Handheld device capable of automatically switching between a handheld mode and a non-handheld mode and control method thereof

Abstract

A handheld device capable of automatically switching between a handheld mode and a non-handheld mode includes a sensing unit, a control unit, an operating unit, and a mode control unit. The sensing unit is used for generating a sensing result based on whether a user touch is received or not. The control unit sends out a charging-and-discharging signal to the sensing unit, and makes use of the charging-and-discharging signal to charge and discharge the sensing unit. The operating unit is coupled to the sensing unit for generating a mode control signal according to the sensing result. The mode control unit is coupled to the operating unit for controlling the handheld device to stay in a handheld mode or a non-handheld mode according to the mode control signal.

1 . A handheld device capable of automatically switching between a handheld mode and a non-handheld mode, comprising:
 a sensing unit, arranged for generating a sensing result based on whether a user touch is received or not;   a control unit, arranged for sending out a charging-and-discharging signal to the sensing unit, and for making use of the charging-and-discharging signal to charge and discharge the sensing unit;   an operating unit, coupled to the sensing unit, arranged for generating a mode control signal according to the sensing result; and   a mode control unit, coupled to the operating unit, arranged for controlling the handheld device to stay in the handheld mode or the non-handheld mode according to the mode control signal.   
     
     
         2 . The handheld device according to  claim 1 , wherein the charging-and-discharging signal is a periodic pulse, and the control unit is arranged for utilizing the periodic pulse to periodically charge and discharge the sensing unit. 
     
     
         3 . The handheld device according to  claim 1 , wherein during a charging stage, the control unit and the sensing unit form a charging path; and during a discharging stage, the control unit and the sensing unit form a discharging path. 
     
     
         4 . The handheld device according to  claim 1 , wherein the sensing result is a sensing voltage, and the operating unit is arranged for generating the mode control signal by measuring a magnitude of the sensing voltage. 
     
     
         5 . The handheld device according to  claim 4 , wherein the operating unit comprises:
 a voltage comparator, arranged for comparing the sensing voltage with a threshold voltage in order to generate the mode control signal;   wherein when the sensing voltage is smaller than the threshold voltage, the mode control signal has a first logic level, and the mode control unit controls the handheld device to stay in the handheld mode according to the mode control signal with the first logic level; and   when the sensing voltage is not smaller than the threshold voltage, the mode control signal has a second logic level, and the mode control unit controls the handheld device to stay in the non-handheld mode according to the mode control signal with the second logic level.   
     
     
         6 . The handheld device according to  claim 1 , wherein the sensing unit comprises a conductive material. 
     
     
         7 . The handheld device according to  claim 1 , wherein the sensing unit is arranged for receiving the user touch by way of indirect induction or direct contact. 
     
     
         8 . The handheld device according to  claim 1 , wherein the handheld device is a mobile phone, a personal digital assistant (PDA), a PDA phone, or a smart phone. 
     
     
         9 . A handheld device capable of automatically switching between a handheld mode and a non-handheld mode, comprising:
 a sensing unit, arranged for generating a sensing result based on whether a user touch is received or not;   a control unit, arranged for sending out a periodic pulse to the sensing unit, and for making use of the periodic pulse to periodically charge and discharge the sensing unit;   a counting module, coupled to the control unit and the sensing unit, arranged for counting a pulse number of the periodic pulse, and for outputting a counting value when the sensing result indicates that the user touch is received;   an operating unit, coupled to the counting module, arranged for generating a mode control signal according to the counting value; and   a mode control unit, coupled to the operating unit, arranged for controlling the handheld device to stay in the handheld mode or the non-handheld mode according to the mode control signal.   
     
     
         10 . The handheld device according to  claim 9 , wherein the control unit is further arranged for generating a first switch signal and a second switch signal, and the handheld device further comprises:
 a first switch, coupled between the control unit and the sensing unit, arranged for determining whether to turn on or turn off the first switch according to the first switch signal in order to transmit the periodic pulse to the sensing unit; and   a second switch, coupled between the sensing unit and a ground terminal, arranged for determining whether to turn on or turn off the second switch according to the second switch signal.   
     
     
         11 . The handheld device according to  claim 10 , wherein during a charging stage, the first switch is turned on and the second switch is turned off; and wherein the control unit, the first switch and the sensing unit form a charging path. 
     
     
         12 . The handheld device according to  claim 10 , wherein during a discharging stage, the first switch is turned off and the second switch is turned on; and wherein the second switch and the sensing unit form a discharging path. 
     
     
         13 . The handheld device according to  claim 9 , wherein the sensing result is a sensing voltage, and the counting module is arranged for determining whether to output the counting value by measuring a magnitude of the sensing voltage. 
     
     
         14 . The handheld device according to  claim 13 , wherein the control unit is further arranged for generating an enable signal, and the counting module comprises:
 a counter, arranged for starting counting the pulse number of the periodic pulse when the enable signal is received, and for stopping counting the pulse number of the periodic pulse to obtain the counting value when a disable signal is received; and   a voltage comparator, arranged for comparing the sensing voltage with a threshold voltage in order to determine whether to output the disable signal;   wherein when the sensing voltage is greater than the threshold voltage, the disable signal is outputted to the counter; and when the sensing voltage is not greater than the threshold voltage, the disable signal is not outputted to the counter.   
     
