U.S. patent application number 14/338141 was filed with the patent office on 2014-11-06 for 3-way led bulb.
The applicant listed for this patent is Switch Bulb Company, Inc.. Invention is credited to Ronald J. LENK.
Application Number | 20140327368 14/338141 |
Document ID | / |
Family ID | 42098242 |
Filed Date | 2014-11-06 |
United States Patent
Application |
20140327368 |
Kind Code |
A1 |
LENK; Ronald J. |
November 6, 2014 |
3-WAY LED BULB
Abstract
A lighting circuit for a light emitting diode (LED) bulb capable
of operating at different light output levels depending on received
AC power includes a first group of LEDs and second group of LEDs,
each of which is configured to emit light as a group. The lighting
circuit also includes an AC/DC converter electrically connected to
the first and second groups of LEDs. A detector circuit detects
received AC power. A selection circuit is operable to cause the
AC/DC converter circuit to provide current into one configuration
of LEDs from the group of configurations of LEDs consisting of: the
first group of LEDs only, the second group of LEDs only, and the
first and second group of LEDs. The configuration of LEDs to
provide current to is selected based on received AC power.
Inventors: |
LENK; Ronald J.; (Woodstock,
GA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Switch Bulb Company, Inc. |
San Jose |
CA |
US |
|
|
Family ID: |
42098242 |
Appl. No.: |
14/338141 |
Filed: |
July 22, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13485911 |
May 31, 2012 |
8816594 |
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14338141 |
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12561514 |
Sep 17, 2009 |
8198819 |
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13485911 |
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61097680 |
Sep 17, 2008 |
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Current U.S.
Class: |
315/201 |
Current CPC
Class: |
Y02B 20/30 20130101;
H05B 45/10 20200101; Y02B 20/383 20130101 |
Class at
Publication: |
315/201 |
International
Class: |
H05B 33/08 20060101
H05B033/08 |
Claims
1. A lighting circuit for a light emitting diode (LED) bulb capable
of operating at different light output levels depending on received
AC power, the LED bulb comprising: a first group of LEDs
electrically connected together to emit light as a group; a second
group of LEDs electrically connected together to emit light as a
group; an AC/DC converter circuit electrically connected to the
first group of LEDs and the second group of LEDs; a detector
circuit configured to detect received AC power; and a selection
circuit operable to cause the AC/DC converter circuit to provide
current into one configuration of LEDs from the group of
configurations of LEDs consisting of: the first group of LEDs only,
the second group of LEDs only, and the first and second group of
LEDs, wherein the configuration of LEDs to provide current to is
selected based on received AC power.
2. The circuit of claim 1, wherein the detector circuit includes an
energization circuit that detects when a plurality of inputs to the
circuit are active.
3. The circuit of claim 1, wherein the selection circuit includes
of a pair of gain-setting circuits.
4. The circuit of claim 3, wherein each of the pair of gain-setting
circuits includes a transistor in series with a current-sense
resistor.
5. The circuit of claim 1, wherein the first group of LEDs and the
second group of LEDs are connected in series.
6. The circuit of claim 5, wherein the AC/DC converter circuit
includes a transistor in series with the first and second groups of
LEDs.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/485,911, filed May 31, 2012, which is a
continuation of U.S. patent application Ser. No. 12/561,514, filed
Sep. 17, 2009 and issued Jun. 12, 2012 as U.S. Pat. No. 8,198,819,
which claims priority to U.S. Provisional Patent Application No.
61/097,680, filed Sep. 17, 2008, each of which is incorporated
herein by this reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to circuitry for a 3-way LED
light bulb, and more particularly, to a circuit that interfaces
with a standard 3-way light socket, and produces three levels of
light corresponding to the three settings of the socket.
BACKGROUND OF THE INVENTION
[0003] An LED (light-emitting diode) consists of a semiconductor
junction, which emits light due to a current flowing through the
junction. An LED light bulb is a device that contains one or more
LEDs and potentially a drive circuit for the LEDs, which are both
located inside a conventionally shaped container (or shell).
Conventional LED light bulbs screw into a standard socket and
receive AC power from the two power connections of the socket.
[0004] However, 3-way sockets differ from standard sockets in that
they have three power connections. The control of the socket is
configured so that, in sequence, a first power configuration (i.e.,
a first pair) consisting of the base and one of the power
connections, which is energized with AC power, a second power
configuration (i.e., a second pair) consisting of the base and a
second power connection which is energized, and a third power
configuration, which includes the base and both connections (i.e.,
the first and the second power connections), which are energized. A
conventional LED light bulb will be energized only in one of the
configurations, and will not respond with different light levels to
the different settings.
