llc converter (full bride, synchronous fets)
the llc converter is a resonant converter that can achieve zvs operation (primary side switch) and zcs operation (secondary side switch) simultaneously. it achieves low noise and high efficiency by generating a sinusoidal current waveform with the switch network and resonant circuit.
this circuit consists of a full-bridge switch circuit on the primary side and a center-tap transformer on the secondary side using fets instead of diodes. this type of configuration is commonly used for relatively high power (around several kw).
- same semiconductor devices
- series resonance between cr and lr
- lr is sometimes implemented as the leakage inductance of the transformer
- voltage control is done through frequency high complexity design
- soft switching is defined by magnetizing inductance lm, not function of the load.
- efficiency around 98% suits titanium!
- frequency 100..200 khz
|primary side (hv)
|600v sj mos
|prestomos (jnx series)
|excellent switching behaviour (low qrr, short trr)
|secondary side (lv)
|100v mosfet in small hsmt8 package
|40v mosfet in hsop8 package
|dual driver, ideal for half- and full-bridge topologies.
|synchronous rectification controller ic