Semiconductor integrated circuit and operation method of the same

• US 9,190,867 B2
• Filed: 11/10/2013
• Issued: 11/17/2015
• Est. Priority Date: 11/28/2012
• Status: Expired due to Fees

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Renesas Electronics Corporation
• Inventors: Shimizu, Kazuya
• Primary Examiner(s): Do, Thuan
• Application Number:
  US14/076,258
• Publication Number:
  US 20140145675A1
• Time in Patent Office: 737 Days
• Field of Search: 320/108
• US Class Current: 1/1
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: H04B 5/24 Inductive coupling
• CPC Class Codes: H04B 5/72 for local intradevice communication
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

The present invention is directed to solve a problem that, in the case where NFC and power supply operation of wireless power supply or the like repeat in a time division manner, the count value of a charge timer is reset to an initial value and a charge timer erroneously operates during an NFC period. A charge output terminal charges a battery using DC output voltage. A voltage detecting circuit detects reach of battery voltage to a predetermined level, generates a control signal, and generates a level determination signal discriminating an NFC period and a wireless power supply period by detection of the level of a DC input, voltage of an input terminal. During execution of operation of counting charge time of the battery by the charge timer, the voltage detecting circuit controls the charge timer by the control signal in the NFC period, and the charge timer holds the count value of the counting operation.

Claims

1. A semiconductor integrated circuit comprising:

an input terminal;

a DC-DC converter;

a charge output terminal;

a voltage detecting circuit; and

a charge timer,

wherein a DC input voltage generated by rectifying and smoothing reception signals repetitively supplied as an RF signal by NFC and an RF signal by wireless power supply can be supplied to the input terminal,

wherein the DC-DC converter can generate a DC output voltage having a desired voltage level from the DC input voltage supplied to the input terminal,

wherein the charge output terminal can charge an external battery by using the DC output voltage generated by the DC-DC converter,

wherein the voltage detecting circuit can detect that battery voltage of the charge output terminal reaches a predetermined voltage level by charging the battery and can generate a control signal in response to the battery voltage and the predetermined voltage level,

wherein the charge timer can count charge time of the battery on the basis of control by the control signal generated from the voltage detecting circuit,

wherein the voltage detecting circuit can generate a level determination signal discriminating a communication period of the NFC and a power supply period of the wireless power supply by detecting the level of the DC input voltage supplied to the input terminal, and

wherein during execution of operation of counting the charge time of the battery by the charge timer, the voltage detecting circuit controls the charge timer by the control signal in the communication period of the NFC so that the charge timer holds a count value of the counting operation.

2. The semiconductor integrated circuit according to claim 1, further comprising a power supply output terminal,

wherein the power supply output terminal can supply the DC output voltage generated by the DC-DC converter to a power-reception-side system on the outside.

3. The semiconductor integrated circuit according to claim 2, further comprising a P-channel MOS transistor enabling electric conduction between the power supply output terminal and the charge output terminal.

4. The semiconductor integrated circuit according to claim 3,

wherein the predetermined voltage level includes a quick charge start voltage and a charge target voltage as a voltage higher than the quick charge start voltage,

wherein, before the battery voltage reaches the quick charge start voltage by the charging of the battery, a trickle charge that the battery is charged with low-level trickle charge current is executed, and

wherein, after the battery voltage reaches the quick charge start voltage by execution of the trickle charge on the battery, a quick charge of charging the battery with quick charge current having a level higher than that of the trickle charge current is executed.

5. The semiconductor integrated circuit according to claim 4,

wherein during operation of executing the trickle charge, the charge timer can count trickle charge time of the battery on the basis of the control executed by the control signal generated from the voltage detecting circuit, and

wherein during execution of operation of counting the trickle charge time of the battery by the charge timer, in the communication period of the NFC, the voltage detecting circuit controls the charge timer by the control signal, and the charge timer holds the count value of the counting operation.

6. The semiconductor integrated circuit according to claim 5,

wherein during operation of executing the quick charge, the charge timer can count quick charge time of the battery on the basis of the control executed by the control signal generated from the voltage detecting circuit, and

wherein during execution of operation of counting the quick charge time of the battery by the charge timer in the communication period of the NFC, the voltage detecting circuit controls the charge timer by the control signal, and the charge timer holds the count value of the counting operation.

