IdealPoE Diode Bridge Integrates Low-Loss MOSFET Base Bridges and Controller
Microsemi Corporation today announced its new PD70224 IdealPoE™ diode bridge, a dual pack of MOSFET-based full-bridge rectifiers. The device's low-RDS 0.16Ohm N-channel MOSFETS allow for much higher overall efficiency and higher output power, particularly when used in powered devices for Power-over-Ethernet (PoE) and Power-over-HDBaseT (PoH) applications in the communications and enterprise markets including wireless LAN access points, small cells and small switches/routers. Unlike similar solutions currently on the market, this highly-integrated device eliminates the need to add additional external components such as controllers and field effect transistors (FETs), reducing overall system cost as well as board real estate.
"In PoE- and PoH-powered solutions when high-efficiency or high-power was required, system designers were used to implementing their designs using discrete components. Now the new IdealPoE diode bridge PD70224 implements the input power device PoE bridge, offering an integrated solution that's unique in the market and provides best-in-class performance," said Iris Shuker, PoE product line manager for Microsemi. "This highly integrated solution dissipates less power, simplifies the customer's design and saves printed circuit board space."
Microsemi's PD70224 can support over 1A of current, making it suited not only for modern energy-saving two-pair applications compliant with IEEE802.3af and IEEE802.3at, but also for four-pair powered devices using Universal PoE (up to 51 watts) and PoH (up to 95 watts). The entire drive circuitry for driving the MOSFETs is on-chip, including a charge pump for driving the high-side N-channel MOSFETs. The total forward drop (bridge offset) introduced by the ideal bridge rectifier is only 192 millivolt (mV) at 0.6A, compared to a standard bridge rectifier that typically presents 2,000mV of forward drop.
Other product features include: Self-contained drive circuitry for MOSFETs; Integrated 0.16Ohm N-channel MOSFETs for 0.3Ohm total path resistance; "Power present" indicator signals for identifying four-pair bridge power; Low leakage of less than 12 micro ampere uA during detection; Wide operating voltage range up to 57 volts; and operation from -40 degrees C to +85 degrees C ambient. This device is available in 40 pin package and isRoHS compliant. Microsemi's new PD70224 ideal diode bridge devices are sampling now, with volume production beginning this month.
