Judgment method of charging end point

Abstract

The present invention is a method for judging the end point of charging, including: using a power input unit to convert the input power into voltage division and output power; using a pulse width modulation (PWM) drive controller to receive the voltage division power and generate a PWM drive signal to control the switching The transistor generates the charging current; the charging inductor is used to conduct the charging current to charge the rechargeable battery unit; the rechargeable battery unit is connected to the ground by the sensing resistor; the PWM driving controller is used to adjust the operation of the PWM driving signal according to the sensing voltage of the sensing resistor Width; and using the PWM drive controller to compare the working width with the preset width to determine whether the current working width is lower than the preset width and end the charging operation. Therefore, the present invention can accurately determine whether charging is completed without the need for a complex amplifier with high sensitivity and high gain.

Description

Technical field [0001] The present invention relates to a method for judging the end point of charging, in particular, it uses a pulse width modulation drive controller to determine whether the working width of a pulse width modulation signal is lower than a preset width during constant voltage and low current charging to determine the end point of charging. Background technique [0002] Many handheld or portable electronic devices, such as watches, mobile phones, laptops (notebook computers), tablet computers, remote controls, radio tape recorders, walkmans, voice recorders, and cameras cannot be used as low-cost electricity To operate with a power source, it requires small, light, and relatively convenient batteries to provide the required power, such as carbon-zinc batteries, alkaline batteries, mercury batteries, or nickel rechargeable batteries Cadmium batteries, nickel-metal hydride batteries, lithium batteries, and lithium iron batteries. Among them, rechargeable batteries...

AI Technical Summary

Problems solved by technology

However, in actual circuits, the resistance is generally as small as possible to avoid waste of power consumption, so the sensing current and sensing voltage are very low.

Especially when the battery is nearly fully charged, the sensing current will be lower, making the sensing voltage too low to be accurately detected, which may cause misjudgment of the charging end point, such as ending too early and insufficient charge, or too late overcharging, even affecting safety

[0005] The prior art solution to the above problems is to use a high-sensitivity and high-gain analog amplifier, which can be configured in the control circuit to accurately amplify the small sensing voltage, which not only leads to increased cost, but also because such amplifiers are easy to The electrical characteristics are affected by the interference of the surrounding electrical environment, which greatly increases the difficulty of physical circuit layout, and even cannot be realized

Images