Detection circuit and device for output state of charging equipment and charging equipment

Abstract

The invention discloses a detection circuit for the output state of charging equipment. The detection circuit comprises a PWM control unit, a first resistor, a second resistor, a reference voltage source, an error amplifier, a first capacitor, a comparator and a reference voltage source; the PWM control unit receives the voltage signal of the input end and outputs a modulated voltage signal; one end of the first resistor is connected with the output end of the PWM control unit, and the other end of the first resistor is grounded after being connected with the second resistor in series; the first resistor is also connected with the input end of the error amplifier; the reference voltage source is also connected with the input end of the error amplifier; the error amplifier outputs an errorvoltage signal; the first capacitor is connected with the error amplifier and the PWM control unit; the input end of the comparator is connected with the first capacitor, the error amplifier and the reference voltage source. The invention further discloses an output state detection device and charging equipment. According to the invention, a charging completion prompt function is realized withoutany detection periphery, and the cost of an external device, the PCB layout area and the power consumption of the device are greatly reduced.

Description

Technical field [0001] The invention relates to the field of detection circuits for the output state of charging equipment, and in particular to a detection circuit, device and charging equipment for the output state of charging equipment. Background technique [0002] Generally, DC chargers (such as car chargers) have only charging power indicator lights, which can only display whether the power is on, but not whether the charging is full. The lights are uniform regardless of whether it is fully charged, and the indication effect is poor. Know the charging status. [0003] At present, if the charging status is to be reflected, the detection method of adding a current sampling resistor is often used. The output current is always detected by the current sampling resistor. The detection signal needs to be amplified by a precision operational amplifier. When the output current is reduced to a certain current ( Such as 200mA), the operational amplifier is flipped to produce a turn lig...

AI Technical Summary

Problems solved by technology

Using this detection method requires an additional current sampling resistor, which has the problems of high power consumption, complicated peripherals, occupying a large area of ​​the printed circuit board (PCB), and high cost. Moreover, this detection method is not conducive to the integration of devices, especially for small For cigarette lighter chargers, the PCB area is very important

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