CN201594815U - Capacitance type touch key circuit - Google Patents
Capacitance type touch key circuit Download PDFInfo
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- CN201594815U CN201594815U CN2010203001215U CN201020300121U CN201594815U CN 201594815 U CN201594815 U CN 201594815U CN 2010203001215 U CN2010203001215 U CN 2010203001215U CN 201020300121 U CN201020300121 U CN 201020300121U CN 201594815 U CN201594815 U CN 201594815U
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Abstract
The utility model discloses a capacitance type touch key circuit in domestic electric appliances. A good or poor key circuit is especially important when using same spring touch keys, and when a PWM port and an A/D port of a single chip microcomputer of the circuit barely distinguish signals clearly or have other interference signals, errors as failed keys or mistakenly key switching due to hypersensitiveness can be caused. The capacitance type touch key circuit is characterized in that a PWM port of an integrated circuit is connected with a front diode and a front resistor which are connected in parallel, the other end of the front diode and the other end of the front resistor are connected with one side of a spring leg, the other side of the spring leg is connected with a rear diode and a rear resistor which are connected in parallel, and the other end of the rear diode and the other end of the rear resistor are connected with the A/D port of the integrated circuit through a grounded capacitor and an RC filter circuit. The capacitance type touch key circuit is clear and certainly symmetrical, and cannot be easily mixed to cause errors in actual production.
Description
Technical field
The utility model relates to button circuit in the household electrical appliance, specifically a kind of capacitance type touch key circuit.
Background technology
The existing used controller of household electrical appliance is often used the touch-induction-type button, under the prerequisite of using identical spring touch key-press, the quality of the circuit particular importance that seems, when the PWM of single-chip microcomputer in circuit port and A/D port signal are differentiated clear inadequately or other interference signals are arranged, to cause button malfunctioning or too sensitivity cause misdeeds such as button Luan Tiao, above-mentioned situation is very common in actual product.
The utility model content
Technical problem to be solved in the utility model is to overcome the defective that above-mentioned prior art exists, and a kind of reliable and stable capacitance type touch key circuit is provided.
For this reason, the utility model adopts following technical scheme: a kind of capacitance type touch key circuit, comprise integrated circuit, the PWM port and the preceding diode that it is characterized in that integrated circuit link to each other with resistance before one, and preceding diode is in parallel with preceding resistance, and preceding diode links to each other with the other end of preceding resistance and a side of spring pin; The opposite side of spring pin connects a back diode and a back resistance, and the back diode is in parallel with back resistance, and the other end of back diode and back resistance links to each other with the A/D port of integrated circuit with a RC filter circuit by the electric capacity of a ground connection; Described forward and backward diode has identical electrical quantity, and forward and backward resistance has identical electrical quantity.Described integrated circuit is single-chip microcomputer, numeral or analog integrated circuit.
The A/D port can be read the high-low level and the concrete numerical value of PWM port clearly, thereby makes as long as the signal of PWM port has change a little, the processing that the utility model can be accurately and timely.
The utlity model has following beneficial effect:
1, circuit is simple, stable, reliable, and high efficiency;
2, available software is suitably adjusted the sensitivity of key circuit;
3, circuit is clear, has certain symmetry, is not easy to mix up in actual production, makes mistakes.
Below in conjunction with specification drawings and specific embodiments the utility model is further described.
Description of drawings
Fig. 1 is circuit theory diagrams of the present utility model.
The resistance of resistance R 1, R2 is 1M Ω among Fig. 1, and the resistance of R3 is 1K Ω, and the capacity of capacitor C 1 is that the capacity of 104pF, C2 is 102pF, and the model of diode D1, D2 is 1N4148.
Embodiment
Capacitance type touch key circuit as shown in Figure 1, the PWM port of integrated circuit links to each other with resistance R 1 with diode D1, and diode D1 and resistance R 1 parallel connection.Diode D1 links to each other with the other end of resistance R 1 and the side of spring pin K, the opposite side of spring pin K is connected with diode D2 and resistance R 2, diode D2 and resistance R 2 also adopt mode in parallel, and the other end of diode D2 and resistance R 2 links to each other with the A/D port of integrated circuit with the RC filter circuit by the capacitor C 1 of ground connection.Diode D1 has identical electrical quantity with D2, and resistance R 1 also has identical electrical quantity with R2.
The course of work of the present utility model is as follows: the square-wave signal of the PWM mouth output certain frequency of integrated circuit, and when being in the positive half cycle of signal, circuit charges to capacitor C 1 by R1, D2; When being in the negative half period of signal, discharge by R2, D1; Because the complete symmetry of circuit, therefore the time that discharges and recharges is identical; When the spring on the human body touch button, be equivalent to connect an equivalent electric capacity at spring pin K place, the original charging interval is prolonged, also just changed the current potential of capacitor C 1 end, the voltage of capacitor C 2 ends is changed, and the A/D port of integrated circuit judge according to detected change in voltage whether button was touched.
In actual applications, often not only one of the button that electronic product uses, this touch key-press circuit can carry out the expansion of number of keys easily, only need add one or more list 8 tunnels analogy switch integrated circuits, just can reach the purpose of expansion.
Claims (2)
1. a capacitance type touch key circuit comprises integrated circuit, it is characterized in that the PWM port of integrated circuit and a preceding diode link to each other with resistance before one, and preceding diode is in parallel with preceding resistance, and preceding diode links to each other with the other end of preceding resistance and a side of spring pin; The opposite side of spring pin connects a back diode and a back resistance, and the back diode is in parallel with back resistance, and the other end of back diode and back resistance links to each other with the A/D port of integrated circuit with a RC filter circuit by the electric capacity of a ground connection; Described forward and backward diode has identical electrical quantity, and forward and backward resistance has identical electrical quantity.
2. capacitance type touch key circuit according to claim 1 is characterized in that described integrated circuit is single-chip microcomputer, numeral or analog integrated circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010203001215U CN201594815U (en) | 2010-01-05 | 2010-01-05 | Capacitance type touch key circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010203001215U CN201594815U (en) | 2010-01-05 | 2010-01-05 | Capacitance type touch key circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201594815U true CN201594815U (en) | 2010-09-29 |
Family
ID=42776880
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010203001215U Expired - Fee Related CN201594815U (en) | 2010-01-05 | 2010-01-05 | Capacitance type touch key circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201594815U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102651646A (en) * | 2012-05-03 | 2012-08-29 | 东莞市精诚电能设备有限公司 | Capacitance type touch press key circuits |
| CN102998619A (en) * | 2012-11-28 | 2013-03-27 | 深圳和而泰智能控制股份有限公司 | Method, device and system for testing sensing buttons |
| CN104079283A (en) * | 2013-03-29 | 2014-10-01 | 北京谊安医疗***股份有限公司 | Capacitive touch key detection circuit |
-
2010
- 2010-01-05 CN CN2010203001215U patent/CN201594815U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102651646A (en) * | 2012-05-03 | 2012-08-29 | 东莞市精诚电能设备有限公司 | Capacitance type touch press key circuits |
| CN102998619A (en) * | 2012-11-28 | 2013-03-27 | 深圳和而泰智能控制股份有限公司 | Method, device and system for testing sensing buttons |
| CN102998619B (en) * | 2012-11-28 | 2015-07-15 | 深圳和而泰智能控制股份有限公司 | Method, device and system for testing sensing buttons |
| CN104079283A (en) * | 2013-03-29 | 2014-10-01 | 北京谊安医疗***股份有限公司 | Capacitive touch key detection circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100929 Termination date: 20150105 |
|
| EXPY | Termination of patent right or utility model |