Frequency detection to perform dynamic peak current control

Abstract

The amount of power being output to the load is sensed by sampling the frequency of the pulse width modulation signal that is controlling the switch that is providing the power to the load. If the pulse width modulation signal has a high frequency, then it will be providing higher power to the load. As the power drawn by the load decreases, the frequency of the pulse width modulation power supply signal will decrease. By sensing and periodically sampling the frequency of the pulse width modulation signal that is providing power, the demand of the load can be quickly and accurately determined. As the power demand of the load decreases, the peak current that the power supply switch can provide also decreases. The permitted peak current dynamically changes to adapt to the power drawn by the load.

Description

BACKGROUNDTechnical Field[0001]This invention is in the field of switching regulators and, in particular, a circuit which adaptively controls, to varying levels, the maximum current that can be supplied from the regulator.Description of the Related Art[0002]Inductive DC-DC switching power supply regulators are known in the art to be efficient power stage converters to provide different voltages within a system. Such a DC-DC switching regulator uses an external inductor as a storage device to transform a voltage level from one voltage to another or, transition from a voltage-based power output to a current-based power output. There are many types of switching regulators, ranging from buck regulators, buck-boost regulators, boost regulators, and the like. These may operate in either continuous or discontinuous mode. Some of these regulators have a fixed frequency, while others have a variable frequency that can depend on the application and the external components that can be selected...

AI Technical Summary

Benefits of technology

[0003]According to principles of the various embodiments discussed herein, a new technique is proposed to managing and controlling the peak current that will be output by a power supply. An entire new technique for sensing the power drawn by the load and varying the peak amount of current that will be permitted is introduced. In particular, the amount of power being output to the load is sensed by sampling the frequency of the pulse width modulation signal that is controlling the switch that is providing the power to the load. If the pulse width modulation signal has a high frequency, then it will be providing higher power to the load. As the power drawn by the load decreases, the frequency of the pulse width modulation power supply signal will decrease. By sensing and periodically sampling the frequency of the pulse width modulation signal that is providing power, the demand of the load can be quickly and accurately determined.

Problems solved by technology

One of the issues that must be addressed in a DC-DC switching regulator is the power ratings of the components to be used in the circuit.

In particular, if a component, such as a transistor, inductor, or the like has a high current rating, it will generally be more robust, but will also be larger, significantly more expensive, and take up more space in the circuit.

As can be appreciated, if components, such as transistors and inductors having a low current rating, are subjected to a current that exceeds their ratings they may be harmed, or even destroyed, thus preventing proper operation of the circuit.

Images