Psu compatible load adaptation

Abstract

The invention relates to a load module for connection to a power source with maximum power capability. The load module includes an input for receiving an input voltage from a 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 a current provided by the power source, a voltage sensor for sensing the input voltage, and a controller for controlling the power regulator. The controller is arranged to operate in a configuration mode wherein the controller is arranged to control the power regulator to draw current from the input, the current gradually increasing until the input voltage drops, where the current when the input voltage drops is indicative of a maximum power capability of the power supply, wherein the controller is arranged to determine a maximum power capability of the power supply based on the sensed current and the sensed input voltage in proximity to an event of the input voltage drop.

Description

Technical Field

[0001] The present invention relates to a load module for connecting to a power supply having a maximum power capability. The present invention also relates to a system. The present invention also relates to a method for determining the maximum power handling capability of a power supply. Background Art

[0002] A power supply is usually used to provide a defined power to a load. The power supply and the load are separate units and may therefore be provided by different suppliers. First, the power supply and the load may have matching power ratings. For example, a load consuming a maximum of 30W may be coupled to a power supply rated at 30W. Over time, the load may change. Additional loads may be connected to the power supply. Alternatively, the load may be replaced with another load. As a result, the power consumption of the load may change, i.e. increase or decrease. The event of an increase in load may cause problems in the lighting system, such as the power supply may not be able to operate at this new power level. Therefore, the power supply may need to be replaced with a power supply that can provide more power. This requires additional actions to be taken and sometimes requires the unnecessary replacement of a good working power supply. Another situation may arise when the power supply is replaced with an unknown driver. The installer may not always know whether the replacement power supply will be able to provide enough power for the load. The installer may use a power supply that is significantly oversized to reduce the risk of a power mismatch between the power supply and the load.

[0003] It would be desirable to provide a method to ensure that identical components can be reused, rather than performing preventative replacement of components of, for example, a power supply or introducing unnecessary oversizing of the power supply. Summary of the invention

[0004] An object of the present invention is to provide a load module which is capable of determining the maximum power capability of a power source to which the load module is connected.

[0005] To overcome this concern, in a first aspect of the present invention, there is provided a load module for connecting to a power source having a maximum power capability, the load module comprising:

[0006] an input for receiving an input voltage from a power source;

[0007] a power regulator adapted to receive an input voltage and adapted to provide regulated power to a load;

[0008] a current sensor for sensing a current provided by a power source;

[0009] a voltage sensor for sensing an input voltage; and

[0010] A controller for controlling a power conditioner,

[0011] wherein the controller is arranged to operate in a configuration mode, wherein the controller is arranged to control the power regulator to draw a current from the input that gradually increases until the input voltage drops, wherein the current when the input voltage drops is indicative of a maximum power capability of the power supply, wherein the controller is arranged to determine the maximum power capability of the power supply based on the sensed current and the sensed input voltage near an event of the input voltage dropping.

[0012] The load module is designed to be coupled to a power supply. The power supply has a maximum power capability. The maximum power capability determines the maximum power that the power supply can provide without damaging the power supply. Exceeding the maximum power capability may cause the power supply to reduce its output power, resulting in a reduction in the power that can be provided to the load module. Exceeding the maximum power capability may be achieved by drawing too much current. For example, this occurs when the load draws too much current. Therefore, it is desirable to know whether the power supply can provide the maximum power that the load can draw. The load module has a detection circuit for determining the maximum power that can be drawn from the power supply. The load module has a current sensor for sensing the current drawn from the power supply. The load module also has a voltage sensor for sensing the voltage provided by the power supply. The controller may receive a current signal from the current sensor and a voltage signal from the voltage sensor. The current signal from the current sensor may be a representation of the current provided by the power supply. The voltage signal from the voltage sensor may be a representation of the voltage provided by the power supply. Preferably, the power supply provides a constant voltage, or the power supply acts as a voltage source. The load module has a power regulator that regulates power through the load. The power regulator receives an input voltage provided by the power supply. The controller is arranged to operate in a configuration mode. In this mode, the controller controls the power regulator to draw a current from the input that gradually increases until the input voltage drops. Preferably, the current at the start is 0A, so the power regulator begins to build up a current from 0A 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 the sensed input voltage present at the event of the input voltage drop. The closer the measurement is to the event of the voltage drop, the more accurately the maximum power capability can be determined.

[0013] In another example, the controller is arranged to set the maximum power that the load module can draw to 80% of the maximum power capability of the power supply.

[0014] After determining the maximum power capability, the controller can provide a derating margin according to the maximum power capability. Preferably, the margin is set to 80% of the maximum power capability. For example, if the maximum power capability of the power supply is determined to be 100W, the controller can allow the load module to consume a maximum of 80W.

[0015] In another example, the controller is arranged to operate in the configuration mode when the power supply starts providing the input voltage to the load module.

