CN101738530A - Electrolytic current detection circuit of variable-frequency washing machine - Google Patents
Electrolytic current detection circuit of variable-frequency washing machine Download PDFInfo
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- CN101738530A CN101738530A CN200910185826A CN200910185826A CN101738530A CN 101738530 A CN101738530 A CN 101738530A CN 200910185826 A CN200910185826 A CN 200910185826A CN 200910185826 A CN200910185826 A CN 200910185826A CN 101738530 A CN101738530 A CN 101738530A
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- comparer
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Abstract
The invention relates to an electrolytic current detection circuit of a variable-frequency washing machine, which comprises a sampling resistor, wherein the sampling resistor is used for collecting an electrolytic current, the sampling resistor is connected with the in-phase end of a comparator, the out-phase end of the comparator is connected with a constant current source, and the output end of the comparator is connected with the input end of an MCU (Main Control Unit) through an optoelectronic coupler. In the invention, a fixed sawtooth wave is generated through the constant current source, a voltage signal after I-V conversion and operation amplification is compared with the constant current source to generate a PWM (Pulse-Width Modulation) signal, and finally the change of pulse width is detected through the MCU to judge the change of the current. The invention successfully replaces the traditional connecting mode of I-V conversion-operation amplification-MCU and completely separates the electrolytic ground from the MCU ground, thereby radically preventing the danger of personal electric shocks.
Description
Technical field
The present invention relates to the washing machine technical field, particularly a kind of electrolytic current detection circuit of variable-frequency washing machine.
Technical background
Variable-frequency washing machine is a kind of the new washing machine of just developing in recent years, the brine electrolysis washing machine is the washing machine of another type, its principle of work is to use electrolytic zinc-coated steel sheet that water is carried out electrolysis, produce chlorate anions and hypochlorite, replaced activating agent originally in order to wash, be a kind of laundry mode of environment protection health, the function of variable-frequency washing machine and brine electrolysis washing machine combined, thereby be born a kind of novel frequency conversion electrolysis washing machine.Also produced simultaneously following problem: 1, because the specific (special) requirements of the integrated power module that frequency conversion must be used, its power supply must be adopted the structure of a kind of non-isolated Switching Power Supply (SMPS), and the demand of detection power blocks current causes master chip and power model altogether, so the reality high pressure that superposeed on the master chip; 2, electrolytic circuit also has the demand that detects electric current, if the ground of electrolytic circuit is also shared with master chip, then inner core that links to each other with electrolytic zinc-coated steel sheet and water are all charged, and in a single day the people touches the danger that electric shock is just arranged; 3, mostly existing current detecting mode is the conversion by I-V, the electric current variation is changed into change in voltage detect by operational amplifier then, and their ground must be public.For these reasons, must design a kind of traditional I-V conversion-amplifier amplification-master chip of current detection circuit replacement of novelty.
Summary of the invention
Technical matters to be solved by this invention provides and a kind ofly can avoid getting an electric shock, the electrolytic current detection circuit of variable-frequency washing machine of high safety.
A kind of electrolytic current detection circuit of variable-frequency washing machine, comprise the sample resistance that is used to gather Faradaic current, sample resistance connects the in-phase end of comparer, the anti-phase termination constant current source charging and discharging circuit of comparer, and the output terminal of comparer connects the input end of main control chip MCU by photoelectrical coupler.
Described comparer is the first comparer IC1, the Faradaic current of sample resistance output is converted into voltage signal through I/V variation, computing amplification, this voltage signal is as the homophase input of the first comparer IC1, the end of the output terminal connecting resistance R1 of the first comparer IC1, the other end of resistance R 1 meets main control chip MCU by photoelectrical coupler, the end of oppisite phase of the anti-phase termination second comparer IC2 of the first comparer IC1, the homophase termination constant pressure source U of the described second comparer IC2
0
The base stage of the output termination triode Q1 of the described second comparer IC2, the collector of triode Q1 is connected with resistance R 2, another termination triode Q2 base stage of resistance R 2, the grounded emitter of triode Q2, resistance R 3 is connected across between the base stage and emitter of triode Q2, the collector of triode Q2 connects the end of oppisite phase of the second comparer IC2, electrochemical capacitor C1, capacitor C 2 parallel connections, and the two terminates on the end of oppisite phase of the second comparer IC2, the other end of the two is connected on the emitter of triode Q2, the in-phase end of the second comparer IC2 passes through resistance R 4 ground connection, and meets constant pressure source U by resistance R 5
0Diode D1 is connected across between the output terminal and in-phase end of the first comparer IC1, the emitter of triode Q3, Q4 links to each other, and this tie point is connected between constant pressure source U0 and the resistance R 5, and collector and the base stage of triode Q4 are joined, and the base stage of triode Q4, Q3 is joined and formed common point, this common point connects the emitter of triode Q5, the base stage of triode Q5 links to each other with the collector of triode Q3, and by resistance R 6 ground connection, the collector of the collector connecting transistor Q2 of triode Q5.
