Relay low-power-consumption control circuit and method

Abstract

The invention discloses a relay low-power-consumption control circuit and method, and relates to the technical field of power electronics, the relay low-power-consumption control circuit comprises a divider resistor and a relay K1, a first end of the divider resistor is connected with a power supply, a second end of the divider resistor is connected with a coil first end of the relay K1, a coil second end of the relay K1 is grounded, and two ends of the divider resistor are connected with a first control circuit in parallel. A second control circuit is connected in series between the divider resistor and the first end of the coil of the relay K1, the first control circuit is used for controlling whether the two ends of the divider resistor are short-circuited, and the second control circuit is used for controlling whether the relay K1 is connected to the power supply loop. The first control circuit and the second control circuit are used for controlling the two ends of the relay coil to be pull-in voltage, maintaining voltage or disconnection with a power supply, the maintaining voltage is provided for the relay in a resistance voltage dividing mode after the relay is pulled in, heating and energy waste of the relay coil are reduced, the service life of the relay is prolonged, and cost is reduced. And the power consumption of the whole circuit is also reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to a relay low-power consumption control circuit and method. Background Art

[0002] The control end of the electromagnetic relay is controlled by the pull-in voltage. When there is a pull-in voltage at the control end of the relay coil, the relay will operate. After the relay is pulled in, it is generally still powered by this pull-in voltage. According to the characteristics of the relay, the maintenance voltage after the relay is pulled in is lower than the pull-in voltage. Therefore, the maintenance voltage can be used to power the relay. Since the pull-in voltage is always applied to both ends of the relay coil, it will cause the coil to heat up and waste energy, further affecting the service life of the relay and the power consumption of the overall circuit. Summary of the Invention

[0003] The purpose of the present invention is to provide a low-power control circuit and method for a relay, which is used to solve the problem in the prior art that after the relay is energized, the energizing voltage is still used to supply power, resulting in heating of the relay coil, energy waste, shortening the relay life, and increasing the power consumption of the overall circuit.

[0004] The present invention solves the above problems through the following technical solutions:

[0005] A low-power control circuit for a relay includes a voltage-dividing resistor and a relay K1. A first end of the voltage-dividing resistor is connected to a power supply, a second end of the voltage-dividing resistor is connected to a first end of a coil of the relay K1, and a second end of the coil of the relay K1 is grounded. A first control circuit is connected in parallel across the voltage-dividing resistor, and a second control circuit is connected in series between the voltage-dividing resistor and the first end of the coil of the relay K1. The first control circuit is used to control whether to short-circuit the two ends of the voltage-dividing resistor, and the second control circuit is used to control whether to connect the relay K1 to a power supply circuit.

[0006] Furthermore, the first control circuit includes a resistor R3, a resistor R4, a MOS transistor Q3, and a MOS transistor Q4. The first end of the resistor R4 and the source of the MOS transistor Q4 are connected to the power supply, the second end of the resistor R4 and the gate of the MOS transistor Q4 are connected to the drain of the MOS transistor Q3, the drain of the MOS transistor Q4 is connected to the second end of the voltage divider resistor, the gate of the MOS transistor Q3 is connected to the external first control signal and the first end of the resistor R3, and the source of the MOS transistor Q3 is connected to the second end of the resistor R3 and to ground.

[0007] Furthermore, the second control circuit includes a resistor R1, a resistor R2, a MOS transistor Q1, and a MOS transistor Q2. The first end of the resistor R2 and the source of the MOS transistor Q2 are connected to the second end of the voltage divider resistor, the second end of the resistor R2 and the gate of the MOS transistor Q2 are connected to the drain of the MOS transistor Q1, the drain of the MOS transistor Q2 is connected to the first end of the coil of the relay K1, the gate of the MOS transistor Q1 is connected to an external second control signal and the first end of the resistor R1, and the second end of the resistor R1 is connected to the source of the MOS transistor Q1 and is grounded.

