PSU-enabled load adaptation

Abstract

The present invention relates to a load module for connection to a power supply having a maximum power capability, the load module having an input for receiving an input voltage from the power supply, a power regulator adapted to receive the input voltage and adapted to supply regulated power to a load, a current sensor for sensing a current supplied by the power supply, a voltage sensor for sensing the input voltage, and a controller for controlling the power regulator, the controller configured to operate in a configuration mode, the controller configured to control the power regulator to draw gradually increasing current from the input until the input voltage drops, the current at which the input voltage drops indicating a maximum power capability of the power supply, and the controller configured to determine the maximum power capability of the power supply based on the sensed current and the sensed input voltage near the event of the input voltage drop.

Description

[Technical Field]

[0001] The present invention relates to a load module for connection to a power source having a maximum power capability.The present invention further relates to a system.The present invention further relates to a method for determining the maximum power handling capability of a power source. [Background technology]

[0002] A power supply is typically used to supply a specified power to a load. The power supply and the load are separate units and therefore may be supplied by different suppliers. Initially, the power supply and the load may have matching power ratings. For example, a load consuming a maximum of 30 W may be coupled to a power supply with a 30 W power rating. Over time, the load may change. Additional loads may be connected to the power supply. Alternatively, the load may be replaced with a different load. Therefore, the power consumption of the load may change, i.e., increase or decrease. The event of a load increase may cause problems in the lighting system; for example, the power supply may not be able to operate at this new power level. Therefore, the power supply may need to be replaced with one that can supply more power. This requires additional measures to be taken, sometimes resulting in the unnecessary replacement of a properly operating power supply. Another situation may arise when a power supply is replaced with an unknown driver. The installer does not always know whether the replaced power supply can supply enough power to the load. Installers sometimes use power supplies that are significantly over-dimensioned to reduce the risk of a power mismatch between the power source and the load.

[0003] Rather than performing preventative replacement of components or introducing unnecessary over-sizing of, for example, a power supply, it is desirable to provide a way to determine that the same components can be reused. Summary of the Invention [Problem to be solved by the invention]

[0004] It is an object of the present invention to provide a load module that is capable of determining the maximum power capability of the power supply to which said load module is connected. [Means for solving the problem]

[0005] To solve this problem, a first aspect of the present invention provides a load module for connection to a power supply having a maximum power capacity, the load module comprising: an input for receiving an input voltage from the power source; a power regulator adapted to receive the input voltage and adapted to provide regulated power to a load; a current sensor for sensing the current supplied by the power supply; a voltage sensor for detecting the input voltage; a controller for controlling the power regulator; A load module is provided, wherein the controller is configured to operate in a configuration mode, the controller is configured to control the power regulator to draw gradually increasing current from the input until the input voltage drops, the current at which the input voltage drops indicating the maximum power capability of the power supply, and the controller is configured to determine the maximum power capability of the power supply based on the sensed current and the sensed input voltage near the event of the input voltage drop.

[0006] A load module is designed to be coupled to a power supply. The power supply has a maximum power capacity. The maximum power capacity determines the maximum power the power supply can supply without damaging the power supply. Exceeding this maximum power capacity can cause the power supply to reduce its output power, resulting in a reduction in the power that can be supplied to the load module. Exceeding the maximum power capacity can be done by drawing too much current. This can occur, for example, when the load draws too much current. Therefore, it is desirable to know whether the power supply can supply the maximum power that can be drawn by the load. The load module has a detection circuit used to determine the maximum power that can be drawn from the power supply. The load module has a current sensor for detecting the current drawn from the power supply. The load module also has a voltage sensor for detecting the voltage supplied by the power supply. A controller can receive a current signal from the current sensor and a voltage signal from the voltage sensor. The current signal from the current sensor can be representative of the current supplied by the power supply. The voltage signal from the voltage sensor can be representative of the voltage supplied by the power supply. Preferably, the power supply provides a constant voltage or acts as a voltage source. The load module includes a power regulator that regulates power through a load. The power regulator receives the input voltage provided by the power supply. The controller is configured to operate in a configuration mode. In this mode, the controller controls the power regulator to draw gradually increasing current from the input until the input voltage drops. Preferably, the starting current is 0 A, so the power regulator begins increasing the current from 0 A to a current level corresponding to the level at which the input voltage drops. The controller determines the maximum power capability of the power supply based on the sensed current and sensed input voltage present at the time of the input voltage drop. The closer the measurement is made to the voltage drop event, the more accurately the maximum power capability can be determined.

