CN2865099Y

CN2865099Y - Breaking protection circuit

Info

Publication number: CN2865099Y
Application number: CN 200520121110
Authority: CN
Inventors: 李伟民; 程永生; 黄光伟; 胡弼
Original assignee: SHENZHEN SED COMMERCIAL MACHINE CO Ltd; SANGDA INDUSTRY Co Ltd SHENZHEN
Current assignee: SHENZHEN SED COMMERCIAL MACHINE CO Ltd; SANGDA INDUSTRY Co Ltd SHENZHEN
Priority date: 2005-12-30
Filing date: 2005-12-30
Publication date: 2007-01-31
Anticipated expiration: 2015-12-30

Abstract

The utility model relates to a power-off protection circuit, mainly comprising a power supply circuit, a voltage detecting circuit electrically connected to the power supply circuit, and a control IC connected to the output end of the voltage detecting circuit; wherein, the power-off protection circuit further comprises a capacitor charging/discharging circuit electrically connected to the power supply circuit, a DC-DC convertor electrically connected to the capacitor charging/discharging circuit, and a switching circuit arranged between the capacitor charging/discharging circuit and the DC-DC convertor, controlled by the output signals from the control IC. The utility model utilizes a capacitor charging/discharging circuit and a DC-DC convertor to substitute the traditional rechargeable battery or storage battery as the backup power source, and is characterized by long service life and free of false voltage, etc.; therefore, the power-off protection circuit provided in the utility model has the advantages such as reliable performance and high interference resistance capability, etc. In addition, all the components and ICs involved in the power-off protection circuit provided in the utility model are commonly seen components; therefore, the utility model is low in cost.

Description

Power-off protecting circuit

[technical field]

The utility model relates to a kind of application circuit, refers in particular to a kind of power-off protecting circuit.

[background technology]

Tax-control cash register is to combine the management of the tax authority and taxpayer's the demand of use two aspects and the product that develops.It has every function that the field of employment needs on the one hand, is convenient to user centric business, use and service management, can satisfy again simultaneously the tax authority to the monitoring of managing the user, make out an invoice and the requirement of tax collection and administration aspect.Clearly stipulate " tax-control cash register is under the situation of sudden power; should guarantee the water control memory; data is correct in invoice memory and the tax-controlling card; complete " in the national new tax-control cash register standard, also should guarantee simultaneously to be in tax control cash receiving function under the print state complete print current invoice information, for this reason, the tax-control cash register that manufacturer produced includes a stand-by power supply, to guarantee tax-control cash register energy operate as normal a period of time under the sudden power situation, the stand-by power supply of each manufacturer's use is generally rechargeable battery or storage battery at present, but rechargeable battery or storage battery existence have certain empty voltage, shortcomings such as useful life is short, thus can't really guarantee stability and the security of storage data that tax-control cash register is worked under off-position.

[utility model content]

Technical problem to be solved in the utility model is: a kind of power-off protecting circuit is provided, has that cost is low, characteristics such as dependable performance, antijamming capability are strong.

For solving the problems of the technologies described above; the technical scheme that the utility model adopted is: a kind of power-off protecting circuit; mainly comprise power circuit, voltage detecting circuit, the control IC that is connected with described voltage detecting circuit output with the power circuit electrical connection; wherein, this power-off protecting circuit also comprise capacitor charge and discharge circuit, the DC-DC transducer that is electrically connected with described capacitor charge and discharge circuit that is electrically connected with power circuit and be located at described capacitor charge and discharge circuit and the DC-DC transducer between the switching circuit that opens and closes by control IC output signal control.

The beneficial effects of the utility model are: the utility model adopts capacitor charge and discharge circuit to substitute traditional rechargeable battery or storage battery power supply in support in conjunction with the DC-DC transducer; have characteristics such as long service life, no empty voltage, thereby make the utility model power-off protecting circuit have the strong advantage of dependable performance, antijamming capability.Simultaneously, components and parts that the utility model power-off protecting circuit is related or IC are daily device commonly used, thereby make the utility model also have lower cost, and then help producing in enormous quantities.