[0016] Preferably, the controller operates in a configuration mode when the power supply starts up. At startup, the power supply provides voltage to the load module, and then the controller determines the maximum power capability of the power supply. After the determination, the load module can allow regulated power to be provided to the load.

[0017] In another example, the power regulator includes a current draw circuit adapted to draw a current from the input that gradually increases until the input voltage drops such that no current flows through the load during the configuration mode.

[0018] The power regulator may have a dedicated current draw circuit that provides a path for drawing current without causing current to flow through the load during the configuration mode. During the configuration mode, the load will not be powered, and therefore, the load will not produce undesirable effects in the configuration mode.

[0019] In another example, the current sinking circuit includes a variable resistor between the input and a return path of the power supply.

[0020] In a preferred example, an addressable LED load is connected between the output terminals of the controller. During power-up, the controller detects the number of nodes connected to the controller through a control signal so that changes in the load can be detected without applying full power to the LED load. Shortly after power-up, the controller increases the output power.

[0021] A preferred example of a current draw circuit may have a variable resistor placed between the input and the return path of the power supply. In this sense, the variable resistor may shunt or bypass the load. The variable resistor may have a resistance that decreases over time so as to provide a current from the input that gradually increases until the input voltage drops.

[0022] In another example, the controller is arranged to control the resistance of the variable resistor during the configuration mode, and wherein the controller is adapted to prevent any current from flowing through the variable resistor when the controller operates in the normal operation mode.

[0023] 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 or only a very small amount of current can flow through the variable resistor. This can be achieved by disconnecting the variable resistor from the input or return path using a switch.

[0024] In another example, the power regulator is adapted to draw a current from the input during the configuration mode that gradually increases until the input voltage drops, wherein the current flows through the load.

[0025] If the load permits, additional dedicated current drawing circuitry may not be required. The power regulator draws current through the load. For a short period of time, this may cause the load to be overloaded, but this may be acceptable and not harmful because the load can tolerate this overload for a short period of time.

[0026] In another example, the load has a maximum current handling capability, wherein the controller is arranged to stop increasing the current when the current exceeds the maximum current handling capacity of the load.

[0027] If the increased current exceeds the maximum current handling capability of the load, the load module needs to protect the load to prevent it from being damaged. This may be done if the overload of the load lasts too long. The controller is arranged to stop increasing the current when the current exceeds the maximum current handling capability of the load. The maximum power capability of the power supply may be significantly greater than the maximum current handling capability of the load. In this case, the maximum power capability of the power supply may not be determined. However, the controller may conclude that the power supply is able to provide sufficient power to the load. Since the overload of the load is taken into account, the power supply will also provide sufficient power to the load when a derating of, for example, 80% is taken into account.

[0028] In another example, the controller includes a memory adapted to store a maximum power capability of the power supply.

[0029] Preferably, the controller is able to store the maximum power capability of the power supply. This can allow the controller to further process the data. For example, the data can be shared with the power system. The data can also be used to determine whether more loads can be added to the load module.

[0030] In another example, the load module includes a load.

[0031] The load can be integrated into the load module. This allows the circuitry for determining the maximum power capability of the load and the power supply to be integrated into a single design.

[0032] In another example, the load is a lighting load.

[0033] In another example, the lighting load is a semiconductor lighting load.

[0034] Preferably, the load is a lighting load. More preferably, the lighting load is a semiconductor lighting load. The semiconductor lighting load can be connected to a power supply used as a driver, such as a light emitting diode LED driver. The driver can be replaced with another driver with different power capabilities. In order to ensure that the driver is not overloaded by the lighting load, the load module can determine how much power the driver can provide.

[0035] In another example, a system is provided, comprising a load module according to any one of the above examples and a power supply.

[0036] In another example, a method for determining a maximum power handling capability of a power supply is provided, the method comprising the steps of:

[0037] coupling the load module to a power source such that the load module is adapted to receive power from the power source;

[0038] draw current from a power source;

[0039] gradually increasing the current until the voltage supplied by the power supply drops below a threshold;

[0040] The voltage and current provided by the power supply when the voltage drops below a threshold are determined to determine the maximum power handling capability of the power supply.

[0041] In another example, the power consumption of the load module is prevented from exceeding the maximum power handling capability of the power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Examples of the present invention will now be described with reference to the accompanying drawings, in which:

[0043] Figure 1 An example of a system with a power source, a load module, and a load is shown.

[0044] Figure 2 An example of a voltage versus current graph for a power supply is shown.

[0045] Figure 3 An example of a load module is shown.

[0046] Figure 4 Another example of a load module is shown.

[0047] Figure 5 A method of determining the maximum power capability of a power supply is shown. DETAILED DESCRIPTION

[0048] The present invention will be described with reference to the accompanying drawings.

