CN104079012A - Charging indication circuit, charging circuit and electronic equipment - Google Patents

Abstract

The invention discloses a charging indication circuit, which is used to be connected between a charging power source and a charging load, and includes two binary state changing units, each of which is charged when the charging current of the charging load is greater than or less than a set value. There are two different states when the current threshold is set; when the charging current of the charging load is greater than or equal to the set current threshold, the combination of states presented by the two binary state change units is used to indicate the full state of the charging load ; When the charging current of the charging load is less than the set current threshold, the combination of states presented by the two binary state change units is used to indicate the charging state of the charging load. Also disclosed are a charging circuit applying the charging indicating circuit and an electronic device. The above charging indicating circuit, charging circuit and electronic equipment can indicate the charging state and the full state of the battery, and are easy to use.

Description

Charging indicating circuit, charging circuit and electronic equipment

technical field

The invention relates to charging technology, in particular to a charging indicating circuit, a charging circuit and an electronic device.

Background technique

Chargers are widely used in various fields, especially in the field of life, they are widely used in common electrical appliances such as mobile phones and cameras. The charger is a static converter device that uses power electronic semiconductor devices to convert alternating current with constant voltage and frequency into direct current. The charger has a wide range of application prospects in the occasions where the battery is used as a working power source or a backup power source.

Chargers can be divided into many types according to charging objects, such as lead-acid battery chargers, nickel-cadmium battery chargers, nickel-metal hydride battery chargers, and lithium-ion battery chargers. According to the use occasion, it can be divided into ordinary chargers, car chargers, etc.

Chargers are basically composed of a stable power supply plus necessary constant current, voltage limiting, time limiting and other control circuits. When designing a charger, it is necessary to consider many aspects such as anti-backflow, anti-reverse connection, anti-short circuit, anti-overvoltage and anti-overcurrent.

Due to many designs in terms of charging safety, some chargers currently do not have a mechanism to indicate whether the battery is fully charged when charging the battery. Generally, there is no need to worry about overcharging, and the battery will be fully charged after charging for a sufficient time. But using this kind of charger can only roughly estimate whether the battery is fully charged through the charging time, so it is more inconvenient to use.

Some chargers provide full charge indication, but do so with only one indicator light, such as the light is off when charging and on when fully charged, or vice versa. If the light is broken, you will get wrong indications.

Contents of the invention

Based on this, it is necessary to provide a charging indication circuit capable of indicating the charging state.

In addition, a charging circuit is also provided.

Finally, an electronic device is also provided.

A charging indicating circuit, used to be connected between a charging power source and a charging load, comprising a first binary state changing unit and a second binary state changing unit; the charging current of the charging load of the first binary state changing unit It is in the first state when it is greater than or equal to the set current threshold, and it is in the second state when the charging current of the charging load is less than the set current threshold; the second binary state change unit is in the charging state of the charging load When the current is greater than or equal to the set current threshold, it is in the third state, and when the charging current of the charging load is less than the set current threshold, it is in the fourth state; when the charging current of the charging load is greater than or equal to the set When the current threshold is set, the combination of states presented by the first binary state change unit and the second binary state change unit is used to indicate the full state of the charging load; when the charging current of the charging load is less than the set current threshold The combination of states presented by the first binary state change unit and the second binary state change unit is used to indicate the charging state of the charging load.

In one of the embodiments, the first binary state change unit and the second binary state change unit are connected in series or in parallel.

In one embodiment, the first binary state changing unit and the second binary state changing unit are connected in parallel, connected in series with the first resistor and connected to both ends of the input charging power supply.

In one of the embodiments, the first binary state changing unit includes a second resistor connected in series with a first indicator light, and the first state of the first binary state changing unit corresponds to the extinguishing of the first indicator light , the second state corresponds to the lighting of the first indicator light.

In one of the embodiments, the second binary state change unit includes a third resistor, a switch tube, and a second indicator light; the positive pole of the charging power supply is connected to the input terminal of the switch tube, and is connected to the switch tube through the third resistor. The control terminal of the switching tube is connected, and the output terminal of the switch tube is connected to the second indicator light; the third state of the second binary state change unit corresponds to the lighting of the second indicator light, and the fourth state corresponds to the lighting of the second indicator light. The second indicator light goes off.

