Monolithic Power Systems (MPS) HF920B Flyback Regulator with EMI Optimization

The HF920B uses peak current control mode to provide an excellent transient response and easy loop compensation. The regulator enters burst mode when the output power falls below a given level. The IC is also optimized to achieve very low power consumption during standby conditions.

MPS’ proprietary, 900V monolithic process enables over-temperature protection (OTP) on the same silicon as the 900V power MOSFET, offering the most precise thermal protection. The HF920B also provides a full suite of protection features, such as V_CC under-voltage lockout (UVLO), overload protection (OLP), over-voltage protection (OVP), and short-circuit protection (SCP).

The Monolithic Power Systems (MPS) HF920B is designed to minimize EMI for power line communications (PLC) in home and building automation applications. The operating frequency is programmed externally with a single resistor, so the power supply’s radiated energy can block interference to the PLC. In addition to the programmable frequency, the HF920B employs frequency jittering that significantly reduces the noise level and EMI filter costs.

Frequency doubling mode can be enabled through a simple external setup. With this special operation mode, the switching frequency is doubled when the converter runs into an overpowering condition. In this way, the converter can handle up to a 50% decrease of the transformer inductance caused by external magnetizing interference.

The HF920B is available in SOIC8-7A and SOIC14-11 packages.