Phase compensation of base station power supply

How difficult is power supply loop compensation design?

Designing and optimizing high performance switching mode power supplies is becoming a more frequent and challenging task. Power supply loop compensation design is usually viewed as a difficult task, especially for inexperienced supply designers.

How to compensate a power supply?

Many books have been written that discuss how to compensate a power supply. The focus of this paper is to provide an overview of important compensation factors. In general terms, compensating a power supply can be simplified into graphically adding and subtracting waveforms on a semilog graph.

What are the components of a power supply compensator?

main elements when compensating a power supply: the modulator, the compensation, and the overall response. The modulator gain is a function of the external filter components (C1, RC1, and L1), the input voltage, and the peak-to-peak ramp voltage.

Should a power supply be externally compensated?

Migrating to an externally compensated design actually can provide a smaller overall solution under these conditions. The external compensation allows the designer to optimize the filter inductor and possibly to use smaller ceramic output capacitors. Let’s compare the solution sizes of two power supplies designed to meet the same specifications.

Can a 5-range power supply be externally compensated?

Internally compensated supplies in the 5-Arange typically are designed for large tantalum or aluminum output capacitors. The ESR of these capacitors is used to help compensate the power supply. Migrating to an externally compensated design actually can provide a smaller overall solution under these conditions.

How do I design an internal compensated power supply with integrated FETs?

The design procedure for an internally com-pensated power supply with integrated FETs is significantly different. It flows as follows. Choose an IC that meets the VIN, VOUT, and IOUT requirements. Choose an external inductor and capacitor from the list of recommended components in the data sheet.