In one embodiment, the first indicator light is a green LED light, the second indicator light is a red LED light, and the switch tube is a PNP transistor.

In one of the embodiments, it further includes a first capacitor connected to both ends of the input charging power source.

In one of the embodiments, it further includes a Schottky diode connected to the positive line of the charging power supply.

A charging circuit, comprising: a voltage conversion module, used to convert an external power supply into a charging power supply that can be directly loaded on a charging load; and the above-mentioned charging indication circuit; the charging indication circuit is connected between the voltage conversion module and the charging between loads.

An electronic device, comprising: a charging interface, used to connect to an external charger that provides charging power; a battery slot, used to accommodate a battery, with positive and negative contacts in contact with the battery; and the above-mentioned charging indication circuit, connected to the Between the charging interface and the positive and negative contacts of the battery slot.

The above charging indicating circuit, charging circuit and electronic equipment can respectively indicate the charging state and the full state of the charging load through the state combination of the first binary state changing unit and the second binary state changing unit, which is convenient to use.

Description of drawings

FIG. 1 is a block diagram of a charging indicating circuit of an embodiment;

Fig. 2 is a schematic diagram of the charging indication circuit of the embodiment shown in Fig. 1;

Fig. 3 is a block diagram of a charging circuit of an embodiment;

FIG. 4 is a schematic diagram of the charging circuit of the embodiment shown in FIG. 3 .

Detailed ways

As shown in FIG. 1 , it is a block diagram of a charging indication circuit of an embodiment. The charging indication circuit 10 is used to be connected between a charging power source and a charging load 20 . The charging indication circuit 10 includes two binary state changing units, namely a first binary state changing unit 102 and a second binary state changing unit 104 . Each binary state change unit 102, 104 respectively exhibits two different states when the charging current of the charging load 20 is greater than or less than a set current threshold.

Specifically, the first binary state change unit 102 is in the first state when the charging current of the charging load is greater than or equal to the set current threshold, and is in the first state when the charging current of the charging load is less than the set current threshold. second state.

The second binary state change unit 104 is in the third state when the charging current of the charging load is greater than or equal to the set current threshold, and is in the fourth state when the charging current of the charging load is smaller than the set current threshold.

Therefore, when the charging current of the charging load 20 is greater than or equal to the preset current threshold, the first binary state changing unit 102 is in the first state, and the second binary state changing unit 104 is in the third state, and the two binary states The change units 102, 104 are in a certain combined state, which is used to indicate that the battery is fully charged. Similarly, when the charging current of the charging load 20 is less than the preset current threshold, the first binary state changing unit 102 is in the second state, the second binary state changing unit 104 is in the fourth state, and the two binary states change The cells 102, 104 are in another certain combined state, which is used to indicate that the battery is not yet fully charged.

That is, when the charging current of the charging load 20 is greater than or equal to the set current threshold, the combination of states presented by the two binary state change units 102, 104 is used to indicate the full state of the charging load 20; The charging current of the load 20 is less than the set current threshold, and the combination of states presented by the two binary state changing units 102 and 104 is used to indicate the charging state of the charging load 20 .

In this way, the problem that a single indicator light is damaged and a wrong prompt can be avoided.

The first binary state changing unit 102 and the second binary state changing unit 104 can be connected in series or in parallel in a specific circuit. When connected in series with each other, the same current flows through the two, so the first binary state change unit 102 and the second binary state change unit 104 can adopt the same circuit structure, but take different element parameters, so as to make different changes to the same current. the response to.

Specifically, in this embodiment, as shown in FIG. 2 , the charging indication circuit 10 includes a first binary state changing unit 102 and a second binary state changing unit 104 connected in parallel. In addition, the first binary state change unit 102 and the second binary state change unit 104 are connected in parallel, connected in series with the first resistor R1 and connected to both ends of the input charging power supply.

