U.S. patent application number 15/296120 was filed with the patent office on 2018-04-19 for systems and methods for a dual function inrush limiting circuit.
This patent application is currently assigned to THE BOEING COMPANY. The applicant listed for this patent is THE BOEING COMPANY. Invention is credited to Randy L. Brandt, Suhat Limvorapun, Minh Van Truong.
Application Number | 20180109177 15/296120 |
Document ID | / |
Family ID | 61902351 |
Filed Date | 2018-04-19 |
United States Patent
Application |
20180109177 |
Kind Code |
A1 |
Truong; Minh Van ; et
al. |
April 19, 2018 |
SYSTEMS AND METHODS FOR A DUAL FUNCTION INRUSH LIMITING CIRCUIT
Abstract
Systems and methods are provided for a dual function inrush
limiting circuit (ILC). The systems and methods may include a level
shift circuit (LSC). The LSC may include a Zener diode, a block
diode and a capacitor. The Zener diode being in anti-series with
respect to the block diode. The ILC may further include a switch
electrically coupled to the LSC, an input terminal and an output
terminal. The LSC may be configured to activate the switch such to
electrically couple the input terminal to the output terminal. The
ILC may include a direct current (DC)-DC converter electrically
coupled to the output terminal. The DC-DC converter being
electrically coupled to the input terminal when the switch is
activated.
Inventors: |
Truong; Minh Van;
(Huntington Beach, CA) ; Brandt; Randy L.;
(Huntington Beach, CA) ; Limvorapun; Suhat; (Seal
Beach, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THE BOEING COMPANY |
Chicago |
IL |
US |
|
|
Assignee: |
THE BOEING COMPANY
Chicago
IL
|
Family ID: |
61902351 |
Appl. No.: |
15/296120 |
Filed: |
October 18, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02H 9/001 20130101;
H02H 9/005 20130101; H02H 9/00 20130101; H02M 1/32 20130101; H02H
9/04 20130101 |
International
Class: |
H02M 1/32 20060101
H02M001/32; H02M 3/04 20060101 H02M003/04; H02M 1/44 20060101
H02M001/44 |
Claims
1. An inrush limiting circuit (ILC) comprising: a level shift
circuit (LSC) including a Zener diode, a block diode and a
capacitor, wherein the Zener diode is in anti-series with the block
diode; a switch electrically coupled to the LSC, an input terminal,
and an output terminal, wherein the LSC is configured to activate
the switch to electrically couple the input terminal to the output
terminal; and a direct current (DC)-DC converter electrically
coupled to the output terminal, wherein the DC-DC converter is
electrically coupled to the input terminal when the switch is
activated.
2. The ILC of claim 1, further comprising: first and second
resistors defining a reference voltage input; and a photovoltaic
coupler configured to adjust a voltage at the output terminal when
a voltage at the reference voltage input is above a predetermined
threshold.
3. The ILC of claim 2, further comprising a shunt regulator,
wherein the shunt regulator is configured to electrically couple
the photovoltaic coupler to ground when the reference voltage input
is above the predetermined threshold.
4. The ILC of claim 2, further comprising an opto-coupler
electrically coupled to the LSC, wherein the photovoltaic is
configured to adjust a current delivered to the opto-coupler.
5. The ILC of claim 2, wherein the photovoltaic coupler is
configured to discharge voltage across the switch when the
reference voltage input is above a predetermined threshold.
6. The ILC of claim 2, wherein the predetermined threshold is
defined based on the first and second resistors.
7. The ILC of claim 1, further comprising an opto-coupler
configured to electrically couple the LSC to the input
terminal.
8. The ILC of claim 7, wherein the opto-coupler is configured to
charge the capacitor of the LSC.
9. The ILC of claim 1, wherein the capacitor of the LSC is
configured to adjust an activation time of the switch.
10. The ILC of claim 9, wherein the activation time is between 10
milliseconds and 35 milliseconds.
11. The ILC of claim 1, further comprising an electromagnetic
interference (EMI) filter, wherein the EMI filter is electrically
coupled to the output terminal.
