Control device, electronic apparatus, and contactless power transmission system

• US 10,333,348 B2
• Filed: 05/13/2016
• Issued: 06/25/2019
• Est. Priority Date: 05/13/2015
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Onishi, Kota
• Primary Examiner(s): Houston, Adam D
• Application Number:
  US15/572,459
• Publication Number:
  US 20180123395A1
• Time in Patent Office: 1,138 Days
• 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 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge

Abstract

A control device that can perform discharging execution and stop of a power receiving device included in a contactless power transmission, electronic apparatus, contactless power transmission system, and the like. The control device is on a receiving side in a contactless power transmission system including a power transmitting device and a power receiving device, and includes: a charging unit that charges a battery based on power received by a power receiving unit that receives power from the power transmitting device; a discharging unit that performs an operation of discharging the battery; a control unit that controls the discharging unit; and a monitoring unit that monitors the operation state of a switch unit. The control unit causes the discharging unit to discharge when removal of the power receiving device has been detected, and stops the discharging when an off operation of the switch unit has been detected by the monitoring unit.

Claims

1. A control device on a power receiving side in a contactless power transmission system including a power transmitting device and a power receiving device, the control device comprising:

a charging unit that charges a battery based on power received by a power receiving unit that receives power from the power transmitting device;

a discharging unit that performs an operation of discharging the battery and supplies power from the battery to a power supply target;

a control unit that controls the discharging unit; and

a monitoring unit that monitors the operation state of a switch unit,

wherein the control unit causes the discharging unit to perform discharging when removal of the power receiving device has been detected, and stops discharging of the discharging unit when an off operation of the switch unit has been detected by the monitoring unit.

2. The control device according to claim 1, wherein the control unit stops discharging of the discharging unit in a normal power transmission period.

3. The control device according to claim 2, further comprising a load modulation unit that transmits communication data to the power transmitting device by load modulation,

wherein the control unit transmits the communication data to the power transmitting device by load modulation performed by the load modulation unit in the normal power transmission period.

4. The control device according to claim 1,

wherein the monitoring unit includes:

a regulator that steps down a battery voltage; and

a resistor that is provided between an output node of the regulator and one end of the switch unit, and

the monitoring unit judges whether or not the off operation of the switch unit has been performed based on a voltage at the one end of the switch unit.

5. The control device according to claim 4,

wherein the monitoring unit includes:

an oscillator circuit that performs oscillation operation based on an output voltage of the regulator, and

a timer that measures a period in which the voltage at the one end is at a first voltage level based on a clock signal from the oscillator circuit, and

the monitoring unit judges whether or not the off operation of the switch unit has been performed based on a measurement result of the timer.

6. The control device according to claim 1, further comprising an over-discharge detection circuit that detects an overdischarged state of the battery,

wherein the monitoring unit stops operation when the overdischarged state is detected by the over-discharge detection circuit.

7. The control device according to claim 1,

wherein the control unit starts discharging of the discharging unit when an on operation of the switch unit is detected by the monitoring unit after discharging of the discharging unit has stopped.

8. The control device according to claim 1,

wherein the control unit starts discharging of the discharging unit after a start-up period of the discharging operation has elapsed, the start-up period being initiated by a decrease in an output voltage of the power receiving unit.

9. The control device according to claim 8, wherein the control unit starts discharging of the discharging unit after the start-up period has elapsed after the output voltage of the power receiving unit has decreased below a judgement threshold.

10. The control device according to claim 9, wherein the control unit starts a discharging operation of a capacitor, which is charged when the power receiving unit is receiving power, when the output voltage of the power receiving unit has decreased below the judgement threshold, and starts discharging of the discharging unit when the voltage of the capacitor has decreased below a given threshold voltage.

11. An electronic apparatus comprising the control device according to claim 1.

12. A contactless power transmission system comprising a power transmitting device and a power receiving device,

wherein the power transmitting device transmits power to the power receiving device,

the power receiving device charges a battery based on power received from the power transmitting device, supplies power from the battery to a power supply target by performing a discharging operation of the battery, and monitors the operation state of a switch unit, and

the power receiving device performs the discharging operation of the battery when removal of the power receiving device is detected, and stops the discharging operation of the battery when an off operation of the switch unit is detected.