Switching Regulators Using LM 2575 and LM 2577
Switching reguÂlators are available is different circuit configurations inÂcluding the flyback, feed-forward, push-pull, and non-isoÂlated single-ended or single-polarity types. Also, the switching regulators can operate in any of three modes â€“ step-down, step-up, or polarity inverting.
LM 2575 series of regulators developed by National Semiconductor are monolithic ICâ€™s that provide the active functions for step-down (back) switching regulator, capable of driving a1A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3V, 5V, 12V, 15V and an adjustable output version.
Requiring a minimum number of external components, these regulators are simple to use and include internal frequency compensation and a fixed-frequency oscillator. LM 2575 series offers a high-efficiency replacement for popular 3-terminal linear regulators. It substantially reduces the size of the heat sink, and in many cases no heat sink is required. Fixed output voltage version is illustrated in figure.
The National Semiconductor LM 1577/LM 2577 Â are monolithic ICs that provide all of the power and control functions for step-up (boost), fly back, and forward converter switching regulators. The device is available in three different output voltage versions: 12 V, 15 V and adjustable.