Power supply switching circuit, electronic device, and control method of power supply switching circuit

Patent metadata

Field	Value
Publication number	US-9811062-B2
Application number	US-201414301137-A
Country	US
Kind code	B2
Filing date	Jun 10, 2014
Priority date	Jun 28, 2013
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

There is provided a power supply switching circuit including a first control signal output unit that outputs a signal exceeding a predetermined potential using a main power supply as a first control signal when a power supply voltage of the main power supply exceeds a predetermined reference voltage, a second control signal output unit that outputs the signal exceeding the predetermined potential using a standby power supply from a battery as a second control signal when a potential of the first control signal does not exceed the predetermined potential, and a power supply output unit that outputs the main power supply when the first control signal exceeds the predetermined potential and outputs the standby power supply when the second control signal exceeds the predetermined potential.

First claim

What is claimed is:

1. A power supply switching circuit comprising:
a power supply output terminal electrically connected directly to a cathode of a main power supply side diode and a cathode of a standby power supply side diode;
power supply output circuitry configured to output a main power supply voltage onto the power supply output terminal when control signal output circuitry detects that the main power supply voltage is higher than a reference voltage.

2. The power supply switching circuit according to claim 1 , wherein the reference voltage differs from the main power supply voltage.

3. The power supply switching circuit according to claim 1 , wherein the control signal output circuitry includes first control signal output circuitry that is configured to output a first signal onto a gate of a standby power supply side control transistor.

4. The power supply switching circuit according to claim 3 , wherein the cathode of the standby power supply side diode is electrically connected directly to a source of a standby power supply side control transistor.

5. The power supply switching circuit according to claim 3 , wherein an anode of the standby power supply side diode is electrically connected directly to a drain of the standby power supply side control transistor.

6. The power supply switching circuit according to claim 3 , wherein the power supply output circuitry is controllable by the first signal to output the main power supply voltage onto the power supply output terminal when the first signal is at a first logic level.

7. The power supply switching circuit according to claim 6 , wherein the first control signal output circuitry is configured to output the first signal at the first logic level when the main power supply voltage is higher than the reference voltage.

8. The power supply switching circuit according to claim 6 , wherein the control signal output circuitry includes second control signal output circuitry that is configured to output a second signal at the first logic level when the first signal is at a second logic level.

9. The power supply switching circuit according to claim 8 , wherein the second logic level differs from the first logic level.

10. The power supply switching circuit according to claim 8 , wherein the second control signal output circuitry is configured to output the second signal at the second logic level when the first signal is at the first logic level.

11. The power supply switching circuit according to claim 1 , wherein the control signal output circuitry includes second control signal output circuitry that is configured to output a second signal onto a gate of a main power supply side control transistor.

12. The power supply switching circuit according to claim 11 , wherein the power supply output circuitry is controllable by the second signal to output the standby power supply voltage onto the power supply output terminal when the second signal is at the first logic level.

13. The power supply switching circuit according to claim 11 , wherein the power supply output circuitry is controllable by the second signal to output the main power supply voltage onto the power supply output terminal when the second signal is at the second logic level.

14. The power supply switching circuit according to claim 1 , wherein the power supply output circuitry is configured to output a standby power supply voltage onto the power supply output terminal when the control signal output circuitry detects that the main power supply voltage is not higher than the reference voltage.

15. The power supply switching circuit according to claim 14 , wherein the standby power supply voltage differs from the reference voltage.

16. The power supply switching circuit according to claim 14 , wherein the standby power supply voltage differs from the main power supply voltage.

17. An electronic device comprising:
the power supply switching circuit according to claim 14 ;
main power supply output circuitry configured to supply the main power supply voltage; and
a battery configured to supply the standby power supply voltage.

18. A control method of a power supply switching circuit, the method comprising:
outputting, by a power supply output circuitry, a main power supply voltage onto a power supply output terminal when control signal output circuitry detects that the main power supply voltage is higher than a reference voltage; and
outputting, by the power supply output circuitry, a standby power supply voltage onto the power supply output terminal when the control signal output circuitry detects that the main power supply voltage is not higher than the reference voltage,
wherein the power supply output terminal electrically connected directly to a cathode of a main power supply side diode and a cathode of a standby power supply side diode.

Assignees

• Sony Corp

Inventors

• Akebono Sachio
• Makigawa Kiyoshi
• Hirono Daisuke
• Jeong Moonjae
• Iguchi Taiki

Classifications

• G05B15/02 Primary

  electric · CPC title

• H03K17/005 Primary

  with several inputs only · CPC title

• H03K17/223

  in field-effect transistor switches · CPC title

• H03K17/6871

  the output circuit comprising more than one controlled field-effect transistor · CPC title

• H03K2217/0081

  Power supply means, e.g. to the switch driver · CPC title