[0007] In a further example, the controller is configured to set the maximum power that can be drawn by the load module to 80% of the maximum power capability of the power supply.

[0008] Upon determining the maximum power supply capability, the controller may provide a derating margin from the maximum power supply capability. Preferably, this margin is set to 80% of the maximum power supply capability. For example, if the maximum power supply capability of a power supply is determined to be 100 W, the controller may allow a maximum of 80 W to be consumed by the load module.

[0009] In a further example, the controller is configured to operate in the configuration mode when the power supply begins to provide the input voltage to the load module.

[0010] Preferably, the controller operates in the configuration mode when the power supply starts up. At start-up, the power supply supplies the voltage to the load module, and the controller then determines the maximum power capability of the power supply. After determination, the load module may enable the regulated power to be supplied to the load.

[0011] In a further example, the power regulator includes a current drawing circuit adapted to draw a gradually increasing current from the input during the configuration mode until the input voltage drops so that no current flows through the load.

[0012] The power regulator may include dedicated current draw circuitry that provides a path for the current to be drawn without passing the current through the load during the configuration mode, such that the load is not powered during the configuration mode and therefore no undesirable effects are caused by the load during the configuration mode.

[0013] In a further example, the current draw circuit includes a variable resistor between the input and a return path to the power supply.

[0014] In a preferred embodiment, an addressable LED load is connected across the output terminals of the controller. During power-up, the controller detects the number of nodes connected to the controller using a control signal so that changes in load can be detected without applying full power to the LED load. Immediately after power-up, the controller increases the output power.

[0015] A preferred example of a current draw circuit may include a variable resistor located between the input and a return to the power supply, which in that sense may shunt or bypass the load, and which may have a resistance that decreases over time to source a gradually increasing amount of the current from the input until the input voltage drops.

[0016] In a further example, the controller is configured to control the resistance of the variable resistor during the configuration mode, and the controller is adapted to prevent any current from flowing through the variable resistor when the controller is operating in a normal operation mode.

[0017] The controller preferably controls the resistance of the variable resistor during the configuration mode, and sets the variable resistor after the configuration mode so that no current can flow through it, or so that very little current can flow through it, which can be done by disconnecting the variable resistor from the input or return using a switch.

[0018] In a further example, the power regulator is adapted to draw a gradually increasing amount of the current from the input during the configuration mode until the input voltage drops, and the current flows through the load.

[0019] If the load allows it, additional dedicated current drawing circuitry may not be needed. The power conditioner draws the current through the load. This may result in an overload of the load for a brief moment, but this may be acceptable and not harmful because the load can withstand such an overload for a short period of time.

[0020] In a further example, the load has a maximum current handling capability, and the controller is configured to stop increasing the current when the current exceeds the maximum current handling capability of the load.

[0021] If the increasing current exceeds the maximum current handling capability of the load, the load module must protect the load to prevent damage to the load. This can occur if the overload of the load occurs for too long a period of time. The controller is configured to stop increasing the current when the current exceeds the maximum current handling capability of the load. The maximum power supply capability of the power supply may be significantly greater than the maximum current handling capability of the load. In this case, the maximum power supply capability of the power supply cannot be determined. However, the controller may determine that the power supply is capable of supplying sufficient power to the load. Because the overload of the load is taken into account, the power supply still supplies sufficient power to the load, even when taking into account a derating of, for example, 80%.

[0022] In a further example, the controller comprises a memory adapted to store the maximum power capability of the power supply.

