CN220491805U - Step-down holding circuit of relay - Google Patents
Step-down holding circuit of relay Download PDFInfo
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- CN220491805U CN220491805U CN202322190586.XU CN202322190586U CN220491805U CN 220491805 U CN220491805 U CN 220491805U CN 202322190586 U CN202322190586 U CN 202322190586U CN 220491805 U CN220491805 U CN 220491805U
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- 239000003990 capacitor Substances 0.000 claims abstract description 89
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- 230000005611 electricity Effects 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 230000001276 controlling effect Effects 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000005669 field effect Effects 0.000 description 3
- 230000003068 static effect Effects 0.000 description 3
- 230000033228 biological regulation Effects 0.000 description 2
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- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
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Abstract
The application proposes a relay step-down holding circuit, the circuit includes: the voltage reducing unit, the first diode, the first resistor, the first capacitor, the target relay, the transistor and the first interface; the target relay comprises a coil and a switch; the cathode of the first diode, the first capacitor, the first resistor and the coil are connected through nodes; the positive electrode of the first diode is connected with the voltage reduction unit; the first capacitor, the coil and the transistor are connected; the first interface is connected with the first resistor; in the case that the first diode is not conductive, the external power supply charges the first capacitor with a first voltage; under the condition that the first diode is conducted, an external power supply charges the first capacitor through the voltage reduction unit by utilizing the second voltage; the first capacitor is used for applying a first voltage to the coil to control the switch to be closed under the condition that the first diode is not conducted; the first capacitor is used for applying a second voltage to the coil when the first diode is conducted so as to control the switch to be kept closed.
Description
Technical Field
The specification belongs to the technical field of power electronics, and particularly relates to a relay voltage-reducing holding circuit.
Background
In a communication power supply system, a relay is generally used in primary power-down and secondary power-down, and the requirement of secondary power-down is achieved by controlling the opening and closing of the relay. However, in use, the relay needs to maintain the starting voltage for a long time so that the switch in the relay is in a closed state, which can cause the coil in the relay to continuously generate heat, and further cause excessive relay loss.
In the prior art, a power chip with a voltage regulation function is generally used, and the starting voltage at two ends of the relay is regulated to a lower maintaining voltage by using the power chip, so that the mode has higher requirements on the performance of the power chip, and therefore, the use cost is higher.
In view of the above technical problems, no effective solution has been proposed at present.
Disclosure of Invention
The present specification provides a relay step-down holding circuit capable of reducing loss generated in a closed state of a relay.
It is an object of embodiments of the present specification to provide a relay step-down holding circuit including at least: the voltage reducing unit, the first diode, the first resistor, the first capacitor, the target relay, the transistor and the first interface; the target relay comprises a coil and a switch; the negative electrode of the first diode, the first capacitor, the first resistor and the coil are connected through nodes; the positive electrode of the first diode is connected with the voltage reduction unit; the first capacitor, the coil and the transistor are connected; the first interface is connected with the first resistor; the first interface and the voltage reducing unit are respectively connected with an external power supply; wherein the voltage of the external power supply is a first voltage; the voltage reducing unit is used for converting the voltage of the external power supply into a second voltage; the first resistor is used for reducing current passing through the first interface; the external power source charges the first capacitor with the first voltage through the first interface if the first diode is non-conductive; wherein the first voltage is greater than or equal to a starting voltage of the target relay; the external power supply charges the first capacitor with the second voltage through the step-down unit with the first diode turned on; wherein the second voltage is greater than or equal to a maintenance voltage of the target relay and less than a starting voltage of the target relay; the first capacitor is used for applying a first voltage to the coil to control the switch to be closed when the first diode is not conductive; the first capacitor is used for applying a second voltage to the coil when the first diode is conducted so as to control the switch to be kept closed.
Further, in another embodiment of the circuit, the first diode is turned on in case the voltage of the node is smaller than the second voltage.
Further, in another embodiment of the circuit, the circuit further comprises a control unit for sending an on signal to the transistor.
Further, in another embodiment of the circuit, the transistor includes a gate, a source, and a drain; the grid electrode is used for receiving the conduction signal and controlling the conduction of the source electrode and the drain electrode according to the conduction signal.
Further, in another embodiment of the circuit, the drain is connected to the coil.