7. The semiconductor integrated circuit according to claim 6,

wherein the charge timer includes a charge state machine, a hold signal generating unit, a charge timer counter, a trickle timer reset signal generating unit, a quick timer reset signal generating unit, a quick charge flag latch, and a selector,

wherein, to the charge state machine, the control signal generated from the voltage detecting circuit, a communication state signal discriminating the communication period of the NFC and the power supply period of the wireless power supply are supplied,

wherein in response to the control signal and the communication state signal, the charge state machine is set to any of an initial state, a trickle charge state, a quick charge state, a charge error state, a charge complete state, and a charge timer hold state,

wherein the initial state is a state before the battery is charged,

wherein the trickle charge state is a state in which the battery is charged by the trickle charge,

wherein the quick charge state is a state in which the battery is charged by the quick charge,

wherein the charge error state is for displaying a trickle charge error or a quick charge error,

wherein the trickle charge error is that the battery voltage of the battery does not reach the quick charge start voltage during a predetermined trickle charge period in spite of the trickle charge,

wherein the quick charge error is that the battery voltage of the battery does not reach the charge target voltage during a predetermined quick charge period in spite of the quick charge,

wherein the charge complete state is a state where the battery voltage reaches the quick charge start voltage during the predetermined trickle charge period by the trickle charge and, after that, the battery voltage reaches the charge target voltage during the predetermined quick charge period by the quick charge,

wherein the charge timer hold state is a state where the count value of the charge timer counter of the charge timer is held in the NFC period,

wherein in response to an output signal of the charge state machine which is set in any of the initial state, the charge error state, the charge complete state, and the charge timer hold state, the hold signal generating unit generates a hold signal and supplies it to a hold terminal of the charge timer counter,

wherein in response to the control signal generated from the voltage detecting circuit when the battery voltage reaches the quick charge start voltage during the predetermined trickle charge period by the trickle charge, the charge state machine supplies a first signal generation instruction to the trickle timer reset signal generation unit,

wherein in response to the first signal generation instruction supplied from the charge state machine, the trickle timer reset signal generating unit generates a trickle timer reset signal and supplies it to a first input terminal of the selector,

wherein in response to the control signal generated from the voltage detecting circuit at the time of start of the quick charge period when the battery voltage reaches the quick charge start voltage during the predetermined trickle charge period by the trickle charge, the charge state machine generates a quick charge flag signal,

wherein the quick charge flag signal is stored in the quick charge flag latch, and an output terminal of the quick charge flag latch is coupled to a selection control terminal of the selector,

wherein in response to the control signal generated from the voltage detecting circuit when the battery voltage reaches the charge target voltage during the predetermined quick charge period by the quick charge, the charge state machine supplies a second signal generation instruction to the quick timer reset signal generating unit,

wherein in response to the second signal generation instruction supplied from the charge state machine, the quick timer reset signal generating unit generates a quick timer reset signal and supplies it to a second input terminal of the selector,

wherein in response to the quick charge flag signal supplied from the output terminal of the quick charge flag latch to the selection control terminal, the selector selects the quick timer reset signal supplied to the second input terminal and supplies it to a reset terminal of the charge timer counter,

wherein a clock signal having a predetermined frequency is supplied to a clock terminal of the charge timer counter, and

wherein in the case where the hold signal is not supplied to the hold terminal but the trickle timer reset signal or the quick timer reset signal is not supplied from the selector to the reset terminal, the charge timer counter executes operation of counting up the count value of the counting operation in response to the clock signal.

8. The semiconductor integrated circuit according to claim 7,

wherein the charge timer further includes an OR circuit, and

wherein the quick timer reset signal selected by the selector is supplied to a first input terminal of the OR circuit, a power-on reset signal is supplied to a second input terminal of the OR circuit, and an output terminal of the OR circuit is coupled to the reset terminal of the charge timer counter.

