CN201788268U - Lithium battery power detection device - Google Patents

Abstract

The utility model relates to the capacity checking technology, and discloses a capacity checking device for lithium batteries, which has low cost and simple wiring. The key points of the technical scheme of the utility model are as follows: the capacity checking device for lithium batteries comprises a voltage-dividing detection circuit and an alarm display circuit, wherein, the voltage-dividing detection circuit is connected with the alarm display circuit, and comprises a first resistor, a second resistor, a capacitor and a first triode; the first resistor is connected with a base electrode of the first triode, and is earthed through the capacitor and the second resistor respectively; the capacitor and the second resistor are connected with the base electrode of the first triode; an emitting electrode of the first triode is earthed; the alarm display circuit comprises a third resistor, a fourth resistor, a fifth resistor, a second triode and a display lamp; a base electrode of the second triode is connected with a collecting electrode of the first triode through the third resistor; an emitting electrode of the second triode is connected with the collecting electrode of the first triode through the fourth resistor; and a collecting electrode of the second triode is earthed through the fifth resistor and the display lamp. The capacity checking device for lithium batteries has the advantages of low cost and simple wiring, and is applicable for the capacity checking of lithium batteries.

Description

Lithium battery power detection device

technical field

The utility model relates to a power detection technology, in particular to a lithium battery power detection device.

Background technique

For digital products currently on the market, lithium batteries have become the preferred power supply batteries due to their advantages of long service life, high rated voltage, strong environmental adaptability and light weight. Lithium batteries are generally divided into square lithium batteries and cylindrical lithium batteries according to their appearance, and are divided into aluminum case lithium batteries, steel case lithium batteries and pouch batteries according to outsourcing materials. But no matter what type it is, it is necessary to perform power detection on it. The purpose is to remind the user to charge in time when the battery power is low, so as to prevent the impact of the battery power on digital products after the battery power is exhausted. At present, there are two kinds of commonly used lithium battery power detection devices: 1. It uses a dedicated chip for detection, which has high detection accuracy, but the cost is very high. 2. A/D conversion detection needs to use a dedicated A/D conversion port line or chip, which is costly and complicated to connect.

Utility model content

The technical problem to be solved by the utility model is to propose a lithium battery power detection device with low cost and simple wiring for the defects of high cost and complicated wiring of the traditional lithium battery power detection device.

The technical scheme adopted by the utility model to solve the above-mentioned technical problems is: a lithium battery power detection device, including a voltage division detection circuit and an alarm display circuit, the voltage division detection circuit is connected to the alarm display circuit; the voltage division detection circuit includes a first resistor, The second resistor, the capacitor and the first triode, the first resistor is connected to the base of the first triode, and is grounded through the capacitor and the second resistor respectively, and the capacitor and the second resistor are connected to the base of the first triode pole, the emitter of the first triode is grounded; the alarm display circuit includes a third resistor, a fourth resistor, a fifth resistor, a second triode and a display lamp; the base of the second triode The pole is connected to the collector of the first triode through the third resistor, the emitter is connected to the collector of the first triode through the fourth resistor, and the collector is grounded through the fifth resistor and the display lamp.

The display lights are light emitting diodes.

The beneficial effects of the utility model are: low cost, simple wiring, and less occupied system resources.

Description of drawings

Fig. 1 is a schematic diagram of the circuit structure of the embodiment.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is described further.

The utility model aims at the defects of high cost and complicated wiring of the traditional lithium battery power detection device, and proposes a lithium battery power detection device with low cost and simple wiring. Since the detection device only uses components such as common transistors, resistors, and light-emitting diodes, the cost is low and the wiring is simple. In addition, when using the detection device to detect the power of the lithium battery, it only needs to use a common interface line of the main control chip to complete the detection, which occupies less system resources.

Example:

As shown in Figure 1, the lithium battery power detection device in this example includes a voltage division detection circuit and an alarm display circuit, and the voltage division detection circuit is connected to the alarm display circuit; the voltage division detection circuit includes a first resistor R1 and a second resistor R2 , a capacitor C and the first transistor Q1, the first resistor R1 is connected to the base of the first transistor Q1, and is grounded through the capacitor C and the second resistor R2 respectively, and the capacitor C and the second resistor R2 are connected to the first The base of the transistor Q1, the emitter of the first transistor Q1 is grounded; the alarm display circuit includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a second transistor Q2 and a light emitting Diode D; the base of the second transistor Q2 is connected to the collector of the first transistor Q1 through the third resistor R3, and its emitter is connected to the collector of the first transistor Q1 through the fourth resistor R4, which The collector is grounded through the fifth resistor R5 and the light emitting diode D.

In specific implementation, Vbat is the output voltage of the lithium battery. First, the first resistor R1 and the second resistor R2 need to be selected according to the threshold voltage of the lithium battery that needs to be alerted and the conduction threshold voltage of the first triode, for example: The first triode Q1 selects the chip transistor 2N3905, and the lithium battery is a series connection of 2 single lithium batteries. It needs to start an alarm when the voltage of the lithium battery drops to 5.5V (Vbat=5.5V). The turn-on threshold voltage is 0.5V (Vbe=0.5V), then the sizes of the first resistor R1 and the second resistor R2 can be determined according to the formula Vbat=Vbe*(R1+R2)/R2.

The emitter of the second triode Q2 is connected to +5V power supply, and a general interface line GPI01 of the main control chip samples the level voltage of point A; when performing detection, GPI01 is initialized to the input state, when the lithium battery voltage is higher than the gate When the limit voltage is reached, the first triode Q1 is turned on, and then the second triode Q2 is turned on, and the light-emitting diode D lights up, indicating that the lithium battery power is normal at this time, and GPI01 detects a low level; when the lithium battery voltage is low When the voltage is at the threshold value, the first triode Q1 is cut off, then the second transistor Q2 is cut off, the light-emitting diode D is off, GPI01 detects a high level, and enters the alarm mode at this time, then, the main control chip sets GPI01 to In output mode, output high level, the first triode Q1 remains off, the light-emitting diode D remains off, and then delays T1 to make GPI01 output low level, then the second triode Q2 is turned on, and the light-emitting diode D Light up; delay T2 again, set GPI01 to input mode, re-detect, and so on. In this way, when the lithium battery voltage is lower than the threshold voltage, the light-emitting diode D presents a periodic flickering state of being off for T1 time and on for T2 time. The third resistor R3 and the fifth resistor R5 act as a current limiter, the fourth resistor R4 acts as a pull-up resistor, and the capacitor C acts as a filter.

The solution claimed by the utility model includes but is not limited to the above-mentioned embodiments. Those skilled in the art can easily modify the technical solution of the utility model according to the above description to achieve the same technical effect, which all belong to the protection scope of the utility model. .

Claims (2)

1. the lithium battery amount detecting device is characterized in that: comprise voltage-dividing detection circuit and alarm indication circuit, voltage-dividing detection circuit connection alarm indication circuit; Described voltage-dividing detection circuit comprises first resistance, second resistance, electric capacity and first triode, described first resistance connects the base stage of first triode, and respectively by the electric capacity and second resistance eutral grounding, electric capacity is connected the base stage of first triode, the grounded emitter of described first triode with second resistance; Described alarm indication circuit comprises the 3rd resistance, the 4th resistance, the 5th resistance, second triode and display lamp; The base stage of described second triode connects the collector of first triode by the 3rd resistance, and its emitter connects the collector of first triode by the 4th resistance, and its collector is by the 5th resistance and display lamp ground connection.

2. lithium battery amount detecting device as claimed in claim 1 is characterized in that: described display lamp is a light emitting diode.

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