Further, in another embodiment of the circuit, the source is connected to the first capacitor.
Further, in another embodiment of the circuit, the circuit further comprises a second resistor; the second resistor is connected with the grid electrode.
Further, in another embodiment of the circuit, the circuit further comprises a protection unit; the protection unit comprises a second capacitor and a third resistor; the second capacitor and the third resistor are connected in parallel between the source electrode and the gate electrode.
Further, in another embodiment of the circuit, the circuit further comprises a third capacitor; the third capacitor is connected in parallel with the first capacitor; the third capacitor is used for expanding the capacity of the first capacitor.
Further, in another embodiment of the circuit, the buck unit further includes a second interface; the step-down unit is connected with the external power supply through the second interface.
Drawings
In order to more clearly illustrate the embodiments of the present disclosure, the drawings that are required for the embodiments will be briefly described below, and the drawings described below are only some embodiments described in the present disclosure, and other drawings may be obtained according to these drawings without inventive effort for a person of ordinary skill in the art.
FIG. 1 is a schematic diagram of one embodiment of a relay buck hold circuit provided herein;
fig. 2 is a schematic diagram of a specific step-down holding circuit of a relay provided in the present specification.
Detailed Description
In order to make the technical solutions in the present specification better understood by those skilled in the art, the technical solutions in the embodiments of the present specification will be clearly and completely described below with reference to the drawings in the embodiments of the present specification, and it is obvious that the described embodiments are only some embodiments of the present specification, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are intended to be within the scope of the present disclosure.
In a communication power supply system, a relay is generally used in primary power-down and secondary power-down, and the requirement of secondary power-down is achieved by controlling the opening and closing of the relay. However, in use, the relay needs to maintain the starting voltage for a long time so that the switch in the relay is in a closed state, which can cause the coil in the relay to continuously generate heat, and further cause excessive relay loss.
Considering that in the prior art, a power supply chip with a voltage regulation function is generally used, and the starting voltage at two ends of the relay is regulated to a lower maintaining voltage by using the power supply chip, the mode has higher requirements on the performance of the power supply chip, and the power supply chip is required to have a feedback loop, so that the use cost is higher; the starting voltage refers to the lowest voltage for changing the relay from the open state to the closed state, and the maintaining voltage refers to the lowest voltage for maintaining the relay in the closed state, and the starting voltage is larger than the maintaining voltage.
In view of the above problems and specific reasons for the above problems in the prior art, the present application contemplates providing a relay step-down holding circuit.
Based on the above-mentioned idea, the present disclosure proposes an embodiment of a voltage-reducing and holding circuit of a relay, referring to fig. 1, the circuit at least includes: the voltage reducing unit U1, the first diode D1, the first resistor R1, the first capacitor C1, the target Relay Relay1, the transistor QF1 and the first interface M1; the target Relay Relay1 comprises a coil KA and a switch K; the negative electrode of the first diode D1, the first capacitor C1, the first resistor R1 and the coil KA are connected through a node P; the anode of the first diode D1 is connected with the voltage reduction unit U1; the first capacitor C1, the coil KA and the transistor QF1 are connected; the first interface M1 is connected with the first resistor R1; the first interface M1 and the step-down unit U1 are respectively connected with an external power supply; wherein the voltage of the external power supply is a first voltage; the step-down unit U1 is used for converting the voltage of the external power supply into a second voltage; the first resistor R1 is used for reducing the current passing through the first interface M1; in case the first diode D1 is not turned on, the external power source charges the first capacitor C1 with the first voltage through the first interface M1; wherein the first voltage is greater than or equal to a starting voltage of the target Relay 1; the external power supply charges the first capacitor C1 with the second voltage through the step-down unit U1 with the first diode D1 turned on; wherein the second voltage is greater than or equal to a sustain voltage of the target Relay1 and less than a start voltage of the target Relay 1; the first capacitor C1 is configured to apply a first voltage to the coil KA to control the switch K to be closed if the first diode D1 is not conductive; the first capacitor C1 is configured to apply a second voltage to the coil KA when the first diode D1 is turned on, so as to control the switch K to be kept closed.
