The equipment and the Contact Type Ic Card holding circuit that have the Contact Type Ic Card slot
Technical field
The present invention relates to a kind of holding circuit, specifically relate to a kind of equipment and Contact Type Ic Card holding circuit that has the Contact Type Ic Card slot.
Background technology
Integrated circuit card (being IC-card) is a kind of mobile memory medium that after magnetic card, occurs, because it has convenient storage, level security is good, advantage such as long service life, the use that is easy to carry and being widely used.
The IC-card core is an IC chip, is to utilize modern advanced microelectric techniques, and large scale integrated chip is embedded among the slight plastic cards.According to the communication mode of IC-card and card reader, can IC-card be divided into two kinds of non-contact IC card and Contact Type Ic Cards.Non-contact IC card communicates through communication and card reader, and contactless IC card need directly not carry out physical connection with card reader during communication.Though noncontact can avoid between card and the card reader contact infringement because its reading speed is slow, and memory capacity is little, and security is not high, read-only not writing and make its usable range limited greatly.And its hard contact through card face of Contact Type Ic Card and card reader are carried out physical connection and are accomplished and communicate by letter and exchanges data, big owing to its memory capacity, firmly, can be mutual etc. advantage be widely used.Most popular now Contact Type Ic Card such as CF card, mmc card, SD card, MS card and XD card etc.Various electronic equipments such as mobile phone, digital camera, notebook computer etc. all are furnished with relevant interface.
But,, in hot plug process, cause the IC-card abnormal state to work because Contact Type Ic Card need carry out physics with card reader and contact.One of the most common situation be data line than the first contact of power lead card reader, the electric current that comes from card reader will directly flow on the IC-card from data port, causes IC-card can't normally reset (initialization), at this moment IC-card just is in abnormal state, can't operate as normal.Therefore need good holding circuit of design, prevent that Contact Type Ic Card is in ERST.
Summary of the invention
Technical matters to be solved by this invention is to provide a kind of Contact Type Ic Card holding circuit of excellence, can prevent that card is in abnormal state and can't works.
For achieving the above object, the present invention realizes through following approach:
A kind of Contact Type Ic Card holding circuit is provided, comprises: first delay circuit, second delay circuit, first switch and second switch, the input termination power of said first switch; Output terminal is used to connect the power end of IC-card; The output of control termination first delay circuit, the input end of said first delay circuit is used to connect the detection pin of card reader, and said second switch is a two-way switch; Its switch one end is used to connect the data terminal of said IC-card; The switch other end is used to connect the data bus of said card reader, the output of said second delay circuit of control termination of second switch, the output terminal of said first switch of input termination of said second delay circuit.
Wherein, said first delay circuit is composed in series by first electric capacity and first resistance, and an end of said first resistance is used to connect the detection pin of said card reader, an end of said first electric capacity of another termination, the said first electric capacity other end ground connection.
Wherein, described first switch is a FET, and its control end is connected with the said end that said first electric capacity connects first resistance.
Wherein, Described second delay circuit is composed in series by the 3rd electric capacity and second resistance; The output terminal of said first switch of one termination of said second resistance, an end of said the 3rd electric capacity of another termination and the control end of said second switch, the other end ground connection of said the 3rd electric capacity.
Wherein, said second switch is a bidirectional analog switch.
Wherein, between the output terminal of first switch and ground, be connected in series filter capacitor.
A kind of equipment that has the Contact Type Ic Card slot also is provided, comprises card reader and IC-card holding circuit, said card reader comprises the detection pin; Said IC-card holding circuit comprises first delay circuit, second delay circuit, first switch and second switch; The input termination power of said first switch, the power end of output termination IC-card, the output of control termination first delay circuit; The detection pin of the input termination card reader of said first delay circuit; Said second switch is a two-way switch, the data terminal of the said IC-card of its switch one termination, the data bus of the said card reader of another termination of switch; The output of said second delay circuit of control termination of second switch, the output terminal of said first switch of input termination of said second delay circuit.
Wherein, said first delay circuit is composed in series by first electric capacity and first resistance, the detection pin of the said card reader of a termination of said first resistance, an end of said first electric capacity of another termination, the said first electric capacity other end ground connection.
Wherein, described first switch is a FET, and its control end is connected with the said end that said first electric capacity connects first resistance.
Wherein, Described second delay circuit is composed in series by the 3rd electric capacity and second resistance; The output terminal of said first switch of one termination of said second resistance, an end of said the 3rd electric capacity of another termination and the control end of said second switch, the other end ground connection of said the 3rd electric capacity.