[0008] A relay low-power control method implemented by the relay low-power control circuit includes the following three control modes:

[0009] 1) Control relay K1 to close: control the second control circuit to form a path, connect relay K1 to the power supply circuit, control the first control circuit to form a path, short-circuit the voltage divider resistor, and power the relay K1 from the power supply, so that relay K1 closes;

[0010] 2) Control relay K1 to maintain closure: After relay K1 is closure, the first control circuit is controlled to be open, and the power supply is supplied to relay K1 after the voltage is divided by the voltage divider resistor and the internal resistance of relay K1;

[0011] 3) Control the relay K1 to disconnect: control the second control circuit to form an open circuit, disconnect the relay K1 from the power supply circuit, and disconnect the relay K1.

[0012] Furthermore, the first control circuit includes a resistor R3, a resistor R4, a MOS transistor Q3, and a MOS transistor Q4. The first end of the resistor R4 and the source of the MOS transistor Q4 are connected to the power supply, the second end of the resistor R4 and the gate of the MOS transistor Q4 are connected to the drain of the MOS transistor Q3, the drain of the MOS transistor Q4 is connected to the second end of the voltage divider resistor, the gate of the MOS transistor Q3 is connected to the external first control signal and the first end of the resistor R3, and the source of the MOS transistor Q3 is connected to the second end of the resistor R3 and to ground.

[0013] Furthermore, the second control circuit includes a resistor R1, a resistor R2, a MOS transistor Q1, and a MOS transistor Q2. The first end of the resistor R2 and the source of the MOS transistor Q2 are connected to the second end of the voltage divider resistor, the second end of the resistor R2 and the gate of the MOS transistor Q2 are connected to the drain of the MOS transistor Q1, the drain of the MOS transistor Q2 is connected to the first end of the coil of the relay K1, the gate of the MOS transistor Q1 is connected to an external second control signal and the first end of the resistor R1, and the second end of the resistor R1 is connected to the source of the MOS transistor Q1 and is grounded.

[0014] Furthermore, the specific method of controlling the relay K1 to be energized is:

[0015] When a high-level external second control signal is input, MOS transistors Q1 and Q2 are turned on. When a high-level external first control signal is input, MOS transistors Q3 and Q4 are turned on. The power supply voltage drives relay K1 to be attracted through MOS transistors Q4 and Q2.

[0016] Furthermore, the specific method of controlling the relay K1 to maintain the energization is:

[0017] After the relay K1 is closed, a low-level external first control signal is input, the MOS tubes Q3 and Q4 are turned off, and the power supply voltage drives the relay K1 through the voltage divider resistor and the MOS tube Q2 to maintain the closure.

[0018] Furthermore, the specific method of controlling the relay K1 to disconnect is: inputting a low-level external second control signal, the MOS transistor Q1 and the MOS transistor Q2 are turned off, the relay K1 is disconnected from the power supply, and the relay K1 loses power and disconnects.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0020] The present invention controls the two ends of the relay coil to be at a pull-in voltage, a holding voltage, or to be disconnected from the power supply through a first control circuit and a second control circuit, so that after the relay is pulled in, a holding voltage is provided to the relay by means of a resistor voltage divider, thereby reducing heating of the relay coil and energy waste, extending the service life of the relay, and reducing the power consumption of the entire circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the circuit of the present invention. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below with reference to the examples, but the embodiments of the present invention are not limited thereto.

[0023] Example 1:

[0024] Combined with attachment Figure 1 As shown, a low-power control circuit for a relay includes a voltage-dividing resistor and a relay K1, wherein a first end of the voltage-dividing resistor is connected to a power supply, a second end of the voltage-dividing resistor is connected to a first end of a coil of the relay K1, and the second end of the coil of the relay K1 is grounded. A first control circuit is connected in parallel across the voltage-dividing resistor, and a second control circuit is connected in series between the voltage-dividing resistor and the first end of the coil of the relay K1. The first control circuit is used to control whether to short-circuit the two ends of the voltage-dividing resistor, and the second control circuit is used to control whether to connect the relay K1 to the power supply circuit.