In some embodiments, the start voltage refers to the lowest voltage that causes the switch K of the target Relay1 to change from an open state to a closed state, and the sustain voltage refers to the lowest voltage that causes the switch K of the target Relay1 to maintain the closed state, and the start voltage is greater than the sustain voltage. Therefore, after the switch K of the target Relay1 is closed, the voltage at both ends of the coil KA is adjusted from the starting voltage to the maintaining voltage, so that the switch K can be maintained in a closed state, heat generation of the coil KA can be reduced, and loss is reduced. The first voltage and the start voltage were set to 12V, and the second voltage and the sustain voltage were set to 8V.
In some embodiments, the target Relay1 further includes pin 1, pin 2, pin 3, pin 4; pin 1, pin 2 are connected to an external main circuit, and pin 3, pin 4 are connected to coil KA. By controlling the opening and closing of the switch K, the main circuit can be controlled to be connected or disconnected.
In some embodiments, the relay step-down holding circuit is provided with a ground GND between the third capacitor C3 and the second capacitor C2.
In some embodiments, the first diode D1 is turned on in case the voltage of the node P is smaller than the second voltage. In case the voltage of the node P is greater than the second voltage, the first diode D1 is not turned on. The voltage of the node P is the negative voltage of the first diode D1; the second voltage is equal to the output voltage of the step-down unit and is also the positive voltage of the first diode D1.
In some embodiments, the circuit further comprises a control unit U2, the control unit U2 being configured to send a turn-on signal to the transistor QF 1; the on signal may be a voltage signal, which satisfies the on voltage of the transistor QF1. The control unit U2 may be a Micro Control Unit (MCU). The control unit U2 may be further configured to receive a conduction command sent by the client, and generate a conduction signal according to the conduction command.
In some embodiments, the transistor QF1 is specifically a metal-oxide-semiconductor field effect transistor (abbreviated as MOS transistor, MOSFET, MOS field effect transistor), the transistor QF1 including a gate G, a source S, a drain D; the gate G is configured to receive the conduction signal, and control the source S and the drain D to be turned on according to the conduction signal, so as to realize conduction of the transistor QF1. When the transistor QF1 is turned on, the coil KA and the first capacitor C1 form a parallel path, the first capacitor C1 can apply a voltage to the coil KA, and one pole to which the first capacitor C1 and the first resistor R1 are connected represents the positive pole (+).
In some embodiments, the drain D is connected to the coil KA.
In some embodiments, the source S is connected to the first capacitor C1.
In some embodiments, the circuit further comprises a second resistor R2; the second resistor R2 is connected to the gate G. The second resistor R2 is a matching impedance for protecting the transistor QF1.
In some embodiments, the circuit further comprises a protection unit; the protection unit comprises a second capacitor C2 and a third resistor R3; the second capacitor C2 and the third resistor R3 are connected in parallel between the source S and the gate G. The second capacitor C2 and the third resistor R3 are respectively connected to the first capacitor C1. Before the transistor QF1 receives the conduction signal, the residual voltage charge or accumulated static electricity exists on the grid electrode G of the transistor QF1, a potential difference is formed between the grid electrode G and the source electrode S, when the potential difference meets the conduction voltage of the transistor QF1, the transistor QF1 is turned on by mistake under the condition that the conduction signal is not received, and therefore the potential difference formed by the residual voltage charge and the accumulated static electricity can be reduced by connecting the third resistor R3 between the grid electrode G and the source electrode S, and the misconduction of the transistor QF1 is avoided. Meanwhile, in the process of discharging the potential difference of the third resistor R3, a higher peak voltage exists, the peak voltage can be reduced by connecting the second capacitor C2, the peak voltage is prevented from exceeding the conducting voltage, and the effect of preventing the transistor QF1 from being conducted by mistake can be achieved.
In some embodiments, the circuit further comprises a third capacitor C3; the third capacitor C3 and the first capacitor C1 are connected in parallel; the third capacitor C3 is used to expand the capacity of the first capacitor C1. The third capacitor C3 is connected in parallel with the first capacitor C1, and it is understood that the cross-sectional area of the first capacitor C1 is enlarged by the third capacitor C3, and the larger the cross-sectional area is, the larger the capacitance of the first capacitor C1 is.
In some embodiments, the buck unit U1 further includes a second interface M2; the step-down unit U1 is connected to the external power supply through the second interface M2.
