The PJ33478 is a versatile Low-Side N-Channel MOSFET controller for switching regulators. It is suitable to drive topologies with a low side N-Channel MOSFET, such as Boost, SEPIC, etc. The operating frequency can be set between 100kHz to 1000kHz by adjusting the resistor value connected to FA/SD pin. Current mode control is adopted to provide high bandwidth, excellent transient response and cycle-by-cycle current limit function.
During output short circuit, the switching frequency is reduced by a factor of 5 to avoid excessive power dissipation until the fault condition is removed. In addition, the PJ33478 has built-in features such as thermal shutdown, over voltage protection, undervoltage lockout, etc. Power saving shut down mode reduces total current to 6uA (Typ.) and allows power supply sequencing. Internal soft-start limits the inrush current at start-up.
