Method and Apparatus for Saving Power in a Radiotelephone

The present invention relates generally to the field of radiotelephones and more particularly to a method and an apparatus for saving power in a radiotelephone.

As radiotelephones became smaller manufacturers started adding batteries to the radiotelephones to make them truly portable. Most efforts at reducing power or current drain have concentrated on reducing the power the individual components draw. While this is helpful, power is often wasted by having the radiotelephone on when the user does not expect or want to receive any phone calls.

One solution has been to add a real time clock to the radiotelephone and have turn on and turn off times. The user then defines a time at which his radiotelephone is automatically turned off, such as 9:00 PM. The user can also a define a time when his radiotelephone is turned on to receive calls, such as 7:00 AM. This allows the user to define a period of time in which he will not receive phone calls without having to remember to turn off the radiotelephone. This also saves battery power since the radiotelephone is not accidentally left on all night.

However, many circumstances exist where the user may want his radiotelephone automatically to turn off that are not related to the time of day. For instance, many user's do not wish to receive any phone calls on their radiotelephone, but only want to place out bound calls. They may wish to do this to extend the operating time between charges or to save money. Presently, the user then has to remember to turn off the radiotelephone when he is done placing calls to achieve this goal. When the user forgets to turn off his radiotelephone in these situations, he significantly limits the time between battery charges. In other cases, the user may not wish to receive phone calls when he is outside the range of his home base. This is known as roaming. Roaming charges can add substantially to user's monthly bill and leaving the radiotelephone on unnecessarily limits the time between charges.

Thus there exists a need for radiotelephone that automatically turns off, when the user does not wish to receive in bound calls or when his radiotelephone is in the roam mode.

FIG. 1 is a flow diagram of a process that automatically turns off a radiotelephone according to the present invention;

FIG. 2 is a flow diagram of an alternative process that automatically turns off a radiotelephone according to the present invention;

FIG. 3 is an electrical block diagram of a radiotelephone; and

FIG. 4 is a left, top perspective view of a radiotelephone.

FIG. 1 shows a flow diagram of a process that automatically turns off a radiotelephone when a user does not wish to receive in bound phone calls or when his radiotelephone is in the roam mode. The user can select either feature. If he does not wish to receive any in bound calls he selects a timer shutoff feature, in which he sets a time period after the end of a phone call that the radiotelephone automatically turns off. Assume the user calls his office, after finishing the call the user either hits an end key or shuts a flip to terminate the call. The timer shutoff feature then turns off the radiotelephone a predetermined period of time thereafter, such as thirty seconds. This allows the user time to find another phone number and place another call before the radiotelephone turns off.

The process of FIG. 1 shows how the timer shutoff feature is implemented. Block 102 determines if a shutoff feature is activated and block 104 determines if the timer shutoff feature is activated. The process then waits, block 106, until the flip is closed or the end button is pushed. A timer is started at block 108. In blocks 110 and 112, it is determined if the predetermined period of time has expired before a new phone call has occurred. If so the radiotelephone is placed, block 114, in the off mode. In the off mode the only function performed by the radiotelephone is to scan a keypad to determine if an on key has been pressed. This requires very little current.

The other power saving and money saving feature is the roam shutoff feature. This feature turns off the radiotelephone when it is outside its home service area, i.e. roaming. This feature is also shown in FIG. 1. Once it has been determined in blocks 102 and 104 that the shutoff feature is enabled and the timer shutoff feature is not activated, the process determines, block 116, if the radiotelephone is roaming, i.e. in roam mode. If the radiotelephone is in the roam mode, the process checks, block 118, to determine if a phone call is ongoing, if not the radiotelephone is placed in the off mode.

FIG. 2 illustrates an alternative way to implement the process of FIG. 1. The only difference being that in the process of FIG. 2 both the timer shutoff feature and the roam shutoff feature can be activated simultaneously. The path in the process where both features are activated simultaneously is shown in blocks 202 through 218.

FIG. 3 shows an electrical block diagram of a radiotelephone 300 able to implement the processes described in FIGS. 1 and 2. The radiotelephone 300 has an antenna 302 connected to a duplexer 304. The duplexer 304 is connected to a transmitter 306 and a receiver 308, and isolates the energy between the transmit and receive paths. A processor 310 having an external memory 312 controls the radiotelephone 300 and implements the process described in FIGS. 1 and 2. The processor 310 is connected to a display and a keypad 314. A battery 316 provides power for portable operation and is connected to a power regulator 318. The power regulator 318 then supplies regulated power to the various part of the radiotelephone 300. When the radiotelephone 300 is in the off mode the processor 310 sends a signal to the power regulator 318 to turn power off to all parts of the radiotelephone 300, except the processor 310. Then the processor 310 scans an on button to determine if the user has depressed the on button. This scanning process requires very little current.

FIG. 4 shows perspective view of the radiotelephone 300. The radiotelephone 300 has a housing 402, a display portion 404 and a keypad 406. The lower portion of the housing 402 is pivotally connected to a flip 408. When the flip 408 is closed it covers the keypad 406. The keypad 406 also has an end key 410. The flip 408 or the end key 410 are used by the timer shutoff feature to determine when a phone call has ended.

In summary, the present invention provides a process and apparatus for saving power and money in a radiotelephone. This is accomplished by automatically turning the radiotelephone off if the radiotelephone is in a roam mode or a predetermined period of time after a phone call has ended. In this way the user never accidentally leaves his radiotelephone on, which extends the time period between battery charges Further, the user can limit his radiotelephone usage to out bound phone calls, thus saving battery power and money.