[0025] Example 2:

[0026] On the basis of Example 1, combined with the attached Figure 1 As shown, the first control circuit includes a resistor R3, a resistor R4, a MOS transistor Q3, and a MOS transistor Q4. The first end of the resistor R4 and the source of the MOS transistor Q4 are connected to the power supply, the second end of the resistor R4 and the gate of the MOS transistor Q4 are connected to the drain of the MOS transistor Q3, the drain of the MOS transistor Q4 is connected to the second end of the voltage divider resistor, the gate of the MOS transistor Q3 is connected to the external first control signal and the first end of the resistor R3, and the source of the MOS transistor Q3 is connected to the second end of the resistor R3 and grounded.

[0027] Furthermore, the second control circuit includes a resistor R1, a resistor R2, a MOS transistor Q1, and a MOS transistor Q2. The first end of the resistor R2 and the source of the MOS transistor Q2 are connected to the second end of the voltage divider resistor, the second end of the resistor R2 and the gate of the MOS transistor Q2 are connected to the drain of the MOS transistor Q1, the drain of the MOS transistor Q2 is connected to the first end of the coil of the relay K1, the gate of the MOS transistor Q1 is connected to an external second control signal and the first end of the resistor R1, and the second end of the resistor R1 is connected to the source of the MOS transistor Q1 and is grounded.

[0028] The present invention selects two low-drive-voltage N-type MOS transistors and two low-drive-voltage P-type MOS transistors as key components of the entire control circuit; the external second control signal RLY_CTR comes from an external control signal (controlled by a single-chip microcomputer). When the relay K1 needs to be driven normally, a high level is output, the Vgs of the MOS transistor Q1 is greater than 0, the MOS transistor Q1 is turned on, the base of the MOS transistor Q2 is pulled down to ground, the Vgs of the MOS transistor Q2 is less than 0, and the MOS transistor Q2 is turned on.

[0029] The first external control signal, RLY_HOLD, comes from an external control signal (controlled by the microcontroller). When relay K1 is required to operate normally, it outputs a high level. The Vgs of MOS transistor Q3 is greater than 0, turning on MOS transistor Q3. The gate of MOS transistor Q4 is pulled down to ground, and the Vgs of MOS transistor Q4 is less than 0, turning on MOS transistor Q4. Relay power supply RLY_12V drives relay K1 through MOS transistors Q4 and Q2.

[0030] When relay K1 is driven and enters the energized state, the external first control signal RLY_HOLD outputs a low level. The Vgs of MOS transistor Q3 is ≤ 0, making MOS transistor Q3 non-conductive. The Vgs of MOS transistor Q4 is > 0, making MOS transistor Q4 non-conductive. The relay power supply RLY_12V drives relay K1 through the voltage divider formed by resistor R5 and the internal resistance of the relay coil, significantly reducing relay power consumption.

[0031] When the relay is not needed to work, the external second control signal RLY_CTR outputs a low level, Vgs of MOS transistor Q1 is ≤ 0, MOS transistor Q1 is turned on, Vgs of MOS transistor Q2 is greater than 0, MOS transistor Q2 is not turned on, and the relay power supply RLY_12V cannot be loaded on the coil of relay K1, which can further reduce the power consumption of relay K1.

[0032] Example 3:

[0033] Based on Example 1, a low-power control method for a relay includes the following three control modes:

[0034] 1) Control relay K1 to close: control the second control circuit to form a path, connect relay K1 to the power supply circuit, control the first control circuit to form a path, short-circuit the voltage divider resistor, and power the relay K1 from the power supply, so that relay K1 closes;

[0035] 2) Control relay K1 to maintain closure: After relay K1 is closure, the first control circuit is controlled to be open, and the power supply is supplied to relay K1 after the voltage is divided by the voltage divider resistor and the internal resistance of relay K1;

[0036] 3) Control the relay K1 to disconnect: control the second control circuit to form an open circuit, disconnect the relay K1 from the power supply circuit, and disconnect the relay K1.