12. The ILC of claim 1, wherein the Zener diode and the block diode
are electrically coupled such that the polarities are directly
opposed with respect to each other.
13. A method of controlling an inrush current, the method
comprising: configuring a level shift circuit (LSC) to include a
Zener diode, a block diode, and a capacitor; electrically coupling
the Zener diode to the block diode in anti-series; electrically
coupling a switch to the LSC, an input terminal, and an output
terminal charging the LSC; outputting a voltage from the LSC to the
switch; activating the switch by the outputting from the LSC;
electrically coupling the input terminal to the output terminal by
the outputting; and electrically coupling a direct current (DC)-DC
converter to the input terminal when the switch is activated.
14. The method of claim 13, further comprising adjusting a voltage
at the output terminal when a reference voltage input is above a
predetermined threshold, wherein the adjusting operation includes
discharging voltage across the switch.
15. The method of claim 14, wherein the Zener diode and the block
diode are electrically coupled such that the polarities are
directly opposed with respect to each other.
16. The method of claim 14, further comprising defining a
predetermined threshold based on first and second resistors,
electrically coupling a photo voltaic coupler to the output
terminal, and adjusting a voltage at the output terminal when the
voltage is above the predetermined threshold.
17. The method of claim 13, further comprising electrically
coupling an opto-coupler to the LSC and the input terminal, and
providing current from the input terminal to the LSC via the
opto-coupler.
18. The method of claim 13, further comprising electrically
coupling an electromagnetic interference (EMI) filter to the input
terminal when the input terminal is electrically coupled to the
output terminal.
19. The method of claim 13, wherein the capacitor of the LSC is
configured to adjust an activation time of the switch during the
delivering operation, the activation time being between 10
milliseconds and 35 milliseconds.
20. An inrush limiting circuit comprising: a level shift circuit
(LSC) including a Zener diode, a block diode and a capacitor,
wherein the Zener diode is in anti-series with the block diode; an
opto-coupler configured to electrically couple the LSC to an input
terminal; a switch electrically coupled to the LSC, the input
terminal, and an output terminal, wherein the LSC is configured to
activate the switch to electrically couple the input terminal to
the output terminal; a direct current (DC)-DC converter
electrically coupled to the output terminal, wherein the DC-DC
converter is electrically coupled to the input terminal when the
switch is activated; a photovoltaic coupler configured to adjust a
voltage at the output terminal when a voltage at a reference
voltage input is above a predetermined threshold; and first and
second resistors defining the reference voltage input.
Description
FIELD OF THE DISCLOSURE
[0001] Embodiments of the present disclosure generally relate to
systems and methods for a dual function inrush limiting circuit for
a direct current (DC)-DC converter.
BACKGROUND OF THE DISCLOSURE
[0002] Inrush current is an instantaneous input current drawing by
an electrical device, such as a DC-DC converter, when first turn
on. Inrush limiting circuits are electrically coupled to the DC-DC
converter and are used to manage power quality along shared power
lines and to sustain electromagnetic interference (EMI)
requirements for operation of DC-DC converters within complex
electronic systems. For example, DC-DC converters typically share
an input power line with other circuits that may be susceptible to
damage due to spikes in voltage and/or current along the input
power line. Additionally, the input circuits for the DC-DC
converter may degrade if over stressed with current and/or voltage
spikes output by conventional inrush limiting circuits.
Conventional inrush limiting circuits typically prevent excess
agitation on input power delivery ports that may damage other
circuits being serviced by the same input power line. Further,
conventional inrush limiting circuits typically prevent excessive
current surges from stressing input EMI filter components when the
DC-DC converter is powered.
[0003] However, conventional inrush limiting circuits use either a
passive approach using an inductor or bypass-resistor/switch
approach, or an active controlled current approach to stabilize the
power line. The conventional inrush limiting circuits generally
include large relays and are generally heavier and bulkier due to
the large components. Further, conventional inrush limiting
circuits exhibit long startup delay times that may not be
acceptable for subsequent circuitry of a DC-DC converter.