[0023] Preferably, the controller is capable of storing the maximum power capacity of the power supply. This may allow the controller to further process this data. The data may be shared with a power system, for example. The data may also be used to determine whether more load can be added to the load module.

[0024] In a further example, the load module comprises the load.

[0025] The load can be integrated into the load module, which allows the load and the circuit for determining the maximum power capability of the power supply to be integrated into a single design.

[0026] In a further example, the load is a lighting load.

[0027] In a further example, the lighting load is a solid state lighting load.

[0028] Preferably, the load is a lighting load. Even more preferably, the lighting load is a solid-state lighting load. The solid-state lighting load can be connected to a power supply that acts as a driver, such as a light-emitting diode (LED) driver. The driver can be replaced with another driver having a different power capability. To ensure that the driver is not overloaded by the lighting load, the load module can determine how much power the driver can supply.

[0029] In a further example, a system is provided, the system comprising a load module according to any of the previous examples and the power supply.

[0030] In another example, a method for determining a maximum power handling capability of a power supply, comprising: coupling the load module to the power source such that the load module is adapted to receive power from the power source; drawing current from the power supply; gradually increasing the current until the voltage supplied by the power supply drops below a threshold; and determining the voltage and the current being supplied by the power supply when the voltage drops below the threshold to determine the maximum power handling capability of the power supply.

[0031] In another example, the power consumption of the load module is prevented from exceeding the maximum power handling capability of the power supply. [Brief explanation of the drawings]

[0032] Examples of the invention will now be described with reference to the accompanying drawings, in which: [Figure 1] 1 illustrates an example of a system having a power supply, a load module, and a load. [Figure 2] 1 shows an example of a voltage versus current graph for a power supply. [Figure 3]1 shows an example of a load module. [Figure 4] 10 shows another example of a load module. [Figure 5] This section describes how to determine the maximum power capability of a power supply. DETAILED DESCRIPTION OF THE INVENTION

[0033] The present invention will be described with reference to the drawings.

[0034] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the devices, systems, and methods, are for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the devices, systems, and methods of the present invention will become better understood from the following description, appended claims, and accompanying drawings. It should also be understood that the figures are schematic only and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the figures to indicate the same or similar parts.

[0035] FIG. 1 shows an example of a system. The system includes a power supply 1. The power supply 1 receives a voltage from an external power source. The external power source may be a mains power supply, and a mains voltage (Mains) may be supplied to the power supply 1. The power supply 1 converts the mains voltage (Mains) into an input voltage. This voltage may be a regulated, stable voltage, such as 12V or 24V. Alternatively, the power supply may provide any regulated voltage level, even a voltage level greater than the mains voltage (Mains). The voltage generated by the power supply 1 is supplied to a load module 2. The load module 2 has an input (IN) through which the voltage generated by the power supply 1 is received as an input voltage. The load module 2 has a power regulator 5 that receives the input voltage and converts the input voltage into regulated power supplied to a load 3. The load module 2 has current sensors R1 and R5 and a voltage sensor 6. The load module 2 has a controller 4 that receives a sensed current signal from the current sensors R1 and R5. The controller 4 also receives a sensed voltage signal from the voltage sensor 6. The controller 4 may be used to control the power regulator 5 to supply regulated power to the load 3. The controller 4 may operate in a configuration mode. In this mode, the controller 4 controls the power regulator 5 to draw a gradually increasing current from the input IN, i.e., the power supply 1, until the input voltage drops. Preferably, the power regulator 5 starts from 0 A and gradually increases the current. Starting from 0 A ensures that the power supply 1 can always supply the required power at the beginning of the current draw. Values ​​other than 0 A may also be used. The power supply 1 can supply the required power during the gradually increasing current while the input voltage does not fluctuate much, although small voltage ripples may be present. Under gradually increasing current, it can be seen that the current increases over time. Preferably, the increase in current over time is linear, but the current can also be increased nonlinearly. The current continues to increase gradually, and therefore the power supplied by the power supply 1 also continues to increase, and as long as the power supply 1 can maintain this power to be supplied to the load module 2, the voltage remains stable.If the current continues to increase, eventually, power supply 1 will no longer be able to supply this amount of power and will be unable to keep the voltage stable. Due to power supply 1 being unable to maintain the power required to be supplied to load module 2, the voltage will drop. This point indicates that power supply 1 is unable to supply the power required or drawn by load module 2. The current sensed by current sensors R1 and R5 and the voltage sensed by voltage sensor 6 at the point in time when the voltage drops can be used to determine the maximum power capability of power supply 1. Multiplying the current sensed by current sensors R1 and R5 by the voltage sensed by voltage sensor 6 at the point in time when the voltage drops provides the power at the point in time when the voltage drops, which provides a suitable indicator of the maximum power capability of power supply 1. Preferably, this maximum power capability of power supply 1 is stored in memory. Preferably, the current increase is not too rapid. If the current is high enough that the input voltage begins to drop, this voltage drop is due to power supply 1 being unable to meet the power requirements of load module 2. Because some capacitance may be present, there may be a delay between the response to the input voltage and the increase in current. The capacitance may maintain the input voltage for a period of time when the power supply 1 has already exceeded its maximum power capability. Preferably, the current is increased at a rate such that the capacitance is discharged so that, at the time of determining the maximum power capability of the power supply 1, the difference between the actual maximum power capability and the determined maximum power capability is as small as possible. Derating may be introduced to ensure that the load module 2 does not draw too much power from the power supply 1. Once the maximum power handling capability is determined, a derating of, for example, 80% may be introduced. This means that the load module 2 does not draw more than 80% of the maximum power that can be drawn from the power supply 1. Derating may also be applied to the load module 2 and the load 3.