Also comprise and be used to produce constant pressure source U
0Power circuit 3, power circuit 3 comprises triode Q6, its collector connects the 30V direct current, its base stage connects the negative electrode of TL431 chip, and a termination 30V direct current of resistance R 7 is connected across on the reference edge of triode Q6 and TL431 chip after resistance R 7 and resistance R 8 series connection, the reference edge of TL431 chip is by resistance R 9 ground connection, the plus earth of TL431 chip, electrochemical capacitor C3 is connected across between the negative electrode and anode of TL431 chip, and the TL431 chip provides constant pressure source U to the second comparer IC2
0
The sampling voltage of described sample resistance output is 0～1.5V.
Described resistance R 4, R5, R8, R9 are metalfilmresistor.
The reference voltage of described TL431 chip is 2.5V, constant pressure source U
0Voltage be 5.6V.
The present invention compared with prior art, the present invention produces fixing sawtooth wave by constant current source, to amplify the sawtooth wave that later voltage signal and constant current source produce through I-V conversion, amplifier compares, produce PWM (width modulation) signal, final by master chip MCU detection pulse width variations, to judge the variation of electric current.Success of the present invention substituted traditional I-V conversion---amplifier amplification---connected mode of master chip MCU, the ground of electrolysis and the ground of master chip MCU are separated fully, fundamentally stopped the danger that the people gets an electric shock.
Description of drawings
Fig. 1 is a circuit diagram of the present invention;
Fig. 2 is that the B point is the voltage oscillogram of the end of oppisite phase of first comparer among the present invention;
Fig. 3 is the in-phase end of first comparer among the present invention, the voltage oscillogram of end of oppisite phase input;
Fig. 4 is the voltage oscillogram of first comparator output terminal output among the present invention.
Embodiment
A kind of electrolytic current detection circuit of variable-frequency washing machine, comprise the sample resistance that is used to gather Faradaic current, the sampling voltage of described sample resistance output is 0～1.5V, sample resistance connects the in-phase end of comparer, the anti-phase termination constant current source charging and discharging circuit of comparer, the output terminal of comparer connects the input end of main control chip MCU 1 by photoelectrical coupler 2, as shown in Figure 1, for ease of explanation, the spy gets node A～E point and is described as follows: the A point is that the Faradaic current of sample resistance output of 0.1 Ω is through I-V, the voltage change signal that amplifier obtains after amplifying, 0～15A variation range is 0～1.5V.
Described comparer is the first comparer IC1, the Faradaic current of sample resistance output is converted into voltage signal through I/V variation, computing amplification, this voltage signal is as the homophase input of the first comparer IC1, the end of the output terminal connecting resistance R1 of the first comparer IC1, the other end of resistance R 1 meets main control chip MCU 1 by photoelectrical coupler 2, the end of oppisite phase of the anti-phase termination second comparer IC2 of the first comparer IC1, the homophase termination constant pressure source U of the described second comparer IC2
0
The base stage of the output termination triode Q1 of the described second comparer IC2, the collector of triode Q1 is connected with resistance R 2, another termination triode Q2 base stage of resistance R 2, the grounded emitter of triode Q2, resistance R 3 is connected across between the base stage and emitter of triode Q2, the collector of triode Q2 connects the end of oppisite phase of the second comparer IC2, electrochemical capacitor C1, capacitor C 2 parallel connections, and the two terminates on the end of oppisite phase of the second comparer IC2, the other end of the two is connected on the emitter of triode Q2, the in-phase end of the second comparer IC2 passes through resistance R 4 ground connection, and meets constant pressure source U by resistance R 5
0, described resistance R 4, R5 are metalfilmresistor, and diode D1 is connected across between the output terminal and in-phase end of the first comparer IC1, and the emitter of triode Q3, Q4 links to each other, and this tie point is connected on constant pressure source U
0And between the resistance R 5, collector and the base stage of triode Q4 are joined, the base stage of triode Q4, Q3 is joined and is formed common point, this common point connects the emitter of triode Q5, the base stage of triode Q5 links to each other with the collector of triode Q3, and by resistance R 6 ground connection, the collector of the collector connecting transistor Q2 of triode Q5.
