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The PM8804 from STMicroelectronics is a PWM peak current-mode power controller which integrates all the circuitry required to create a smart and efficient 48V converter for Power over Ethernet (PoE) and mid-power telecoms applications.

The PM8804 is suitable for use in various high- efficiency power-converter topologies, including flyback forward conversion, flyback with synchronous rectification, flyback with active clamp and forward with active clamp. Internal gate drivers with a peak current capability of 1A may be used in the implementation of high- power converter topologies.

Functions integrated into the PM8804 chip:

  • Programmable oscillator to set the switching frequency
  • Adjustable slope compensation
  • Programmable soft-start
  • Dual complementary low-side drivers with programmable dead time
  • Soft turn-off
  • Programmable current-sense blanking time up to 200ns

An internal high-voltage linear regulator with a 20mA output current means that the device requires few external components to perform its start-up routine.

FTM Development Board

STEVAL-POE00xV1 implement PoE converters which operate at high efficiency over a wide load range. They are based on a PM8805 PoE-PD interface, which complies with the IEEE 802.3bt standard, and DC-DC converters run by a PM8804 controller. STEVAL-POE00xV1 differentiate for topology, flyback or active clamp forward, and output conditions. STEVAL-ISA204V1 implements a 5V/20A active clamp forward converter based on PM8804 controller.

  • 75V maximum input voltage
  • Programmable fixed frequency up to 1MHz
  • 80% maximum duty cycle with internal slope compensation
  • <1.5mA operating current consumption
  • Over-current protection, latching after four events
  • Delayed overload protection with automatic restart
  • Over-voltage protection
  • Thermal shut-down protection
  • Internet phones
  • Wireless access points
  • Networked cameras
  • Telecoms power supplies


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