[0005] It can be appreciated that one solution to this problem is
to have separate driving circuits energized by each of the
configurations (or pairs). It can be appreciated that the circuits
can be designed to deliver different drive power to the LEDs, and
to deliver the sum of these two drive powers when both are
energized. However, in practice, this solution may be expensive,
and very difficult to fit inside the bulb.
SUMMARY OF THE INVENTION
[0006] This invention has the object of developing a circuit for an
LED light bulb such that the above-described primary problem is
effectively solved by providing an inexpensive circuit that drives
the LEDs in the bulb at different power levels depending on the
energization of the 3-way socket. In accordance with an exemplary
embodiment, the invention includes at least two (or a pair of)
rectifier bridges attached to a pair of AC input connections,
either of which may power an AC/DC converter. Each pair of inputs
also includes a set (or pair) of low-power bridges. In accordance
with an exemplary embodiment, the low-power bridges can be used to
detect which of the pairs of AC connections are powered. In
accordance with an embodiment, detection is accomplished, for
example, by a resistor and a capacitor acting as an integrator. If
the first pair of AC connections is powered, the first detector
signals the AC/DC converter to produce a first level of power into
the LEDs. Similarly, if the second pair of AC connections is
powered, the second detector signals the AC/DC converter to produce
a second level of power into the LEDs. Finally, if both pairs of AC
connections are powered, both detectors signal the AC/DC converter,
causing it to produce the sum of the two power levels into the
LEDs.
[0007] In an alternative circuit, if the first pair of AC
connections is powered, the first detector signals the AC/DC
converter to produce current into a first string of LEDs.
Similarly, if the second pair of AC connections is powered, the
second detector signals the AC/DC converter to produce current into
a second string of LEDs. Finally, if both pairs of AC connections
are powered, both detectors signal the AC/DC converter, causing it
to produce current into both strings (i.e., a plurality of LEDs in
series) of LEDs. In accordance with an exemplary embodiment, this
configuration can be desirable to avoid slight changes in color (or
color spectrum) of the LEDs caused by running the LEDs at different
currents.
[0008] In accordance with an exemplary embodiment, the time
constant of the integrator must be set appropriately for both
circuits. In particular, the time constant of the integrator must
be substantially longer than half a line cycle of the AC power. In
a preferred embodiment, the time constant of the integrator is
approximately 5 to 10 times as long as half a line cycle of the AC
power.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The accompanying drawings are included to provide a further
understanding of the invention, and are incorporated in and
constitute a part of this specification. The drawings illustrate an
embodiment of the invention and, together with the description,
serve to explain the principles of the invention.
[0010] FIG. 1 is a circuit schematic of a circuit that drives the
LEDs in an LED bulb at different power levels depending on the
energization of a 3-way socket.
[0011] FIG. 2 is a circuit schematic of a circuit that selectively
drives the LEDs in an LED bulb depending on the energization of a
3-way socket.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0012] Reference will now be made in detail to the present
preferred embodiments of the invention, an example of which is
illustrated in the accompanying drawing. Wherever possible, the
same reference numbers are used in the drawing and the description
to refer to the same or like parts.
[0013] According to the design characteristics, a detailed
description of the preferred embodiments is given below.
[0014] FIG. 1 is a schematic of a circuit 10 that drives at least
one string of LEDs 110 (i.e., a plurality of LEDs 110 in series) in
an LED bulb at different power levels depending on the energization
of a 3-way socket (not shown). In accordance with a preferred
embodiment, the circuit 10 includes a base 120 and a first ring 121
of the socket, which are connected to an AC power bridge (or bridge
rectifier) 20. The AC power bridge 20 is preferably a standard AC
power bridge, which includes a first half 21 consisting of a first
pair of diodes 31, 32, and a second half 22 consisting of a second
pair of diodes 33, 34. In accordance with an exemplary embodiment
the first and second pairs of diodes 31, 32, 33, 34 (i.e., the four
(4) diodes) are configured in a standard full-wave rectification
configuration. The output and ground of the bridge 20 are connected
to a power system 130, which drives the at least one LED 110.
[0015] In a preferred embodiment, the circuit 10 also includes a
second ring 122 of the socket, which is connected to a bridge
rectifier circuit 23, which consists of a third pair (i.e., two) of
diodes 35, 36. In accordance with an exemplary embodiment, the
second half 22 of the bridge rectifier 20 is the same as the first
half 21 of the first bridge rectifier 20. In operation, current
being drawn from the second ring 122 is rectified by the first and
third pairs of diodes 31, 32, 35, 36, which acts as a complete
bridge rectifier. The output of this bridge rectifier is used to
power the power system 130, in parallel with the output of the
bridge rectifier 20.
