CN201622303U - Anti-interference alternating current zero-crossing detection circuit - Google Patents
Anti-interference alternating current zero-crossing detection circuit Download PDFInfo
- Publication number
- CN201622303U CN201622303U CN2009203160721U CN200920316072U CN201622303U CN 201622303 U CN201622303 U CN 201622303U CN 2009203160721 U CN2009203160721 U CN 2009203160721U CN 200920316072 U CN200920316072 U CN 200920316072U CN 201622303 U CN201622303 U CN 201622303U
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- China
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- comparer
- detection circuit
- resistor
- crossing detection
- comparator
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Abstract
The utility model discloses an anti-interference alternating current zero-crossing detection circuit. A first resistor (RS6) and a second resistor (RS7) form a first series circuit which is connected to a negative end of a comparator (U3A) to provide an input circuit for signals, a third resistor (RS8) and a fourth resistor (RS9) form a second series circuit which is connected to a positive end of the comparator (U3A) to provide comparison voltage for the same, a feedback resistor (RS11) is connected between the positive end and an output end of the comparator (U3A), a pull-up resistor (RS10) is connected between the output end and a 5V power end of the comparator (U3A), and the output end of the comparator (U3A) is connected with an interruption port (eight pins) of a master control single chip microcomputer (U1). The anti-interference alternating current zero-crossing detection circuit adopts a hysteresis comparison circuit to stabilize output the edge of the zero-crossing detection circuit without shaking, thereby increasing phase modulation precision of a fan, and avoiding spurious triggering of a thyristor.
Description
Technical field
The utility model relates to forced-ventilated gas water heater, especially relates to a kind of jamproof ac zero-crossing detection circuit of forced-ventilated gas water heater.
Background technology
Forced-ventilated gas water heater is to utilize the blower fan of water heater inside to provide needed air for burning, and force to discharge waste gas outdoor, in the process that water heater uses, need regulate the rotating speed of blower fan according to the size of thermal load, blower fan generally is divided into dc brushless motor and AC induction motor, the control of general AC blower fan is to utilize ac zero-crossing detection circuit to detect zero crossing, conducting angle by machine controllable silicon, thereby realize the stepless time adjustment of blower fan, but because zero cross detection circuit output edge is shaken easily, can cause controllable silicon false triggering or phase modulation inaccurate, thereby make that the rotating speed of blower fan is inaccurate.
The utility model content
The purpose of this utility model provides a kind of jamproof ac zero-crossing detection circuit, can accurately detect ac zero-crossing point, guarantees the precision of phase modulation control.
In order to achieve the above object, the utility model adopts following technical scheme: a kind of jamproof ac zero-crossing detection circuit, the all-wave signal of 8V AC signal after by two rectifies, through comprising comparer, 6 zero cross detection circuits that resistance is formed, detect this zero cross signal by main control singlechip again, wherein first resistance and second resistance are formed first series circuit, be connected in the comparer negative terminal, for signal provides input circuit, the 3rd resistance and the 4th resistance are formed second series circuit, be connected in the comparer anode, for comparer provides comparative voltage, feedback resistance is connected between comparer anode and the output terminal, pull-up resistor is connected between comparator output terminal and the 5V power end, and comparator output terminal links to each other with the interruptive port of main control singlechip.
Described main control singlechip is a chip 7805, and described 5V power supply is the output end voltage of main control singlechip 7805, and described comparer is the unit of general comparator LM339.
The beneficial effects of the utility model are: what the utility model adopted is the hysteresis comparator circuit, therefore comparator circuit has had hysteretic characteristic, makes zero cross detection circuit output edge stable, can not shake, thereby improved blower fan phase modulation precision, avoided the controllable silicon false triggering.
Description of drawings
The utility model will illustrate by example and with reference to the mode of accompanying drawing, wherein:
Fig. 1 is a circuit diagram of the present utility model.
Embodiment
Disclosed all features in this instructions, or the step in disclosed all methods or the process except mutually exclusive feature and/or step, all can make up by any way.
Disclosed arbitrary feature in this instructions (comprising any accessory claim, summary and accompanying drawing) is unless special narration all can be replaced by other equivalences or the alternative features with similar purpose.That is, unless special narration, each feature is an example in a series of equivalences or the similar characteristics.