[0036] FIG. 2 shows an example graph illustrating how maximum power capability can be determined. In the example shown, power supply 1 supplies an input voltage of 24 V to load module 2. The input voltage to load module 2 does not change until the current reaches 2.5 A, and only after 2.5 A. Therefore, gradually increasing the current from 0 A to 2.5 A does not cause the input voltage to drop. Therefore, maximum power capability is not reached. After increasing the current above 2.5 A, near 2.55 A, the input voltage drops. This is the moment when controller 4 determines that maximum power capability has been reached. In this example, the maximum power capability of power supply 1 can be determined to be 2.55 × 24 V = 61.2 W. In this example, the input voltage level used to determine maximum power capability is 24 V. However, because the input voltage drops, this voltage could also be lower, for example, 23 V.

[0037] FIG. 3 shows a detailed example of the load module 2. The load module 2 has an input IN coupled to the output of the power supply 1. The input voltage is supplied to the load module 2 via the input IN and preferably via an input return RETURN. A voltage sensor 6 is provided to detect the input voltage. In this example, the voltage sensor 6 is located between the input IN and the return RETURN. The output of the voltage sensor 6 is coupled to the input IN of the controller 4 and provides a signal representative of the input voltage. The load module 2 also has a current sensor R1. The current sensor R1 is used to detect the current drawn from the input IN. The current is supplied by the power supply 1. The output of the current sensor R1 is coupled to the input of the controller 4. The load module 2 has a power regulator 5, which in this example is a buck converter. The buck converter includes an inductor L1, a switching element M1, and a freewheeling diode D1. The buck converter may be coupled to a load LED. In this example, the current sensor R1 is used to detect the current flowing through the load LED. In this example, power regulator 5 is used to regulate power to the load LEDs. Furthermore, power regulator 5 is used to draw a gradually increasing current during configuration mode. During configuration mode, a gradually increasing current flows through the load LEDs. The load LEDs have a maximum current capability. If power supply 1 has a maximum power capability that causes the current through the load LEDs to exceed the maximum current capability of the load LEDs, the load LEDs may be overloaded, resulting in damage to the load LEDs. If the configuration mode is sufficiently short, this may not be a problem because the load LEDs may be able to withstand the overload for a short period of time, for example, within a few milliseconds, without damaging the load LEDs. However, it may happen that the maximum power capability significantly exceeds the maximum current capability. Even for a short period of time, the current through the load LEDs may be high enough to damage the load LEDs. To prevent damage to the load, the gradually increasing current needs to be stopped when it exceeds the maximum current handling capability of the load.Therefore, if the maximum power capability of the power supply 1 and the maximum current capability of the load LEDs are within an acceptable range, the power supply regulator 5 may be able to determine the maximum power capability of the power supply 1. If at least one of the maximum power capability of the power supply 1 and the maximum current capability of the load LEDs is outside this acceptable range, the power supply regulator 5 cannot determine the maximum power capability of the power supply 1 to prevent the load LEDs from being damaged. Those skilled in the art will understand that the maximum current capability of the load LEDs during the configuration mode is greater than the maximum current supplied during normal operation of the load LEDs due to the period during which current flows through the load LEDs. In that case, the maximum current capability of the load LEDs may be based on the current flowing through the load LEDs during the configuration mode.

