CN202903970U - Button detection circuit for electric energy meter - Google Patents
Button detection circuit for electric energy meter Download PDFInfo
- Publication number
- CN202903970U CN202903970U CN 201220638513 CN201220638513U CN202903970U CN 202903970 U CN202903970 U CN 202903970U CN 201220638513 CN201220638513 CN 201220638513 CN 201220638513 U CN201220638513 U CN 201220638513U CN 202903970 U CN202903970 U CN 202903970U
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- China
- Prior art keywords
- pull
- resistor
- button
- button detection
- electric energy
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Abstract
Disclosed is a button detection circuit for an electric energy meter. The button detection circuit comprises a pull-up resistor, a button, a capacitor, and a pull-down resistor, wherein a power supply is serially connected with the button via the pull-up resistor and then is serially connected with the pull-down resistor and then is grounded; the power supply is grounded after being serially connected with the capacitor via the pull-up resistor; and one end of the capacitor, which is connected with the pull-up resistor, is connected with a button detection signal terminal. The button detection effective signals output by the button detection signal terminal are high level, so the appeared low level interference signals are the ineffective level signals to the output, thereby being capable of avoiding the influence of interference upon the effective output of the circuit, ensuring that the circuit does not generate misoperation, and substantially improving the reliability of the button detection.
Description
Technical field
The utility model relates to a kind of testing circuit, particularly a kind of key press detecting circuit for electric energy meter.
Background technology
At present, existing key press detecting circuit for electric energy meter comprises pull-up resistor R1, button K1 and filter capacitor C1, button K1 is connected to behind the power supply DVBB directly ground connection by pull-up resistor R1, the an end series filtering capacitor C 1 rear ground connection that pull-up resistor R1 does not link to each other with power supply, the end that filter capacitor C1 links to each other with pull-up resistor R1 links to each other with button detection signal end KeyDet.In the electric energy meter performance test, some electromagnetic interference (EMI) can affect the action validity of this button.The reliability of button is one of electric energy meter test item, and the reliability that how to improve the button detection is the problem that the electric energy meter design must be considered.
The utility model content
The purpose of this utility model provides a kind of key press detecting circuit that is used for electric energy meter of high reliability.
This key press detecting circuit for electric energy meter that the utility model provides, comprise pull-up resistor, button, filter capacitor and pull down resistor, button links to each other with power supply by pull-up resistor, by ground connection behind the pull down resistor, power supply is by ground connection behind the pull-up resistor series filtering electric capacity again, and the end that filter capacitor links to each other with pull-up resistor links to each other with button detection signal end.
It is high level that the button of described button detection signal end output detects useful signal.
It is high level that button of the present utility model detects useful signal, the low level undesired signal that occurs is the inactive level signal to it, thereby can avoid interference the effectively impact of output of circuit, guarantee that circuit can not produce misoperation, greatly improve the reliability that button detects.
Description of drawings
Fig. 1 is circuit diagram of the present utility model.
Fig. 2 is the circuit diagram of prior art.
Embodiment
As shown in Figure 1, the utility model comprises pull-up resistor R1, button K1, filter capacitor C1 and pull down resistor R2, button K1 is connected to power supply DVBB by pull-up resistor R1, the ground connection behind the pull down resistor R2 of connecting again, the end that filter capacitor C1 links to each other with pull-up resistor R1 links to each other with button detection signal end KeyDet.
When button K1 was failure to actuate, button detection signal end KeyDet exported high level; When button K1 pressed, button detection signal end KeyDet also exported high level.
Filter capacitor C1 is the passage in electromagnetic interference environment medium-high frequency undesired signal.In performance test, because large tracts of land is applied copper, the high-frequency electromagnetic undesired signal often is added on the signal wire by filter capacitor C1 over the ground, and low level undesired signal will occur on the signal wire this moment.If it is low level (as shown in Figure 2) that button detects useful signal, then this undesired signal can trigger an event, causes system's misoperation.And the utility model circuit is high level owing to its button detects useful signal, and the low level undesired signal that occurs in the electromagnetic interference (EMI) experiment is inactive level, thereby guarantees can not produce misoperation.For guaranteeing the validity of signal, the value of pull-up resistor R1 and pull down resistor R2 can be selected according to the concrete condition of rear and circuit (for example late-class circuit is the CMOS level, or Transistor-Transistor Logic level) in this circuit.
Claims (2)
1. key press detecting circuit that is used for electric energy meter, comprise pull-up resistor (R1), button (K1), filter capacitor (C1), it is characterized in that, also comprise pull down resistor (R2), button (K1) links to each other with power supply (DVBB) by pull-up resistor (R1), again by ground connection behind the pull down resistor (R2), power supply (DVBB) is by ground connection behind pull-up resistor (R1) the series filtering electric capacity (C1), and the end that filter capacitor (C1) links to each other with pull-up resistor (R1) links to each other with button detection signal end (KeyDet).
2. the key press detecting circuit for electric energy meter according to claim 1 is characterized in that, it is high level that the button of described button detection signal end (KeyDet) output detects useful signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220638513 CN202903970U (en) | 2012-11-28 | 2012-11-28 | Button detection circuit for electric energy meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220638513 CN202903970U (en) | 2012-11-28 | 2012-11-28 | Button detection circuit for electric energy meter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202903970U true CN202903970U (en) | 2013-04-24 |
Family
ID=48124624
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220638513 Expired - Lifetime CN202903970U (en) | 2012-11-28 | 2012-11-28 | Button detection circuit for electric energy meter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202903970U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107786209A (en) * | 2016-08-31 | 2018-03-09 | 厦门雅迅网络股份有限公司 | A kind of key press detecting circuit and method |
| CN108227940A (en) * | 2017-12-12 | 2018-06-29 | 天津津航计算技术研究所 | A kind of ultralow radiation keyboard |
-
2012
- 2012-11-28 CN CN 201220638513 patent/CN202903970U/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107786209A (en) * | 2016-08-31 | 2018-03-09 | 厦门雅迅网络股份有限公司 | A kind of key press detecting circuit and method |
| CN108227940A (en) * | 2017-12-12 | 2018-06-29 | 天津津航计算技术研究所 | A kind of ultralow radiation keyboard |
| CN108227940B (en) * | 2017-12-12 | 2021-04-09 | 天津津航计算技术研究所 | Ultra-low radiation keyboard |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130424 |
|
| CX01 | Expiry of patent term |