The present invention also comprises and is used to produce constant pressure source U
0Power circuit 3, power circuit 3 comprises triode Q6, its collector connects the 30V direct current, the 30V of this 30V and electrolytic zinc-coated steel sheet power supply takes from one the tunnel, its base stage connects the negative electrode of TL431 chip, one termination 30V direct current of resistance R 7, be connected across on the reference edge of triode Q6 and TL431 chip after resistance R 7 and resistance R 8 series connection, the reference edge of TL431 chip is by resistance R 9 ground connection, described resistance R 8, R9 is metalfilmresistor, the plus earth of TL431 chip, electrochemical capacitor C3 is connected across between the negative electrode and anode of TL431 chip, and the TL431 chip provides constant pressure source U to the second comparer IC2
0
The reference voltage of described TL431 chip is 2.5V, constant pressure source U
0Voltage be 5.6V.Power circuit is the form of emitter follower, and the base stage of triode Q6 is the output terminal V of TL431 chip
2, output terminal V
2As constant pressure source U
0, V
2By obtaining after the resistance R 7 of TL431 chip three ends, R8, the R9 dividing potential drop, computing formula is V
2=V
REF* (1+R8/R9)=2.5* (1+12.4/10)=5.6V.The reason of using the TL431 chip is because V
2Be used for producing constant current source, need to stablize with consistent, its divider resistance must use 1% error with interior metalfilmresistor.V
1=V
2-0.6=5V, V
1Be used for supplying with comparer and photoelectrical coupler 2 power supplies.
Because collector and the base stage of Q4 are connected together, can equivalence be a diode in fact for emitter.V
C-V
D=0.6V is under this fixing forward voltage, by the collector current I of triode Q3
CIt is steady state value.The I that this is constant
CFlowing through R6, also is a steady state value V at the E point voltage
E, because V
2, (V
C-V
D), V
EBe steady state value, so V
2-(V
C-V
D)-V
EBe steady state value equally, the collector current by triode Q5 also will be constant current.This constant current is to the charging of the shunt capacitance of electrochemical capacitor C1, capacitor C 2, got by the formula of electric capacity:
This shows that it is the oblique line of slope with (1/C) I that the waveform that B is ordered is one, reach the threshold value U of the second comparer IC2 when the charging of B point
MaxThe time, second comparer IC2 upset, output 0 makes triode Q1 saturation conduction, then triode Q2 saturation conduction thereupon, because it is collector and the equivalent resistance between the emitter of triode Q2 are very little, very fast that tele-release is intact by triode Q2 by the shunt capacitance that electrochemical capacitor C1, capacitor C 2 are formed.The output V thereby the second comparer IC2 overturns once more
1, triode Q2, Q1 end, and the charging of shunt capacitance is begun once more, and waveform enters next circulation, and the waveform that B is ordered is as shown in Figure 2.
For the first comparer IC1, the input of its end of oppisite phase be sawtooth wave shown in B point, its positive terminal input be voltage V through the reflection Faradaic current size variation of I-V, amplifier amplification
A, as shown in Figure 3.Finally, the first comparer IC1 output pulse width changes, the constant waveform of frequency, as shown in Figure 4.The pulse signal that this pulsewidth constantly changes is detected by main control chip MCU 1 by the isolation of photoelectrical coupler 2, in order to judge the electric current of electrolysis, and the isolation of process photoelectrical coupler 2, the ground of the ground of electrolysis and main control chip MCU 1 has been spaced, and has stopped the danger that the people gets an electric shock.
Claims (7)
1. electrolytic current detection circuit of variable-frequency washing machine, it is characterized in that: comprise the sample resistance that is used to gather Faradaic current, sample resistance connects the in-phase end of comparer, the anti-phase termination constant current source charging and discharging circuit of comparer, the output terminal of comparer connects the input end of main control chip MCU (1) by photoelectrical coupler (2).
2. electrolytic current detection circuit of variable-frequency washing machine according to claim 1, it is characterized in that: described comparer is the first comparer IC1, the Faradaic current of sample resistance output changes through I/V, the computing amplification is converted into voltage signal, this voltage signal is as the homophase input of the first comparer IC1, the end of the output terminal connecting resistance R1 of the first comparer IC1, the other end of resistance R 1 meets main control chip MCU (1) by photoelectrical coupler (2), the end of oppisite phase of the anti-phase termination second comparer IC2 of the first comparer IC1, the homophase termination constant pressure source U of the described second comparer IC2
0
3. electrolytic current detection circuit of variable-frequency washing machine according to claim 2, it is characterized in that: the base stage of the output termination triode Q1 of the described second comparer IC2, the collector of triode Q1 is connected with resistance R 2, another termination triode Q2 base stage of resistance R 2, the grounded emitter of triode Q2, resistance R 3 is connected across between the base stage and emitter of triode Q2, the collector of triode Q2 connects the end of oppisite phase of the second comparer IC2, electrochemical capacitor C1, capacitor C 2 parallel connections, and the two terminates on the end of oppisite phase of the second comparer IC2, the other end of the two is connected on the emitter of triode Q2, the in-phase end of the second comparer IC2 passes through resistance R 4 ground connection, and meets constant pressure source U by resistance R 5
0Diode D1 is connected across between the output terminal and in-phase end of the second comparer IC2, the emitter of triode Q3, Q4 links to each other, and this tie point is connected between constant pressure source U0 and the resistance R 5, and collector and the base stage of triode Q4 are joined, and the base stage of triode Q4, Q3 is joined and formed common point, this common point connects the emitter of triode Q5, the base stage of triode Q5 links to each other with the collector of triode Q3, and by resistance R 6 ground connection, the collector of the collector connecting transistor Q2 of triode Q5.
