Power circuit

• US 6,525,666 B1
• Filed: 12/16/1999
• Issued: 02/25/2003
• Est. Priority Date: 12/16/1998
• Status: Expired due to Term

• Current Assignee: Ablic Inc. (MinebeaMitsumi Inc.)
• Original Assignee: Seiko Instruments Incorporated (Seiko Group)
• Inventors: Shimoda, Sadashi
• Primary Examiner(s): TRIEU, VAN THANH
• Application Number:
  US09/465,079
• Time in Patent Office: 1,167 Days
• Field of Search: 340/635, 340/657, 340/660, 340/661, 340/662, 340/663, 340/636, 340/7.32, 340/7.36, 340/7.37, 340/3.1, 396/228, 396/230, 396/231, 363/15, 363/49, 363/59, 323/280, 323/281, 323/283, 318/782, 318/805, 62/77, 621/27
• US Class Current: 340/636.1
• CPC Class Codes: H02J 9/005 using a power saving mode for copiers G03G15/5004
• CPC Class Codes: H02M 1/0032 Control circuits allowing low power mode operation, e.g. in standby mode
• CPC Class Codes: H02M 7/12 using discharge tubes with control electrode or semiconductor devices with control electrode
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y04S 20/20 End-user application control systems

Abstract

Household appliances such as televisions require the continuous supply of power to a remote control receiving circuit and microcomputer to receive remote control signals when turned off. To reduce power consumption, charge is stored in a battery or capacitor to supply power to the microcomputer and remote control receiving circuit without continuous operation of an AC-DC converter. Before a voltage of the charge storing device is reduced below a given level, such as the lowest operating voltage of the microcomputer and remote control receiving circuit, the AC-DC converter is activated to charge the charge storing device. When the voltage rises to a given level, such as the highest operating voltage of the microcomputer and the remote control receiving circuit, the AC-DC converter stops charging the charge storing device, so that the operating frequency of the AC-DC converter is reduced.

Claims

1. A power supply circuit for an electrical apparatus having an internal circuit with a remote control function, the power supply circuit comprising:

a converter for converting an a.c. voltage into a d.c. voltage and driving the internal circuit;

a charge storage device for storing a charge produced by the converter;

a voltage detector driven by the charge storage device for detecting a voltage of the charge storage device;

a remote control signal receiver driven by the charge storage device for receiving a remote control signal from an external controller and producing a corresponding output signal; and

a controller having a sub-microcomputer driven by the charge storage device and a main microcomputer driven by the converter, the sub-microcomputer for receiving the output signal of the remote control signal receiver and outputting a signal for activating the converter so that the converter drives the internal circuit.

2. A power supply circuit according to claim 1;

wherein the controller, the remote control signal receiver, the charge storage device and the voltage detector are disposed on the same printed circuit board.

3. A power supply circuit according to claim 1;

wherein the voltage detector outputs a signal to activate the converter to charge the charge storage device when the detected voltage of the charge storage device falls below a first predetermined level and outputs a signal to deactivate the converter when the detected voltage is above a second predetermined level.

4. A power supply circuit according to claim 3;

wherein the first predetermined level is lower than the second predetermined level.

5. A power supply circuit according to claim 3;

wherein the first and second predetermined levels are equal.

6. A power supply circuit according to claim 1;

wherein the voltage detector outputs a signal to activate the converter to charge the charge storage device when the detected voltage of the charge storage device falls below the lower one of the minimum operating voltages of the remote control signal receiver and the sub-microcomputer and to deactivate the converter when the detected voltage is above the higher one of the minimum operating voltages of the remote control signal receiver and the sub-microcomputer.

7. A power supply circuit according to claim 1;

wherein the remote control signal is a signal for turning on the internal circuit.

8. A power supply circuit for an electrical apparatus having an internal circuit with a remote control function, the power supply circuit comprising:

a charge storage device for storing a charge;

a voltage detector for detecting a voltage across the charge storage device;

a converter for converting an a.c. voltage into a d.c. voltage for driving the internal circuit, charging the charge storage device if the detected voltage across the charge storage device becomes lower than a given voltage, and stopping the charging operation of the charge storage device if the voltage becomes equal to or more than the given voltage;

a remote control signal receiver driven by the charge storage device for receiving a remote control signal and producing a corresponding output signal; and

a controller having a sub-microcomputer driven by the charge storage device and a main microcomputer driven by the converter, the sub-microcomputer for receiving the output signal of the remote control signal receiver and outputting a signal for activating the converter so that the converter drives the internal circuit and the main microcomputer is supplied power by the converter and turns on.