Additionally, DC-DC converters often require additional and
separate circuitry for input voltage surges to accommodate output
surges of the conventional inrush limiting circuits. Conventional
systems typically require large transient voltage suppressors that
add significant cost and weight to the systems.
SUMMARY OF THE DISCLOSURE
[0004] A need exists for a system and method for a dual function
inrush limiting circuit that reduces an amount of components to
improve reliability, while limiting the input current with a short
delay time of input current to a DC-DC converter while limiting the
output voltage of the inrush limiting circuit.
[0005] With this need in mind, certain embodiments of the present
disclosure provide an inrush limiting circuit (ILC). The ILC may
include a level shift circuit (LSC). The LSC may include a Zener
diode, a block diode and a capacitor. The Zener diode being in
anti-series with respect to the block diode. The ILC may further
include a switch electrically coupled to the LSC, an input terminal
and an output terminal. The LSC may be configured to activate the
switch such that when activated the switch electrically couples the
input terminal to the output terminal. The ILC may include a direct
current (DC)-DC converter electrically coupled to the output
terminal. The DC-DC converter being electrically coupled to the
input terminal when the switch is activated.
[0006] The ILC may further include first and second resistors
defining a reference voltage input, and a photovoltaic coupler
configured to adjust a voltage at the output terminal when a
voltage at the reference voltage input is above a predetermined
threshold. Optionally, the ILC includes a shunt regulator that may
be configured to electrically couple the photovoltaic coupler to
ground when the reference voltage input is above the predetermined
threshold. Additionally or alternatively, the ILC includes an
opto-coupler electrically coupled to the LSC such that the
photovoltaic coupler is configured to adjust a current delivered to
the opto-coupler. Optionally, the photovoltaic coupler is
configured to discharge voltage across the switch when the
reference voltage input is above a predetermined threshold.
[0007] In at least one embodiment, the ILC may include an
opto-coupler configured to electrically couple the LSC to the input
terminal. The opto-coupler may be configured to charge the
capacitor of the LSC. Additionally or alternatively, the capacitor
of the LSC is configured to adjust an activation time of the
switch.
[0008] Certain embodiments of the present disclosure provide a
method controlling an inrush current. The method may include
configuring a level shift circuit (LSC) to include a Zener diode, a
block diode, and a capacitor, and electrically coupling the Zener
diode to the block diode in anti-series. The method may include
electrically coupling a switch to the LSC, an input terminal, and
an output terminal charging the LSC. The method may include
outputting a voltage from the LSC to the switch, activating the
switch by the outputting, and electrically coupling the input
terminal to the output terminal by the outputting. The method may
include electrically coupling a direct current (DC)-DC converter to
the input terminal when the switch is activated.
[0009] Optionally, the method includes adjusting a voltage at the
output terminal when a reference voltage input is above a
predetermined threshold. Additionally or alternatively, when the
voltage at the output terminal is adjusted the voltage across the
switch is discharged as well.
[0010] Certain embodiments of the present disclosure provides an
inrush limiting circuit (ILC). The ILC may include a level shift
circuit (LSC). The LSC having a Zener diode, a block diode and a
capacitor. The Zener diode being in anti-series with respect to the
block diode. The ILC may include an opto-coupler configured to
electrically couple the LSC to an input terminal, and a switch
electrically coupled to the LSC, the input terminal and an output
terminal. The LSC may be configured to activate the switch, such
that when the switch is activated the switch electrically couples
the input terminal to the output terminal. The ILC may include a
direct current (DC)-DC converter electrically coupled to the output
terminal. The DC-DC converter being electrically coupled to the
input terminal when the switch is activated. The ILC may include a
photovoltaic coupler configured to adjust a voltage at the output
terminal when a voltage at a reference voltage input is above a
predetermined threshold.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 illustrates a schematic diagram of an inrush limiting
circuit, according to an embodiment of the present disclosure.
[0012] FIG. 2 illustrates a schematic diagram of an inrush limiting
circuit, according to an embodiment of the present disclosure.
