Abstract:
A circuit for preventing temporally power off of potable electric devices by loose contact of battery is disclosed. The circuit includes a power charge unit for receiving a first state signal representing a state of the mobile terminal from a main chip set, changing or maintaining a state of a second state signal according to the state of the first state signal, and outputting the second state signal; an enable power signal generator for generating a power-on enable signal by receiving the second state signal or by receiving a power key input signal; and a voltage control unit for supplying electric power to the main chip set of the mobile terminal in response to the power-on enable signal by controlling the electric power to the mobile terminal. The present invention can increase efficiency of packaging size.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a circuit and method for preventing unintentional power off of a mobile terminal caused by loose contact with a battery; and, more particularly, to a circuit and method for preventing temporally power off of a mobile terminal caused by loose contact with the battery by automatically turning on the mobile terminal.  
         DESCRIPTION OF RELATED ARTS  
         [0002]    [0002]FIG. 1A is a circuit diagram showing conventional power circuit. The conventional power circuit includes a first resistor  101  connected to an input line of a power hold signal PS_HOLD; a second resistor  102  having a first end connected to an input line of a power on key input signal ON_SW; a first capacitor  103  having a first end connected to a second end of the second resistor  102  and having a second end connected to a ground; a third resistor  104  having a first end connected to an input line of control voltage 2.7 V_D and having a second end forming an output end of a power on key transfer signal ON_SW_SEN/; a TR switch  105  electrically connecting an emitter end and a collector end in case that a second logical step (high) signal inputted from a base end; a first diode  106  having a positive end connected to the second end of the second resistor  101  for passing a power maintaining signal; a fourth resistor  108  having a first end connected to negative ends of the first diode  106  and a second diode  107  and having a second end connected to the ground; a second capacitor  109  having a first end connected to a power of battery and having a second end connected to a ground; a regulator  110  having an input end IN connected to a power of battery (VBATT), having a ground end (GND) connected to the ground, having an enable end for receiving an enable signal and having an output end for outputting a voltage level controlled battery power after controlling a regulated voltage level of the power of battery (VBATT) received through the input end; a third capacitor  111  having a first end connected to a reference end of the regulator  110  and having a second end connected to the ground; a fourth capacitor  112  having a first end connected to the output end OUT of the regulator  110  and having a second end connected to the ground and a fifth capacitor  113  having a first end connected to the output end OUT of the regulator and having a second end connected to the ground.  
           [0003]    [0003]FIG. 1B is a timing diagram illustrating operations of the conventional power circuit of FIG. 1.  
           [0004]    Referring to the FIG. 1B, operations of the conventional power circuit is explained hereinafter. When a power is temporally off by loose contact of the battery, a power hold signal (PS_HOLD) becomes a first logical stage (LOW) and an enable signal ( 110 _EN) becomes un-activated. Therefore, an ON state of mobile terminal is transferred to OFF state.  
           [0005]    In case of the conventional mobile terminal such as a potable electric device including a personal data assistance PDA, a mobile phone, a radio and a notebook computer equipping the above mentioned conventional power circuit, a tensile force of a battery is decreased corresponding to time of using the conventional mobile terminal and also an oxidation or damage of contact parts of the battery caused by carelessness use of the mobile terminal such as accidentally dropping the mobile terminal. As a result, a power frequently and temporally becomes a power off state by loose contact between the battery and the mobile terminal.  
           [0006]    For overcoming abovementioned problems, various methods for preventing temporal power off have been suggested. A first method is disclosed at Korean Patent No. 313922. It includes an additional battery. A power source of the mobile terminal is changed from main battery to the additional battery by operations of a switch when the contact becomes loosen. In more detail, the mobile terminal having a first and a second power source providing a power to main circuit of the mobile terminal includes a first switching unit for switching a power of the first power source to a main circuit of the mobile terminal; a power voltage level measure unit for measuring a level of power voltage outputting from the first power source; a second switching unit for switching in order to selectively connect the first power source and the second power source in series; a mobile station modem (MSM) for controlling the second switching unit in order to connect the first power source and the second power source in series when the power voltage level measured by the power voltage level measuring unit is decreased under pre-set power voltage level. A second method for preventing temporal power off of potable electric device is implementation of high capacity capacitor at a power unit of the battery.  
           [0007]    However, the above-mentioned methods increase complexity of switching circuit and manufacture cost. Furthermore, a size of packaging is increased by the additional elements.  
