CN101465638A - Low power consumption solid relay - Google Patents

Abstract

The invention discloses a low-power solid state relay, which includes a switch circuit, control pins A, J, controlled pins G, H, an energy storage capacitor connected to the switch circuit, and first and second capacitors respectively connected to the energy storage capacitor. Charging circuit and discharging circuit; when the control pin A inputs a high level and the rising edge appears instantly, the first charging circuit fully charges the energy storage capacitor, the switch circuit is turned on, and the controlled pins G and H are turned on, so that the The relay is turned on; and when the control pin A inputs a low level and the falling edge appears, the discharge circuit discharges the power on the energy storage capacitor, and the controlled pin G and H are turned off, so that the solid state relay is turned off. It is realized that the relay only generates a certain power consumption when the control level changes, and has zero power consumption at other times, so the average power is extremely low.

Description

A low-power solid-state relay

【Technical field】

The invention relates to the technical field of electrical appliances and electronics, in particular to a low-power solid state relay.

【Background technique】

Solid state relay is a non-contact on-off electronic switch, which is a four-terminal active device. Two of the terminals are input control terminals, while the other two terminals are output controlled terminals. Adding a DC or pulse signal to the input terminal, the output terminal can change from the off state to the on state (blocking state when there is no signal), that is, when the voltage is applied between the control pins, the solid state relay is on, and when the When the voltage between the control pins is withdrawn, the solid state relay is turned off, thereby controlling a large load. Since the composition of the solid state relay is a non-contact switching element, it has reliable operation, long life, little interference to the outside world, compatibility with logic circuits, strong anti-interference ability, fast switching speed and convenient use compared with electromagnetic relays. A wide range of applications. Chinese Patent No. 200520084249.1 discloses a solid state relay, the principle of which is the same as that of conventional relays. However, these solid state relays all have a defect, that is, when the control pin continues to apply voltage, the control pin continues to absorb about 0.1W of power consumption. High, and its application in some circuits with low power consumption requirements is greatly limited.

【Content of invention】

In order to solve the above problems, the main purpose of the present invention is to provide a low-power solid-state relay with low power consumption, so that the current flowing into the control pin is only large at the moment of level change, and the current is zero at other times, so as to reduce the power consumption of the solid-state relay. average power.

To achieve the above object, the technical solution of the present invention is:

A low-power solid state relay, including a switch circuit, control pins A, J, controlled pins G, H, an energy storage capacitor connected to the switch circuit, and first and second charging circuits and the first and second charging circuits respectively connected to the energy storage capacitor Discharge circuit; when the control pin A inputs a high level and the rising edge appears instantly, the first charging circuit fully charges the energy storage capacitor, and the switch circuit is turned on, then the controlled pins G and H are turned on, making the relay turn on ; And when the control pin A inputs a low level, the moment the falling edge appears, the discharge circuit discharges the electricity on the energy storage capacitor, and the controlled pins G and H are turned off, so that the solid state relay is turned off.

Compared with the prior art, the low power consumption solid state relay of the present invention changes the control level from low to high, and charges the energy storage capacitor through the coupling capacitor and the optocoupler, so that the positive electrode of the energy storage capacitor remains at a high level for a long time, thereby maintaining solid state The relay is turned on, and the controlled alternating current charges the energy storage capacitor when it is turned on, and it is not charged when it is turned on, so as to maintain the logic level of the positive pole of the energy storage capacitor. The control level changes from high to low, and the energy storage capacitor is discharged through the coupling capacitor and the optocoupler, so that the positive pole of the energy storage capacitor is at a low level, thereby maintaining the solid state relay off. It is realized that the relay only generates a certain power consumption when the control level changes, and has zero power consumption at other times, so the average power is extremely low.

【Description of drawings】

Fig. 1 is a functional block diagram of the low power consumption solid state relay of the present invention.

Fig. 2 is a schematic circuit diagram of the low power consumption solid state relay of the present invention.

【Detailed ways】

Please refer to FIG. 1 , a low-power solid state relay of the present invention includes a switch circuit, an energy storage capacitor connected to the switch circuit, and first and second charging circuits and discharge circuits respectively connected to the energy storage capacitor. Among them, the A and J pins are the control pins, and the G and H pins are the controlled pins, which are connected to the alternating current and controlled whether there is continuity between the two. When the energy storage capacitor is charged and the switch circuit is turned on, the G and H pins are turned on; if the energy storage capacitor is fully charged, the G and H pins are turned off. When the A pin inputs a high level and the rising edge appears, the first charging circuit fully charges the energy storage capacitor, making the solid state relay conduct; when the A pin inputs a low level and the falling edge appears, the discharge circuit After the electricity on the energy capacitor is discharged, the solid state relay is turned off. The energy storage capacitor can only store the charge for one week when the charging and discharging circuit does not operate. The second charging circuit supplements the charge to the capacitor only when the energy storage capacitor has electricity (that is, the solid state relay is turned on); if the energy storage capacitor has no charge (that is, the solid state relay is turned off), it does not charge. The charging energy of the second charging circuit comes from the controlled alternating current of the G and H pins, and its function is to maintain the logic level of the positive pole of the energy storage capacitor.

