CN202145576U - Lithium battery charger turning off system - Google Patents

Abstract

The utility model provides a lithium battery charger turning off system used for turning off the charger when the lithium battery is fully charged and automatically turning off the charger when the charger is not connected with the lithium battery. The system can determine the charging state of the battery by detecting battery charging signals of the charger, and then a turning off system controls on and off of the charger output. The system can realize the function of protection by identifying the charging state of the charger and automatically turning off the charger, and can substantially increase safety of the charger and prolong effective usage service life of the lithium battery.

Description

A kind of lithium battery charger turn-offs system

Technical field

The utility model relates to the battery charger field, particularly a kind of lithium battery charger protective circuit.

Background technology

Producing the quick increase of device in recent years along with portable electronic, also is increasing to the demand of lithium battery, and the demand to lithium battery charger also is increasing simultaneously.At present, most lithium battery all carries the over-charge protective function on the market, and therefore lithium battery charger is not with the over-charge protective function mostly; But because the lithium battery product is various on the market, over-charge protective overcharges the function quality and differs, and makes the fail safe of lithium battery and useful life to be guaranteed.Also have the senior relatively battery charger of part can have the over-charge protective function, but generally all be to integrate with monolithic processor controlled mode and other defencive function.

The utility model content

The purpose of the utility model is to carry the situation that over-charge protective function quality differs through providing a kind of charger overcharge protection circuit to solve the lithium battery product.

The utility model is that a kind of lithium battery charger turn-offs system, comprises delay circuit 101 and breaking circuit 102;

Described delay circuit 101, when being used for charger and powering in a period of time no matter whether charger connects battery and also can hold normal output;

Described breaking circuit 102 is used to receive back charger battery-charge signal when charging signals demonstration battery is full of or does not charge, and turn-offs charger output.

Preferred embodiment as the utility model patent; Described delay circuit 101 comprises charge-discharge circuit and reference circuit, and described charge-discharge circuit comprises: first electric capacity, second electric capacity, first resistance, second resistance, the 3rd resistance, the 4th resistance, first triode, second triode, first comparator;

Described first electric capacity and said second capacitances in series; Its non-series connection end connects first power end and the first power supply ground respectively; Its series connection end connects described first transistor base and the described first comparator end of oppisite phase through described first resistance; To first power end, its emitter passes through described the 3rd resistance to the first power supply ground to described its collector electrode of first triode through described second resistance;

Described first comparator output terminal connects said second transistor base through said the 4th resistance, and described its collector electrode of second triode links to each other with the said first comparator end of oppisite phase, and its emitter connects the first power supply ground.

As another preferred embodiment of the utility model patent, described breaking circuit 102 comprises: first photoelectrical coupler, first diode, second diode, the 3rd triode, the 4th triode, the 5th resistance, the 8th resistance, the 9th resistance, first relay;

Described first photoelectrical coupler; Its light-emitting diode is anodal to arrive described first comparator output terminal through described the 5th resistance; Its light-emitting diode negative pole connects the first power supply ground, and its collector electrode connects described battery-charge signal, and its emitter connects first diode cathode; Described first diode cathode arrives described the 3rd transistor base through described the 8th resistance; Described the 3rd transistor collector was connected described the 9th resistance to described first relay control end positive pole and said second diode cathode with described the 4th transistor base; Arrive the second source end again; Described the 4th transistor collector links to each other with the described first relay control end negative pole with described second diode cathode, and described the 3rd transistor emitter and described the 4th transistor emitter connect second source ground.

The utility model beneficial effect is through detecting the charger battery-charge signal, does not charge or battery turn-offs charger output after being full of electricity at charger, thereby has prevented that effectively lithium cell charging from overcharging.

Description of drawings

Accompanying drawing 1 is the theory diagram of the utility model;

Accompanying drawing 2 is the circuit theory diagrams of the utility model.

Embodiment

Come the utility model is further specified below in conjunction with Fig. 1,2;

The reference circuit of being made up of delay circuit among Fig. 2 resistance R 6, resistance R 7 through R6 and R7 series connection, meets the first power end VCC1 and the first power supply ground GND1 respectively again, at R6 and reference voltage of R7 series connection place generation to the first comparator U1A in-phase end.

