Information processing apparatus

Patent metadata

Field	Value
Publication number	US-2016282931-A1
Application number	US-201615074862-A
Country	US
Kind code	A1
Filing date	Mar 18, 2016
Priority date	Mar 24, 2015
Publication date	Sep 29, 2016
Grant date	—

Abstract

The present invention relates to an information processing apparatus including a power supply part and a voltage compensating circuit. The power supply part is configured to supply electric power to a first electronic device and a second electronic device. The voltage compensating circuit is configured, when the first electronic device is connected to the information processing apparatus, to increase a voltage output from the power supply part and to switch a power supply path for supplying the output voltage to the second electronic device from a first power supply path to a second power supply path including a step-down element so as to decrease the increased output voltage and to supply the decreased output voltage to the second electronic device.

First claim

What is claimed is:

1 . An information processing apparatus comprising:
a power supply part configured to supply electric power to a first electronic device and a second electronic device; and a voltage compensating circuit configured, when the first electronic device is connected to the information processing apparatus, to increase a voltage output from the power supply part and to switch a power supply path for supplying the output voltage to the second electronic device from a first power supply path to a second power supply path comprising a step-down element so as to decrease the increased output voltage and to supply the decreased output voltage to the second electronic device.

2 . The information processing apparatus according to claim 1 , wherein before the first electronic device is connected to the information processing apparatus, the voltage compensating circuit supplies the voltage output from the power supply part to the second electronic device through the first power supply path, and after the first electronic device is connected to the information processing apparatus, the voltage compensating circuit supplies the increased output voltage of the power supply part to the second electronic device through the second power supply path.

3 . The information processing apparatus according to claim 2 , wherein the first power supply path comprises a switch that turns off when the first electronic device is connected to the information processing apparatus.

4 . The information processing apparatus according to claim 2 , wherein the switch comprises a p-channel field effect transistor.

5 . The information processing apparatus according to claim 1 , wherein the step-down element comprises a Schottky diode.

6 . The information processing apparatus according to claim 1 , wherein the step-down element comprises a low drop-out regulator.

7 . The information processing apparatus according to claim 1 , wherein the first electronic device is connected to a substrate comprising the power supply part and the voltage compensating circuit through a cable.

8 . The information processing apparatus according to claim 7 , wherein the second electronic device is mounted on the substrate.

9 . The information processing apparatus according to claim 1 , wherein the voltage compensating circuit comprises a current detection circuit configured to detect that the first electronic device is connected to the information processing apparatus.

10 . The information processing apparatus according to claim 9 ,
wherein the current detection circuit comprises:
a resistor disposed between the power supply part and the first electronic device;
a comparator comprising an input terminal connected to one end of the resistor and an input terminal connected to another end of the resistor; and
a high-side switch.

11 . The information processing apparatus according to claim 10 , wherein the voltage compensating circuit switches the power supply path from the first power supply path to the second power supply path based on an output from the comparator.

12 . The information processing apparatus according to claim 10 , wherein the resistor comprises a resistor in the high-side switch.

13 . The information processing apparatus according to claim 1 , wherein at least one of the first electronic device and the second electronic device comprises an interface circuit.

14 . The information processing apparatus according to claim 13 , wherein the interface circuit comprises a universal serial bus (USB) interface circuit.

15 . The information processing apparatus according to claim 1 , further comprising a printer configured to form an image on a sheet.

Assignees

• Canon Kk

Inventors

• Hagiwara Yuichi

Classifications

• G06F13/4221

  being an input/output bus, e.g. ISA bus, EISA bus, PCI bus, SCSI bus · CPC title

• G06F1/3296 Primary

  by lowering the supply or operating voltage · CPC title

• G06F1/266 Primary

  Arrangements to supply power to external peripherals either directly from the computer or under computer control, e.g. supply of power through the communication port, computer controlled power-strips · CPC title

• G05F1/44

  semiconductor devices only · CPC title

• G01R15/04

  Voltage dividers · CPC title