[0038] FIG. 4 shows another detailed example of the load module 2. A voltage sensor 6 similar to that shown in FIG. 3 may be used. The voltage sensor 6 may consist of a first resistor R2 and a second resistor R3. These resistors act as a voltage divider to ensure that a voltage within the acceptable voltage range for the controller 4 is supplied to the controller 4. The power regulator 5 is divided into two sections. The first section is responsible for providing regulated power to the load LEDs. This section is shown as a buck converter. The buck converter receives an input voltage from the input IN and converts this input voltage to a regulated voltage across the load LEDs while regulating the current through the load LEDs. In the example shown, regulation is achieved using current feedback. A current sensor R1 is used to regulate the current through the load LEDs.

[0039] The second section of the power regulator 5 is used to provide a path for gradually increasing current to flow so that current does not flow through the load LED. This allows the load LED to remain inactive while the maximum power supply capability can be determined during configuration mode. The second section may be a current sink circuit. The current sink circuit may include a resistor R4, a switching element Q1, and a resistor R5 connected in series. This series connection may be coupled between the input IN and the return path RETURN. Resistor R5 may be used to sense the current through the series connection. The voltage drop across resistor R5 is provided to the controller 4 via resistor R6. Therefore, the controller 4 has knowledge of the current flowing through the current sink circuit. The controller 4 has a control output for controlling the switching element Q1. The controller 4 may control the switching element Q1 to operate in its linear mode of operation. Therefore, the controller can control the total resistance or impedance of the series connection. This allows the controller 4 to control the current through the series connection and gradually increase the current until the input voltage drops.

[0040] The switching elements are shown as bipolar transistors, although other switch types such as MOSFETs may also be envisioned.

[0041] FIG. 5 shows an example of a method for determining maximum power supply capability. This method relates to a method for operating an LED strip. In this example, the load LED is an LED strip whose length can be changed. The length can be increased, resulting in a larger load, or the length can be decreased, resulting in a smaller load. The first step is to power on the system. The system can have a power supply 1, a load module 2, and a load 3.

[0042] After power-up, the load module 2 is configured to size the LED string to determine the maximum power that can be drawn by the load 3. If the load module 2 has already implemented the maximum power capability of the power supply 1 and stored this value in memory, the maximum output power can be set for the load 3. If the maximum power capability is not stored, the maximum power capability needs to be determined. Preferably, the current drawn from the power supply 1 is set to its minimum value, preferably 0 A. The input voltage and current supplied by the power supply 1 are measured by the load module 2, preferably using the voltage sensor 6 and current sensors R1 and R3. The current is gradually increased over time until the input voltage drops. This point, when the corresponding current and input voltage are measured, indicates that the power supply is overloaded, i.e., has reached its power limit. This maximum power capability of the power supply 1 can be stored in memory so that no decision needs to be made at startup if there are no changes to the LED string. The configuration mode can then be skipped. After determining the maximum power capability of the power supply 1, the maximum current capability of the load 3 can be reduced to provide safe derating. The maximum current capability of the load 3 can be set so that the driver can never supply more than, for example, 80% of its maximum power.

