Method for eliminating flicker in emergency lighting driver devices during pulse charging

Patent metadata

Field	Value
Publication number	US-2018062425-A1
Application number	US-201715664569-A
Country	US
Kind code	A1
Filing date	Jul 31, 2017
Priority date	Aug 31, 2016
Publication date	Mar 1, 2018
Grant date	—

Abstract

An emergency lighting driver device is configured to assume an operation mode in which: the battery is charged by applying the pulse signal to the transistor from the control unit, while the LED load is driven, wherein the emergency lighting driver device is configured to delay the pulse signal such that the rising edge(s) and/or falling edge(s) of the pulse signal have a transition time of at least 0.5 seconds, preferably at least 1 second, more preferred more than 1.5 seconds and preferably less than 3 seconds; and/or wherein the pulse signal is fed through a low pass filter unit of the emergency lighting driver device delaying the transition time of the rising edge(s) and/or falling edge(s) of the pulse signal before feeding it to the transistor.

First claim

1 . An emergency lighting driver device ( 1 ) for driving a lighting unit ( 10 ) comprising at least one emergency lighting source with a LED unit comprising at least one LED, wherein the emergency lighting driver device ( 1 ) comprises
a) an input terminal ( 2 ) being configured to be supplied with a supply voltage ( 11 ), b) a battery ( 4 ) connected in series to a transistor ( 5 ), wherein the series connection ( 6 ) of the battery ( 4 ) and the transistor ( 5 ) is directly or indirectly connected in parallel to the input terminal ( 2 ), such that the battery ( 4 ) is chargeable starting from the supply voltage ( 11 ), c) a LED driver ( 8 ) connected in parallel to the series connection ( 6 ) of the battery ( 4 ) and the transistor ( 5 ), the LED driver ( 8 ) having an output terminal ( 9 ) for driving a LED load ( 10 ), and d) a control unit ( 7 ) being configured to feedback-control the current through the LED load ( 10 ) by controlling the LED driver ( 8 ) and being configured to apply a pulse signal to the transistor ( 5 ) for controlling the charging of the battery ( 4 ), e) wherein the emergency lighting driver device ( 1 ) is configured to assume an operation mode in which:
the battery ( 4 ) is charged by applying the pulse signal to the transistor ( 5 ) from the control unit ( 7 ), while the LED load ( 10 ) is driven, and
the emergency lighting driver device ( 1 ) is configured to delay the pulse signal such that the rising edge(s) and/or falling edge(s) of the pulse signal have a transition time of at least 0.5 seconds.

2 . An emergency lighting driver device ( 1 ) according to claim 1 , wherein the emergency lighting driver device ( 1 ) comprises a low pass filter unit ( 12 ) configured to delay the transition time of the rising edge(s) and/or falling edge(s) of the pulse signal before feeding it to the transistor ( 5 ).

3 . An emergency lighting driver device ( 1 ) for driving a lighting unit ( 10 ) comprising at least one emergency lighting source with a LED unit comprising at least one LED, wherein the emergency lighting driver device ( 1 ) comprises
a) an input terminal ( 2 ) being configured to be supplied with a supply voltage ( 11 ), b) a battery ( 4 ) connected in series to a transistor ( 5 ), wherein the series connection ( 6 ) of the battery ( 4 ) and the transistor ( 5 ) is directly or indirectly connected in parallel to the input terminal ( 2 ), such that the battery ( 4 ) is chargeable starting from the supply voltage ( 11 ), c) a LED driver ( 8 ) connected in parallel to the series connection ( 6 ) of the battery ( 4 ) and the transistor ( 5 ), the LED driver ( 8 ) having an output terminal ( 9 ) for driving a LED load ( 8 ), and d) a control unit ( 7 ) being configured to feedback-control the current through the LED load ( 10 ) by controlling the LED driver ( 8 ) and being configured to apply a pulse signal to the transistor ( 5 ) for controlling the charging of the battery ( 4 ), e) wherein the emergency lighting driver device ( 1 ) is configured to assume an operation mode in which:
the battery ( 4 ) is charged by applying the pulse signal to the transistor ( 5 ) from the control unit ( 7 ), while the LED load ( 10 ) is driven, and
the pulse signal is fed through a low pass filter unit ( 12 ) of the emergency lighting driver device ( 1 ) delaying the transition time of the rising edge(s) and/or falling edge(s) of the pulse signal before feeding it to the transistor ( 5 ).