[0037] Furthermore, the first control circuit includes a resistor R3, a resistor R4, a MOS transistor Q3, and a MOS transistor Q4. The first end of the resistor R4 and the source of the MOS transistor Q4 are connected to the power supply, the second end of the resistor R4 and the gate of the MOS transistor Q4 are connected to the drain of the MOS transistor Q3, the drain of the MOS transistor Q4 is connected to the second end of the voltage divider resistor, the gate of the MOS transistor Q3 is connected to the external first control signal and the first end of the resistor R3, and the source of the MOS transistor Q3 is connected to the second end of the resistor R3 and to ground.

[0038] Furthermore, the second control circuit includes a resistor R1, a resistor R2, a MOS transistor Q1, and a MOS transistor Q2. The first end of the resistor R2 and the source of the MOS transistor Q2 are connected to the second end of the voltage divider resistor, the second end of the resistor R2 and the gate of the MOS transistor Q2 are connected to the drain of the MOS transistor Q1, the drain of the MOS transistor Q2 is connected to the first end of the coil of the relay K1, the gate of the MOS transistor Q1 is connected to an external second control signal and the first end of the resistor R1, and the second end of the resistor R1 is connected to the source of the MOS transistor Q1 and is grounded.

[0039] Furthermore, the specific method of controlling the relay K1 to be energized is:

[0040] When a high-level external second control signal is input, MOS transistors Q1 and Q2 are turned on. When a high-level external first control signal is input, MOS transistors Q3 and Q4 are turned on. The power supply voltage drives relay K1 to be attracted through MOS transistors Q4 and Q2.

[0041] Furthermore, the specific method of controlling the relay K1 to maintain the energization is:

[0042] After the relay K1 is closed, a low-level external first control signal is input, the MOS tubes Q3 and Q4 are turned off, and the power supply voltage drives the relay K1 through the voltage divider resistor and the MOS tube Q2 to maintain the closure.

[0043] Furthermore, the specific method of controlling the relay K1 to disconnect is: inputting a low-level external second control signal, the MOS transistor Q1 and the MOS transistor Q2 are turned off, the relay K1 is disconnected from the power supply, and the relay K1 loses power and disconnects.

[0044] The present invention can provide a holding voltage to the relay by means of a resistor voltage divider after the relay is energized, thereby reducing heating of the relay coil and energy waste, extending the service life of the relay, and reducing the power consumption of the entire circuit.

[0045] Although the present invention is described herein with reference to illustrative embodiments of the present invention, the above embodiments are merely preferred embodiments of the present invention, and the embodiments of the present invention are not limited to the above embodiments. It should be understood that those skilled in the art can design many other modifications and implementations, which will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. A relay low power consumption control circuit, characterized in that: It includes a voltage-dividing resistor and a relay K1, wherein the first end of the voltage-dividing resistor is connected to a power supply, the second end of the voltage-dividing resistor is connected to the first end of the coil of the relay K1, and the second end of the coil of the relay K1 is grounded. A first control circuit is connected in parallel to both ends of the voltage-dividing resistor, and a second control circuit is connected in series between the voltage-dividing resistor and the first end of the coil of the relay K1. The first control circuit is used to control whether to short-circuit the two ends of the voltage-dividing resistor, and the second control circuit is used to control whether to connect the relay K1 to the power supply circuit.

2. A relay low power consumption control circuit according to claim 1, characterized in that: The first control circuit includes a resistor R3, a resistor R4, a MOS transistor Q3, and a MOS transistor Q4. The first end of the resistor R4 and the source of the MOS transistor Q4 are connected to the power supply. The second end of the resistor R4 and the gate of the MOS transistor Q4 are connected to the drain of the MOS transistor Q3. The drain of the MOS transistor Q4 is connected to the second end of the voltage divider resistor. The gate of the MOS transistor Q3 is connected to an external first control signal and the first end of the resistor R3. The source of the MOS transistor Q3 is connected to the second end of the resistor R3 and to ground.

