The feedback arrangement of typical switching regulators doesn’t allow the regulated outputs to go lower than the reference voltage. If you try to lower the output by modifying the feedback network, the compensation components the manufacturer recommends may no longer stabilize the regulator’s error amplifier. An external reference voltage helps overcome this problem. source

By using a gated-oscillator architecture instead of a clocked-PWM one, gated-oscillator-type switching regulators permit high efficiency over extended ranges of output current. This architecture eliminates the housekeeping currents associated with the continuous operation of fixed-frequency designs. Gated-oscillator regulators simply self-clock at whatever frequency is necessary to maintain the output voltage. Typically, loop-oscillation frequency ranges from a few hertz to the kilohertz region, depending on the load.source

A programmable reference diode, such as the Motorola TL431A, can supply constant-current bias for a silicon pressure-sensor bridge. This circuit is simpler than using an op amp and separate reference diode or than using a current diode, which requires temperature compensation.source

The universal input power supply shown in Figure above has multiple outputs, ±26 VDC, ±15 VDC, and +5 VDC. The ±26 V outputs can each deliver a minimum output current of 2.42 A peak (thermally limited) and 1.45 A continuous. Additionally, the voltage regulation and, importantly, transient response is excellent over the entire load range (no-load to full load).source

This document is an engineering report giving performance characteristics of a 24 W Flyback converter – 8 V @ 3 A. This design uses TOPSwitch-GX – an integrated IC comprising a high voltage MOSFET, and PWM controller.This document contains power supply specification, schematic, bill-of-materials, transformer documentation, printed circuit layout, and performance data. A photo of the power supply prototype is shown in Figure above.source