[0013] FIG. 3 illustrates a schematic diagram of an inrush limiting
circuit, according to an embodiment of the present disclosure.
[0014] FIG. 4 illustrates graphical representations of electrical
signals measured from the inrush limiting circuit shown in FIG.
3.
[0015] FIG. 5 illustrates a flow chart of a method of controlling
an inrush current, according to an embodiment of the present
disclosure.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0016] The foregoing summary, as well as the following detailed
description of certain embodiments will be better understood when
read in conjunction with the appended drawings. As used herein, an
element or step recited in the singular and preceded by the word
"a" or "an" should be understood as not necessarily excluding the
plural of the elements or steps. Further, references to "one
embodiment" are not intended to be interpreted as excluding the
existence of additional embodiments that also incorporate the
recited features. Moreover, unless explicitly stated to the
contrary, embodiments "comprising" or "having" an element or a
plurality of elements having a particular condition may include
additional elements not having that condition.
[0017] Various embodiments of the present disclosure provide
systems and methods for a dual function inrush limiting circuit.
The inrush limiting circuit described herein may relate to
switching power DC-DC converters using the active controlled
current circuit approach and more particularly to an input level
shifter in association with an input integrator that controls the
rise time of the controlled inrush current source subsequent to
saturation. The inrush limiter circuit may be configured to charge
an input to an electromagnetic interference (EMI) filter at a rate
that limits or otherwise reduces magnitudes of turn-on current
surges to safe levels in order to prevent excess perturbations on
input power delivery ports that may disturb and/or damage other
circuits being serviced by the same input power source. The inrush
limiting circuit is configured to prevent excessive current surges
from stressing components of the EMI filter during the power on
trajectory of the DC-DC converter. Additionally or alternatively,
the inrush limiting circuit may be configured to limit the output
voltage down-stream should the input supply voltage encounter
temporary surge voltage.
[0018] FIG. 1 is a schematic diagram of an inrush limiting circuit
(ILC) 100, according to an embodiment of the present disclosure.
The ILC 100 includes a level shift circuit (LSC) 123. The LSC 123
includes a Zener Diode 125, a block diode 126 and a capacitor 124.
The Zener Diode 125 and the block diode 126 are configured in
anti-series with respect to each other. For example, the Zener
diode 125 and the block diode 126 are electrically coupled such
that the polarities are directly opposed with respect to each
other. The LSC 123 is electrically coupled to a switch 122. The
switch 122 may be a solid state switch such as a metal oxide
semiconductor field-effect transistor (MOSFET). The switch 122 is
electrically coupled to an input terminal 102 and an output
terminal 104. The input terminal 102 is provided voltage and/or
current via a power source 106 representing an input power rail.
Optionally, a rectifying diode 120 may be interposed between the
switch 122 and the input terminal 102.
[0019] An opto-coupler 121 may be configured to electrically couple
the LSC 123 to the input terminal 102. The opto-coupler 121 may
include a first and second series of diodes 129 and 130 that are
coupled together utilizing light. For example, current from a
current source 131 flows through the first series of diodes 129.
The first series of diodes 129 may be light emitting diodes that
generate light based on an amount of current and/or voltage. The
light traverses through an optical channel 110 and is detected by
the second series of diodes 130. The second series of diodes 130
may be a plurality of photosensors, which generate current based on
the detected light. The generated current flows through the second
series of diodes 130, which is received by the LSC 123 and is
utilized to charge the capacitor 124.
[0020] As the capacitor 124 of the LSC 123 is being charged, the
block diode 126 reaches a reverse bias, which activates the switch
122. For example, during the reverse bias of the block diode 126,
the Zener diode 125 increases a gate voltage of the switch 122
reaching a Miller threshold (e.g., 3.2 volts, 7 volts), thereby
activating the switch 122. When the switch 122 is activated, the
switch 122 is configured to electrically couple the input terminal
102 to the output terminal 104 such that current flows through the
terminals 102, 104.
