10W Isolated Power Supply
Created: Oct 14, 2016
No description available.
This circuit is an isolated power supply capable of converting a voltage input into a stable output suitable for a variety of applications. This isolated power supply can handle voltage inputs ranging from 17V- 36V converting to 12V output that can provide up to 800mA of current. The design uses a flyback topology featuring the MAX17597ATE+ from Maxim.
Isolated power supplies provide dependable power regulation and gives benefits such as ground loop prevention and circuit protection. The peak-current-mode controller MAX17597ATE+ 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 by setting R10 to 20kΩ. For EMI-sensitive applications, the MAX17597ATE+ 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 circuit design is capable of delivering 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.