LM2673S-12/NOPB

The LM2673S-12/NOPB is a monolithic switching step-down voltage regulator with a typical efficiency of 90 percent. The device operates from 4.5V to 28V input voltage and provides up to several amps of output current. It is designed with a pulse frequency modulation (PFM) control loop for maximum efficiency without sacrificing fast load transient response. The LM2673S-12/NOPB operates with a nominal fixed frequency of 800 kHz and is self-biased.

The LM2673S-12/NOPB is well-suited for a wide range of application fields such as renewable energy, medical, automotive, industrial and communication systems. The device offers a wide range of features, including input under-voltage measurement, output voltage regulation, programmable soft-start, enable/disable and a low-duty-cycle mode. In addition to these features, the device also includes thermal shutdown, short-circuit protection, under-voltage protection, over-current protection and over-temperature protection.

LM2673S-12/NOPB Working Principle

The LM2673S-12/NOPB utilizes pulse frequency modulation (PFM) to maintain a constant frequency operation. It uses a pulse waveform to regulate the output voltage. On each clock cycle, the output transistor is switched on and pulled to ground for a certain period of time before switching off again. Depending on the load, the duty cycle of the waveform changes, resulting in an output voltage regulated output. Therefore, PFM is an efficient and reliable way to regulate an output voltage.

The LM2673S-12/NOPB also integrates a low-side MOSFET switch which is driven by an internal oscillator and then pulses the output voltage to its regulated voltage level, determined by an external feedback resistor. An internal over-current protection circuit monitors the current in the switching MOSFET. If the current reaches a level that is too high, the device will reduce the duty cycle, in turn reducing the power to the output and resetting the over-current protection circuitry.

The LM2673S-12/NOPB also features an integrated low dropout linear regulator. The linear regulator enables the device to remain in continuous operation in light-load conditions. This ensures high efficiency in all load conditions. In addition, the LM2673S-12/NOPB also features a dynamic switching frequency, which allows it to further improve efficiency by switching between 600 kHz and 1.2 MHz (depending on load conditions) to achieve the best possible efficiency.

Conclusion

In conclusion, the LM2673S-12/NOPB is a monolithic switching step-down voltage regulator that is suitable for a wide range of application fields. It utilizes pulse frequency modulation (PFM) to regulate the output voltage and also includes an integrated low dropout linear regulator, dynamic switching frequency and other features to ensure a high efficiency in all load conditions.