A relay loss reduction circuit

Abstract

The utility model provides a relay loss reduction circuit belongs to relay field. Including power conversion circuit and loss reduction control circuit, including BUCK chip in power conversion circuit, its FB foot and resistance R4 one end connection, the loss reduction control circuit includes MCU and photoelectric coupling U1, 4, 3 feet of U1 are connected to R4 both ends respectively, wherein 3 feet and R4 connection one end with FB foot and R4 connection one end is same, 2 feet of U1 connect the I / O port of MCU, power conversion circuit still includes resistance R1, R5 and R4 series connection, one end of R5 is grounded, the other end is connected with R4 and BUCK chip's FB foot, the other end of R4 is connected with R1, the other end of R1 is connected to output. When the I / O port output of MCU is low level, control U1 will be shorted after R4, and the relay holding voltage is less than the pull-in voltage before R4 short circuit, the holding voltage is reduced, the power consumption of relay work reduces along with, can obviously reduce the temperature rise of relay, guarantees its work efficiency, solves the problem that the relay works and generates heat seriously, improves the reliability.

Description

TECHNICAL FIELD

[0001] The utility model relates to a relay technical field, concretely relates to a relay loss reduction circuit. BACKGROUND

[0002] The relay is a kind of commonly used electrical control device, and its working principle is based on the principle of electromagnetic attraction and mechanical transmission, can realize the switching control of circuit, can play the role of amplifying signal, circuit separation and protection and control large current equipment, and is commonly used in power system, automation equipment.

[0003] As an important circuit element in power supply circuit design, the reliability and temperature rise of relay in use are the key points of circuit design, especially in the use of high-power circuit design, the specification parameter of used relay is large, the inducting power of coil is very large, and the coil power after inducting is very large, which can cause the relay to heat seriously, and further can cause the system efficiency to reduce, the temperature rise of relay is too high, and the reliability of relay used can also be reduced. UTILITY MODEL CONTENTS

[0004] The technical problem to be solved by the utility model lies in how to reduce the power consumption and temperature rise generated by relay in use.

[0005] To solve the above technical problem, the utility model provides the following technical scheme: including power conversion circuit and loss reduction control circuit, the BUCK control chip is included in the power conversion circuit, and the FB foot is connected with one end of resistance R4;The loss reduction control circuit includes MCU and photoelectric coupler U1, the 4, 3 feet of photoelectric coupler U1 are connected to the two ends of resistance R4 respectively, wherein the one end connected with resistance R4 of 3 feet is same with the one end connected with FB foot and resistance R4 of resistance R4, the 2 feet of photoelectric coupler U1 are connected to the I / O port of MCU, and the 1 foot is connected to power supply;The resistance R1, R5 are also included in the power conversion circuit, the resistance R1, R4, R5 are connected in series, wherein one end of resistance R5 is grounded, the other end is connected with resistance R4 and the FB foot of BUCK control chip, the other end of resistance R4 is connected with resistance R1, and the other end of resistance R1 is connected to output end.

[0006] Preferably, the VIN foot of the BUCK control chip is connected to one end of the capacitor C4, and the other end of the capacitor C4 is grounded.

[0007] Preferably, the SS foot of the BUCK control chip is connected to one end of the capacitor C5, and the other end of the capacitor C5 is grounded.

[0008] Preferably, the BOOT foot and the SW foot of the BUCK control chip are respectively connected with the two ends of the capacitor C1.

[0009] The capacitor C1 is connected to the BOOT pin and the SW pin of the BUCK control chip as a bootstrap capacitor, and provides a driving voltage for an internal switch tube.

[0010] Preferably, the SW pin of the BUCK control chip is further connected to the cathode of the diode D2, and the anode of the diode D2 is grounded.

[0011] Preferably, the SW pin of the BUCK control chip is further connected to one end of the inductor L1, the other end of the inductor L1 is connected to one end of the capacitor C3, the other end of the capacitor C3 is grounded, and the end of the inductor L1 connected to the capacitor C3 is connected to the output end.

[0012] The diode D2 is connected to the SW pin of the BUCK control chip at one end and to the GND at the other end, thereby providing a freewheeling loop for the inductor L1, and the inductor L1 serves as an energy storage inductor for the BUCK topology control.

[0013] Preferably, the output end is connected to the 1 pin of the relay K1 coil, and the 2 pin of the coil is grounded.

[0014] Preferably, the I / O port of the MCU in the loss reduction control circuit is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the 2 pin of the optocoupler U1.

