A4401

• Multiple output regulator
• 7 to 40 V input supply
• Low EMI conducted and radiated emissions
• Adaptive quasi-resonant turn on/off control
• Minimal number of external components
• Enable input which can be driven with respect to the battery voltage

Description

This device A4401 provides all the necessary control functions to provide the power rails for driving a vacuum fluorescent display (VFD) using minimal external components. The power supply is based on a quasi-resonant, discontinuous flyback converter, operating near the critical conduction boundary. A novel adaptive turn-on control scheme is used to optimize the turn-on and turn-off phase of the MOSFET, to reduce EMI emissions while minimizing switching losses.

The converter A4401 is self-oscillating, operating at switching frequencies depending on the input voltage, load, and external components. An onboard linear regulator that is powered directly from the battery provides the housekeeping supply, avoiding the need for complex bias supplies.

Internal diagnostics provide comprehensive protection against overloads, input undervoltage, and overtemperature conditions..

The A4401 is supplied in an 8-pin narrow SOIC package (suffix L), which is lead (Pb) free, with 100% matte-tin leadframe plating.