Patent Abstract:
The present invention relates to an external storage device, such as a hard disk drive, having a replaceable protection device. In one embodiment, the storage device comprises an overvoltage protection device coupled in parallel with a power adapter. The protection device may be configured to fail in short circuit in the event of an overvoltage condition. In order to make the protection device readily replaceable, it may be located on the storage device such that it is accessible by a user. The storage device is configured to continue operations if the protection device is removed.

Full Description:
BACKGROUND 
     Electronic devices, such as data storage devices, computers, etc., comprise sensitive electrical circuits. Electrical transients caused by power surges, electrostatic discharge, and the like can damage these circuits. 
     Transient voltage suppression (TVS) diodes have been commonly used to protect these sensitive circuits in power adapters for electronic devices. Unfortunately, however, TVSDs often fail as short circuits in response to a transient and will render the power adapter unusable. This leads to either the product or the power adapter having to be replaced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Systems and methods which embody the various features of the invention will now be described with reference to the following drawings, in which: 
         FIG. 1  conceptually shows a protection device, such as a TVS diode, protecting a protected device from a transient. 
         FIG. 2  shows an embodiment where a protection device is provided in removable or replaceable form on a power adapter for the protected device. 
         FIG. 3  shows another embodiment where the protection device is provided in removeable or replaceable form on a plug to the protected device. 
         FIG. 4  shows yet another embodiment where the protection device is provided in removable or replaceable form on the casing for the protected device. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments provide a transient protection device for protecting a device, such as a data storage device. In the embodiments, the transient protection device may be a TVS diode that is connected in parallel with the device and its power input. Furthermore, the TVS diode is provided in a replaceable or removable form at an accessible location on the power adapter for the load or on the casing of the load itself. 
       FIG. 1  conceptually shows a protection device, such as a TVS diode, protecting a device from a transient. As shown, the protected device  100  may be any electrical device. In the embodiments shown, the protected device  100  is a data storage device, such as a hard disk drive, a network attached storage, etc. 
     The protected device  100  is powered by a direct current (DC) power signal  104 . The DC power signal  104  may be provided by a variety of means, such as a battery, a power adapter, etc. For example, power adapters that convert alternating current (AC) power, such as from a wall outlet, to DC power are well known to those skilled in the art. 
     As shown, the DC power signal  104  may suffer from various transients. Such transients may be caused, for example, by power fluctuations in the AC power, component failure, lightning strikes, electrostatic discharge, and the like. These transients should ideally be suppressed or prevented in order to prevent the electronics of the protected device  100 . 
     The protection device  102  provides a protection level to limit a transient in the power signal  104  to a certain level. In the embodiment shown, the protection device  102  is a TVS diode which is connected in parallel between the power input of the DC power signal  104  and the protected load  102 . Furthermore, the protection device  102  is configured to be in removable/replaceable form. In operation, the protection device  102  will conduct current in forward biased direction, but clamp over-voltage when reversed biased. If the duration and amplitude of the current present when in this clipping mode is significant the protection device  102  may eventually short to prevent the overvoltage from damaging sensitive circuitry downstream in the protected device  100 . 
     In contrast to the prior art, in the embodiments, to protection device  102  is not located on the circuit board of the protected device  100 . Instead, the protection device  102  is implemented in removable, field replaceable, form. In these embodiments, implemented as such, TVS diodes can also be eliminated as an internal component of the power adapter for the protected device  100 . By implementing the protection device in removable form, it provides transient protection while still being easily replaced if it shorts. 
     Furthermore, if necessary, the protection device  102  can be simply removed and the device  100  can be operated normally with the device removed. For example, the AC/DC power adapter may be configured to transition into safety mode if the output current exceeds a specified threshold beyond a minimal period of time. The adapter can remain in this safety mode indefinitely without damage until the short caused by failure of the protection device  102  is removed. At a later time, the protection device  102  may be replaced or removed so that the power adapter can return to normal operation. 
     In other embodiments, the protection device  102  can be implemented in standalone form, such as a clip or plug that fits on the DC plug. In this form, the protection device can be retrofitted to existing and prior products to improve their robustness to harsh power conditions. 
       FIG. 2  shows an embodiment where a protection device is provided in removable or replaceable form on a power adapter  200  for the protected device  100 . As shown, the power adapter  200  may comprise an AC plug  202 , an AC/DC converter  204 , and a DC plug  206 . Furthermore, the protected device  100  may comprise a DC jack  208 , a control circuit  210 , and electronics  212 . 
     In this embodiment, the protection device  102  is provided in removable or replaceable form on the body of the AC/DC converter  204 . For example, the protection device  102  may be in a form factor similar to a fuse that can be plugged into a receptacle provided on the body of the AC/DC converter  204 . This form allows the protection device  102  to be placed in an accessible location and to be easily removable. 
       FIG. 3  shows another embodiment where the protection device is provided in removeable or replaceable form on a plug to the protected device. As shown, the power adapter  300  may comprise an AC plug  302 , an AC/DC converter  304 , and a DC plug  306 . The protected device  100  may still comprise DC jack  208 , a control circuit  210 , and electronics  212 . 
     In this embodiment, the protection device  102  is provided in removable or replaceable form on the body of the DC plug  306 . For example, the protection device  102  may be in a form factor similar to a fuse that can be plugged into a receptacle provided on the body of the DC plug  306 . 
       FIG. 4  shows yet another embodiment where the protection device is provided in removeable or replacable form on the casing for the protected device. As shown, the power adapter  400  may comprise an AC plug  402 , an AC/DC converter  404 , and a DC plug  406 . The protected device  100  may still comprise DC jack  208 , a control circuit  210 , and electronics  212 . 
     In this embodiment, the protection device  102  is provided in removable or replaceable form on the body of the protected device  100 . As shown, the protected device  102  is provided on the casing above the DC jack  408 . The protection device  102  may be in a form factor similar to a fuse that can be plugged into a receptacle provided on the body of the protected device  100 . 
     The features and attributes of the specific embodiments disclosed above may be combined in different ways to form additional embodiments, all of which fall within the scope of the present disclosure. Although the present disclosure provides certain embodiments and applications, other embodiments that are apparent to those of ordinary skill in the art, including embodiments, which do not provide all of the features and advantages set forth herein, are also within the scope of this disclosure. Accordingly, the scope of the present disclosure is intended to be defined only by reference to the appended claims.

Technology Classification (CPC): 7