Powering an emergency lighting system

Patent metadata

Field	Value
Publication number	US-2018368221-A1
Application number	US-201816009587-A
Country	US
Kind code	A1
Filing date	Jun 15, 2018
Priority date	Jun 19, 2017
Publication date	Dec 20, 2018
Grant date	—

Abstract

An emergency LED lighting system maintains power to an LED lighting source based on measured voltages and currents provided to the LED lighting source; rolls back or decreases power provided to an LED lighting source over time in order to increase the amount of time the battery can power the LED lighting source; executes a soft start procedure, such that the power provided to the LED lighting source is gradually ramped up during activation of the LED lighting sources; identifies a type of battery coupled to the emergency LED lighting system; cycles the emergency LED lighting system between charging mode and standby mode to reduce power consumption over a window of time; detects AC power or an absence of AC power; and/or uses a status LED to communicate information about the emergency LED lighting system with a remote device.

First claim

What is claimed is:

1 . An emergency LED lighting system comprising:
a first battery connection point configured to be coupled to a first terminal of a battery; a second battery connection point configured to be coupled to a second terminal of the battery; a first LED lighting source connection point configured to be coupled to a first terminal of an LED lighting source; a second LED lighting source connection point configured to be coupled to a second terminal of the LED lighting source; an emergency LED driver coupled to the first battery connection point, the second battery connection point, the first LED lighting source connection point, and the second LED lighting source connection point, the emergency LED driver comprising:
a voltage sensor for sensing an LED voltage across the LED lighting source and providing a first sensed voltage based on the LED voltage;
a current sensor for sensing an LED current through the LED lighting source and providing a second sensed voltage based on the LED current;
a converter coupled between the first battery connection point and the first LED lighting source connection point for providing the LED current to the LED lighting source; and
a current controller coupled to the converter for adjusting the LED current provided by the converter; and
a controller coupled to the emergency LED driver, the controller comprising:
a first input for receiving the first sensed voltage;
a second input for receiving the second sensed voltage; and
a current control output coupled to an input of the current controller for controlling the LED current through the LED lighting source to maintain LED power when the emergency LED lighting system is powered by the battery in an emergency mode.

2 . The emergency LED lighting system of claim 1 , wherein the voltage sensor comprises a voltage divider including a first resistor coupled to the first LED lighting source connection point and a second resistor and the second resistor conductively coupled between the first resistor and the second battery connection point, and the first sensed voltage corresponds to a voltage between the first resistor and the second resistor.

3 . The emergency LED lighting system of claim 1 , wherein the current sensor comprises a resistor conductively coupled in series between the second LED lighting source connection point and the second battery connection point.

4 . The emergency LED lighting system of claim 1 , wherein the converter is a single-ended primary inductor converter (“SEPIC”) or a boost converter.

5 . The emergency LED lighting system of claim 1 , wherein when emergency mode is entered, the controller monitors the first sensed voltage and controls the current controller to increase the LED current while the first sensed voltage is within a voltage range until the LED power reaches a predetermined power level.

6 . The emergency LED lighting system of claim 1 , wherein when emergency mode is entered, the controller monitors the first sensed voltage and controls the current controller to reduce the LED current when the first sensed voltage is indicative of a short or an out of range LED lighting source.

7 . The emergency LED lighting system of claim 1 , further comprising:
an AC detect circuit that outputs a signal indicating a presence of AC input power; a battery charging circuit; and a battery, wherein the emergency LED lighting system enters a standby mode based on a battery voltage and the presence of AC input power and remains in the standby mode until the battery voltage reaches a battery recharge level, wherein the battery powers the controller and the battery charging circuit is disabled during the standby mode.

8 . The emergency LED lighting system of claim 1 , further comprising a resistor with a first end of the resistor being conductively coupled to the first battery connection point and a second end of the resistor being conductively coupleable to a battery identification resistor associated with a battery connected to the first battery connection point and the second battery connection point, wherein the controller is further configured to determine characteristics of the battery using a signal derived from a voltage between the resistor and the battery identification resistor.

9 . The emergency LED lighting system of claim 1 , further comprising:
a light pulse communication circuit coupled to the controller that communicates with an external device using light pulses, wherein the controller transmits status information for the battery or the lighting system via the light pulse communication circuit.

10 . The emergency LED lighting system of claim 1 , further comprising:
a light pulse communication circuit coupled to the controller that receives light pulses from an external device, wherein the controller receives a signal from the light pulse communication circuit and determines configuration data from the signal.

11 . A method comprising:
providing, by a battery, a battery output for powering an emergency LED lighting system during an emergency mode; providing, by a current converter coupled between a first battery connection point and a first LED lighting source connection point, LED current to an LED lighting source; measuring, by a voltage sensor, an LED voltage across the LED lighting source; measuring, by a current sensor, the LED current passing through the LED lighting source; using, by a controller, the LED voltage and the LED current to determine an LED power; and controlling a current controller, by the controller, to maintain the LED power during the emergency mode, wherein the controller instructs the current controller to adjust the LED current provided by the current converter to an adjusted LED current to maintain the LED power as the battery discharges during the emergency mode.

12 . The method of claim 11 , further comprising:
detecting, by the controller, a short condition based on the LED voltage; and controlling the current controller, by the controller, to reduce the LED current to be below a threshold current level during the short condition.

13 . The method of claim 11 , further comprising:
when emergency mode is initiated, controlling the current controller, by the controller, to gradually increase the LED current from a minimal LED current level to a predetermined LED current level at a predetermined rate.

14 . The method of claim 11 , further comprising:
determining a battery type, by the controller, by evaluating a battery ID signal received from a circuit comprising at least one component associated with a battery pack that includes the battery and at least one component associated with the emergency LED lighting system.

15 . The method of claim 11 , further comprising:
determining, by the controller, an ambient temperature associated with the battery; and when the ambient temperature falls within a rollback temperature range, controlling the current controller, by the controller, to decrease the LED current to a first rollback current at a first rollback time.

16 . The method of claim 15 , further comprising:
controlling the current controller, by the controller, to decrease the LED current from the first rollback current to a second rollback current at a second rollback time; and maintaining the second rollback current until emergency mode is exited.

17 . The method of claim 11 , further comprising:
during a charging mode, determining, by the controller, a charge level of the battery; when the charge level is beyond a battery full level, contro

Assignees

• Abl Ip Holding Llc

Inventors

• Johnson James Clarence
• Mavis Dean W
• Marques Antonio
• Patel Gunjan P
• Altenburger Ray

Classifications

• H02J7/865

  Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence) · CPC title

• H05B47/105

  in response to determined parameters · CPC title

• F21S9/022

  Emergency lighting devices · CPC title

• F21V23/02

  the elements being transformers, impedances {or power supply units, e.g. a transformer with a rectifier} · CPC title

• F21Y2115/10

  Light-emitting diodes [LED] · CPC title