Compact printed circuit board

This application claims the benefit of U.S. Provisional Application No. 62/519,985, filed Jun. 15, 2017, which application is hereby incorporated herein by reference in its entirety.

The subject matter of this application relates to printed circuit boards and, more particularly, to a compact printed circuit board for integration with a solenoid used to control irrigation valves.

Irrigation systems are primarily used in the monitoring and controlling of watering of vegetation, such as landscapes, gardens, golf courses, municipal parks, and sports venues. Irrigation systems include valves, wires, pipes, sensors, controllers, and water emission devices (e.g., sprinklers, drip emitters, and dripline). Modern day irrigation systems use integrated circuits to facilitate communication between various aspects of an irrigation system, such as between a controller and a solenoid.

Valves are typically controlled electronically by a solenoid. Valves can be standalone valves that control flow through the irrigation piping or can be integrated into the sprinklers so that water flow is controlled at the sprinkler. Solenoids are typically wired to a controller, and the power and signal to actuate them is transmitted via the wires. In some cases, the wires are attached to a printed circuit board on or near a solenoid. The controllers include schedules that communicate through the wires to the printed circuit board connected to the solenoid to turn on and off the valves for controlling irrigation. In some instances, the printed circuit board can decode the signal to determine whether the signal is for that particular solenoid. If it is, watering is enabled, and if not, then the signal is ignored.

Printed circuit boards contain micro-electronics required for enabling functionality at a valve. Printed circuit boards can often be relatively large to accommodate the requisite micro-electronics. Printed circuit boards have been housed near or on a solenoid in an enclosure. It is desired to have a more compact configuration for the printed circuit board without sacrificing the functionality and being able to add additional performance capabilities. Such a compactified printed circuit board results in easier association of the printed circuit board with a solenoid.

FIG. 1 is a plan view of a prior art printed circuit board for controlling functionality at a valve;

FIG. 2 is a top perspective view of a printed circuit board for controlling functionality at a valve embodying features of the present invention;

FIG. 3 is a bottom perspective view of the printed circuit board of FIG. 2 ;

FIG. 4 is a perspective view of the printed circuit board of FIG. 2 in a folded configuration;

FIG. 5 is a perspective view of the printed circuit board of FIG. 4 housed in an enclosure associated with a solenoid enclosure;

FIG. 6 is a perspective view of an irrigation valve and a solenoid using the printed circuit board of FIG. 4 ;

FIG. 7 is a perspective view of a sprinkler and a solenoid using the printed circuit board of FIG. 4 ; and

FIG. 8 is a cross-sectional view of FIG. 7 .

With reference to FIG. 1 , there is illustrated a prior printed circuit board 10 . The printed circuit board 10 may include a rigid board 12 with integrated micro-electronics, such as a lightning protection component 14 , signal conditioning circuits 16 , energy storage devices 18 and 20 , and a micro-controller (on the opposite side). Printed circuit boards, such as printed circuit board 10 , are used in irrigation systems. In an irrigation system, a controller communicates with the micro-electronics of the printed circuit board at a valve or sprinkler to activate and control the amount and frequency of watering. The controller sends a watering signal along the wiring (e.g., a 24 AC power line) to a valve or sprinkler to be activated. For example, the printed circuit board 10 may be attached to a solenoid at the valve or sprinkler. The printed circuit board may decode the signal to determine whether the signal is for that solenoid to cause activation. When the solenoid is activated, it functions to open the valve.

Printed circuit boards have been found to take up too much space, so it is desirable to have configurations that decrease size without sacrificing capabilities. FIG. 2 is a printed circuit board 30 in an alternative configuration to the printed circuit board 10 of FIG. 1 . The printed circuit board 30 takes on a dumbbell-like shape. The printed circuit board 30 includes two smaller boards 24 a,b connected by a flexible rigid board connector 22 . The flexible connector 22 enables the smaller boards 24 a,b to be folded on top of one another which produces a smaller footprint while retaining the same micro-electronics and functionality as the larger printed circuit board 10 of FIG. 1 .

A 3-dimensional distribution of the circuitry by folding of the printed circuit board 30 may allow room for additional micro-electronic features, such as wireless and sensor technologies, to be included on the printed circuit board 30 . For example, a transceiver may be included and may operate using any conventional wireless communication technology, such as WiFi, Low Energy Bluetooth, Zigbee, Z-Wave, and Insteon. The transceiver could enable the solenoid to be part of a communication network, such as a mesh network. Alternatively, the printed circuit board 30 could include a motion, temperature, humidity, solar radiation, light or other common sensor. Data from these sensors can be communicated back to the controller for processing, such as to adjust watering schedules or provide various alerts, via a wired or wireless communication connection.

The flexible connector 22 may consist of copper clad flexible dielectrics, such as polyimide film constructed with an adhesive, while epoxy-based material may be used for construction of the rigid boards 24 a,b.