[0015] Preferably, the end of the resistor R3 connected to the optocoupler U1 is further connected to the resistor R2, and the other end of the resistor R2 is connected to the power supply.

[0016] Preferably, the loss reduction control circuit includes the capacitor C2, one end of the capacitor C2 is connected to the power supply, and the other end is grounded.

[0017] Compared with the prior art, the utility model has the advantages that: by changing the I / O port output of the MCU to low level, the resistor R4 is short-circuited by the optocoupler U1, after the resistor R4 is short-circuited, the holding voltage of the relay is less than the relay pull-in voltage before the resistor R4 is short-circuited, thereby realizing the reduction of the relay holding voltage, when the holding voltage of the relay after pull-in is reduced, the power consumed after the relay normally works is also reduced, thereby ensuring the working efficiency of the relay, the temperature rise of the relay can be obviously reduced, the problem of serious heating of the relay during working is solved, and the use reliability of the relay is improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a structural schematic view of the relay loss reduction circuit of the utility model embodiment. DETAILED DESCRIPTION

[0019] In order to make the person skilled in the art better understand the utility model scheme, the technical scheme in the utility model embodiment will be clearly and completely described below in combination with the drawings in the utility model embodiment. Obviously, the described embodiments are only a part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the person skilled in the art without creative labor should belong to the protection scope of the utility model.

[0020] Embodiment

[0021] In combination with Figure 1 The utility model provides a relay's loss reduction circuit, including power conversion circuit and loss reduction control circuit.

[0022] The power conversion circuit passes through BUCK control chip and reduces the input voltage to the attraction voltage needed for the relay work, the power conversion circuit includes BUCK control chip, capacitor C1, C3, C4, C5, resistance R1, R4, R5, inductance L1.

[0023] Wherein one end of capacitor C4 is connected to the input filter of the VIN foot of BUCK control chip, and the other end is grounded;Capacitor C5 is connected to the SS foot of BUCK control chip as input buffer, and the other end is grounded. Capacitor C1 is connected to the BOOT foot and SW foot of BUCK control chip as bootstrap capacitor, to provide driving voltage for internal switch tube, one end of inductance L1 is connected to the SW foot of BUCK control chip, and the other end is connected with one end of capacitor C3, the other end of capacitor C3 is grounded, inductance L1 is used as the energy storage inductance of BUCK topology control, and capacitor C3 is used as output filter. The cathode of diode D2 is connected to the SW foot of BUCK control chip, and the anode is connected to GND, to provide freewheeling loop for inductance L1. Resistance R1, R4, R5 are connected in series as feedback resistance of output voltage control of BUCK control chip, one end of resistance R5 is grounded, and the other end is connected with R4 and the FB foot of BUCK control chip, one end of resistance R1 is connected with output Vo_Relay, and the other end is connected with R4, when the resistance value of R1, R4, R5 is changed, the output voltage will change.

[0024] The loss reduction control circuit comprises an MCU, an optical coupler U1, resistors R2 and R3, the 4th and 3rd pins of the optical coupler U1 are respectively connected to two ends of a resistor R4, wherein the 3rd pin and one end of the resistor R4 connected to the 3rd pin are the same as the FB pin and one end of the resistor R4 connected to the FB pin, the 2nd pin of the U1 is connected to a current-limiting resistor R3, the other end of the resistor R3 is connected to an I / O port of the MCU, one end of the resistor R3 connected to the optical coupler U1 is also connected to the resistor R2, the other end of the resistor R2 is connected to a +5V power supply. The 1st pin of the optical coupler U1 is connected to the +5V power supply, and the loss reduction control circuit further comprises a capacitor C2, one end of the capacitor C2 is connected to a power supply, and the other end is grounded.

[0025] The loss reduction control circuit can change the feedback resistance value of the power conversion circuit output by changing the high and low levels of the I / O port output of the MCU in combination with the optical coupler U1, so that the holding voltage after the relay is attracted is reduced, and the specific implementation manner is as follows:

[0026] In combination with Figure 1 When the I / O port of the MCU outputs a high level, the optical coupler U1 outputs a non-conduction, the 1st pin of the relay K1 wire package is connected to Vo_Relay, and the 2nd pin is connected to GND, wherein the 1st pin of the wire package is also connected to the cathode of a diode D1, the 2nd pin is connected to the anode of the diode D1, and the 3rd and 4th pins of the relay K1 are switches. After the BUCK control chip reduces the input voltage to the attraction voltage required for the relay to work, the relay K1 is in an attraction state at this time, and then the I / O port of the MCU outputs a low level, and the resistor R4 is short-circuited through the optical coupler U1. Because the FB pin voltage of the BUCK control chip after stabilization is a fixed voltage value V fb , after the resistor R4 is short-circuited, the output voltage Vo_Relay1 at this position is V fb / R5*(R1+R5), and before the resistor R4 is short-circuited, the output voltage Vo_Relay2 is Vfb / R5*(R1+R5+R4). After comparison, it is obvious that Vo_Relay1 is less than Vo_Relay2, Vo_Relay2 is the relay attraction voltage, and Vo_Relay1 is the relay holding voltage, so that the reduction of the relay holding voltage is realized, and the power consumption of the relay work is reduced. For example, the attraction voltage of a relay wire package is 12V, and the holding voltage is 7V, that is, Vo_Relay1=7V and Vo_Relay2=12V. According to the formula P=U 2 / R, after the voltage is reduced to 7V, the loss is equivalent to 34% of the original, and the loss reduction amplitude is very large.

[0027] The embodiment realizes the reduction of the holding voltage after the relay is attracted by changing the output feedback resistance method of the BUCK control chip, further reduces the power consumption after the relay is normally operated, the loss reduction is very considerable, and the relay temperature rise is obviously reduced, the problem of serious heating of the relay is better solved, and the use reliability of the relay is improved. Different resistance values of R1, R4 and R5 can be designed to match the demand of different relay working voltages, and the applicability is strong.

[0028] The above disclosed is only the preferred embodiment of the utility model, and cannot be used to limit the protection scope of the utility model, therefore, equivalent changes made according to the patent application range of the utility model still belong to the range covered by the utility model.

Claims

1. A relay loss reduction circuit, characterized in that, The system includes a power conversion circuit and a loss reduction control circuit. The power conversion circuit includes a BUCK control chip, whose FB pin is connected to one end of resistor R4. The loss reduction control circuit includes an MCU and an optocoupler U1. Pins 4 and 3 of the optocoupler U1 are connected to the two ends of resistor R4, respectively. The end where pin 3 is connected to resistor R4 is the same as the end where the FB pin is connected to resistor R4. Pin 2 of the optocoupler U1 is connected to the I / O port of the MCU, and pin 1 is connected to the power supply. The power conversion circuit also includes resistors R1 and R5, which are connected in series. One end of resistor R5 is grounded, and the other end is connected to resistor R4 and the FB pin of the BUCK control chip. The other end of resistor R4 is connected to resistor R1, and the other end of resistor R1 is connected to the output terminal.

2. The relay loss reduction circuit according to claim 1, characterized in that, The VIN pin of the BUCK control chip is connected to one end of capacitor C4, and the other end of capacitor C4 is grounded.

3. The relay loss reduction circuit according to claim 2, characterized in that, The SS pin of the BUCK control chip is connected to one end of capacitor C5, and the other end of capacitor C5 is grounded.

4. The relay loss reduction circuit according to claim 3, characterized in that, The BOOT and SW pins of the BUCK control chip are respectively connected to the two ends of capacitor C1.

5. A relay loss reduction circuit according to claim 4, characterized in that, The SW pin of the BUCK control chip is also connected to the cathode of diode D2, and the anode of diode D2 is grounded.

6. The relay loss reduction circuit according to claim 5, characterized in that, The SW pin of the BUCK control chip is also connected to one end of inductor L1, and the other end of inductor L1 is connected to one end of capacitor C3. The other end of capacitor C3 is grounded, and the end of inductor L1 connected to capacitor C3 is connected to the output terminal.

7. A relay loss reduction circuit according to claim 1, characterized in that, The output terminal is connected to pin 1 of the relay K1 coil, and pin 2 of the relay K1 coil is grounded.

8. A relay loss reduction circuit according to claim 1, characterized in that, The I / O port of the MCU in the loss reduction control circuit is connected to one end of resistor R3, and then the other end of resistor R3 is connected to pin 2 of optocoupler U1.

9. A relay loss reduction circuit according to claim 8, characterized in that, The end of resistor R3 connected to optocoupler U1 is also connected to resistor R2, and the other end of resistor R2 is connected to the power supply.

10. A relay loss reduction circuit according to claim 1, characterized in that, The loss reduction control circuit includes a capacitor C2, one end of which is connected to the power supply and the other end is grounded.

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