         SUMMARY OF THE INVENTION  
         [0008]    It is, therefore, an object of the present invention to provide a circuit and method for preventing temporal power off of a mobile terminal such as a potable electric device including a personal data assistance PDA, a mobile phone, a radio and a notebook computer by automatically turning on temporal power off state of the mobile terminal by using a flip-flop.  
           [0009]    In accordance with an aspect of the present invention, there is provided a circuit for preventing unintentional power off of a mobile terminal, including: a power charge unit for receiving a first state signal representing one of a state of the mobile terminal, which are a state of power-on or a state of power-off, from a main chip set of the mobile terminal, changing or maintaining a state of a second state signal according to the state of the first state signal, and outputting the second state signal when the state of the second state signal is a state of power-on; an enable power signal generator for generating a power-on enable signal by receiving the second state signal from the power charge unit or by receiving a power key input signal, which is generated by a user of the mobile terminal to turn on the mobile terminal; and a voltage control unit for supplying electric power from the power charge unit to the main chip set of the mobile terminal in response to the power-on enable signal from the enable power signal generator by controlling the electric power to be suitable for the mobile terminal.  
           [0010]    In accordance with an aspect of the present invention, there is also provided a method for preventing unintentional power off of a mobile terminal, which has a power charge unit for supplying electric power to the mobile terminal, an enable signal generator for generating a power-on enable signal to turn on the mobile terminal, and a voltage controller for supplying the suitable electric power to a main chip set of the mobile terminal in response to the power-on enable signal, the method including the steps of: a) turning on the mobile terminal when one of a second state signal from the power charger unit and the power key input signal inputted from a user of the mobile terminal is inputted to the enable signal generator; b) generating a first state signal at the main chip set of the mobile terminal and outputting the first state signal to the power charger unit to set the state of the first state signal as power-on after turning on the mobile terminal; c) changing or maintaining a state of the second state signal according to the state of the first state signal, which is power-on, in order to generate the second state signal at the power charger unit; d) generating the first state signal at the main chip set and outputting the first state signal to the power charger unit to set the first state signal&#39;s state as power-off when a power off signal is inputted by a user; e) changing the state of the second state signal according to the state of the first state signal, which is power-off, in order to inactivate the second state signal at the power charger unit; and f) turning off the mobile terminal after inactivating the second state signal.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING(S)  
       [0011]    The above and other objects and features of the present invention will become apparent from the following description of the preferred embodiments given in conjunction with the accompanying drawings, in which:  
         [0012]    [0012]FIG. 1A is a circuit diagram showing a conventional power circuit;  
         [0013]    [0013]FIG. 1B is a timing diagram for explaining operations of the conventional power circuit;  
         [0014]    [0014]FIG. 2 is a block diagram illustrating a circuit for preventing unintentional power off of a mobile terminal in accordance with a preferred embodiment of the present invention;  
         [0015]    [0015]FIG. 3 is a truth table of a flip-flop equipped in the circuit of FIG. 2 in accordance with a preferred embodiment of the present invention; and  
         [0016]    [0016]FIGS. 4A and 4B are flowcharts for explaining operations of a circuit for preventing unintentional power off of a mobile terminal in accordance with a preferred embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]    Other objects and aspects of the invention will become apparent from the following description of the embodiments with reference to the accompanying drawings, which is set forth hereinafter.  
         [0018]    [0018]FIG. 2 is a circuit diagram representing a circuit for preventing unintentional power off of a mobile terminal in accordance with a preferred embodiment of the present invention. Referring to the FIG. 2, the circuit includes a power charger  210 , an enable signal generator  220  and a voltage controller  230 . The enable signal generator  220  and the voltage controller  230  are included in the mobile terminal.  
         [0019]    The power charger  210  receives a first state signal (OFF_STATE_WR), which represents a state of the mobile terminal, from GPIO pin of a main chip set MSM. _The power charger  210  generates a second state signal (OFF_STATE_RD), which represents one of RESET, SET or INVARIANT according to the first state signal (OFF_STATE_WR). The second state signal is outputted to the voltage controller  230  as an enable signal (EN) through the enable signal generator  220 . Hereinafter, the power charger  210  is explained in detail.  
         [0020]    The power charger  210  includes an inverter  211 , a first resistor  212 , a second resistor  213 , a third resistor  214 , a JK flip-flop, a fourth resistor  216  and a first diode  217 .  
