The MAX17596 is a peak-current-mode controller for design of wide input-voltage flyback

and boost regulators. The reference design operates over a 17V to 36V input voltage

range, and provides up to 800mA (plus 20% overhead) at 12V output. The MAX17596 has

an internal amplifier with 1% accurate reference, eliminating the need for an external

reference. The switching frequency is programmable from 100kHz to 1MHz with an

accuracy of 8%, allowing optimization of magnetic and filter components, resulting in

compact and cost-effective power conversion. This design is set to switch at 500kHz. For

EMI-sensitive applications, the MAX17596 incorporates a programmable frequency

dithering scheme, enabling low-EMI spread-spectrum operation.

The input undervoltage lockout (EN/UVLO) is provided for programming the input-supply

start voltage (set to 17V in the design), and to ensure proper operation during brownout

conditions. The EN/UVLO input is also used to turn on/off the IC. The overvoltage input

(OVI) protection scheme is provided to make sure that the controller shuts down when the

input supply exceeds its maximum allowed value (set to 36V in the design).

A capacitor is connected to the SS pin to program the soft-start period hence reduces the

input inrush current during startup. Hiccup-mode overcurrent protection and thermal

shutdown are provided to minimize dissipation in overcurrent and overtemperature fault

conditions.

The reference design delivers a peak efficiency of 88% with the supplied components

when the input is 24V. This general-purpose power solution can be used in many different

types of power applications, such as programmable logic controllers (PLC), industrial

process control, industrial sensors, telecom power supplies, isolated battery chargers,

servers, and embedded computing.

System Diagram