In some embodiments, the voltage step-down unit U1 provides the second voltage to the anode of the first diode D1, the external power source provides the first voltage to the cathode of the first diode D1, and since the second voltage is smaller than the first voltage, the first diode D1 is not turned on, and at this time, the external power source charges the first capacitor C1 through the first interface with the first voltage until the voltage of the first capacitor C1 reaches the first voltage, and the charging is ended. The control unit U2 sends an on signal to the transistor QF1, the source S and the drain D of the transistor QF1 are turned on, a path is formed between the first capacitor C1 and the coil KA, the first capacitor C1 applies a first voltage to the coil KA (i.e., the first capacitor C1 starts discharging), the first voltage satisfies a start voltage of the target Relay1, the coil KA is attracted, and the switch K is switched from an open state to a closed state. As the first capacitor C1 discharges, the amount of electricity in the first capacitor C1 gradually decreases, the voltage of the first capacitor C1 gradually decreases from the first voltage, and when the voltage of the first capacitor C1 decreases from the first voltage to be lower than the second voltage, the negative voltage of the first diode D1 (i.e., the voltage at the node P) is smaller than the second voltage, the positive voltage of the first diode is equal to the second voltage, and the first diode D1 is turned on, and since this process is an instantaneous process, the voltage of the first capacitor C1 is smaller than the second voltage for a small period of time, and the second voltage is generally larger than the sustain voltage, the instantaneous process does not cause the switch K to be turned off. At this time, due to the presence of the first resistor R1, the first resistor R1 causes the current supplied from the external power supply to be smaller than the current supplied from the voltage-decreasing unit U1, and the first resistor R1 causes the current driving capability supplied from the external power supply to be weak, so the first capacitor C1 is charged again with the second voltage supplied from the voltage-decreasing unit U1 until the voltage of the first capacitor C1 is equal to the second voltage, and the charging is ended. The first capacitor C1 applies the second voltage to the coil KA as the sustain voltage, so that the switch K is kept closed, and since a large amount of electricity is not consumed in the process of applying the sustain voltage, the first capacitor C1 can be charged and discharged while maintaining the voltage thereof equal to the second voltage.
Based on the above embodiment, the voltage at the two ends of the coil KA can be converted from the first voltage to the second voltage without maintaining the first voltage all the time when the target Relay1 is operated, and the loss power of the target Relay1 is proportional to the square of the voltage because the second voltage is lower than the first voltage.
In some embodiments, in the case that the switch K is kept in the closed state, the control unit U2 may be further configured to send an off signal to the transistor QF1, and after receiving the off signal, the transistor QF1 controls the opening between the source S and the drain D, so that the coil KA is disconnected from the first capacitor C1, the voltage across the coil KA becomes 0, and the switch K is opened.
In some embodiments, the resistor and capacitor parameter settings of FIG. 1 are shown in Table 1.
TABLE 1
| First resistor R1 | 1kΩ |
| Second resistor R2 | 2kΩ |
| Third resistor R3 | 10kΩ |
| First capacitor C1 | 1000μF/16V |
| Second capacitor C2 | 1nF/50V |
| Third capacitor C3 | 100n F/50V |
In a specific example of a scenario, referring to fig. 2, the present application further provides a specific schematic diagram of a step-down holding circuit of a relay, where the circuit components and parameters corresponding to the circuit components in fig. 2 may be set according to table 2. Referring to fig. 2, gnd denotes a ground terminal; m1 represents a first interface, and is connected with an external power supply; m2 represents a second interface of the voltage reducing unit U1 and is connected with an external power supply; m3 represents a third interface, which is used for connecting a universal meter, and the universal meter is used for detecting whether the voltage at the third interface is equal to the second voltage; the negative electrode of the first diode D1, the first capacitor C1, the first resistor R1, and the coil KA are connected through the node P. Relay1 represents a target Relay, and switch K and coil KA are included in Relay 1. QF1 represents a transistor, and QF1 includes a gate G, a source S, and a drain D. The step-down unit U1 includes a power management chip (IC chip), VIN (power supply voltage input terminal) pin 11, ena (on/off control) pin 12, nc1 (empty port 1) pin 13, nc2 (empty port 2) pin 14, gnd (ground terminal) pin 15, output of a boost capacitor of a boot (high-side FET gate driver), FET refer to field effect transistor) pin 8, ph (source of high-side power MOSFET) pin 9, vsns (feedback voltage of voltage regulator) pin 10, pwpd (chip heat dissipation terminal) pin 16. In the step-down unit U1, the first inductor L1 is used for output filtering, and the filtering can eliminate a voltage spike in the second voltage, so that the second voltage becomes a gentle waveform output. The second diode D2 is used to prevent static electricity from being generated, the sixth resistor R6 and the seventh resistor R7 are used to set the output voltage value, and the seventh capacitor C7 is specifically an aluminum electrolytic capacitor. The control unit U2 includes a Micro Control Unit (MCU), where VCC (power supply voltage inlet) pin 5, gnd pin 6, gpio (general purpose input output) pin 7, and pin 7 is connected to the second resistor R2. One pole of the sixth capacitor C6 connected to the first inductor L1 represents the positive pole (+).
