The MAX17690 is a peak current mode, fixed-frequency switching controller specifically designed for the isolated flyback topology operating in Discontinuous Conduction Mode (DCM). The device senses the isolated output voltage directly from the primary-side flyback waveform during the off-time of the primary switch. No auxiliary winding or optocoupler is required for output voltage regulation.
This reference design uses the MAX16834 to create a high-powered LED driver for a very long string(s) of LEDs. The LED current is adjustable with a potentiometer, and can be set as high as 1.5A into as many as 20 LEDs (75V total). For long life, ceramic capacitors are used for both input and output decoupling.
The PCA9532 evaluation board features LEDs for color mixing, blinking and dimming display.
Due to its simplicity and low cost, the flyback converter is the preferred choice for low-to-medium isolated DC-DC power-conversion applications. However, the use of an optocoupler or an auxiliary winding on the flyback transformer for voltage feedback across the isolation barrier increases the number of components and design complexity. The MAX17690 eliminates the need for an optocoupler or auxiliary transformer winding and achieves ±5% output voltage regulation over line, load, and temperature variations.
This reference design is ideal for running IR LEDs (up to 3A) in high current pulse mode in automotive ADAS systems. The design supports continuous and pulsed operation even during load dump and hot start events. Other features include analog dimming and CISPR-25 Class 3 EMI filtering.
TI reference design TIDA-00948 demonstrates a 15mmx20mm, 94% efficient low electromagnetic interference (EMI) DC/DC module using the TPS54202, replacing low dropout regulators (LDOs) in most appliance applications. High efficiency eliminates the need for a heat sink, resulting in a smaller, lower cost solution. Higher current capacity enables the addition of more functionality (WiFi, sensors, etc.). High efficiency and low current consumption help achieve stringent energy efficiency ratings.