[0021] In at least one embodiment, the switch 122 is a solid state
switch, such as a MOSFET. When the gate voltage is below 3 volts,
the MOSFET is not activated (e.g., powered OFF), which prohibits
current from flowing between the input and output terminals 102,
104. When the gate voltage is between 3 volts and 3.2 volts, the
MOSFET reaches the Miller threshold representing a linear mode of
the MOSFET and is utilized to regulate current through the input
and output terminals 102, 104. When the gate voltage is above the
Miller threshold, such as above 3.2 volts, the MOSFET is saturated
(e.g., ON).
[0022] It is noted that an activation time of the switch 122 may be
based on a value of the capacitor 124. The activation time may
represent a delay time to activate the switch 122. For example, the
activation time may represent a period of time to increase the
voltage at the gate of the switch 122 from 0 volts to the Miller
threshold (e.g., 3.2 volts) to activate the switch 122. Optionally,
the activation time may represent an inrush ramp time representing
an amount of time to deliver current from the input terminal 102 to
the output terminal 106, which may range from 10 milliseconds to 35
milliseconds, for example.
[0023] The output terminal 104 may be electrically coupled to an
electromagnetic interface (EMI) filter 108. The EMI filter 108 may
include a plurality of components (e.g., inductor 132, capacitor
133, resistor 134) configured to filter out high frequency input
that may cause instabilities, such as for a DC-DC converter 136.
Additionally or alternatively, the output terminal 104 may be
electrically coupled to the DC-DC converter 136.
[0024] FIG. 2 illustrates a schematic diagram of an ILC 200,
according to an embodiment of the present disclosure. A topology of
the ILC 200 may be adjusted relative to the ILC 100 shown in FIG.
1. For example, the ILC 100 is positioned on a "high side" relative
to the power rail, such that the LSC 123 is coupled to the output
terminal 106. The ILC 200 is positioned on a "low side" or return
side of the power rail.
[0025] When the voltage and/or current is received from the power
rail, the capacitor 124 is charged via the resistor 257. As the
capacitor 124 of the LSC 123 is being charged, the block diode 126
reaches a reverse bias. During the reverse bias of the block diode
126, the Zener diode 125 increases a gate voltage of the switch 122
reaching a Miller threshold (e.g., 3.2 volts, 7 volts). When the
switch 122 is activated, the bulk capacitor 261 is grounded thereby
charging the bulk capacitor 261 for the DC-DC converter 130.
Optionally, the ILC 200 may include a Zener diode 254 that is
configured to limit the gate voltage of the switch 122, for example
at 15 volts. The resistor 256 is configured to discharge the
capacitor 124 of the LSC 123 when the voltage and/or current
received from the power rail is deactivated.
[0026] FIG. 3 illustrates a schematic diagram of an ILC 300,
according to an embodiment of the present disclosure. The ILC 300
has a similar topology to the ILC 100 shown in FIG. 1. The ILC 300
includes a shunt regulator 308 and a photovoltaic coupler 310,
which enable the ILC 300 to clamp the input voltage to the DC-DC
converter 136. The shunt regulator 308 may be a Zener diode, an
avalanche breakdown diode, and/or the like.
[0027] For example, similar to the ILC 100 described in FIG. 1,
when voltage and/or current is delivered to the input terminal 102
the opto-coupler 121 transfers current from the first series of
diodes 129 to the second series of diodes 130. The current flowing
through the second series of diodes 130 charges the capacitor 124
of the LSC 123. As the capacitor 124 charges, the gate voltage of
the switch 122 is increased to have the switch 122 saturated and/or
activated. When the switch 122 is activated, current flows from the
input terminal 102 to the output terminal 104 forming a voltage
drop at a reference voltage input 306.
[0028] The reference voltage input 306 is formed by the pair of
resistors 302 and 304 configured as a voltage divider. Optionally,
the pair of resistors 302 and 304 define a predetermined threshold
for the shunt regulator 308. The predetermined threshold is
configured to represent a voltage spike (e.g., over voltage) along
the output terminal 104. For example, the predetermined threshold
may indicate a voltage level at the output terminal 104 that may
damage secondary components electrically coupled to and/or apart of
the ILC 300, such as the EMI filter 108 and/or the DC-DC converter
136. The pair of resistors 302 and 304 may be configured such that
the reference voltage input at the predetermined threshold
corresponds to a break down voltage of the shunt regulator 308. For
example, when the reference voltage input is at the predetermined
threshold, the shunt regulator 308 allows current to flow to
ground.