[0049] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the apparatus, system, and method, are for illustrative purposes only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, system, and method of the invention will be better understood through the following description, the appended claims, and the accompanying drawings. It should also be understood that the drawings are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the drawings to indicate the same or similar components.

[0050] Figure 1An example of a system is shown. The system has a power supply 1. The power supply 1 receives a voltage from an external power supply. The power supply may be a mains supply, and the mains voltage Mains may be provided to the power supply 1. The power supply 1 converts the mains voltage Mains into an input voltage. The voltage may be a regulated stable voltage of, for example, 12V or 24V. Alternatively, the power supply may provide any regulated voltage level, or a voltage level greater than the mains voltage Mains. The voltage generated by the power supply 1 is provided to the load module 2. The load module 2 has an input IN, through which the load module 2 receives the voltage generated by the power supply 1 as an input voltage. The load module 2 has a power regulator 5, which receives the input voltage and converts the input voltage into regulated power provided to the load 3. The load module 2 has current sensors R1, 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, 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 provide regulated power to the load 3. The controller 4 may operate in a configuration mode. In the operation mode, the controller 4 controls the power regulator 5 to draw current from the input IN (i.e., from the power supply 1), which gradually increases until the input voltage drops. Preferably, the power regulator 5 starts from 0A and gradually increases the current. Starting from 0A ensures that the power supply 1 can provide the required power at the beginning of the moment of drawing current. Other values ​​other than 0A can also be used. Although the power supply 1 can provide the required power during the gradual increase of the current, the input voltage will not fluctuate too much, but a small voltage ripple may occur. In the case of gradually increasing current, the increase of current over time can be understood. Preferably, the increase of current over time occurs in a linear manner, but the current can also increase nonlinearly. The current continues to increase gradually, and therefore the power provided by the power supply 1 is also gradually increasing, as long as the power supply 1 can maintain the power provided to the load module 2, the voltage remains stable. When the current increases further, since the power supply 1 cannot provide this amount of power, the power supply 1 will eventually be unable to maintain voltage stability. Since the power supply 1 cannot maintain the power provided to the load module 2, the voltage will drop. This moment indicates that the power supply 1 cannot provide the power required or drawn by the load module 2. The current sensed by the current sensors R1, R5 and the voltage sensed by the voltage sensor 6 at the moment of the voltage drop can be used as a determination of the maximum power capability of the power supply 1. The product of the current sensed by the current sensors R1, R5 and the voltage sensed by the voltage sensor 6 at the moment of the voltage drop provides the power at the moment of the voltage drop, which is a good indication of the maximum power capability of the power supply 1. Preferably, this maximum power capability of the power supply 1 is stored in a memory. Preferably, the increase in current does not occur too quickly.When the current is high enough, the input voltage starts to drop, and it is hoped that this voltage drop is caused by the inability of the power supply 1 to meet the power requirements of the load module 2. Since there may be some capacitance, there may be a delay between the response to the input voltage and the increased current. The capacitance can maintain the input voltage during the period when the power supply 1 has exceeded its maximum power capability. Preferably, the increase in current is carried out at a rate that causes the capacitance to be discharged so that at the moment of determination of 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 low as possible. In order to ensure that the load module 2 does not draw too much power from the power supply 1, a derating can be introduced. When establishing the maximum power handling capability, a derating of, for example, 80% can be introduced. This means that the load module 2 will not draw more than 80% of the maximum power that can be drawn from the power supply 1. Derating can also be applied to the load module 2 and the load 3.

[0051] Figure 2 An example of a diagram is shown, which shows how the maximum power capability is determined. In the example provided, the power supply 1 provides an input voltage of 24V to the load module 2. At a current not exceeding 2.5A, the input voltage of the load module 2 does not change significantly. Only after 2.5A. Therefore, gradually increasing the current from 0A to 2.5A does not cause the input voltage to drop. Therefore, the maximum power capability is not reached. After increasing the current to above 2.5A, close to 2.55A, the input voltage drops. This is the moment when the controller 4 determines that the maximum power capability has been reached. In this example, the maximum power capability of the power supply 1 can be determined as 2.55×24V=61.2W. In this example, the input voltage level used to determine the maximum power capability is 24V. However, due to the input voltage drop, this voltage can also be lower, such as 23V.

