Electrostatic discharge connector and method for an electronic device
View Patent ↗An illustrative electronic assembly having an electrical connector therein to ground an electronic component of the electronic assembly to a grounding feature of a printed wiring assembly (PWA) of the electronic assembly. The electronic assembly may include a housing, the PWA, the electronic component and the electrical connector. The electrical connector may be a conductive and resilient extender or connector that may have a first portion connected to the PWA and a second portion extending generally away from the PWA toward the electronic component. The second portion of the electrical connector may be in mechanical and electrical contact with the electronic component.
1. A thermostat, comprising:
a housing;
a printed wiring assembly having a ground plane situated in the housing;
a temperature sensor on the printed wiring assembly
a display having a metal backing and situated in the housing, the metal backing having a back surface facing the printed wiring assembly;
an insulative spacer sandwiched between the printed wiring assembly and the display to define a distance between the printed wiring assembly and the display;
a conductive resilient extender, wherein:
the conductive resilient extender is configurable between an original configuration and an articulated configuration, wherein once in the articulated configuration, the conductive resilient extender provides a spring force back toward the original configuration;
the conductive resilient extender is electrically connected to the ground plane of the printed wiring assembly and extends through an opening in the spacer to the back surface of the metal backing of the display to thereby mechanically contact the metal backing of the display and provide an electrical connection between the ground plane of the printed wiring assembly and the metal backing of the display;
the conductive resilient extender is in the articulated configuration and the spring force of the conductive resilient extender is exerted against the metal backing of the display and the printed wiring assembly; and
wherein the spacer extends around an edge of the printed wiring assembly to align the spacer with the printed wiring assembly and to align the opening in the spacer with the conductive resilient extender connected to the printed wiring assembly.
2. The thermostat of claim 1 , wherein:
the conductive resilient extender is a single piece clip having a spring portion and a connector portion;
the spring portion is configured to mechanically contact the metal backing; and
the connector portion is configured to be mechanically connected to the printed wiring assembly.
3. The thermostat of claim 2 , wherein a top of the spring portion is configured to extend 2.0-3.0 millimeters from the printed wiring assembly when the conductive resilient extender is in the original configuration.
4. The thermostat of claim 2 , wherein the top of the spring portion is configured to extend 1.0-2.0 millimeters from the printed wiring assembly when the insulative spacer is sandwiched between the printed wiring assembly and the display and the metal backing is acting upon the spring portion to cause the conductive resilient extender to be in the articulated position.
5. The thermostat of claim 2 , wherein the spring portion has a contact portion for contacting the metal backing of the display.
6. The thermostat of claim 1 , wherein the display includes a touch screen liquid crystal display.
7. The thermostat of claim 1 , wherein the conductive resilient extender is mechanically connected to the printed wiring assembly via surface mount technology.
8. The thermostat of claim 1 , wherein the conductive resilient extender includes phosphor bronze.
9. A heating, ventilation, and air conditioning (HVAC) controller, comprising:
a housing;
a surface of a printed wiring assembly (PWA) situated inside the housing and electrically connected to a grounding feature;
a touch screen display in the housing and spaced from the surface of the printed wiring assembly (PWA) by a spacer;
a one-piece electrical connector having a first portion soldered to the surface and a second portion extending away from the surface and toward the spaced touch screen display;
the second portion of the electrical connector is configured to spring with respect to the first portion of the electrical connector; and
the second portion of the electrical connector is mechanically in contact with the touch screen display and exerts a spring force against the touch screen display.
10. The HVAC controller of claim 9 , wherein the electrical connector forms an electrical connection between the grounding feature and the touch screen display.
11. The HVAC controller of claim 9 , wherein the spacer is situated between the surface and the touch screen display and defines a distance between the surface of the printed wiring assembly (PWA) and the touch screen display, wherein the electrical connector extends through an opening through the spacer.
12. The HVAC controller of claim 9 , wherein the first portion of the electrical connector and the second portion of the electrical connector are integrally formed.
13. The HVAC controller of claim 9 , wherein the touch screen display includes a liquid crystal touch screen display having a metal backing, wherein the second portion of the electrical connector makes contact with the metal backing of the liquid crystal touch screen display.
14. The HVAC controller of claim 9 , wherein the second portion has a protrusion for contacting the touch screen display.
15. A method of grounding a display of a thermostat to help avoid electrical damage to the thermostat from an Electro Static Discharge (ESD) event, where the display has a metal backing, the method comprising:
electrically connecting a resilient electrical connector to a ground plane of a printed wiring assembly of the thermostat by soldering the resilient electrical connector to a conductive layer of the printed wiring assembly;
providing an insulative spacer between at least part of the metal backing of the display and the printed wiring assembly;
aligning the spacer with the printed wiring assembly by placing one or more spacer side walls of the insulative spacer along at least one side edge of the printed wiring assembly; and
situating the display adjacent the insulative spacer, such that the resilient electrical connector extends through an opening in the insulative spacer from the printed wiring assembly and makes electrical contact with the metal backing of the display, the electrical connector being bent and exerts a spring force against the metal backing of the display, wherein the spring force maintains an electrical connection with the metal backing over a range of spacings between the printed wiring assembly and the display.
16. The method of claim 15 , further comprising securing the printed wiring assembly, the insulative spacer and the display together to form a sub-assembly.