         [0021]    The inverter  211  equipped inside of the battery receives the first state signal (OFF_STATE_WR) outputted from the GPIO pin of MSM and inverts the first state signal. The inverted first state signal is outputted.  
         [0022]    The first resistor  212  equipped inside of the battery supplies a resistance value. The first resistor  212  has a first end connected to the OFF_STATE_WR and has a second end connected to the ground.  
         [0023]    The second resistor  213  equipped inside of the battery also supplies a resistance value. The second resistor  212  has a first end connected to an output end of the K-port of flip-flop and has a second end connected to the ground.  
         [0024]    The third resistor  214  is equipped inside of the battery and supplies a resistance value. The third resistor  214  has a first end is connected to a voltage of battery (VBATT).  
         [0025]    The JK flip-flop  215  is equipped inside of the battery and has a power supply end connected to the second end of the third resistor  214 . The JK flip-flop  215  receives the first state signal (OFF_STATE_WR) to a J end and receives an output signal of the inverter  211  to a K end. Also, the JK flip-flop  215  outputs an output signal of a Q end as the second state signal (OFF_STATE_RD). Inhere, a truth table of the JK flip-flop  215  is shown in FIG. 3.  
         [0026]    The fourth resistor  216  supplies a resistance value. The fourth resistor  216  has a first end connected to the Q end of the JK flip-flop  215 .  
         [0027]    The first diode  217  has a positive end connected to the second end of the fourth resistor  216  and passes the second state signal (OFF_STATE_RD) as the enable signal.  
         [0028]    In a meantime, the enable signal generator  220  receives a power key input signal (ON_SW) and a power hold signal (PS_HOLD). At the initialization, the enable signal generator  220  activates the enable signal by activation of the power key input signal (ON_SW) and after the initialization, the enable signal generator  220  maintains to activate the enable signal by activation of the power hold signal (PS_HOLD). Hereinafter, the enable signal generator  220  is explained in detail.  
         [0029]    The enable signal generator  220  includes a fifth resistor  221   a  and a power input unit  222 .  
         [0030]    The fifth resistor  221   a  supplies a resistance value. The fifth resistor has a first end connected to an input line of the power hold signal (PS_HOLD) and has a negative end connected to a signal transfer unit  223 .  
         [0031]    The power input unit  222  receives the power key input signal (ON_SW) and outputs the key input signal (ON_SW) to the signal transfer unit  223 . The power input unit  222  also generates and outputs a power key transfer signal (ON_SW_SEN/) which represents an activation of the power key input signal (ON_SW). Hereinafter the power input unit  222  is explained in detail.  
         [0032]    The power input unit  222  includes a sixth resistor  222   a , a first capacitor  222   b , a seventh resistor  222   c  and a TR switch  222   d.    
         [0033]    The sixth resistor  222   a  supplies a predetermined resistance value by being connected to the input line of the power key input signal (ON_SW).  
         [0034]    The first capacitor  222   b  supplies a capacitance. The first capacitor has a first end connected to the second end of the sixth resistor  222   a  and has a second end to the ground.  
         [0035]    The seventh resistor  222   c  supplies a predetermined value of resistor. The seventh resistor  222   c  has a first end connected to an input line of control voltage 2.7 V_D and has a second end forming an output end of the power key transfer signal (ON_SW_SEN/).  
         [0036]    The TR switch  222   d  has a gate end connected to the second end of the sixth resistor  222   a  and establishes electrical paths of a emitter end and a collector end in case of receiving a second logical stage (HIGH) into a base end.  
         [0037]    In a meantime, the 2 port-diodes  223  received the power hold signal (PS_HOLD) from the power charger  221  and transfers the power key input signal (ON_SW) from the power input unit  222 . Hereinafter, the signal transfer unit  223  is explained in detail.  
         [0038]    The 2port-diode  223  includes a second diode  223   a  and a third diode  223   b.    
         [0039]    The second diode  223   a  has a positive end connected to the power charger  221  and transfers the power hold signal (PS_HOLD) to the voltage control unit  230 .  
         [0040]    In a meantime, the voltage controller  230  received the power of battery (VBATT) and control the power of battery (VBATT) to be suitable power (2.7 V_D) for supplying to the mobile terminal in case that the enable signal (EN) is activated by the second state signal inputted from the power charger  210  or the power key input signal and the power hold signal inputted from the enable signal generator  220 .  
         [0041]    Hereinafter, the voltage controller  230  is explained in detail.  
