Output power control circuit, control chip and power supply system

Abstract

The embodiment of the invention discloses an output power control circuit, a control chip and a power supply system. The output power control circuit is provided with a voltage regulation unit, a voltage comparison unit and a control unit, wherein the voltage regulation unit forms a first voltage signal according to the input voltage of a power supply chip, the first voltage signal is in negative correlation with the input voltage of the power supply chip, the voltage comparison unit outputs a comparison signal according to the input voltage of the power supply chip and a first reference voltage, the control unit forms a control signal according to the first voltage signal, the comparison signal and a feedback signal of the output current of the power supply chip, and the control signal is used for controlling the state of a power tube of the power supply chip to adjust the output power of the power supply chip; and therefore, the output power can be adjusted according to the input voltage, the problem that when the input voltage is changed to be low, the output power is kept unchanged, so that the discharging current of the battery is increased, and the endurance and the service life of the battery are affected is solved, the endurance of the battery is improved, and the service life of the battery is guaranteed.

Description

technical field [0001] The embodiments of the present invention relate to the technical field of control circuits, and in particular to an output power control circuit, a control chip, and a power supply system. Background technique [0002] In the field of lighting applications where the battery is used as the power supply terminal, the voltage at both ends of the battery continues to drop during the discharge process. When the power of the load remains constant, the discharge current of the battery will continue to rise to maintain the power required by the load. From the voltage at both ends of the battery U=E-IR (where U is the voltage at both ends of the battery, E is the electromotive force of the battery, I is the discharge current of the battery, and R is the internal resistance of the battery), it can be known that when the discharge current of the battery increases, the battery The voltage at both ends drops further, so that the battery further increases the discha...

AI Technical Summary

Problems solved by technology

At this time, the battery has a large discharge current, which will cause a high temperature rise of the battery and affect its service life.

Moreover, when the voltage at both ends of the battery is relatively low, the energy stored in the battery is relatively small (take a single-cell lithium battery as an example, when the voltage at both ends of the battery is between 3.7V and 4.2V, the battery stores about 80% of the energy, and the battery at both ends When the voltage is below 3.7V, the energy stored in the battery is very little), at this time the battery maintains a large discharge current, which will further increase the energy consumption rate of the battery, thereby reducing the discharge time of the battery, that is, reducing the working time of the battery and reducing battery life

In addition, a large discharge current will cause a high circuit loss of the battery, resulting in a low overall efficiency of the lighting system, which further reduces the battery life and affects the user experience.

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