HF920B

The HF920B is a flyback regulator with a monolithic, 900V MOSFET. The HF920B is an enhanced version of the HF920 with EMI optimization. It provides excellent power regulation with very few external components for AC/DC applications that require high reliability, such as smart meters, large appliances, industrial controls, and products powered by AC grids.

The HF920B uses peak current control mode 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 is also optimized to achieve very low power consumption during standby conditions.

MPS’s 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 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 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 greatly reduces the noise level and EMI filter costs.

Frequency doubling mode 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.

The HF920B is available in SOIC8-7A and SOIC14-11 packages, and the maximum output power is listed in Table 1 respectively.