Output power control circuit and 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 adjustment unit, a voltage comparison unit and a control unit; wherein the voltage adjustment unit forms a first voltage signal according to the input voltage of the power chip, the first voltage signal is negatively correlated with the input voltage of the power chip, and the voltage comparison unit according to The input voltage of the power chip and the first reference voltage output a comparison signal, and the control unit forms a control signal according to the first voltage signal, the comparison signal and the feedback signal of the output current of the power chip, and the control signal is used to control the state of the power tube of the power chip to adjust The output power of the power chip; the output power can be adjusted according to the input voltage, avoiding the output power remaining unchanged when the input voltage changes to a low level, causing the battery discharge current to increase and affecting the battery life and life, improving the battery life 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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