[0016] In accordance with an exemplary embodiment, in order to
determine which light level is desired, the first and second rings
121, 122 each have an independent detection circuit 40, 50 (i.e., a
first detection circuit 40, and a second detection circuit 50). In
the first detection circuit 40, an input connection in the form of
AC power (AC3) from the second ring 122 is half-wave rectified by
diode 41. This signal is integrated by an RC circuit consisting of
a resistor 42 and a capacitor 44. When AC power (AC3) from the
second ring 122 is energized, the voltage on the capacitor 44 rises
to a level set approximately by the values of the resistor dividers
42, 43. When AC power (AC3) from the second ring 122 is not
energized, the voltage on capacitor 44 falls to zero, as energy is
bled out through the resistor 43. The voltage on the capacitor 44
is thus indicative of the presence or absence of energization of AC
power (AC3) on the second ring 122. In accordance with an exemplary
embodiment, the functionality and structure of the second detection
circuit 50 for energization detection of an input or input
connection in the form of AC power (AC2) on the first ring 121 is
essentially identical to the first detection circuit 40.
[0017] In accordance with an exemplary embodiment, the voltage
present on capacitors 44, 54 is used to determine the on or off
state of transistors 60, 70. The transistors 60, 70 are used in
turn to determine the value of the current sense resistor used in a
power switcher 130, which sets the power level. In particular, if
the AC power (AC2) in the first ring 121 is energized, capacitor 54
will have a voltage on it. By suitable selection of resistors 52
and 53, this voltage can be designed to be high enough to turn on
transistor 70. When transistor 70 is on, resistor 71 in series with
transistor 70 is used as a current sensor by the power switching
circuit 130. The current sensor (resistor 71 in series with
transistor 70) is used by the power switcher 130 to set the amount
of current that flows through the at least one LED 110. If AC power
(AC2) in the first ring 121 is not energized, the voltage on
capacitor 54 will be zero, transistor 70 will be off, and the power
switcher 130 will use the default resistor 80 to set the LED
current.
[0018] In the similar case wherein the AC power (AC3) in the second
ring 122 is energized, transistor 60 is turned on, and resistor 61
in series with transistor 60 is used as a current sensor by the
power switching circuit 130. If both AC power (AC2) and (AC3) from
the first and second rings 121, 122 are energized, both capacitors
44 and 54 will be charged, both transistors 60 and 70 will be on,
and the two current sense resistors 61 and 71 in series with their
respective transistors 60 and 70 will be used as current
sensors.
[0019] Thus in this circuit 10, three different light levels are
available by suitably selecting the values of current sense
resistors 61 and 71. When AC power (AC2) from the first ring 121 is
energized, the current generated by the power switcher 130 will be
set by resistor 71. When AC power (AC3) is energized, the current
generated by power switcher 130 will be set by resistor 61. When
both the AC power (AC2), (AC3) from the first and second rings 121,
122 are energized, the current generated by power switcher 130 will
be set by the parallel combination of resistors 61, 71. In
accordance with an exemplary embodiment, resistor 80 is
preferentially selected to set a very low current through the at
least one LED 110, so that during the time it takes for the
capacitors 44 and/or 54 to charge, no destructive switching occurs
in the power switcher 130.
[0020] FIG. 2 is a schematic of a circuit 11 that drives at least
two series or strings of LEDs 110, 111 (i.e., a first series and a
second series of LEDs 110, 111) in an LED bulb with differing LEDs
on or off depending on the energization of a 3-way socket. In
accordance with an exemplary embodiment, each of the at least two
strings of LEDs 110, 111 includes at least one LED 110, 111. It can
be appreciated that in accordance with an exemplary embodiment,
each of the at least two strings of LEDs 110, 111 are comprised of
a single LED 110, 111. In accordance with a preferred embodiment,
the base 120 and the first ring 121 of the socket are connected to
an AC power bridge 20 (i.e., a standard AC power bridge or bridge
rectifier), consisting of two halves 21, 22 (i.e., a first half 21
and a second half 22). The first half 21 consists of a first pair
(i.e., two) diodes 31, 32, and the second half 22 consists of a
second pair (i.e., two) of diodes 33, 34. The four diodes 31, 32,
33, 34 (i.e., the first and second pair of diodes) being configured
in a standard full-wave rectification configuration. In accordance
with an exemplary embodiment, the output and ground of the bridge
20 are connected to the power system 130, which drives the at least
one two strings of LEDs 110 and 111.