[0029] The photovoltaic coupler 310 and/or the shunt regulator 308
are configured to adjust the voltage at the output terminal when a
voltage at the reference voltage input 306 is above the
predetermined threshold by clamping the voltage at the output
terminal 104 to prevent damage to the secondary components. For
example, when the switch 122 is activated, the shunt regulator 308
is configured to monitor and/or detect the reference voltage input
306. When the voltage at the reference voltage input 306 is above
the predetermined threshold the shunt regulator is configured to
electrically couple the photovoltaic coupler 310 to ground. As the
photovoltaic coupler 310 is electrically coupled to ground, the
photovoltaic coupler 310 is configured to discharge voltage across
the switch 122 to clamp the voltage at the output terminal 104. For
example, when the photovoltaic coupler 310 is electrically coupled
to ground, current flows through the input diode 312 of the
photovoltaic coupler 310 from the node 316 which activates the
switch 314 (e.g., solid state switch, transistor, and/or the like),
thereby discharging voltage across the switch 122. Based on the
adjusted gate voltage of the switch 122, for example, the switch
122 may transition from a saturation state (e.g., gate voltage at
3.3 volts) to a linear region regulating output (e.g., gate voltage
below 3.2 volts). As the gate voltage is adjusted (e.g., reduced)
by the photovoltaic coupler 310, an amount of current flowing
between the input terminal 102 and the output terminal 104 is
reduced by the switch 122, thereby reducing the voltage at the
output terminal 104.
[0030] Additionally or alternatively, the photovoltaic coupler 310
is configured to adjust a current delivered to the opto-coupler
121. For example, the photovoltaic coupler 310 diverts a portion of
the current at node 316. As the current flows at node 316 through
the photovoltaic coupler 310 an amount of current received by the
first series of diodes 129 of the opto-coupler 121 is reduced
relative to when the photovoltaic coupler 310 is not grounded by
the shunt regulator 308. Based on the reduced current delivered to
the first series of diodes 129, an amount of current delivered to
the second series of diodes 130 is also reduced, which reduces the
voltage at the gate of the switch 122.
[0031] As the voltage at the output terminal 104 is reduced, the
voltage at the reference voltage input may fall below the
predetermined threshold, which deactivates the shunt regulator 308
such that the photovoltaic coupler 310 is no longer electrically
coupled to ground. As no current is flowing to the photovoltaic
coupler 310 at the node 316, the amount of current received by the
opto-coupler 121 is increased thereby increasing the gate voltage
of the switch 122.
[0032] FIG. 4 illustrates graphical representations 402-404 of
electrical signals measured from the ILC 300 shown in FIG. 3,
according to an embodiment of the disclosure. The graphical
representation 402 represents a voltage 412 measured at the output
terminal 104. The graphical representation 403 represents a current
413 at the inductor 132 of the EMI filter 108 (e.g., current at the
output terminal 104). The graphical representation 404 represents
the voltages 410, 412 at the input terminal 102 and the output
terminal 104, respectively. Each of the graphical representations
402-404 are plotted along a horizontal axis 400 representing
time.
[0033] The voltage 410 is delivered to the input terminal 102 at
418 for time period 414. During the time period 414, the capacitor
124 of the LSC 123 is charged, thereby linearly increasing the
voltage 412 of the output terminal 104. For example, the current
413 ramps up linearly (e.g., no current spikes) to approximately 7
amperes (shown in graphical representation 404) with the voltage 42
at the output terminal 104 within 35 milliseconds. It may be noted
that the rise time may be adjusted (e.g., increased, decreased) by
adjusting the value of the capacitor 124.
