STMicroelectronics – Synchronous rectification controller SRK2001 is ideal for LLC resonant converters


SRK2001: two high-current gate-drive outputs

The SRK2001 from STMicroelectronics is a power controller which implements a control scheme specifically intended for secondary-side synchronous rectification in LLC resonant converters.

It provides two high-current gate-drive outputs, each capable of driving one or more N-channel power MOSFETs. Each gate driver is controlled separately, and an interlock logic circuit prevents the two synchronous rectifier MOSFETs from conducting simultaneously. When used to implement synchronous rectification in LLC resonant converters, the SRK2001 requires very few external components.

The control scheme in this IC provides for each synchronous rectifier to be switched on as the corresponding half-winding starts conducting, and switched off as its current falls to zero. The innovative turn-on logic with adaptive masking time, and the adaptive turnoff logic, have the effect of prolonging the time during which the MOSFETs are conducting: this eliminates the need for a circuit to compensate for parasitic inductance.

A low-power mode reduces the current through the converter in light-load and no-load conditions to a typical 50μA.


  • Operating-voltage range: 4.5V to 32V
  • High voltage drain-to-source Kelvin sensing for each MOSFET
  • Up to 500kHz switching frequency
  • 35ns total delay at turn-off
  • Protection against current reversal


  • AC-DC adapters
  • High-end flat-panel TVs
  • Servers
  • Industrial equipment


The STEVAL-ISA170V1 is a 150W converter tailored to a typical specification for an all-in-one computer power supply or a high-power adapter. This highly efficient power supply complies with the Energy Star eligibility criteria for adapters and computers.
Orderable Part Number: STEVAL-ISA170V1