Please refer to FIG. 2, the switch circuit includes a first field effect transistor Q1 connected to the energy storage capacitor C1, a third transistor Q3 connected to the field effect transistor Q1 through a second resistor R2, and a third transistor Q3 connected to the transistor Q3. The thyristor Q4, the bridge rectifier circuit and the controllable transistor Q5 connected with the bridge rectifier circuit. Wherein, the collector of the third triode Q3 is connected to the control electrode of the thyristor Q4, and the control electrode of the thyristor Q4 is also grounded together with the cathode of the thyristor Q4 and the emitter of the third triode Q3 through the ninth resistor R9; The collector of the transistor Q3 is connected to the bridge rectifier circuit through a fourth resistor R4 and the anode of the thyristor Q4.

The first charging circuit includes a first optocoupler M1 and a first diode D1. The optocoupler is connected to the energy storage capacitor C1 through the first diode D1. The second charging circuit includes a sixth transistor Q6 and a seventh field effect transistor Q7 connected between the base and the collector of the transistor. The sixth transistor Q6 is a PNP transistor, and its collector passes through the third Diode D3 is connected to energy storage capacitor C1. The discharge circuit includes a second optocoupler M2 and a second field effect transistor Q2. The second field effect transistor Q2 is connected to the energy storage capacitor C1 through the first resistor R1. The control pin A is respectively connected to the first optocoupler M1 of the first charging circuit and the second optocoupler M2 of the discharging circuit through the eighth resistor R8 and the coupling capacitor C2.

The first and second optocouplers M1 and M2 are photocell optocouplers, which contain LED light-emitting elements and photocell light-receiving elements. When the LED emits light, the photocell generates electric energy and outputs a high level; otherwise, the LED does not emit light, and outputs a low level. Input a high level from the control pin A, the moment the level changes from low to high, the level is coupled through the coupling capacitor C2, the LED inside the first optocoupler M1 emits light, and the energy storage capacitor C2 starts to charge, and the LED does not emit light when it is fully charged. During the time period of charging and emitting light, the photocell receives light and outputs a high level, which is charged to the energy storage capacitor C1 through the first diode D1, and the point F is high level. During the charging period of the coupling capacitor C2, the LED in the second optocoupler M2 is under back pressure and does not light up, the corresponding photocell outputs a low level, the second transistor Q2 is turned off, and the energy storage capacitor C1 is not discharged. If the energy storage capacitor C1 is not charged and discharged, point F can maintain a high level for a week. When the control pin A becomes low level, and the level changes from high to low instantly, the LED cathode inside the second optocoupler M2 gets negative pressure and emits light. At this time, the coupling capacitor C2 discharges, and the LED does not light up after the discharge. During the period of time when the photocell receives light and outputs a high level, the second field effect transistor Q2 is turned on from the drain to the source, the charge on the energy storage capacitor C1 is discharged through the first resistor R1, and point F is at a low level. During the time period when the coupling capacitor C2 is discharging, the LED in the first optocoupler M1 is under back pressure and does not light up, corresponding to the fact that the internal photocell does not charge the energy storage capacitor C1.

Point F is high level, the first field effect transistor Q1 is turned on, and the third triode Q3 is turned off. When the voltage of point B relative to point D rises to exceed U _T , the control pole of thyristor Q4 passes through the fourth resistor R4, the third transistor Q3 The divided voltage level of the nine resistors R9 makes the thyristor Q4 turn on, and the alternating current passes through the fifth resistor R5, the bridge rectifier circuit, the thyristor Q4, and returns to the bridge rectifier circuit to the sixth resistor R6; or passes through the sixth resistor R6, the bridge Type rectification circuit, thyristor Q4, return bridge type rectification circuit to fifth resistor R5. The voltage drop on the diode D2 and the thyristor Q4 of the bridge rectifier circuit is small, and the voltage of the control pole of the control transistor Q5 can be regarded as the result of the series voltage division of the fifth resistor R5 and the sixth resistor R6, so that the control pole of the control transistor Q5 gets a trigger pulse , the control tube Q5 is turned on, that is, the controlled pins G and H are turned on. When point F is low level, the first field effect transistor Q1 is cut off, the third triode Q3 is saturated and turned on, the control pole of the thyristor Q4 is always low level, the thyristor Q4 is turned off, and the control pole of the control transistor Q5 has no conduction pulse. The control tube Q5 is cut off, so that the points G and H of the control pins are turned off.