[0034] Beginning at the time period 416 (e.g., at approximately 200
milliseconds), the voltage 410 at the input terminal 102 is
increased (e.g., voltage spike, voltage surge) from 24 volts to 44
volts. For example, the predetermined threshold at the reference
voltage input 306 may represent a voltage of 27 volts at the output
terminal 104. As described above, the photovoltaic coupler 410 and
the shunt regulator 308 are activated to clamp the voltage 412 at
the output terminal 104. For example, the gate voltage of the
switch 122 may be continually adjusted to linearly regulate the
voltage 412 and the current 413. It is noted that during the time
period 420 (e.g., starting at approximately 300 milliseconds), the
voltage 410 at the input terminal is adjusted back to 24 volts
indicating the voltage surge has ended.
[0035] FIG. 5 illustrates a flow chart of a method of controlling
an inrush current, according to an embodiment of the present
disclosure. The method 500, for example, may employ structures or
aspects of various embodiments (e.g., systems and/or methods)
discussed herein. For example, the ILC 300 of FIG. 3 may be
configured to operate according to the flow chart shown in FIG. 5.
In various embodiments, certain steps (or operations) may be
omitted or added, certain steps may be combined, certain steps may
be performed simultaneously, certain steps may be performed
concurrently, certain steps may be split into multiple steps,
certain steps may be performed in a different order, or certain
steps or series of steps may be re-performed in an iterative
fashion.
[0036] Beginning at 502, the opto-coupler 121 may charge the LSC
123. For example, the input terminal 102 may receive the voltage
410 at 418 (FIG. 4) providing current to the opto-coupler 121 (FIG.
3). The current flowing through the first series of diodes 129 may
be light emitting diodes that generate light based on the current
from the current source 131. The light traverses through an optical
channel and is detected by a photosensor, which generates current
based on the detected light. The generated current flows through
the second series of diodes 130, which is received by the LSC 123
and charges the capacitor 124.
[0037] At 504, the LSC 123 may deliver a voltage to activate the
switch 122. For example, as the capacitor 124 of the LSC 123 is
being charged, the block diode 126 reaches a reverse bias
delivering current to the Zener diode 125 of the LSC 123. The Zener
diode 125, electrically coupled to the switch 122 (e.g., the gate
of the switch 122) increases the gate voltage of the switch 122 to
reach the Miller threshold (e.g., 3.2 volts, 7 volts).
[0038] At 506, the switch 122 may deliver current to the EMI Filter
108 and the DC-DC converter 136. For example, as the gate voltage
increases to the Miller threshold the switch 122 is activated. When
the switch 122 is activated the input terminal 102 is electrically
coupled to the output terminal 104 such that current flows through
the terminals 102, 104. The current at the output terminal 104 is
received by the EMI filter 108 and the DC-DC converter 136 that are
electrically coupled to the output terminal 104.
[0039] At 508, the shunt regulator 308 may detect when the
reference voltage input 306 is above a predetermined threshold. For
example, the pair of resistors 302 and 304 may be configured such
that the reference voltage input 306 reaches a breakdown voltage of
the shunt regulator 308 when the predetermined threshold is
reached, thereby electrically coupling the photovoltaic coupler 310
and/or the node 316 to ground.
[0040] The reference voltage input 306 is based on the pair of
resistors 302 and 304. For example, the reference voltage input 306
is interposed between the pair of resistors 302 and 304. The pair
of resistors 302 and 304 are configured as a voltage divider
defining the reference voltage input 306. Optionally, the pair of
resistors 302 and 304 define a predetermined threshold for the
shunt regulator 308. The predetermined threshold is configured to
indicate when a voltage spike (e.g., over voltage) is present at
the output terminal 104. For example, the predetermined threshold
is utilized to indicate when a voltage at the output terminal 104
may damage secondary components electrically coupled to and/or
apart of the ILC 300, such as the EMI filter 108 and/or the DC-DC
converter 136. The photo voltaic coupler 310 and/or the shunt
regulator 308 are configured to adjust the voltage at the output
terminal 104 when a voltage at the reference voltage input 306 is
above the predetermined threshold to prevent damage to the to clamp
the voltage at the output terminal 104 to prevent damage to the
secondary components. For example, the photo voltaic coupler 310
and/or the shunt regulator 308 are configured to maintain the
voltage at the output terminal 104.