         [0042]    The voltage controller  230  includes the eighth resistor  231 , a second capacitor  232 , a regulator  233 , a third capacitor  234 , a fourth capacitor  235  and a fifth capacitor  236 .  
         [0043]    The eighth resistor supplies a resistance value. The eight resistor has a first end connected to the output end of the signal transfer unit  223  and has a second end connected to the ground.  
         [0044]    The second capacitor  232  supplies a capacitance. The second capacitor  232  has a first end connected to the power of the battery (VBATT) and has a second end connected to the ground.  
         [0045]    The regulator  233  has an input end (IN) connected to the power of the battery (VBATT) and a ground end (GND) connected to the ground. Also, an enable end (EN) of the regulator  233  receives the enable signal from the power charger  210  or the enable signal generator  220  and controls a voltage level of the power of battery (VBATT) inputted from the input end. The voltage-controlled power of battery is outputted through an output end of the regulator  233 .  
         [0046]    The third capacitor  234  supplies a capacitance. The third capacitor  234  has a first end connected to a reference end (REF) of the regulator and has a second end connected to the ground.  
         [0047]    The fourth capacitor  235  supplies a capacitance. The fourth capacitor  235  has a first end connected to the output end (OUT) of the regulator and has a second end connected to the ground.  
         [0048]    The fifth capacitor  236  supplies a capacitance. The fifth capacitor  236  has a first end connected to the output end (OUT) of the regulator  233  and has a second end connected to the ground.  
         [0049]    Hereinafter, operations of the circuit for preventing temporally power off of the mobile terminal in accordance with a preferred embodiment of the present invention are explained.  
         [0050]    At first, a flip-flop  215  is equipped inside of the battery for noticing a state of the mobile terminal in order to indicate unintentional power off of the mobile terminal. The flip-flop  215  reflects a value of the first state signal (OFF_STATE_WR) according to a truth table shown in FIG. 3. If the state signal (OFF_STATE_WR) of the mobile terminal becomes a floating state by unintentional power off of the mobile terminal, a final value of the second state signal (OFF_STATE_RD) is maintained by becoming the input of JK as ‘00’ based on two resistance values of a battery pull down resistor  212  and  213  since the flip-flop  215  is equipped inside of the battery.  
         [0051]    [0051]FIGS. 4A and 4B are flowcharts for explaining a method for preventing unintentional power off of a mobile terminal in accordance with a preferred embodiment of the present invention. Referring to FIGS. 4A and 4B, operations of the method for preventing unintentional power off of the mobile terminal are explained.  
         [0052]    At first, a power of the mobile terminal is turned on by a user at step S 401 .  
         [0053]    At step  402 , if the second state signal (OFF_STATE_RD) is 0 (normal power-off), then the second state signal (OFF_STATE_RD) is changed to 1 (power-on), by the MSM setting a first state signal (OFF_STATE_WR) as 1. If the second state signal (OFF_STATE RD) is 1, then the second state signal (OFF_STATE_RD) is maintained to 1 by setting the first state signal (OFF_STATE_WR) as 1. By the above-mentioned operations, a state of the mobile terminal is set to the state of use at step  402 .  
         [0054]    After step S 402 , it is determined whether the mobile terminal is powered OFF or not at step S 403 .  
         [0055]    At step S 404 , if the mobile terminal is powered off, then the first state signal value is set to ‘0’ by the MSM and the second state signal value is set to ‘0’ by the flip-flop. That is, it means the mobile terminal is normally powered off by user&#39;s key input.  
         [0056]    After step S 404 , the MSM equipped in the mobile terminal stores a state of power off and then the mobile terminal is normally turned off at step  405 .  
         [0057]    In a meantime, if the mobile terminal is unintentionally powered off by loose contact of the battery, the second state signal is stored in the flip-flop as ‘1’ because two pull-down registers  212  and  211  make the flip-flop invariant state. Then the mobile terminal is automatically powered on at step S 406 .  
         [0058]    [0058]FIG. 4B is a flowchart for explaining a method for preventing unintentional power off of a mobile terminal in accordance with another preferred embodiment of the present invention in more detail.  
         [0059]    As mentioned above, the present invention can prevent unintentionally power off of the mobile terminal caused by loose contact with the battery by equipping a flip-flop inside of the battery. Therefore, it can decrease complexity of switching circuit and manufacture cost since the present invention does not require additional power source or the switching circuit. Furthermore, the present invention can increase efficiency of packaging of the mobile terminal.  
         [0060]    While the present invention has been described with respect to certain preferred embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the following claims.