HF500A-20

The HF500A-20 is a fixed-frequency flyback controller with current control mode and internal slope compensation. The device integrates a 700V MOSFET and a full-featured controller for low-power, offline, flyback switch-mode power supplies.

At medium and heavy loads, the controller operates at a fixed frequency with frequency jittering (f_JITTER). f_JITTER helps dissipate energy generated by conducted noise, which reduces electromagnetic interference (EMI). At light loads, the controller maintains the peak current (I_PEAK) at its present level and reduces the switching frequency (f_SW) to 25kHz for excellent light-load efficiency. At very light loads, the controller enters burst mode to achieve low standby power consumption.

The HF500A-20 employs over-power line compensation to ensure that the overload protection point is independent of the input voltage (V_IN).

Full protection features include brown-in protection, brownout protection, VCC voltage (V_CC) under-voltage lockout (UVLO) protection, overload protection (OLP), short-circuit protection (SCP), input over-voltage protection (OVP), V_CC over-voltage protection (OVP), and over-temperature protection (OTP).

The HF500A-20 is available in a PDIP8-7B package.