[0041] If the reference voltage input 306 is above the
predetermined threshold, then at 510, the photovoltaic coupler 310
may discharge voltage across the switch 122. For example, when the
photovoltaic coupler 310 is electrically coupled to ground, current
flows through the input diode 312 of the photovoltaic coupler 310.
The voltage drop across the input diode 312 activates the switch
314 (e.g., solid state switch, transistor, and/or the like),
thereby discharging voltage across the switch 122. Based on the
adjusted gate voltage, for example, the switch 122 may transition
from a saturation state (e.g., gate voltage at 3.3 volts) to a
linear region regulating output (e.g., gate voltage below 3.2
volts). As the gate voltage is adjusted (e.g., reduced) by the
photovoltaic coupler 310, an amount of current flowing between the
input terminal 102 and the output terminal 104 is reduced by the
switch 122 thereby reducing the voltage at the output terminal 104,
a shown during the time period 416 (FIG. 4).
[0042] As described above, embodiments of the present disclosure
provide systems and methods for a dual function inrush limiting
circuit. Various embodiments provide a light weight, compact, and
low coast approach for an inrush limiting circuit configured to
limit inrush current and suppress voltage and/or current surges at
an output terminal electrically coupled to a DC-DC converter and/or
an EMI filter. Various embodiments provide a faster and controlled
timing to activate a switch (e.g., the switch 122) and deliver
current and/or voltage to the DC-DC converter.
[0043] While various spatial and directional terms, such as top,
bottom, lower, mid, lateral, horizontal, vertical, front and the
like may be used to describe embodiments of the present disclosure,
it is understood that such terms are merely used with respect to
the orientations shown in the drawings. The orientations may be
inverted, rotated, or otherwise changed, such that an upper portion
is a lower portion, and vice versa, horizontal becomes vertical,
and the like.
[0044] As used herein, a structure, limitation, or element that is
"configured to" perform a task or operation is particularly
structurally formed, constructed, or adapted in a manner
corresponding to the task or operation. For purposes of clarity and
the avoidance of doubt, an object that is merely capable of being
modified to perform the task or operation is not "configured to"
perform the task or operation as used herein.
[0045] It is to be understood that the above description is
intended to be illustrative, and not restrictive. For example, the
above-described embodiments (and/or aspects thereof) may be used in
combination with each other. In addition, many modifications may be
made to adapt a particular situation or material to the teachings
of the various embodiments of the disclosure without departing from
their scope. While the dimensions and types of materials described
herein are intended to define the parameters of the various
embodiments of the disclosure, the embodiments are by no means
limiting and are exemplary embodiments. Many other embodiments will
be apparent to those of skill in the art upon reviewing the above
description. The scope of the various embodiments of the disclosure
should, therefore, be determined with reference to the appended
claims, along with the full scope of equivalents to which such
claims are entitled. In the appended claims, the terms "including"
and "in which" are used as the plain-English equivalents of the
respective terms "comprising" and "wherein." Moreover, the terms
"first," "second," and "third," etc. are used merely as labels, and
are not intended to impose numerical requirements on their objects.
Further, the limitations of the following claims are not written in
means-plus-function format and are not intended to be interpreted
based on 35 U.S.C. .sctn. 112(f), unless and until such claim
limitations expressly use the phrase "means for" followed by a
statement of function void of further structure.
[0046] This written description uses examples to disclose the
various embodiments of the disclosure, including the best mode, and
also to enable any person skilled in the art to practice the
various embodiments of the disclosure, including making and using
any devices or systems and performing any incorporated methods. The
patentable scope of the various embodiments of the disclosure is
defined by the claims, and may include other examples that occur to
those skilled in the art. Such other examples are intended to be
within the scope of the claims if the examples have structural
elements that do not differ from the literal language of the
claims, or if the examples include equivalent structural elements
with insubstantial differences from the literal language of the
claims.
* * * * *