The charge-discharge circuit of forming delay circuit among Fig. 2 by first capacitor C 1, second capacitor C 2, first resistance R 1, second resistance R 2, the 3rd resistance R 3, the 4th resistance R 4, the first triode Q1, the second triode Q2, the first comparator U1A; VCC1 charges to C2 through C1 when powering on; Make C1 and C2 series connection place obtain a high level; This high level makes the Q1 conducting through R1 to the Q1 base stage, and the Q1 of conducting and R2, R3 form a dividing potential drop relation, makes the high level of Q1 emitter voltage a little less than C1 and C2 series connection place; Therefore high level passes through R1; The base stage of Q1 and emitter, R3 form a discharge process slowly to GND1, also make the voltage of Q1 base stage obtain a process that slowly descends simultaneously, when the Q1 base voltage drops to when being lower than the U1A in-phase end; U1A output output high level arrives the Q2 base stage through R4; Make the Q2 conducting, the voltage with the Q1 base stage is pulled to 0V rapidly then, U1A output recurrent fluctuations between high level and low level when having prevented like this that the Q1 base stage is discharged to reference voltage (being U1A in-phase end voltage) critical point; Finish to this delay circuit.

Between the delay circuit time delay, the light-emitting diode of the first photoelectrical coupler PC1 is in off state always, so the collector electrode of PC1 and emitter also be in off state always, makes battery-charge signal to pass through, and causes relay to be in conducting state always;

When time-delay finishes; The conducting of PC1 light-emitting diode; PC1 collector electrode and emitter conducting, (the desirable power supply of battery-charge signal refers to modulating signal to battery-charge signal, when charger is in non-charged state; Non-charging indicator light is lighted, and therefrom obtains a high level as the non-charged state signal of battery) arrive the 8th resistance R 8 through PC1; When battery-charge signal is high level (being non-charged state); High level causes the Q3 conducting through R8; Then making the 4th triode Q4 base voltage be pulled to low level turn-offs Q4; Therefore first relay K 1 is turn-offed, and the charger output voltage can't arrive relay OUT through K1 to relay IN place, so the output of charger no-voltage; Otherwise, when battery-charge signal is low level (being that charger is a charged state), the K1 conducting, charger is normally exported.

The utility model provides a kind of shutoff system that is used for lithium battery charger, is applicable to various lithium battery chargers, particularly need automatically shut down the occasion of charger output to the relatively stricter occasion of protection lithium battery life requirements with when the non-charged state.

Above-described the utility model execution mode does not constitute the qualification to the utility model protection range.The modification of being done within any spirit and principle at the utility model, be equal to replacement and improvement etc., all should be included within the claim protection range of the utility model.

Claims (4)

1. a lithium battery charger turn-offs system, it is characterized in that: comprise delay circuit (101) and breaking circuit (102);

Described delay circuit (101), when being used for charger and powering in a period of time no matter whether charger connects battery and also can hold normal output;

Described breaking circuit (102) is used to receive the charger battery-charge signal, when charger does not charge or charging signals when showing that battery is full of, turn-offs charger output.

2. lithium battery charger as claimed in claim 1 turn-offs system, and it is characterized in that: described delay circuit (101) comprises charge-discharge circuit and reference circuit.

3. lithium battery charger as claimed in claim 2 turn-offs system, and it is characterized in that: described charge-discharge circuit comprises: first electric capacity, second electric capacity, first resistance, second resistance, the 3rd resistance, the 4th resistance, first triode, second triode, first comparator;

Described first electric capacity and said second capacitances in series; Its non-series connection end connects first power end and the first power supply ground respectively; Its series connection end connects described first transistor base and the described first comparator end of oppisite phase through described first resistance; To first power end, its emitter passes through described the 3rd resistance to the first power supply ground to described its collector electrode of first triode through described second resistance;

Described first comparator output terminal connects said second transistor base through said the 4th resistance, and described its collector electrode of second triode links to each other with the said first comparator end of oppisite phase, and its emitter connects the first power supply ground.

4. lithium battery charger as claimed in claim 1 turn-offs system, and it is characterized in that: described breaking circuit (102) comprising: first photoelectrical coupler, first diode, second diode, the 3rd triode, the 4th triode, the 5th resistance, the 8th resistance, the 9th resistance, first relay;

Described first photoelectrical coupler; Its light-emitting diode is anodal to arrive described first comparator output terminal through described the 5th resistance; Its light-emitting diode negative pole connects the first power supply ground, and its collector electrode connects described battery-charge signal, and its emitter connects first diode cathode; Described first diode cathode arrives described the 3rd transistor base through described the 8th resistance; Described the 3rd transistor collector was connected described the 9th resistance to described first relay control end positive pole and said second diode cathode with described the 4th transistor base; Arrive the second source end again; Described the 4th transistor collector links to each other with the described first relay control end negative pole with described second diode cathode, and described the 3rd transistor emitter and described the 4th transistor emitter connect second source ground.

Images