The printed circuit board 30 may also have etched circuitry trace solder pads instead of soldered hand-wired connections of previous rigid circuit boards, eliminating costs and wiring errors. Furthermore, production of printed circuit boards with flexible connectors, such as printed circuit board 30 , require less manual labor and have a reduced probability of production malfunctions. Circuit boards, such as printed circuit board 30 , can be installed or replaced as completely fabricated interconnection systems, rather than having to install or replace individual rigid printed circuit boards that require reconnection to other boards. This also greatly eliminates wiring errors and reduces manufacturing costs.

In addition, connected at each end of the flexible connector 22 are the boards 24 a,b . The flexible rigid board connector 22 may consist of multiple layers of flexible circuit substrate polyimide film with adhesives. The connection of the flexible rigid board connector to the rigid boards 24 a,b is done internally through metallization connection vias. Each board 24 a,b can have the same shape or different shapes to one another. Each board 24 a,b has holes 34 for connection to a solenoid enclosure. For example, pins 43 (see FIG. 4 ) may be inserted through the holes 34 and soldered to a solenoid enclosure. The boards contain various micro-electronics depending on the required functionality. For example, rigid board 24 a contains the lightning protection component 14 , the energy storage devices 18 and 20 . Rigid board 24 b includes an H-Bridge driver 26 and the signal conditioning circuits 16 .

FIG. 3 is the reverse side of the printed circuit board 30 of FIG. 2 . The back side of rigid board 24 a has the control wiring 28 , such as from a controller, attached thereto, and may contain load resistors 36 . The back side of rigid board 24 b may contain a crystal oscillator 38 , a micro-controller 40 , a voltage regulator 42 , and an input signal device 44 .

The preferred flexible rigid board connector 22 includes a ground back layer 46 as a shield and four control lines 35 and two driver output interconnection traces 37 for the solenoid. The flexible rigid connector alternatively could have additional lines as needed.

The micro-controller 40 and the crystal oscillator 38 coordinate the control request of a remote host and can trigger solenoid commands, sense power line conditions, and communicate the status of the module. The input signal device 44 provides the signal conditioning to interface with the micro-controller 40 . The H-Bridge driver 26 enables the micro-controller 40 to control the latched or unlatched state of a latching type solenoid. The voltage regulator 42 regulates the power for a circuit module. The energy storage devices 18 and 20 may be capacitors of energy reservoirs used to latch/un-latch a solenoid and may also function as back-up energy for un-latching a solenoid in the case of power failure. The circuit board 30 also can be used with a non-latching solenoid.

The format of the printed circuit board 30 allows for a more compact configuration. Specifically, FIG. 4 shows how the rigid boards 24 a,b may be oriented perpendicularly to the flexible rigid board connector 22 , resulting in the printed circuit board 30 of FIG. 2 being folded into a sandwich-like configuration. The printed circuit board 10 of FIG. 1 has a footprint of 1.5 inches×1.5 inches in area; however, the folded printed circuit board 30 with the same functionality or more could occupy a footprint of approximately 1 inch×1 inch area, i.e., only two-thirds the area of the printed circuit board 10 . The folded circuit board 30 also could have an approximate height of 1 inch, thus giving it roughly one cubic inch in volume. While the height of printed circuit board 30 is greater than the height of printed circuit board 10 , the height difference is marginal compared to the savings in footprint size. In some cases, there is height space available in the application, whereas the footprint space is limited. As will be discussed below, this compact cubic size accommodates the size limitations associated with integration of printed circuit boards with a solenoid used with a valve.

With reference to FIG. 5 , the compact printed circuit board 30 is enclosed in a housing 48 . The housing 48 may be made of rigid material, such as plastic and may sit atop a solenoid enclosure 50 containing a solenoid 52 . The pins 43 are mounted to extend from board 24 b with a short extension in one direction and a larger extension in the other direction. The large extensions are inserted through the holes 34 in the printed circuit board 24 a and are soldered to maintain the folded configuration. The shorter extensions are fitted into holes in the top of the solenoid enclosure 50 . The base of the housing 48 is attached to the top of the solenoid enclosure 50 with an adhesive, such as epoxy. In this way, the micro-electronics (e.g., the signal conditioning circuits 16 , the micro-controller 40 , the voltage regulator 42 , etc.) can be integrated with the solenoid enclosure 50 in a relatively small configuration that does not expand the transverse dimension of the combined unit. The resulting compact design of the printed circuit board 30 coupled to the solenoid 52 makes for easier installation and maintenance in the field.

The pins 43 can be used to determine the spacing between the printed circuit boards 24 a,b . For example, the pins 43 and the flexible rigid board connector 22 can be longer to space the printed circuit boards 24 a,b farther apart. Also, the stacked configuration of the printed circuit boards 24 a,b provide options on locating components. For instance, if it is preferred to separate certain components, then one component could be mounted on the top of the upper printed circuit board 24 a and the other component can be mounted on the bottom of the lower printed circuit board 24 b.