4 . An emergency lighting driver device ( 1 ) according to claim 3 , wherein the low pass filter unit ( 12 ) is configured to delay the pulse signal such that the rising edge(s) and/or falling edge(s) of the pulse signal have a transition time of at least 0.5 seconds.

5 . An emergency lighting driver device ( 1 ) according to claim 3 , wherein the low pass filter unit ( 12 ) comprises at least one RC-element (R 1 , C 3 ).

6 . An emergency lighting driver device ( 1 ) according to claim 3 , wherein
the LED driver ( 8 ) comprises at least one switched converter (S 2 , L 3 , D 2 , C 2 ), and the control unit ( 7 ) is configured to feedback-control the current through the LED load ( 10 ) by adapting the switching of the at least one switched converter (S 2 , L 3 , D 2 , C 2 ).

7 . An emergency lighting driver device ( 1 ) according to claim 3 , wherein the emergency lighting driver device ( 1 ) is configured to delay the pulse signal such that the current through the LED load ( 10 ) being feedback-controlled by the control unit ( 7 ) is within 10% of the nominal value for the current through the LED load ( 10 ).

8 . An emergency lighting driver device ( 1 ) according to claim 3 , wherein the transistor ( 5 ) is a MOSFET and the control unit ( 7 ) is configured to apply the pulse signal to the gate-terminal of the MOSFET.

9 . An emergency lighting driver device ( 1 ) according to claim 8 , wherein the emergency lighting driver device ( 1 ) is configured to delay the pulse signal such that the MOSFET is driven through its active region during the transition time of the rising edge(s) and/or falling edge(s) of the pulse signal.

10 . (canceled)

11 . An emergency lighting driver device ( 1 ) according to claim 3 , wherein
for charging the battery ( 4 ) the control unit ( 7 ) is configured to control the transistor ( 5 ) such that the transistor ( 5 ) is alternately switched between the conducting state and the non-conducting state, the transistor ( 5 ) is in the conducting state for a predetermined conducting time and in the non-conducting state for a predetermined non-conducting time, and the predetermined non-conducting time is longer than the predetermined conducting time.

12 . An emergency lighting driver device ( 1 ) according to claim 11 , wherein the predetermined conducting time corresponds to 4 minutes and the predetermined non-conducting time corresponds to 16 minutes.

13 . An emergency lighting driver device ( 1 ) according to claim 11 , wherein
for charging the battery ( 4 ) the control unit ( 7 ) is configured to control the transistor ( 5 ) such that the transistor ( 5 ) is in the conducting state for a predetermined initial conducting time before being alternately switched between the conducting state and the non-conducting state, and the predetermined initial conducting time is longer than the predetermined non-conducting time.

14 . An emergency lighting driver device ( 1 ) according to claim 13 , wherein the predetermined initial conducting time corresponds to 20 hours.

15 . An emergency lighting device comprising
an emergency lighting driver device ( 1 ) according to claim 3 , and a lighting unit ( 10 ) comprising at least one emergency lighting source with a LED unit comprising at least one LED, wherein the emergency lighting driver device ( 1 ) is configured to drive the lighting unit ( 10 ) starting from a voltage supply ( 11 ) via its input terminal ( 2 ) in a normal operation mode and to drive the lighting unit ( 10 ) starting from the battery ( 4 ) in an emergency operation mode.

16 . (canceled)

17 . (canceled)

18 . An emergency lighting driver device ( 1 ) according to claim 1 , wherein the emergency lighting driver device ( 1 ) is configured to delay the pulse signal such that the rising edge(s) and/or falling edge(s) of the pulse signal have a transition time of at least 1.0 seconds and less than 3 seconds.

19 . An emergency lighting driver device ( 1 ) according to claim 3 , wherein the emergency lighting driver device ( 1 ) is configured to delay the pulse signal such that t

Assignees

• Tridonic Gmbh & Co Kg

Inventors

• Frankland James

Classifications

• H02J7/927

  with introduction of pulses during the charging process · CPC title

• H02J7/865

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

• H02J9/061 Primary

  for DC powered loads · CPC title

• H02J9/06 Primary

  with automatic change-over {, e.g. UPS systems} · CPC title

• H05B45/59

  for reducing or suppressing flicker or glow effects · CPC title