9. A power supply circuit for an electrical apparatus having an internal circuit with a remote control function, the power supply circuit comprising:

a converter for converting an a.c. voltage into a d.c. voltage and driving the internal circuit;

a charge storage device for storing a charge;

a voltage detector for detecting a voltage of the charge storage device;

a controller for controlling an on/off state of the internal circuit; and

a remote control signal receiver for receiving a remote control signal from an external controller and outputting a corresponding signal to the controller to control the internal circuit;

wherein the controller has a sub-microcomputer driven by the charge storage device and a main microcomputer driven by the converter, the sub-microcomputer for receiving the output signal of the remote control signal receiver and outputting a signal for activating the converter so that the converter drives the internal circuit and the main microcomputer is supplied power by the converter and turns on, and the voltage detector and the remote control signal receiver are supplied with a supply voltage from the charge storage device and the internal circuit is supplied with a supply voltage from the converter and the converter is activated only when a remote control signal for activating the internal circuit has been received by the remote control signal receiver.

10. A power supply circuit according to claim 9;

wherein the main microcomputer is disposed separately from the sub-microcomputer, and the sub-microcomputer is responsive to a signal from the remote control signal receiver to activate the main microcomputer.

11. A power circuit according to claim 9;

wherein the converter comprises a first converter for converting an a.c. voltage into a first d.c. voltage for driving the main microcomputer and the internal circuit and a second converter for converting the a.c. voltage into a second d.c. voltage to charge the charge storage device.

12. A power supply circuit for an electrical apparatus having an internal circuit with a remote control function, the power supply circuit comprising:

a remote control signal receiver for receiving a remote control signal from an external controller;

a converter for converting an a.c. voltage into a d.c. voltage and driving the internal circuit;

a charge storage device for storing a charge produced by the converter;

a main microcomputer driven by the controller for controlling the internal circuit; and

a sub-microcomputer driven by the charge storage device for receiving an output signal of the remote control signal receiver and starting operation of the converter to drive the main microcomputer and the internal circuit in response thereto;

wherein the main microcomputer stops operation of the sub-microcomputer when the remote control signal receiver receives a first signal for activating the converter, and starts the operation of the sub-microcomputer and thereafter stops the operation of the main microcomputer when the remote control signal receiver receives a second remote control signal which allows the converter to stop operating.

13. A power supply circuit for an electrical apparatus having an internal circuit with a remote control function, comprising:

a power source for driving the internal circuit;

a charge storage device for storing a charge produced by the power source;

a remote control circuit driven by the charge storage device for receiving a remote control signal for activating the internal circuit from an external controller and outputting a corresponding signal for activating the power source to drive the internal circuit and a controller having a sub-microcomputer driven by the charge storage device and a main microcomputer driven by the power source, the sub-microcomputer for receiving the output signal of the remote control circuit and outputting a signal for activating the power source so that the power source drives the internal circuit.

14. A power supply circuit according to claim 13;

wherein the power source comprises a converter for converting an a.c. signal from an a.c. power source into a d.c. signal to drive the internal circuit.

15. A power supply circuit according to claim 14;

wherein the power source further comprises a switch having an on/off state disposed between the a.c. power source and the converter, the on/off state of the switch being controlled by an output signal of the remote control circuit.

16. A power supply circuit according to claim 13;

wherein the charge storage device comprises one of a battery and a capacitor.

17. A power supply circuit according to claim 13;

further comprising a voltage detecting circuit driven by the charge storage device for detecting a voltage of the charge storage device and outputting a corresponding signal for activating the power source when the detected voltage falls below a first predetermined level and for deactivating the power source when the detected voltage rises above a second predetermined level.

18. A power supply circuit according to claim 17;

wherein the voltage detecting circuit outputs a signal to activate the power source to charge the charge storage device when the detected voltage of the charge storage device below the lower one of the minimum operating voltages of the remote control circuit and the sub-microcomputer and to deactivate the power source when the detected voltage is above the higher one of the minimum operating voltages of the remote control circuit and the sub-microcomputer.

19. A power supply circuit according to claim 17;

wherein the first predetermined level is lower than the second predetermined level.

20. A power supply circuit according to claim 17;

wherein the first and second predetermined levels are equal.