switched mode power supplies. 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 complies with IEC1000-3-2 specification. Intended as a BiCMOS enhancement of the industry-standard ML4824, the ML4804 includes circuits for the implementation of leading edge, average current, "boost" type power factor correction and a trailing edge, pulse width modulator (PWM). It also includes a TriFault Detect™ function to help ensure that no unsafe conditions will result from single component failure in the PFC. 1A gate-drive outputs minimize the need for external driver circuits. Low power requirements of ML4804 improve efficiency and reduce component costs.
An over voltage comparator ML4804 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.
ML4804 Data Sheet