[0021] In this preferred embodiment, the second ring 122 of the
socket is connected to a bridge rectifier circuit 23, which
consists of a third pair (i.e., two) diodes 35, 36. In accordance
with an exemplary embodiment, the second half 22 of the bridge
rectifier 20 is the same as the first half 21 of the first bridge
rectifier 20. In operation, current being drawn from the second
ring 122 is rectified by the first and third pair of diodes 31, 32,
35, 36, which act as a complete bridge rectifier. The output from
the bridge rectifier is used to power the power system 130, in
parallel with the output of the bridge rectifier 20.
[0022] In order to determine which light level is desired, the two
rings 121, 122 have independent detection circuits 40, 50 (i.e., a
first detection circuit and a second detection circuit). In the
first detection circuit 40, the AC power (AC3) from second ring 122
is half-wave rectified by diode 41. The signal from diode 41 is
integrated by an RC circuit consisting of a resistor 42 and a
capacitor 44. When the AC power (AC3) from the second ring 122 is
energized, the voltage on the capacitor 44 rises to a level set
approximately by the values of the resistor divider, which is
comprised of resistors 42, 43. When the AC power (AC3) from the
second ring 122 is not energized, the voltage on the capacitor 44
falls to zero, as energy is bled out through the resistor 43. The
voltage on the capacitor 44 is thus indicative of the presence or
absence of energization of AC power (AC3) on the second ring 122.
The second detection circuit 50 works identically for energization
detection of the AC power (AC2) on the first ring 121.
[0023] The voltage present on the capacitors 44, 54 is used to
determine the on or off state of transistors 160, 170,
respectively. The transistors 160, 170 are used in turn to
determine which of the string or series of LEDs 110, 111 are
shunted, setting the light level of the bulb. In particular, if the
AC power (AC2) in the first ring 121 is energized, capacitor 55
will have a voltage on it. By suitable selection of resistors 52,
53, the voltage can be designed to be high enough to turn on
transistor 170. When transistor 170 is on, shunting circuit 140 is
off, permitting current to flow through the first series of LEDs
110. When transistor 170 is off, shunting circuit 140 is on, which
shunts current around the first series of LEDs 110, keeping the
first series of LEDs 110 in an unlit state or condition.
[0024] In accordance with an exemplary embodiment, the circuit 11
also includes a first shunting circuit 140, which consists of a
transistor 141, resistors 142, 144 and a diode 143. When transistor
170 is off, the gate voltage on the transistor 141 is pulled up to
its drain voltage by resistor 142. If the voltage across the gate
to source of transistor 141 exceeds the rating of the transistor,
the gate to source voltage can be clamped by a zener diode (not
shown). When transistor 170 is on, the gate voltage on transistor
141 is pulled down. In accordance with an exemplary embodiment, the
diode 143 and the resistor 144 limit how negative the gate to
source voltage of transistor 141 can go, which avoids exceeding the
rating of transistor 141.
[0025] In the similar case wherein the AC power (AC3) in the second
ring 122 is energized, transistor 160 is turned on, and a second
shunting circuit 150 is de-activated, permitting current to flow
through second series LEDs 111. The second shunting circuit 150
consists of a transistor 151, resistors 152, 154 and a diode 153.
If both AC power (AC2), (AC3) in the first and second rings 121,
122 are energized, both the capacitors 44, 54 will be charged, both
the transistors 160, 170 will be on, and both the shunt circuits
140, 150 will be de-activated, permitting current to flow through
both the first series or string of LEDs 110 and the second series
or string of LEDs 111.
[0026] Thus in this circuit, three different light levels are
available by suitably selecting which of the shunt units or shunt
circuits 140, 150 are de-activated. When AC power (AC2) in the
first ring 121 is energized, the current generated by the power
switcher 130 flows through the second series or string of LEDs 110.
When AC power (AC3) in the second ring 122 is energized, the
current generated by the power switcher 130 flows through the
second series or string of LEDs 111. When AC power (AC2), (AC3) in
both the first and second rings 121, 122 are energized, the current
generated by power switcher 130 flows through both the first and
second series or strings of LEDs 110, 111.
[0027] It will be apparent to those skilled in the art that various
modifications and variation can be made to the structure of the
present invention without departing from the scope or spirit of the
invention. In view of the foregoing, it is intended that the
present invention cover modifications and variations of this
invention provided they fall within the scope of the following
claims and their equivalents.
* * * * *