Referring to FIG. 6 , an example of a valve 56 in an irrigation system is shown. The solenoid enclosure 50 and the integrated printed circuit board 30 are directly attached to the valve 56 via a threaded stem 58 ( FIG. 5 ) at the base of the solenoid enclosure 50 . Irrigation pipes 62 are secured to an inlet 64 and an outlet 66 of the valve 56 . A controller 60 controls when to allow flow to run through the pipe 62 downstream of the valve 56 . The wiring 28 couples the controller 60 to the solenoid of the valve 56 . The controller 60 includes schedules that turn on and off the valves via the solenoids for controlling irrigation. The wiring 28 alternatively can be connected to the printed circuit board 30 . This enables the printed circuit board 30 to analyze information or data being sent in analog form through the wires 28 . This data can include whether or not a particular signal is for one solenoid or a different solenoid. This allows valves to be electrically connected in series as opposed to having independent wire runs. This also can be used with sprinklers having built-in valves controlled by solenoids.

Referring to FIGS. 7 and 8 , there is shown an irrigation sprinkler in the form of a pop-up rotor sprinkler 70 . The sprinkler 70 includes a stationary housing 74 with an inlet 76 configured to connect to a fluid supply line (not shown). The sprinkler 70 further includes a riser 78 that extends from the housing 74 during irrigation operations. The terminal end of the riser 78 includes at least one nozzle 80 . A second nozzle 82 also may be included and designed for short distance range, while the nozzle 80 would be designed for longer range. The nozzles 80 , 82 are mounted in a rotating turret 84 that is rotated by a fluid driven rotor mechanism 86 to cause the nozzles 80 , 82 to rotate while distributing water from the sprinkler 70 via the nozzles 80 , 82 . Although the following is described in connection with a rotor type irrigation sprinkler, the following disclosure can be applicable to other irrigation devices where pressure control in desired, such as, for example, impact sprinklers, spray heads, drip irrigation devices and lines, valves, etc.

An inlet control valve 88 is disposed in the housing 74 adjacent the inlet 76 to allow irrigation and to compensate for changes in flow rates and water pressure from the supply line. The sprinkler 70 also includes a pressure regulating system 90 that monitors the fluid pressure in the housing 74 and controls the inlet control valve 88 based on such monitoring. The pressure regulating system 90 provides a three-position valve (ON-OFF-AUTO) 92 , and a mount 98 for the solenoid 52 all in a single component. The ON position bypasses the solenoid 52 , the OFF position disables the sprinkler 70 , and the AUTO position is controlled by the solenoid 52 . A housing supply line 94 provides water from the housing 74 to the pressure regulating system 90 , and a housing return line 96 provides water from the pressure regulating system 90 back to the housing 74 .

As illustrated, the solenoid enclosure 50 and the integrated printed circuit board 30 are directly attached to the sprinkler 70 with the threaded stem 58 onto the solenoid mount 98 of the pressure regulating system 90 . The solenoid mount 98 has interior threads for receiving the threaded stem 58 . In a manner similar to the example of FIG. 6 , the controller 60 sends on/off analog signals over the wires 28 , the wires 28 being connected to the printed circuit board 30 . The printed circuit board 30 is electrically coupled to the solenoid 52 and, upon analyzing the on/off signal, the printed circuit board 30 sends an electromagnetic signal to a coil housed in the solenoid 52 when the three-position valve 92 is set to the AUTO position. The coil develops an electromagnetic flux sufficient to cause actuation of the valve in the sprinkler 70 , the actuation being to either open or close the valve based upon the analog signal sent from the controller 60 . The data can include whether or not a particular signal is for one solenoid or a different solenoid, allowing sprinklers to be electrically connected in series as opposed to having independent wire runs. The printed circuit board 30 could include a receiver or transceiver to receive control signals wirelessly from the controller 60 and to feedback information to the controller.

In some examples, solenoid enclosures may already be attached to valves or sprinklers in the field. The folded circuit boards and their housing may simply be attached and wired to the existing solenoid enclosure and re-threaded onto the valve. Alternatively, the current solenoid could be replaced with a solenoid having the folded circuit board 30 already associated with it in separate enclosure or a single-piece enclosure.

With the separate enclosure for the printed circuit boards, the circuitry is separated from the solenoid, and is less susceptible to thermal transfer from the solenoid which can degrade the circuitry, thereby extending the lifetime of the printed circuit board. Additionally, the solenoid enclosure and the housing may be potted with separate materials to further reduce heat transfer from the solenoid to the printed circuit board. Alternatively, an extended solenoid enclosure can be used with one compartment for the solenoid components and a second compartment for the folded printed circuit board. This single piece enclosure with the separate components can still permit the use of separate/different potting materials.

The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the broader aspects of the technological contribution. The actual scope of the protection sought is intended to be defined in the following claims.