The first binary state changing unit 102 includes a second resistor R2 and a first indicator light D1 connected in series. The resistance of the second resistor R2 is larger than that of the first indicator light D1, and can obtain a larger voltage. By adjusting the resistance ratio of the second resistor R2 and the first indicator light D1, the first indicator light D1 can be turned on or off near the charging current threshold. Generally, when the charging current exceeds the threshold, the first indicator light D1 is off, and when it is less than the threshold, the first indicator light D1 is on. In this embodiment, the first indicator light D1 is a green LED light.

The second binary state change unit 104 includes a third resistor R3, a switch tube Q1 and a second indicator light D2. The anode of the charging power source is connected to the input terminal of the switch tube Q1, and is connected to the control terminal of the switch tube Q1 through the third resistor R3, and the output terminal of the switch tube Q1 is connected to the second indicator light D2. One end of the resistor R3 connected to the switch tube Q1 is used as the positive pole output to the charging load. In this embodiment, the second indicator light D2 is a red LED light. The switch tube Q1 is a PNP transistor, the emitter of which is used as an input terminal, the base is used as a control terminal, and the collector is used as an output terminal.

It can be understood that, in other embodiments, the colors of the first indicator light D1 and the second indicator light D2 may be exchanged, or identified by other colors. The switch tube Q1 may use other devices capable of realizing the switch control function.

Further, in the charging indication circuit 10 of this embodiment, it further includes a first capacitor C1 connected to both ends of the input charging power source. The first capacitor C1 is used for filtering.

Further, in the charging indication circuit 10 of this embodiment, a Schottky diode connected to the positive line of the charging power supply is also included. In the embodiment shown in FIG. 1 , two Schottky diodes connected in parallel are included. Two Schottky diodes can increase the current that can be handled.

The working principle of the above circuit is explained below.

When the charging power supply is charging the load and the load current is greater than the charging current threshold, the first indicator light D1 turns from off to on, and the second indicator light D2 turns from on to off. When the load current is less than the charging current threshold, the first indicator light D1 turns from on to off, and the second indicator light D2 turns from off to on.

The details are as follows: when the load current is greater than the charging current threshold, since the transistor Q1 has a sufficiently large base current, the transistor Q1 is turned on, and the second indicator light D2 is on. At the same time, the resistance value of the second resistor R2 is larger than the resistance value of the first indicator light D1, so the voltage obtained is also large, and the voltage obtained by the first indicator light D1 becomes smaller, which is not enough to make the first indicator light D1 light up.

When the load current is less than the charging current threshold, since the base current of the transistor Q1 is very small, which is smaller than the conduction current of the transistor Q1, the transistor Q1 is cut off, and the second indicator light D2 is off. At the same time, although the resistance value of the second resistor R2 is large, because the current of the load becomes smaller, the voltage shared by the second resistor R2 is also correspondingly smaller, and the voltage of the first indicator light D1 exceeds the voltage required for lighting. Bright.

As shown in FIG. 3 , it is a block diagram of a charging circuit of an embodiment. The charging circuit includes a voltage conversion module 30 and the charging indication circuit 10 provided in the above-mentioned embodiments. The voltage conversion module 30 is used to convert the external power source into a charging power source that can be directly loaded on the charging load 20 . The charging indication circuit 20 is connected between the voltage conversion module 30 and the charging load 20 .

As shown in FIG. 4 , the voltage conversion module 30 includes a rectification and filtering unit 310 and a voltage adjustment unit 320 . The rectifying and filtering unit 310 rectifies and filters the input AC power and then inputs it to the voltage adjusting unit 320 . The voltage adjustment unit 320 performs step-down processing on the rectified and filtered voltage and adjusts it to a charging voltage and outputs it to the charging load 20 .

The rectification and filtering unit 310 includes a rectification bridge and an electrolytic capacitor. The input end of the rectification bridge is used to connect to an AC power source, and perform full-wave rectification on the AC power. The electrolytic capacitor is connected to the output terminal of the rectifier bridge for filtering processing.