As shown in Figure 1, a kind of jamproof ac zero-crossing detection circuit, 8V AC signal (1 pin of transformer output terminal XS14,2 pin) by commutation diode (Dt9, Dt10) after the rectification, through comprising comparer U3A, 6 resistance (RS6, RS7, RS8, RS9, RS10, RS11) zero cross detection circuit of Zu Chenging detects this zero cross signal by main control singlechip U1 again, and carries out control corresponding, wherein the first resistance R S6 and the second resistance R S7 form first series circuit, be connected in comparer U3A negative terminal, for signal provides input circuit, the 3rd resistance R S8 and the 4th resistance R S9 form second series circuit, be connected in comparer U3A anode, U3A provides comparative voltage for comparer; Feedback resistance RS11 is connected between comparer U3A anode and the output terminal, and pull-up resistor RS10 is connected between comparer U3A output terminal and the 5V power end, and comparer U3A output terminal links to each other with the interruptive port (8 pin) of main control singlechip U1.Described main control singlechip U1 is a chip 7805, and described 5V power supply is the output end voltage of chip 7805, and described comparer is the unit of general comparator LM339.
In Fig. 1 circuit, the 5V power supply is connected to comparer U3A negative terminal after the first resistance R S6 and the second resistance R S7 form first series circuit dividing potential drop, for comparer provides DC reference voltage, the all-wave signal is connected to comparer U3A anode after the 3rd resistance R S8 and second series circuit dividing potential drop of the 4th resistance R S9 composition, for comparer provides comparative voltage, feedback resistance RS11 is connected between comparer U3A anode and the output terminal, therefore comparator circuit has had hysteretic characteristic, make the comparer output waveform can not shake because of the fluctuation of voltage, during circuit working, the zero crossing of each AC signal produces the negative edge waveform, with this waveform by the detected time of singlechip interruption mouth as basic point, control silicon controlled ON time, thus the rotating speed of control blower fan is realized the stepless time adjustment of blower fan.
The above only is preferred embodiment of the present utility model; not in order to restriction the utility model; all any modifications of within spirit of the present utility model and principle, being done, be equal to and replace and improvement etc., all should be included within the protection domain of the present utility model.
Claims (3)
1. jamproof ac zero-crossing detection circuit, it is characterized in that: first resistance (RS6) and second resistance (RS7) are formed first series circuit and are connected in comparer (U3A) negative terminal and provide input circuit for signal, and the 3rd resistance (RS8) and the 4th resistance (RS9) are formed second series circuit to be connected in comparer (U3A) anode is that comparer (U3A) provides comparative voltage; Feedback resistance (RS11) is connected between comparer (U3A) anode and the output terminal, pull-up resistor (RS10) is connected between comparer (U3A) output terminal and the 5V power end, and comparer (U3A) output terminal links to each other with the interruptive port (8 pin) of main control singlechip (U1).
2. jamproof ac zero-crossing detection circuit according to claim 1 is characterized in that: described main control singlechip (U1) is a chip 7805.
3. jamproof ac zero-crossing detection circuit according to claim 1 is characterized in that: described comparer (U3A) is the unit of general comparator LM339.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009203160721U CN201622303U (en) | 2009-11-27 | 2009-11-27 | Anti-interference alternating current zero-crossing detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009203160721U CN201622303U (en) | 2009-11-27 | 2009-11-27 | Anti-interference alternating current zero-crossing detection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201622303U true CN201622303U (en) | 2010-11-03 |
Family
ID=43025761
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009203160721U Expired - Fee Related CN201622303U (en) | 2009-11-27 | 2009-11-27 | Anti-interference alternating current zero-crossing detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201622303U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107957514A (en) * | 2016-10-14 | 2018-04-24 | 佛山市顺德区美的电热电器制造有限公司 | A kind of zero crossing detection device, method and electric appliance |
| CN112378440A (en) * | 2020-09-22 | 2021-02-19 | 武汉海尔热水器有限公司 | Gas water heater and water flow detection circuit thereof |
-
2009
- 2009-11-27 CN CN2009203160721U patent/CN201622303U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107957514A (en) * | 2016-10-14 | 2018-04-24 | 佛山市顺德区美的电热电器制造有限公司 | A kind of zero crossing detection device, method and electric appliance |
| CN112378440A (en) * | 2020-09-22 | 2021-02-19 | 武汉海尔热水器有限公司 | Gas water heater and water flow detection circuit thereof |
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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 | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20101103 Termination date: 20181127 |