9. The semiconductor integrated circuit according to claim 6, further comprising a linear regulator coupled in parallel to the DC-DC converter coupled between the input terminal and the power supply output terminal,

wherein the linear regulator operates promptly in response to supply of the DC input voltage of the input terminal, and

wherein the DC-DC converter operates as a switching regulator having power efficiency higher than that of the linear regulator.

10. The semiconductor integrated circuit according to claim 9, wherein the input terminal is configured so that, to the input terminal, the DC input voltage can be supplied via a first schottky diode and an AC-DC conversion voltage of an AC power supply coupling interface can be supplied via a second schottky diode.

11. The semiconductor integrated circuit according to claim 10, further comprising another input terminal and a switch,

wherein the another input terminal is configured so that a USB power supply voltage of a USB coupling interface can be supplied to the another input terminal, and

wherein one end and the other end of the switch are coupled to the another input terminal and the power supply output terminal, respectively.

12. An operation method of a semiconductor integrated circuit comprising an input terminal, a DC-DC converter, a charge output terminal, a voltage detecting circuit, and a charge timer,

wherein a DC input voltage generated by rectifying and smoothing reception signals repetitively supplied as an RF signal by NFC and an RF signal by wireless power supply can be supplied to the input terminal,

wherein the DC-DC converter can generate a DC output voltage having a desired voltage level from the DC input voltage supplied to the input terminal,

wherein the charge output terminal can charge an external battery by using the DC output voltage generated by the DC-DC converter,

wherein the voltage detecting circuit can detect that battery voltage of the charge output terminal reaches a predetermined voltage level by charging the battery and can generate a control signal in response to the battery voltage and the predetermined voltage level,

wherein the charge timer can count charge time of the battery on the basis of control by the control signal generated from the voltage detecting circuit,

wherein the voltage detecting circuit can generate a level determination signal discriminating a communication period of the NFC and a power supply period of the wireless power supply by detecting the level of the DC input voltage supplied to the input terminal, and

wherein during execution of operation of counting the charge time of the battery by the charge timer, the voltage detecting circuit controls the charge timer by the control signal in the communication period of the NFC so that the charge timer holds a count value of the counting operation.

13. The operation method of a semiconductor integrated circuit according to claim 12,

wherein the semiconductor integrated circuit further comprises a power supply output terminal, and

wherein the power supply output terminal can supply the DC output voltage generated by the DC-DC converter to a power-reception-side system on the outside.

14. The operation method of a semiconductor integrated circuit according to claim 13, wherein the semiconductor integrated circuit further comprises a P-channel MOS transistor enabling electric conduction between the power supply output terminal and the charge output terminal.

15. The operation method of a semiconductor integrated circuit according to claim 14,

wherein the predetermined voltage level includes a quick charge start voltage and a charge target voltage as a voltage higher than the quick charge start voltage,

wherein, before the battery voltage reaches the quick charge start voltage by the charging of the battery, a trickle charge that the battery is charged with low-level trickle charge current is executed and,

wherein, after the battery voltage reaches the quick charge start voltage by execution of the trickle charge on the battery, a quick charge of charging the battery with quick charge current having a level higher than that of the trickle charge current is executed.

16. The operation method of a semiconductor integrated circuit according to claim 15,

wherein during operation of executing the trickle charge, the charge timer can count trickle charge time of the battery on the basis of the control executed by the control signal generated from the voltage detecting circuit, and

wherein during execution of operation of counting the trickle charge time of the battery by the charge timer, in the communication period of the NFC, the voltage detecting circuit controls the charge timer by the control signal, and the charge timer holds the count value of the counting operation.

17. The operation method of a semiconductor integrated circuit according to claim 16,

wherein during operation of executing the quick charge, the charge timer can count quick charge time of the battery on the basis of the control executed by the control signal generated from the voltage detecting circuit, and

wherein during execution of operation of counting the quick charge time of the battery by the charge timer, in the communication period of the NFC, the voltage detecting circuit controls the charge timer by the control signal, and the charge timer holds the count value of the counting operation.