[description of drawings]

Fig. 1 is the functional-block diagram of the utility model power-off protecting circuit.

Fig. 2 is the circuit diagram of the utility model power-off protecting circuit.

[embodiment]

The utility model will be further described below in conjunction with accompanying drawing.

As shown in Figure 1; a kind of power-off protecting circuit of the utility model, voltage detecting circuit, the control IC that is connected with described voltage detecting circuit output, the capacitor charge and discharge circuit that is electrically connected with power circuit, the DC-DC transducer that is electrically connected with described capacitor charge and discharge circuit that mainly comprise power circuit, is electrically connected with power circuit and be located at described capacitor charge and discharge circuit and the DC-DC transducer between control the switching circuit of keying by the control IC output signal.

This power circuit also is electrically connected with the DC-DC transducer.

This capacitor charge and discharge circuit comprises a farad capacitor.

As shown in Figure 2, this switching circuit comprises the first transistor Q1, transistor seconds Q2 and the 3rd transistor Q3, the emitter of this first transistor Q1 links to each other with farad capacitor C0, collector electrode links to each other with DC-DC transducer U1, base stage links to each other with the collector electrode of transistor seconds Q2, is connected with first resistance R 4 between the emitter of described the first transistor Q1 and base stage; The grounded emitter of this transistor seconds Q2, base stage links to each other with the collector electrode of voltage source Vcc and the 3rd transistor Q3, is connected with second resistance R 6 between the emitter of described transistor seconds Q2 and base stage; The grounded emitter of the 3rd transistor Q3, base stage links to each other with control IC U1.

Wherein this first transistor Q1 is a PNP transistor, and this transistor seconds Q2, the 3rd transistor Q3 are NPN transistor.

When outage, voltage detecting circuit output sensing signal is to control IC U1, control IC U1 response and output low level control signal to the base stage of the 3rd transistor Q3, the 3rd transistor Q3 by, transistor seconds Q2, the first transistor Q1 conducting, the initial discharge of farad capacitor C0, and by DC-DC transducer output direct current; When the power circuit operate as normal, control IC U1 exports high-level control signal, the 3rd transistor Q3 conducting, transistor seconds Q2, the first transistor Q1 by, farad capacitor C0 is in charged state.

Claims

1, a kind of power-off protecting circuit; the voltage detecting circuit that mainly comprises power circuit, is electrically connected with power circuit, with the control IC that described voltage detecting circuit output is connected, it is characterized in that: this power-off protecting circuit also comprise capacitor charge and discharge circuit, the DC-DC transducer that is electrically connected with described capacitor charge and discharge circuit that is electrically connected with power circuit and be located at described capacitor charge and discharge circuit and the DC-DC transducer between control the switching circuit of keying by the control IC output signal.

2, power-off protecting circuit as claimed in claim 1 is characterized in that: this power circuit also is electrically connected with the DC-DC transducer.

3, power-off protecting circuit as claimed in claim 1 is characterized in that: this capacitor charge and discharge circuit comprises a farad capacitor.

4, power-off protecting circuit as claimed in claim 1, it is characterized in that: this switching circuit comprises the first transistor (Q1), transistor seconds (Q2) and the 3rd transistor (Q3), the emitter of this first transistor (Q1) links to each other with capacitor charge and discharge circuit, collector electrode links to each other with the DC-DC transducer, base stage links to each other with the collector electrode of transistor seconds (Q2), is connected with first resistance (R4) between the emitter of described the first transistor (Q1) and base stage; The grounded emitter of this transistor seconds (Q2), base stage links to each other with the collector electrode of voltage source (Vcc) and the 3rd transistor (Q3), is connected with second resistance (R6) between the emitter of described transistor seconds (Q2) and base stage; The grounded emitter of the 3rd transistor (Q3), base stage links to each other with control IC.

5, power-off protecting circuit as claimed in claim 4 is characterized in that: this first transistor (Q1) is a PNP transistor, and this transistor seconds (Q2), the 3rd transistor (Q3) are NPN transistor.