Electronetics has extensive experience designing and building custom high frequency magnetic components in virtually every shape, size, frequency and power level. We can also optimize your overall circuit design with a transformer or inductor precisely customized for your application.
Single-Ended Buck
Operates at a higher frequency than a typical line transformer. Used in a class of power supplies known as "switched-mode." Part of a circuit topology known as a buck regulator, which indicates to the designer that a special set of parameters is required for proper performance.
Important specifications: Operating frequency; maximum "on time" or maximum duty-cycle; maximum DC output voltage at the minimum input voltage; maximum input voltage and total output power.
Push-Pull Buck - Derived Forward
Switched-mode transformer that differs from single-ended buck in that the latter only works magnetically in one direction, whereas push-pull topology works in both directions for superior core utilization. Primary and secondary coil(s) typically have a winding with a tap directly in the center of the coil.
A common variation is a full bridge, or "H" bridge, consisting of 4 power transistors with the transformer primary connected in between, thus forming an "H". The primary is simpler with a single winding while the secondary is often identical to the push-pull version.
Important specifications: Same as single-ended buck. Operating frequency is usually specified for a full cycle.
Flyback - Discontinuous Current (or Continuous Current)
Switched-mode transformer that stores transferred energy to the secondary. "Continuous/discontinuous" indicates whether current flowing through the secondary decays to zero before the next cycle commences (discontinuous), or whether some current is flowing when the next cycle commences (continuous).
Important specifications:
Operating frequency; maximum "on time" or maximum duty-cycle; output voltage(s); specify which secondary is the point of regulation (typically one output is used by the power supply circuitry to actively regulate while the others run passively); absolute maximum output power, which is especially critical because the transformer core stores power in energy bursts for each cycle.
Gate / Base Drive
Designed to interface a power transistor drive circuit to the power transistor gate (if a MOSFET) or base (if a bipolar junction transistor). Must comply with strict isolation voltage requirements and feature superior electrical coupling between primary and secondary. Circuit topology can vary significantly; e.g, single primary and single secondary; single primary with dual isolated secondaries; push-pull primary with either of the two secondary types.
Important specifications:
Minimum operating frequency; isolation voltage between primary and secondary(ies); maximum duty-cycle; maximum leakage ; minimum secondary rise/fall time.
High Frequency Inductors
Used in switched-mode power supplies to filter high frequency pulses common in switched-mode power supplies. Can be designed to work with substantial DC current with AC superimposed on top, or with no DC at all.
Important specifications:
Maximum instantaneous peak current; maximum RMS operating current; nominal inductance and tolerance; frequency range or operating frequency of power supply.
RF Power Transformers
This is a special class of high frequency transformer for very high operating frequencies. Requires special consideration in the selection of appropriate core and wire materials.