When the relay is turned on, the level at point F is high, the seventh field effect transistor Q7 is turned on, and thus the sixth triode Q6 is turned on, and the pulse at point B passes through the sixth triode Q6 and the eighth diode D8 to the energy storage Capacitor C1 is charged, and if the charging and discharging circuit does not operate, the energy storage capacitor C1 only lasts for one week, maintaining the high level of point F. When the solid state relay is turned off, due to the low level at point F, the seventh field effect transistor Q7 is turned off, so the sixth triode Q6 is turned off, point B will not charge the energy storage capacitor C1, and the level at point F will not be changed .

As long as the low-power solid state relay of the present invention is continuously turned on for no more than one week during the application process, or if it is turned on for more than one week but the no-load of the controlled pins G and H does not exceed one week, the input high-level solid relay is turned on, and the low-level solid relay is turned on. due. Since the coupling capacitor C2 plays the role of blocking DC, the current of the low-power solid state relay in this creation is large only at the moment when the control level changes (that is, from high to low or from low to high), and the current is 0 at other times, so the consumption The average power is very small.

The control level of the low-power solid relay of the present invention changes from low to high, and the energy storage capacitor is charged through the coupling capacitor and the photocoupler, so that the positive pole of the energy storage capacitor maintains a high level for a long time, thereby maintaining the conduction of the solid relay. The controlled alternating current charges the energy storage capacitor and stops charging to maintain the logic level of the positive electrode of the energy storage capacitor. The control level changes from high to low, and the energy storage capacitor is discharged through the coupling capacitor and the optocoupler, so that the positive pole of the energy storage capacitor is at a low level, thereby maintaining the solid state relay off. It is realized that the relay only generates a certain power consumption when the control level changes, and has zero power consumption at other times, so the average power is extremely low.

The preferred embodiments described above are only illustrative and illustrative of the invention, but are not limited to any specific form disclosed, as many modifications and variations are possible.

Claims (9)

1. A low-power solid state relay, comprising a switch circuit, control pins A, J, and controlled pins G, H, characterized in that: it also includes an energy storage capacitor connected to the switch circuit and connected to the energy storage capacitor respectively The first and second charging circuits and discharging circuits; when the control pin A inputs a high level and the rising edge appears, the first charging circuit fully charges the energy storage capacitor, and the switch circuit is turned on, and the controlled pin G, H When the control pin A inputs a low level and the falling edge appears, the discharge circuit discharges the power on the energy storage capacitor, and the controlled pins G and H are turned off, so that the solid state The relay is off. 2. The low-power solid-state relay as claimed in claim 1, characterized in that: the charge of the energy storage capacitor can only be stored for one week when the charging and discharging circuit does not operate; when the energy storage capacitor has electricity, the second The charging circuit replenishes the charge to the capacitor through the controlled alternating current from the controlled pins G and H. When the energy storage capacitor has no charge, it will not be charged. 3. The low power consumption solid state relay as claimed in claim 2, characterized in that: said switching circuit includes a first field effect transistor (Q1) connected to an energy storage capacitor (C1), and a second resistor (R2 ) a third transistor (Q3) connected to the field effect transistor (Q1), a thyristor (Q4) connected to the transistor (Q3), a bridge rectifier circuit, and a controllable transistor (Q5) connected to the bridge rectifier circuit ). 4. The low power consumption solid state relay as claimed in claim 3, characterized in that: the collector of the third triode (Q3) is connected to the control pole of the thyristor (Q4), and the control pole of the thyristor (Q4) is also passed through The cathode of the ninth resistor (R9) and the thyristor (Q4) and the emitter of the third transistor (Q3) are commonly grounded; the collector of the third transistor (Q3) is connected to the thyristor (Q3) through a fourth resistor (R4). The anodes of Q4) are commonly connected to the bridge rectifier circuit. 5. The low power consumption solid state relay as claimed in claim 4, characterized in that: the first charging circuit includes a first optocoupler (M1) and a first diode (D1), and the optocoupler passes through the first The diode (D1) is connected to the energy storage capacitor (C1). 6. The low power consumption solid state relay as claimed in claim 5, characterized in that: the second charging circuit includes a sixth triode (Q6) and is connected between the base and the collector of the triode (Q6). The seventh field effect transistor (Q7) and the sixth transistor (Q6) are PNP transistors, the collector of which is connected to the energy storage capacitor (C1) through the third diode (D3). 7. The low power consumption solid state relay as claimed in claim 6, characterized in that: said discharge circuit includes a second optocoupler (M2) and a second field effect transistor (Q2); said second field effect transistor ( Q2) is connected to the storage capacitor (C1) through a first resistor (R1). 8. The low power consumption solid state relay as claimed in claim 7, characterized in that: the control pin A is respectively connected to the first optocoupler ( M1) and the second optocoupler (M2) of the discharge circuit. 9. The low power consumption solid state relay according to claim 8, characterized in that: said first and second optocouplers (M1), (M2) are optocouplers of photocells, which contain LED light-emitting elements and photocell light-receiving elements ; When the LED emits light, the photoelectric cell generates electric energy and outputs a high level; otherwise, the LED does not emit light, and the output is a low level.

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