# US 2014/0197780 A1 · Charging apparatus for secondary battery

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- Number: US 2014/0197780 A1
- Document ID: US20140197780A1
- Status: Published application
- Kind: A1
- Application number: 14/148,089
- Filed: 2014-01-06
- Published: 2014-07-17
- Earliest claimed: 2013-01-17
- Assignees: Makita Corporation; Tamura Corporation
- Applicants: Makita Corporation; Tamura Corporation
- Inventors: Koji IMAMURA; Takeshi YAMAMOTO; Yasuhiro TABUCHI; Makihiro KOBAYASHI
- Web page: https://patentgrep.com/patent/US20140197780A1

## CPC

- H02J 7/00: Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
- H02J 7/825: {Detection of fully charged condition}
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY

## Abstract

A charging apparatus for a secondary battery comprises: a power supply circuit connected to a primary winding 11a of a transformer T1; a main winding 11b and a sub winding 11c connected to a secondary side of the transformer T1; a charging circuit 110 connected to the main winding 11b, the charging circuit 110 supplying power to a battery pack 130 to be charged; and a control circuit 120 connected to the sub winding 11c, the control circuit 120 controlling the charging circuit 110, wherein the charging circuit 110 comprises a LED 140 indicating a standby state or a charge completion state, the LED 140 being lighted at light-load time of the charging circuit 110 based on a command of the control circuit 120.

## Claims

### Claim 1

A charging apparatus for a secondary battery, comprising:
a power supply circuit connected to a primary winding of a transformer;
a main winding and a sub winding connected to a secondary side of the transformer;
a charging circuit connected to the main winding, the charging circuit supplying power to a battery pack to be charged; and
a control circuit connected to the sub winding, the control circuit controlling the charging circuit,
wherein the charging circuit comprises a LED indicating a standby state or a charge completion state, the LED being lighted at light-load time of the charging circuit based on a command of the control circuit.

### Claim 2 (depends on 1)

The charging apparatus for the secondary battery according to claim 1, wherein the LED is connected to the charging circuit via a constant voltage circuit connected in series with the LED.

### Claim 3 (depends on 2)

The charging apparatus for the secondary battery according to claim 2, wherein the charging circuit comprises a resistor connected to a connection point of the LED and the constant voltage circuit at one end and connected to the control circuit at the other end.

### Claim 4 (depends on 3)

The charging apparatus for the secondary battery according to claim 3, wherein the control circuit allows the LED to blink responding to a charge state of the battery pack at light-load time of the charging circuit, controls current not to flow to the resistor when the LED is lighted up, and controls current to flow to the resistor when the LED is lighted out.