     
         15 . The handheld device according to  claim 9 , wherein the operating unit comprises:
 a comparator, arranged for comparing the counting value with a threshold value in order to generate the mode control signal;   wherein when the counting value is greater than the threshold value, the mode control signal has a first logic level; and wherein the mode control unit controls the handheld device to stay in the handheld mode according to the mode control signal with the first logic level; and   when the counting value is not greater than the threshold value, the mode control signal has a second logic level; and wherein the mode control unit controls the handheld device to stay in the non-handheld mode according to the mode control signal with the second logic level.   
     
     
         16 . The handheld device according to  claim 9 , wherein the sensing unit comprises a conductive material. 
     
     
         17 . The handheld device according to  claim 9 , wherein the sensing unit is arranged for receiving the user touch by way of indirect induction or direct contact. 
     
     
         18 . A method for controlling modes of a handheld device, comprising the following steps:
 sending out a charging-and-discharging signal to a sensing unit, and making use of the charging-and-discharging signal to charge and discharge the sensing unit;   the sensing unit generating a sensing result based on whether a user touch is received or not;   generating a mode control signal according to the sensing result; and   controlling the handheld device to stay in a handheld mode or a non-handheld mode according to the mode control signal.   
     
     
         19 . The method according to  claim 18 , wherein the charging-and-discharging signal is a periodic pulse, and the step of making use of the charging-and-discharging signal to charge and discharge the sensing unit comprises:
 utilizing the periodic pulse to periodically charge and discharge the sensing unit.   
     
     
         20 . The method according to  claim 18 , wherein the sensing result is a sensing voltage, and the step of generating the mode control signal according to the sensing result comprises:
 generating the mode control signal by measuring a magnitude of the sensing voltage.   
     
     
         21 . The method according to  claim 20 , wherein the step of generating the mode control signal by measuring a magnitude of the sensing voltage further comprises:
 comparing the sensing voltage with a threshold voltage;   when the sensing voltage is smaller than the threshold voltage, generating the mode control signal with a first logic level; and   when the sensing voltage is not smaller than the threshold voltage, generating the mode control signal with a second logic level; and   the step of controlling the handheld device to stay in the handheld mode or the non-handheld mode according to the mode control signal comprises:   when the sensing voltage is smaller than the threshold voltage, controlling the handheld device to stay in the handheld mode according to the mode control signal with the first logic level; and   when the sensing voltage is not smaller than the threshold voltage, controlling the handheld device to stay in the non-handheld mode according to the mode control signal with the second logic level.   
     
     
         22 . A method for controlling modes of a handheld device, comprising the following steps:
 sending out a periodic pulse to a sensing unit, and making use of the periodic pulse to periodically charge and discharge the sensing unit;   the sensing unit generating a sensing result based on whether a user touch is received or not;   counting a pulse number of the periodic pulse, and outputting a counting value when the sensing result indicates that the user touch is received;   generating a mode control signal according to the counting value; and   controlling the handheld device to stay in a handheld mode or a non-handheld mode according to the mode control signal.   
     
     
         23 . The method according to  claim 22 , further comprising:
 generating a first switch signal and a second switch signal;   determining whether to turn on or turn off the first switch according to the first switch signal in order to transmit the periodic pulse to the sensing unit; and   determining whether to turn on or turn off the second switch according to the second switch signal in order to couple the sensing unit to a ground terminal;   wherein during a charging stage, the first switch is turned on and the second switch is turned off; and wherein during a discharging stage, the first switch is turned off and the second switch is turned on.   
     
     
         24 . The method according to  claim 22 , wherein the sensing result is a sensing voltage, and the step of outputting the counting value comprises:
 determining whether to output the counting value by measuring a magnitude of the sensing voltage.   
     
     
         25 . The method according to  claim 24 , wherein the step of determining whether to output the counting value by measuring the magnitude of the sensing voltage further comprises:
 comparing the sensing voltage with a threshold voltage;   when the sensing voltage is greater than the threshold voltage, outputting a disable signal; and   when the sensing voltage is not greater than the threshold voltage, not outputting the disable signal.   
     
     
         26 . The method according to  claim 25 , further comprising:
 generating an enable signal;   when the enable signal is received, starting counting the pulse number of the periodic pulse; and   when the disable signal is received, stopping counting the pulse number of the periodic pulse to obtain the counting value.   
     
     
         27 . The method according to  claim 22 , wherein the step of generating the mode control signal according to the counting value comprises:
 comparing the counting value with a threshold value;   when the counting value is greater than the threshold value, generating the mode control signal with a first logic level; and   when the counting value is not greater than the threshold value, generating the mode control signal with a second logic level; and   the step of controlling the handheld device to stay in the handheld mode or the non-handheld mode according to the mode control signal further comprises:   when the counting value is greater than the threshold value, controlling the handheld device to stay in the handheld mode according to the mode control signal with the first logic level; and   when the counting value is not greater than the threshold value, controlling the handheld device to stay in the non-handheld mode according to the mode control signal with the second logic level.