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.
15W 5V Offline Flyback Converter Using the MAX17595
The MAX17595 is a peak-current-mode controller for designing wide input-voltage flyback regulators. The MAX17595 offers optimized input thresholds for universal input AC-DC converters and telecom DC-DC (36V to 72V input range) power supplies. It contains a built-in gate driver for an external n-channel MOSFET. The MAX17595 houses an internal error amplifier with 1% accurate reference, eliminating the need for an external reference.
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.
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 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.
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.
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.
Due to its simplicity and low cost, the flyback converter is the preferred choice for low-to-medium isolated DC-DC power-conversion applications.
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