3. A relay low power consumption control circuit according to claim 1, characterized in that: The second control circuit includes a resistor R1, a resistor R2, a MOS transistor Q1, and a MOS transistor Q2. The first end of the resistor R2 and the source of the MOS transistor Q2 are connected to the second end of the voltage divider resistor. The second end of the resistor R2 and the gate of the MOS transistor Q2 are connected to the drain of the MOS transistor Q1. The drain of the MOS transistor Q2 is connected to the first end of the coil of the relay K1. The gate of the MOS transistor Q1 is connected to an external second control signal and the first end of the resistor R1. The second end of the resistor R1 is connected to the source of the MOS transistor Q1 and is grounded.

4. A relay low power consumption control method implemented by a relay low power consumption control circuit according to claim 1, characterized in that: There are three control modes: 1) Control relay K1 to close: control the second control circuit to form a path, connect relay K1 to the power supply circuit, control the first control circuit to form a path, short-circuit the voltage divider resistor, and power the relay K1 from the power supply, so that relay K1 closes; 2) Control relay K1 to maintain closure: After relay K1 is closure, the first control circuit is controlled to be open, and the power supply is supplied to relay K1 after the voltage is divided by the voltage divider resistor and the internal resistance of relay K1; 3) Control the relay K1 to be disconnected: control the second control circuit to form an open circuit, disconnect the relay K1 from the power supply circuit, and disconnect the relay K1.

5. A relay low power consumption control method according to claim 4, characterized in that: The first control circuit includes a resistor R3, a resistor R4, a MOS transistor Q3, and a MOS transistor Q4. The first end of the resistor R4 and the source of the MOS transistor Q4 are connected to the power supply. The second end of the resistor R4 and the gate of the MOS transistor Q4 are connected to the drain of the MOS transistor Q3. The drain of the MOS transistor Q4 is connected to the second end of the voltage divider resistor. The gate of the MOS transistor Q3 is connected to an external first control signal and the first end of the resistor R3. The source of the MOS transistor Q3 is connected to the second end of the resistor R3 and to ground.

6. A relay low power consumption control method according to claim 5, characterized in that: The second control circuit includes a resistor R1, a resistor R2, a MOS transistor Q1, and a MOS transistor Q2. The first end of the resistor R2 and the source of the MOS transistor Q2 are connected to the second end of the voltage divider resistor. The second end of the resistor R2 and the gate of the MOS transistor Q2 are connected to the drain of the MOS transistor Q1. The drain of the MOS transistor Q2 is connected to the first end of the coil of the relay K1. The gate of the MOS transistor Q1 is connected to an external second control signal and the first end of the resistor R1. The second end of the resistor R1 is connected to the source of the MOS transistor Q1 and is grounded.

7. A relay low power consumption control method according to claim 6, characterized in that: The specific method of controlling the relay K1 to be energized is as follows: When a high-level external second control signal is input, MOS transistors Q1 and Q2 are turned on. When a high-level external first control signal is input, MOS transistors Q3 and Q4 are turned on. The power supply voltage drives relay K1 to be attracted through MOS transistors Q4 and Q2.

8. A relay low power consumption control method according to claim 6, characterized in that: The specific method of controlling the relay K1 to maintain the closure is as follows: After the relay K1 is closed, a low-level external first control signal is input, the MOS tubes Q3 and Q4 are turned off, and the power supply voltage drives the relay K1 through the voltage divider resistor and the MOS tube Q2 to maintain the closure.

9. A relay low power consumption control method according to claim 6, characterized in that: The specific method of controlling the relay K1 to be disconnected is: inputting a low-level external second control signal, the MOS transistor Q1 and the MOS transistor Q2 are turned off, the relay K1 is disconnected from the power supply, and the relay K1 loses power and is disconnected.

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