Pulse Electronics integrates CM and DM chokes

May 3, 2014. Pulse Electronics has announced its new series of chokes that integrate a common mode (CM) and differential mode (DM) choke into the same component. Combining two separate magnetic components into a single integrated component reduces power losses across the EMI filter portion of the power supply because it reduces the resistance. It also allows for a reduction in the overall space needed for the choke.

Pulse Electronics' new PA4040 integrated choke has a small 31 x 24.9-mm footprint, making this single CMDM component over 40% smaller than the combined footprint of equivalent CM and DM components. The low direct current resistance, between 32 and 245 mΩ, increases efficiency by 30%. Placing one component, instead of two, saves manufacturing time and cost and increases throughput.

The PA4040 integrated choke has 1500-V (rms) hi-pot rating and 3.0 mm of creepage and clearance safety distance, so it suits a wide range of safety agency (UL/CSA/VDE) requirements. It can be used in any AC/DC or DC/AC power supply that uses both a DM and CM filter and where the currents through the filter are less than 3.5 A (rms). Applications include LED lighting drives, solar microinverters, motor drives and controls, and datacom and computing applications. It's a cost-efficient option, as the cost is approximately 20% lower than that of two separate CM and DM components.

“Integrated chokes have been available before, but mainly for custom applications,” explained Geoff Wildman, product line manager (power), at Pulse Electronics. “This catalog release allows for a wider range of customers to enjoy the benefits of integrating the CM and DM chokes.”

Common Mode Chokes are used to block or divert unwanted common-mode noise in a power supply. Common mode is noise that is common to both the line and neutral in a power supply and essentially circulates through line/neutral and then returns through earth ground by way of parasitic elements in the power supply. Differential Mode Chokes block or divert unwanted differential mode noise in a power supply. Differential mode is noise that circulates through the line and returns through the neutral. Pulse Electronics' component combines these two functions into a single integrated CMDM choke.


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