The voltage adjustment unit 320 includes a switching power supply chip, a transformer and required peripheral devices. The specific required devices and connections are shown in Figure 4. The power terminal of the switching power supply chip is connected to the positive voltage output of the rectification and filtering unit 310 through a resistor, and the pulse control terminal is connected to the positive voltage output of the rectification and filtering unit 310 through a resistor, a diode, and a parallel circuit of a resistor and a capacitor, and the pulse control terminal is simultaneously Connect the negative terminal of the transformer input. The positive pole of the input terminal of the transformer is connected to the positive pole of the voltage output by the rectification and filtering unit 310 . Among them, the switching power supply chip adjusts the voltage input to the transformer through pulse width modulation to keep it stable, and the transformer outputs the high voltage through step-down processing.

The voltage conversion module 30 also includes a feedback unit 330 connected to the output terminal. The feedback signal of the feedback unit 330 is sent to the switching power supply chip. The feedback terminal of the switching power chip is connected to the feedback unit 330 .

The present invention also provides an electronic device, which includes a charging interface for connecting an external charger providing charging power and a battery slot for accommodating a battery. The battery well has positive and negative contacts that contact the battery.

The charging indication circuit provided in the above embodiments can be connected between the charging interface and the positive and negative contacts of the battery slot, so as to provide a charging indication for the battery of the electronic equipment as a part of the electronic equipment.

The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (10)

1. A charging indication circuit for connecting between a charging power source and a charging load, comprising a first binary state change unit and a second binary state change unit; The first binary state change unit is in the first state when the charging current of the charging load is greater than or equal to the set current threshold, and is in the second state when the charging current of the charging load is smaller than the set current threshold ; The second binary state change unit is in the third state when the charging current of the charging load is greater than or equal to the set current threshold, and is in the fourth state when the charging current of the charging load is smaller than the set current threshold ; When the charging current of the charging load is greater than or equal to the set current threshold, the combination of states presented by the first binary state change unit and the second binary state change unit is used to indicate the full state of the charging load; When the charging current of the load is less than the set current threshold, the combination of states presented by the first binary state changing unit and the second binary state changing unit is used to indicate the charging state of the charging load. 2. The charging indication circuit according to claim 1, wherein the first binary state changing unit and the second binary state changing unit are connected in series or in parallel. 3. The charging indication circuit according to claim 1, wherein the first binary state change unit and the second binary state change unit are connected in parallel, connected in series with the first resistor and connected to both ends of the input charging power supply . 4. The charging indication circuit according to claim 3, wherein the first binary state change unit includes a second resistor and a first indicator light connected in series, and the first binary state change unit of the first The state corresponds to turning off the first indicator light, and the second state corresponds to turning on the first indicator light. 5. The charging indication circuit according to claim 4, wherein the second binary state change unit comprises a third resistor, a switch tube and a second indicator light; the positive pole of the charging power supply and the input of the switch tube terminal, and connected to the control terminal of the switch tube through the third resistor, and the output terminal of the switch tube is connected to the second indicator light; the third state of the second binary state change unit corresponds to the second indicator light is turned on, and the fourth state corresponds to the extinguishment of the second indicator light. 6. The charging indicating circuit according to claim 5, wherein the first indicator light is a green LED light, the second indicator light is a red LED light, and the switching tube is a PNP transistor. 7. The charging indication circuit according to claim 3, further comprising a first capacitor connected to both ends of the input charging power source. 8. The charging indication circuit according to claim 3, further comprising a Schottky diode connected to the positive line of the charging power supply. 9. A charging circuit, characterized in that it comprises: a voltage conversion module for converting an external power source into a charging power source that can be directly loaded on a charging load; and The charging indication circuit according to any one of claims 1-8; The charging indication circuit is connected between the voltage conversion module and the charging load. 10. An electronic device comprising: Charging interface, used to connect to an external charger that provides charging power; a battery well for receiving a battery having positive and negative contacts for contacting the battery; and The charging indicating circuit according to any one of claims 1 to 8, connected between the charging interface and the positive and negative contacts of the battery slot.