HF920

The HF920 is a flyback regulator with a monolithic, 900V MOSFET. The HF920 provides excellent power regulation in AC/DC applications that require high reliability, such as smart meters, large appliances, industrial controls, and products powered by poor AC grids. The HF920 requires a minimal number ofexternal components. The HF920 uses peak-current-mode control to provide excellent transient response and easy loop compensation. When the output power falls below a given level, the regulator enters burst mode. The IC consumption is also specially optimized. As a result, the HF920 achieves very low power consumption during standby conditions. MPS’s proprietary, 900V, monolithic process enables an over-temperature protection (OTP) that is on the same silicon as the 900V power MOSFET, offering the most precise thermal protection. The HF920 also offers a full suite of protection features such as VCC under-voltage lockout (UVLO), overload protection (OLP), over-voltage protection (OVP), and short-circuit protection (SCP). The HF920 is designed to minimize electromagnetic interference 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 be designed to block interference to the PLC. In addition to the programmable frequency, the HF920 employs frequency jittering that reduces the noise level and EMI filter cost greatly. Frequency-doubling mode operation can be enabled through a simple external set-up. With this special operation mode, the switching frequency is doubled when the converter runs into an over-power condition. In this way, the converter is able to handle up to a 50% decrease of the transformer inductance caused by external magnetizing interference.