4. electrolytic current detection circuit of variable-frequency washing machine according to claim 2 is characterized in that: also comprise being used to produce constant pressure source U
0Power circuit (3), power circuit (3) comprises triode Q6, its collector connects the 30V direct current, its base stage connects the negative electrode of TL431 chip, and a termination 30V direct current of resistance R 7 is connected across on the reference edge of triode Q6 and TL431 chip after resistance R 7 and resistance R 8 series connection, the reference edge of TL431 chip is by resistance R 9 ground connection, the plus earth of TL431 chip, electrochemical capacitor C3 is connected across between the negative electrode and anode of TL431 chip, and the TL431 chip provides constant pressure source U to the second comparer IC2
0
5. electrolytic current detection circuit of variable-frequency washing machine according to claim 1 and 2 is characterized in that: the sampling voltage of described sample resistance output is 0～1.5V.
6. according to claim 3 or 4 described electrolytic current detection circuit of variable-frequency washing machine, it is characterized in that: described resistance R 4, R5, R8, R9 are metalfilmresistor.
7. electrolytic current detection circuit of variable-frequency washing machine according to claim 4 is characterized in that: the reference voltage of described TL431 chip is 2.5V, constant pressure source U
0Voltage be 5.6V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009101858269A CN101738530B (en) | 2009-12-04 | 2009-12-04 | Electrolytic current detection circuit of variable-frequency washing machine |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009101858269A CN101738530B (en) | 2009-12-04 | 2009-12-04 | Electrolytic current detection circuit of variable-frequency washing machine |
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| Publication Number | Publication Date |
|---|---|
| CN101738530A true CN101738530A (en) | 2010-06-16 |
| CN101738530B CN101738530B (en) | 2011-12-28 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103323763A (en) * | 2013-06-24 | 2013-09-25 | 北京大学 | Degradation circuit for measuring threshold voltage and saturation drain current |
| CN104281186A (en) * | 2013-07-13 | 2015-01-14 | 廖馗任 | Intelligent type electrolysis control circuit |
| CN104506172A (en) * | 2014-11-26 | 2015-04-08 | 四川长虹欣锐科技有限公司 | 4-20mA current loop control PWM (Pulse Width Modulation) output circuit |
-
2009
- 2009-12-04 CN CN2009101858269A patent/CN101738530B/en active Active
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103323763A (en) * | 2013-06-24 | 2013-09-25 | 北京大学 | Degradation circuit for measuring threshold voltage and saturation drain current |
| CN103323763B (en) * | 2013-06-24 | 2015-10-14 | 北京大学 | A kind of measurement threshold voltage and drain saturation current degenerative circuit |
| CN104281186A (en) * | 2013-07-13 | 2015-01-14 | 廖馗任 | Intelligent type electrolysis control circuit |
| CN104281186B (en) * | 2013-07-13 | 2016-07-27 | 廖馗任 | A kind of intelligent electrolysis control circuit |
| CN104506172A (en) * | 2014-11-26 | 2015-04-08 | 四川长虹欣锐科技有限公司 | 4-20mA current loop control PWM (Pulse Width Modulation) output circuit |
| CN104506172B (en) * | 2014-11-26 | 2017-03-15 | 四川长虹欣锐科技有限公司 | A kind of 4 20mA current loop control PWM output circuits |
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| Publication number | Publication date |
|---|---|
| CN101738530B (en) | 2011-12-28 |
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Owner name: WHIRLPOOL (CHINA) CO., LTD. Free format text: FORMER NAME: HEFEI RONGSHIDA SANYO ELECTRIC CO., LTD. |
|
| CP01 | Change in the name or title of a patent holder |
Address after: 230088 No. 96 science Avenue, hi tech Zone, Anhui, Hefei Patentee after: Whirlpool (China) Limited by Share Ltd Address before: 230088 No. 96 science Avenue, hi tech Zone, Anhui, Hefei Patentee before: Hefei Rongshida Sanyo Electric Co., Ltd. |