18. The operation method of a semiconductor integrated circuit according to claim 17,

wherein the charge timer includes a charge state machine, a hold signal generating unit, a charge timer counter, a trickle timer reset signal generating unit, a quick timer reset signal generating unit, a quick charge flag latch, and a selector,

wherein, to the charge state machine, the control signal generated from the voltage detecting circuit, and a communication state signal discriminating the communication period of the NFC and the power supply period of the wireless power supply are supplied,

wherein in response to the control signal and the communication state signal, the charge state machine is set to any of an initial state, a trickle charge state, a quick charge state, a charge error state, a charge complete state, and a charge timer hold state,

wherein the initial state is a state before the battery is charged,

wherein the trickle charge state is a state in which the battery is charged by the trickle charge,

wherein the quick charge state in which the battery is charged by the quick charge,

wherein the charge error state is for displaying a trickle charge error or a quick charge error,

wherein the trickle charge error is that the battery voltage of the battery does not reach the quick charge start voltage during a predetermined trickle charge period in spite of the trickle charge,

wherein the quick charge error is that the battery voltage of the battery does not reach the charge target voltage during a predetermined quick charge period in spite of the quick charge,

wherein the charge complete state is a state where the battery voltage reaches the quick charge start voltage during the predetermined trickle charge period by the trickle charge and, after that, the battery voltage reaches the charge target voltage during the predetermined quick charge period by the quick charge,

wherein the charge timer hold state is a state where the count value of the charge timer counter of the charge timer is held in the NFC period,

wherein in response to an output signal of the charge state machine which is set in any of the initial state, the charge error state, the charge complete state, and the charge timer hold state, the hold signal generating unit generates a hold signal and supplies it to a hold terminal of the charge timer counter,

wherein in response to the control signal generated from the voltage detecting circuit when the battery voltage reaches the quick charge start voltage during the predetermined trickle charge period by the trickle charge, the charge state machine supplies a first signal generation instruction to the trickle timer reset signal generation unit,

wherein in response to the first signal generation instruction supplied from the charge state machine, the trickle timer reset signal generating unit generates a trickle timer reset signal and supplies it to a first input terminal of the selector,

wherein in response to the control signal generated from the voltage detecting circuit at the time of start of the quick charge period when the battery voltage reaches the quick charge start voltage during the predetermined trickle charge period by the trickle charge, the charge state machine generates a quick charge flag signal,

wherein the quick charge flag signal is stored in the quick charge flag latch, and an output terminal of the quick charge flag latch is coupled to a selection control terminal of the selector,

wherein in response to the control signal generated from the voltage detecting circuit when the battery voltage reaches the charge target voltage during the predetermined quick charge period by the quick charge, the charge state machine supplies a second signal generation instruction to the quick timer reset signal generating unit,

wherein in response to the second signal generation instruction supplied from the charge state machine, the quick timer reset signal generating unit generates a quick timer reset signal and supplies it to a second input terminal of the selector,

wherein in response to the quick charge flag signal supplied from the output terminal of the quick charge flag latch to the selection control terminal, the selector selects the quick timer reset signal supplied to the second input terminal and supplies it to a reset terminal of the charge timer counter,

wherein a clock signal having a predetermined frequency is supplied to a clock terminal of the charge timer counter, and

wherein in the case where the hold signal is not supplied to the hold terminal but the trickle timer reset signal or the quick timer reset signal is not supplied from the selector to the reset terminal, the charge timer counter executes operation of counting up the count value of the counting operation in response to the clock signal.

19. The operation method of a semiconductor integrated circuit according to claim 18,

wherein the charge timer further includes an OR circuit, and

wherein the quick timer reset signal selected by the selector is supplied to a first input terminal of the OR circuit, a power-on reset signal is supplied to a second input terminal of the OR circuit, and an output terminal of the OR circuit is coupled to the reset terminal of the charge timer counter.

20. The operation method of a semiconductor integrated circuit according to claim 17, further comprising a linear regulator coupled in parallel to the DC-DC converter coupled between the input terminal and the power supply output terminal,

wherein the linear regulator operates promptly in response to supply of the DC input voltage of the input terminal, and

wherein the DC-DC converter operates as a switching regulator having power efficiency higher than that of the linear regulator.