The invention has the advantages that: the present invention designs two groups of delay circuits and many group switches, and the power lead that makes card is prior to data line contact and conducting, to reach the purpose of protection card.Specifically be that the power supply of card is in low level when card when also not injecting card reader, the data bus that second switch makes card is ground connection all; Through first group of delay circuit, control first switch open behind the plug-in card, make the power supply of card be in high level after a period of time; Through second group of delay circuit, after the second switch conducting, the data bus of card is connected with the data bus of master control again, thereby keeps the stable communication of card.The present invention is simple in structure, has protected Contact Type Ic Card effectively, makes it avoid abnormal state, makes the IC-card operate as normal.
Description of drawings
Combine embodiment that the present invention is done further description with reference to the accompanying drawings.
Accompanying drawing 1 is a structured flowchart of the present invention.
Accompanying drawing 2 is structural representations of embodiments of the invention.
Embodiment
Below will the Contact Type Ic Card holding circuit structure according to preferred embodiment of the present invention be described with reference to accompanying drawing.Wherein among the embodiment in the label of element and the accompanying drawing 2 label consistent, and the element numbers in the accompanying drawing 2 has been represented the title of this class component.
Like accompanying drawing 1; Contact Type Ic Card holding circuit of the present invention comprises first delay circuit 1, second delay circuit 3, first switch 2 and second switch 4; The input termination power of said first switch 2, output terminal are used to connect the power end 202 of IC-card, the output terminal of control termination first delay circuit 1; The detection pin of the input termination card reader of said first delay circuit 1; Said second switch 4 is a two-way switch, and its switch one end is used to connect the data terminal 203 of said IC-card, the data bus 204 of the said card reader of another termination of switch; The output terminal of said second delay circuit 3 of control termination of switch, the output terminal of said first switch 2 of input termination of said second delay circuit 3.This circuit is applicable to the equipment that has Contact Type Ic Card, through the two-stage delay circuit, can effectively protect the safety and the normal communication of card.
The present invention relates to the equipment that has this Contact Type Ic Card holding circuit equally, comprises card reader (figure does not show) and IC-card holding circuit, and said card reader comprises the detection pin; Said IC-card holding circuit comprises first delay circuit 1, second delay circuit 3, first switch 2 and second switch 4; The input termination power of said first switch 2, the power end 202 of output termination IC-card, the output terminal of control termination first delay circuit 1; The detection pin of the input termination card reader of said first delay circuit 1; Said second switch 4 is a two-way switch, the data terminal 203 of the said IC-card of its switch one termination, the data bus 204 of the said card reader of another termination of switch; The output of said second delay circuit 3 of control termination of switch, the output terminal of said first switch 2 of input termination of said second delay circuit 3.
Practical implementation below in conjunction with 2 pairs of these inventions of accompanying drawing is described further.
Shown in accompanying drawing 1, comprise first resistance R, 1, the second resistance R 2 according to the Contact Type Ic Card holding circuit of preferred embodiment of the present invention; First capacitor C, 1, the second capacitor C, 2, the three capacitor C 3; The first switch Q1, and second switch, said second switch are bidirectional analog switches set S1.In the present embodiment, first resistance R 1 and first capacitor C, 1 common first delay circuit of forming, wherein an end of resistance first resistance R 1 is connected with the detection pin 201 of deck, another termination first capacitor C 1.The input termination external power supply of the first switch Q1, control end connects said first capacitor C, 1 one ends with first resistance R 1, first capacitor C, 1 other end ground connection.The output terminal of the first switch Q1 connects power end 202, the second capacitor C 2 other end ground connection of an end, second resistance R, 2 one ends and the card of second capacitor C 2 respectively.Second resistance R 2 and the 3rd capacitor C 3 common second delay circuits of forming, wherein second resistance R, 2 other ends are connected with second switch S1 control end with the 3rd capacitor C 3 one ends respectively, the 3rd capacitor C 3 other end ground connection.Two input/output terminals of said two-way second switch S1 are the data terminal 203 of Connection Cards and the data bus 204 of master control respectively.Wherein the first switch Q1 can use FET.
As stated; In Contact Type Ic Card holding circuit, when card inserts slot, through first delay circuit time-delay of forming by first resistance R 1 and first capacitor C 1 according to preferred embodiment of the present invention; The voltage of first capacitor C 1 slowly raises, and is elevated to and to a certain degree then controls the first switch Q1 conducting.After the first switch Q1 conducting, the power lead of card is switched to external power supply VCC.Outputing to second delay circuit of being made up of second resistance R 2 and the 3rd capacitor C 3 after the first switch Q1 conducting prolongs; The voltage of the 3rd capacitor C 3 slowly raises; Be elevated to and to a certain degree then control second switch S1 conducting; The data bus of card is connected on the data bus of master control, and card and main frame begin normal communication.And electric capacity second capacitor C 2 plays necessary filter action.
Through the two-stage delay circuit, the present invention has effectively protected the safety and the normal communication of card.