TABLE 2
Various embodiments in this specification are described in a progressive manner, and identical or similar parts are all provided for each embodiment, each embodiment focusing on differences from other embodiments.
Although the present specification has been described by way of example, it will be appreciated by those skilled in the art that there are many variations and modifications to the specification without departing from the spirit of the specification, and it is intended that the appended claims encompass such variations and modifications as do not depart from the spirit of the specification.
Claims (10)
1. A relay buck holding circuit, the circuit comprising at least: the voltage reducing unit, the first diode, the first resistor, the first capacitor, the target relay, the transistor and the first interface; the target relay comprises a coil and a switch;
the negative electrode of the first diode, the first capacitor, the first resistor and the coil are connected through nodes;
the positive electrode of the first diode is connected with the voltage reduction unit;
the first capacitor, the coil and the transistor are connected;
the first interface is connected with the first resistor;
the first interface and the voltage reducing unit are respectively connected with an external power supply; wherein the voltage of the external power supply is a first voltage;
the voltage reducing unit is used for converting the voltage of the external power supply into a second voltage;
the first resistor is used for reducing current passing through the first interface;
the external power source charges the first capacitor with the first voltage through the first interface if the first diode is non-conductive; wherein the first voltage is greater than or equal to a starting voltage of the target relay;
the external power supply charges the first capacitor with the second voltage through the step-down unit with the first diode turned on; wherein the second voltage is greater than or equal to a maintenance voltage of the target relay and less than a starting voltage of the target relay;
the first capacitor is used for applying a first voltage to the coil to control the switch to be closed when the first diode is not conductive;
the first capacitor is used for applying a second voltage to the coil when the first diode is conducted so as to control the switch to be kept closed.
2. The circuit of claim 1, wherein the first diode is turned on if the voltage at the node is less than the second voltage.
3. The circuit of claim 1, further comprising a control unit for sending an on signal to the transistor.
4. The circuit of claim 3, wherein the transistor comprises a gate, a source, and a drain; the grid electrode is used for receiving the conduction signal and controlling the conduction of the source electrode and the drain electrode according to the conduction signal.
5. The circuit of claim 4, wherein the drain is connected to the coil.
6. The circuit of claim 4, wherein the source is connected to the first capacitor.
7. The circuit of claim 4, further comprising a second resistor; the second resistor is connected with the grid electrode.
8. The circuit of claim 4, further comprising a protection unit; the protection unit comprises a second capacitor and a third resistor; the second capacitor and the third resistor are connected in parallel between the source electrode and the gate electrode.
9. The circuit of claim 1, further comprising a third capacitor; the third capacitor is connected in parallel with the first capacitor; the third capacitor is used for expanding the capacity of the first capacitor.
10. The circuit of claim 1, wherein the buck unit further comprises a second interface; the step-down unit is connected with the external power supply through the second interface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322190586.XU CN220491805U (en) | 2023-08-14 | 2023-08-14 | Step-down holding circuit of relay |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322190586.XU CN220491805U (en) | 2023-08-14 | 2023-08-14 | Step-down holding circuit of relay |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN220491805U true CN220491805U (en) | 2024-02-13 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202322190586.XU Active CN220491805U (en) | 2023-08-14 | 2023-08-14 | Step-down holding circuit of relay |
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|---|---|
| CN (1) | CN220491805U (en) |
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- 2023-08-14 CN CN202322190586.XU patent/CN220491805U/en active Active
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