# US 2019/0319480 A1 · Emergency driver system for providing a low float charge power to a rechargeable battery

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- Number: US 2019/0319480 A1
- Document ID: US20190319480A1
- Status: Published application
- Kind: A1
- Application number: 15/959,060
- Filed: 2018-04-20
- Published: 2019-10-17
- Earliest claimed: 2018-04-13
- Applicants: Fulham Company Limited
- Inventors: Qixiang CUI; Chunyan Han
- Web page: https://patentgrep.com/patent/US20190319480A1

## CPC

- H02J 9/065: {for lighting purposes}
- H01M 4/5805: {Phosphides}
- H01M 10/44: Methods for charging or discharging (circuits for charging H02J7/00)
- H01M 10/46: Accumulators structurally combined with charging apparatus (circuits for charging H02J7/00)
- H02J 7/90: Regulation of charging or discharging current or voltage
- H02J 7/953: {in response to charge current gradient}
- H02J 9/04: in which the distribution system is disconnected from the normal source and connected to a standby source
- H05B 45/00: Circuit arrangements for operating light-emitting diodes [LED]
- H05B 45/375: using buck topology
- H05B 45/385: using flyback topology
- H05B 47/172: {Emergency operational modes}
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H02J 2207/10: Control circuit supply, e.g. means for supplying power to the control circuit
- H05B 45/355: Power factor correction [PFC]; Reactive power compensation
- Y02B 20/40: Control techniques providing energy savings, e.g. smart controller or presence detection
- Y02E 60/10: Energy storage using batteries
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

An emergency driver system is disclosed for providing a low float charge power to a rechargeable battery. For one example, an emergency light emitting diode (LED) driver system includes a LED light source, a rechargeable battery, and emergency (EM) driver. The emergency LED driver system can also include a multi-color indicator circuit configured to a provide at least two LED light indicators providing information regarding the mode of operation for the EM driver. The rechargeable battery is coupled with the LED light source. The EM driver is coupled with the rechargeable battery and the LED light source. In one example, the EM driver includes a charge circuit configured to supply a charge current to the rechargeable battery, and a micro-controller unit configured to control the charge current from the charge circuit such that a power loss in at least standby mode is less than 0.5 watts (W). The rechargeable battery can be a LiFePO4 rechargeable battery providing an emergency illumination light source. By providing standby power of less than 0.5W for a LiFePO4 rechargeable battery, the EM driver with a flyback circuit followed by a buck circuit can save energy when the rechargeable battery is fully charged.

## Claims

### Claim 1

An emergency light emitting diode (LED) driver system comprising:
a LED light source;
a rechargeable battery coupled with the LED light source; and
an emergency (EM) driver coupled with the rechargeable battery and the LED light source, the EM driver including
a charge circuit configured to supply a charge current to the rechargeable battery, and
a micro-controller unit configured to control the charge current from the charge circuit such that a power loss in at least standby mode is less than 0.5 watts (W).

### Claim 2 (depends on 1)

The emergency LED driver system of claim 1, wherein the rechargeable battery is a LiFePO4 rechargeable battery.

### Claim 3 (depends on 2)

The emergency LED driver system of claim 2, wherein the LiFePO4 rechargeable battery is an emergency illumination light source.

### Claim 4 (depends on 1)

The emergency LED driver system of claim 1, wherein the charge circuit includes a flyback circuit followed by a buck circuit, and wherein the micro-controller unit is configured to control charge current supplied by the charge circuit to the rechargeable battery.

### Claim 5 (depends on 4)

The emergency LED driver system of claim 4, wherein the micro-controller unit is configured to control the charge current at a charge rate (C-rate) of at least 0.005 C for providing at least 9.6 volts (V) and 3000 mili-amps (mA) to the rechargeable battery.

### Claim 6 (depends on 4)

The emergency LED driver system of claim 4, wherein the micro-controller unit is configured to provide a minimum switching frequency of 600 Hz to 1 kHZ.

### Claim 7 (depends on 6)

The emergency LED driver system of claim 6, wherein the minimum switching frequency is user configurable.

### Claim 8 (depends on 6)

The emergency LED driver system of claim 6, wherein the switching frequency is to maintain a standby power consumption of less than 200 mW.

### Claim 9 (depends on 1)

The emergency LED driver system of claim 1, wherein the micro-controller unit is configured to provide a charge current of 15 mA to the rechargeable battery and maintain the rechargeable battery when fully charged to about 10.65 V.

### Claim 10 (depends on 1)

The emergency LED driver system of claim 1, further comprising:
a multi-color indicator circuit configured to a provide at least two LED light indicators providing information regarding the mode of operation for the EM driver.

### Claim 11

An emergency (EM) driver method comprising:
determining if a voltage for a rechargeable battery is below a first threshold;
charging the rechargeable battery with a constant charge current if the voltage for rechargeable battery is determined to be below the first threshold;
determining if the voltage for the rechargeable battery is not increasing; and
floating the charge current for the rechargeable battery if the voltage for the rechargeable battery is determined not to be increasing.

### Claim 12 (depends on 11)

The EM driver method of claim 11, further comprising:
determining if the rechargeable battery is fully charged and the voltage on the rechargeable battery is below a second threshold; and
maintaining the constant charge current to the rechargeable battery if the rechargeable battery is determined to be fully charged and the voltage on the rechargeable battery is determined to below the second threshold.

### Claim 13 (depends on 12)

The EM driver method of claim 12, further comprising stopping the constant charge current to the rechargeable battery if the rechargeable battery is determined to be fully charged and the voltage on the rechargeable battery is determined not to be below the second threshold.

### Claim 14 (depends on 13)

The EM driver method of claim 13, wherein the first threshold is 10.3V and the second threshold is 10.65V.

### Claim 15 (depends on 11)

The EM driver method of claim 11, wherein the rechargeable battery is a LiFePO4 rechargeable battery.

### Claim 16 (depends on 11)

The EM driver method of claim 11, wherein the constant charge current is approximately 15 mA.

### Claim 17 (depends on 11)

The EM driver method of claim 11, wherein charging the rechargeable battery with the constant charge current includes sustaining a standby power loss of less than 0.5 W.

### Claim 18 (depends on 17)

The EM driver method of claim 17, further comprising providing the constant charge current from a charge circuit including a flyback circuit followed by a buck circuit.

### Claim 19 (depends on 17)

The EM driver method of claim 17, further comprising providing power to a multi-color indicator circuit and a micro-controller unit of about 100 mW.

### Claim 20 (depends on 19)

The EM driver method of claim 19, further comprising turning on at least two LED light indicators providing information regarding the mode of operation for the EM driver.