Data authentication circuit, battery pack and portable electronic device
View Patent ↗Suppression malfunction of an authentication circuit for authenticating a battery pack. Signal line for applying an intermediate potential between the power supply and ground and for reading the potential of a thermistor for detecting the temperature is used as a transmission path for exchanging data between a battery pack and main device. A master-authentication circuit and slave-authentication circuit comprise level-correction circuits, which are connected to the signal line by way of a voltage-comparator circuit. The level-correction circuits are constructed such that they correct the signal applied to the signal line so that it is greater than or less than the unstable-region voltage, and outputs it to the input end of the authentication circuits, so that unstable-region voltage is not applied to the input end. Output circuits overlap in turn authentication information onto the signal line when performing authentication, and the level-correction circuits receive the respective information, and authentication is performed.
1. A data-authentication circuit comprising:
an input/output terminal on a battery-pack-device side;
a temperature sensor of which one terminal is connected to said input/output terminal and the other terminal is connected to a reference power supply;
a level-correction circuit on the battery-pack-device side whose input end is connected to said input/output terminal, and whose output end is connected to the input end of an authentication circuit on the battery-pack-device side; and
said authentication circuit that outputs a signal related to authentication to said input/output terminal; wherein
said level-correction circuit corrects a voltage applied to said input/output terminal so as to make the voltage greater than or less than an unstable-region voltage, and outputs a resultant voltage to said authentication circuit.
2. The data-authentication circuit of claim 1 wherein said level-correction circuit has a function for correcting the voltage applied to said input/output to high level or low level and outputting it to said authentication circuit.
3. The data-authentication circuit of claim 1 wherein said level-correction circuit comprises a voltage-comparator circuit that compares a first voltage that is input to its input end with a second voltage that is obtained by way of an integrator circuit that integrates said first voltage, and outputs the output from said voltage-regulator circuit to said level-correction circuit.
4. The data-authentication circuit of claim 1 wherein
said level-correction circuit comprises a voltage-comparator circuit that compares a first voltage that is input to its input end, with a second voltage that differs from said first voltage; wherein
said second voltage supplies a specified voltage from a voltage-regulator circuit, and
an output from said voltage-comparator circuit provides an output from said level-correction circuit.
5. The data-authentication circuit of claim 1 wherein said level-correction circuit comprises a buffer circuit the cuts the direct-current portion of a first voltage that is input to its input end, and where an output from said buffer circuit provides an output of said level-correction circuit.
6. A battery pack comprising the data-authentication circuit of claim 1 .
7. A battery pack comprising: the data-authentication circuit of claim 1 , a first switch between the output end of said level-correction circuit and the input end of said authentication circuit, and a second switch between said input/output terminal and the output end of said authentication circuit; where said first switch and said second switch open and close opposite of each other in correspondence to the battery pack start-authentication signal.
8. A portable electronic device that is connected to the data-authentication circuit of claim 1 , and that performs an authentication operation and comprising:
an input/output terminal on the main-device side that is connected to said input/output terminal of said data-authentication circuit or said battery pack, and a master-data-authentication circuit; wherein
said master-data-authentication circuit comprises a level-correction circuit on a main-device side, and an authentication circuit on the main-device side; and
said level-correction circuit on the main-device side whose input end is connected to the input/output terminal on said main-device side, and whose output end is connected to the input end of the authentication circuit on the main-device side, corrects the voltage applied to the input/output terminal on the main-device side such that it is greater than or less than an unstable-region voltage and outputs it to the authentication circuit on the main-device side.
9. The portable electronic device of claim 8 wherein said level-correction circuit on the main-device side has a function for correcting the voltage applied to the said input/output terminal on the main-device side such that it is high level or low level, and outputting it to said authentication circuit on the main-device side.
10. A portable electronic device that is connected to the battery pack of claim 6 , and that performs an authentication operation, said device comprising:
an input/output terminal on the main-device side that is connected to said input/output terminal of said data-authentication circuit or said battery pack, and a master-data-authentication circuit; wherein
said master-data-authentication circuit comprises a level-correction circuit on a main-device side, and an authentication circuit on the main-device side; and
said level-correction circuit on the main-device side whose input end is connected to the input/output terminal on said main-device side, and whose output end is connected to the input end of the authentication circuit on the main-device side, corrects the voltage applied to the input/output terminal on the main-device side such that it is greater than or less than an unstable-region voltage and outputs it to the authentication circuit on the main-device side.