[0043] In Figure 1, the example shows that power supply 1, load module 2, and load 3 are all coupled to a voltage reference level, also referred to as a ground reference. Those skilled in the art will understand that this may not be necessary or possible in all configurations. If power regulator 3 is, for example, a buck converter, load 3 is not coupled to a ground reference. Therefore, the ground reference for load 3 may be omitted depending on whether the configuration requires a ground reference.

[0044] In the example shown, power regulator 5 is shown as a buck converter, but those skilled in the art will understand that any type of converter, such as a boost converter, buck converter, buck-boost converter, flyback converter, resonant converter, or linear current regulator, can be used for the function of power regulator 5. In its simplest form, a linear current regulator may be a switching element in series with a current-limiting resistor.

[0045] In the example shown, the load 3 may be a lighting load. Preferably, the lighting load is a semiconductor lighting load such as a light emitting diode (LED) or a laser diode.

[0046] Those skilled in the art can understand and effect other variations to the disclosed embodiments in practicing the claimed invention, from a study of the drawings, the specification and the appended claims. In the claims, the word "comprises" does not exclude other elements or steps, and the singular does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be interpreted as limiting the scope.

Claims

1. 1. A load module for connecting to a power source having a maximum power capacity, said load module comprising: an input for receiving an input voltage from the power source; a power regulator adapted to receive the input voltage and adapted to provide regulated power to a load; a current sensor for sensing the current supplied by the power supply; a voltage sensor for detecting the input voltage; a controller for controlling the power regulator; the controller is configured to operate in a configuration mode, the controller is configured to control the power regulator to draw gradually increasing current from the input until the input voltage drops, the current at which the input voltage drops indicates the maximum power capability of the power supply, and the controller is configured to determine the maximum power capability of the power supply based on the sensed current and the sensed input voltage near the event of the input voltage drop; The load module includes a current drawing circuit adapted to draw a current from the input that gradually increases until the input voltage drops during the configuration mode, such that no current flows through the load.

2. 2. The load module of claim 1, wherein the controller is configured to set a maximum power that can be drawn by the load module to 80% of the maximum power capability of the power supply.

3. 3. The load module of claim 1 or 2, wherein the controller is configured to operate in the configuration mode when the power supply begins to supply the input voltage to the load module.

4. 4. A load module according to any preceding claim, wherein the current draw circuitry includes a variable resistor between the input and a return path to the power supply.

5. 5. The load module of claim 4, wherein the controller is configured to control the resistance of the variable resistor during the configuration mode, and the controller is adapted to prevent any current from flowing through the variable resistor when the controller is operating in a normal operation mode.

6. 4. A load module as claimed in any one of claims 1 to 3, wherein the power regulator is adapted to draw a gradually increasing current from the input during the configuration mode until the input voltage drops, and the current flows through the load.

7. 7. The load module of claim 6, wherein the load has a maximum current handling capability, and the controller is configured to stop increasing the current when the current exceeds the maximum current handling capability of the load.

8. 8. A load module according to any one of claims 1 to 7, wherein the controller comprises a memory adapted to store the maximum power capability of the power supply.

9. 9. The load module of claim 1, further comprising the load.

10. The load module of claim 9 , wherein the load is a lighting load.

11. The load module of claim 10 , wherein the lighting load is a solid-state lighting load.

12. A system comprising a load module according to any one of claims 1 to 11 and the power supply.

13. 1. A method for determining a maximum power handling capability of a power supply, comprising: coupling the load module to the power source such that the load module is adapted to receive power from the power source; drawing current from the power supply; gradually increasing the current until the voltage supplied by the power supply drops below a threshold; determining the voltage and the current being supplied by the power supply when the voltage drops to determine the maximum power handling capability of the power supply; The current drawn is gradually increased until the input voltage from the power supply drops so that no current flows from the power regulator through the load during a configuration mode.

14. 14. The method of claim 13, wherein the power consumption of the load module is prevented from exceeding the maximum power handling capability of the power supply.

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