11. The portable electronic device of claim 10 wherein said level-correction circuit on the main-device side has a function for correcting the voltage applied to the said input/output terminal on the main-device side such that it is high level or low level, and outputting it to said authentication circuit on the main-device side.
12. A data-authentication circuit comprising:
an input/output terminal;
an authentication circuit that outputs a signal related to authentication to said input/output terminal; and
a level-correction circuit whose input end is connected to said input/output terminal, and whose output end is connected to the input end of said authentication circuit; wherein,
said level-correction circuit corrects a voltage applied to said input/output terminal so as to make the voltage greater than or less than an unstable-region voltage, and outputs a resultant voltage to said authentication circuit.
13. The data-authentication circuit of claim 12 wherein,
said level-correction circuit has a function for correcting the voltage applied to said input/output terminal to high level or low level and outputting it to said authentication circuit.
14. The data-authentication circuit of claim 12 wherein,
said level-correction circuit comprises a voltage-comparator circuit that compares a first voltage that is input to its input end with a second voltage that is obtained by way of an integrator circuit that integrates said first voltage, and outputs an output from said voltage-comparator circuit as an output of said level-correction circuit.
15. The data-authentication circuit of claim 12 , wherein,
said level-correction circuit comprises a voltage-comparator circuit that compares a first voltage that is input to its input end with a second voltage that is supplied from a voltage-regulator circuit, and outputs an output from said voltage-comparator circuit as an output of said level-correction circuit.
16. The data-authentication circuit of claim 12 wherein,
said level-correction circuit comprises a buffer circuit that cuts off a direct-current portion of a first voltage that is input to its input end, and outputs an output from said buffer circuit as Sri output of said level-correction circuit.
17. A battery pack comprising:
the data-authentication circuit of claim 12 ; and
a temperature sensor of which one terminal is connected to said input/output terminal and the other terminal is connected to a reference power supply.
18. The battery pack of claim 17 comprising:
a first switch that is disposed between the output end of said level-correction circuit and the input end of said authentication circuit; and
a second switch that is disposed between said input/output terminal and the output end of said authentication circuit; wherein
said first switch and said second switch open and close oppositing each other in correspondence to a battery pack start-authentication signal.
19. A portable electronic device that is connected to the battery pack of claim 17 , and that performs authentication operation and comprising:
a supply circuit that supplies said unstable-region voltage to the one terminal of said temperature sensor to operate the temperature sensor;
an input/output terminal on the main-device side;
a master-data-authentication circuit that outputs a signal related to authentication to said input/output terminal on the main-device side; and
a level-correction circuit on the main-device side whose input end is connected to said input/output terminal on the main-device side, and whose output end is connected to the input end of said authentication circuit on the main-device side, said level-correction circuit on the main-device side further comprising:
a data-authentication circuit on the main-device side that corrects a voltage applied to said input/output terminal on the main-device side so as to make the voltage greater than or less than said unstable-region voltage, and outputs a resultant voltage to said authentication circuit on the main-device side, wherein
the input/output terminal of said battery pack the output of said supply circuit and the input/output terminal of said authentication circuit on the main-device side are connected in common.
20. A portable electronic device that is connected to the battery pack of claim 18 , and that performs authentication operation and comprising:
a supply circuit that supplies said unstable-region voltage to the one terminal of said temperature sensor to operate the temperature sensor;
an input/output terminal on the main-device side;
a level-correction circuit on the main-device side whose input end is connected to said input/output terminal on the main-device side, and whose output end is connected to the input end of said authentication circuit on the main-device side, said level-correction circuit on the main-device side further comprising:
a data-authentication circuit on the main-device side that corrects a voltage applied to said input/output terminal on the main-device side so as to make the voltage greater than or less than said unstable-region voltage, and outputs a resultant voltage to said authentication circuit on the main-device side, wherein
the input/output terminal of said battery pack, the output of said supply circuit and the input/output terminal of said authentication circuit on the main-device side are connected in common.