[0052] Figure 3A detailed example of a load module 2 is shown. The load module 2 has an input IN coupled to the output of the power supply 1. The input voltage is provided to the load module 2 via the input IN, and is preferably provided via the input return RETURN. A voltage sensor 6 is provided to sense the input voltage. In this example, the voltage sensor 6 is placed between the input IN and the return path RETURN. The output of the voltage sensor 6 is coupled to the input IN of the controller 4, and a signal is provided as a representation of the input voltage. The load module 2 also has a current sensor R1. The current sensor R1 is used to sense the current drawn from the input IN. The current is provided 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 is a buck converter in this example. The buck converter has an inductor L1, a switching element M1 and a freewheeling diode D1. The buck converter can be coupled to a load LED. In this example, the current sensor R1 is used to sense the current flowing through the load LED. In this example, the power regulator 5 is used to regulate the power of the load LED. In addition, the power regulator 5 is used to draw a current that gradually increases during the configuration mode. During the configuration mode, a gradually increasing current flows through the load LED. The load LED has a maximum current capability. If the power supply 1 has a maximum power capability that causes the current through the load LED to exceed the maximum current capability of the load LED, the load LED may be overloaded, resulting in damage to the load LED. If the configuration mode is short enough, this may not be a problem, because the load LED may be able to withstand overloads for a short period of time, such as in the millisecond range, without damaging the load LED. However, there may be a situation where the maximum power capability significantly exceeds the maximum current capability. Even for a very short duration, the current through the load LED may be high enough to damage the load LED. In order to avoid damage to the load, the gradual increase in current needs to be stopped when the current handling capacity of the load reaches a maximum. Therefore, when the maximum power capability of the power supply 1 and the maximum current capability of the load LED are within an acceptable range, the power regulator 5 may be able to determine the maximum power capability of the power supply 1. When at least one of the maximum power capability of the power supply 1 and the maximum current capability of the load LED exceeds the acceptable range, the power regulator 5 cannot determine the maximum power capability of the power supply 1 to prevent damage to the load LED. Those skilled in the art will understand that due to the duration of the current flowing through the load LED, the maximum current capability of the load LED during the configuration mode is greater than the maximum current provided during normal operation of the load LED. The maximum current capability of the load LED may then be based on the current flowing through the load LED during the configuration mode.

[0053] Figure 4 Another detailed example of the load module 2 is shown. Figure 3As with the detailed example shown, a similar voltage sensor 6 can be used. The voltage sensor 6 can be composed of a first resistor R2 and a second resistor R3. The resistors act as a voltage divider so that a voltage within the acceptable voltage range of the controller 4 can be provided to the controller 4. The power regulator 5 is divided into two parts. The first part is used to provide regulated power to the load LED. This part is shown as a buck converter. The buck converter receives an input voltage from an input IN and converts the input voltage to a regulated voltage across the load LED while regulating the current through the load LED. In the example provided, the regulation is implemented based on the use of current feedback. The current sensor R1 is used to regulate the current through the load LED.

[0054] The second part of the power regulator 5 is used to provide a flow path for the gradually increasing current so that no current flows through the load LED. This allows the load LED to remain inactive during the configuration mode while the maximum power capability can be determined. The second part can be a current draw circuit. The current draw circuit can have a resistor R4, a switching element Q1, and a resistor R5 connected in series. The series connection can be coupled between the input IN and the return path RETURN. Resistor R5 can be used to sense the current through the series connection. The voltage drop across the resistor R5 is provided to the controller 4 via the resistor R6. Therefore, the controller 4 knows the current flowing through the current draw circuit. The controller 4 has a control output for controlling the switching element Q1. The controller 4 can control the switching element Q1 to operate in its linear operating mode. Therefore, the controller can control the total resistance or impedance of the series connection. This allows the controller 4 to control the current flowing through the series connection to allow the current to gradually increase until the input voltage drops.

[0055] The switching elements are shown as bipolar transistors, but other switch types are also contemplated, such as MOSFETs.

[0056] Figure 5 An example of a method for determining maximum power capability is shown. The method relates to a method for operating an LED light strip. In this example, the load LED is an LED light 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 up the system. The system can include a power supply 1, a load module 2, and a load 3.

[0057] The load module 2 is arranged after power-up to determine the size of the LED string and thus the maximum power that can be drawn by the load 3. If the load module 2 has performed the maximum power capability of the power supply 1 and this value is stored in the memory, the maximum output power can be configured for the load 3. When the maximum power capability is not stored, the maximum power capability needs to be determined. Preferably, the current to be drawn from the power supply 1 is set to its minimum value, preferably 0A. The input voltage and current provided by the power supply 1 are measured by the load module 2 preferably using the voltage sensor 6 and the current sensors R1, R3. The current gradually increases over time until the input voltage drops. At this point, the corresponding measured current and input voltage indicate that the power supply has been overloaded, that is, its power limit has been reached. This maximum power capability of the power supply 1 can be stored in the memory so that it does not need to be determined at startup when there is no change in the LED light strip. The configuration mode can then be omitted. After determining the maximum power capability of the power supply 1, the maximum current capability of the load 3 can be reduced to provide a safety derating. The maximum current capability of the load 3 can be set so that the driver can never provide more than 80% of its maximum power.

[0058] exist Figure 1 In the example shown, the power supply 1, the load module 2 and the load 3 are all coupled to a voltage reference level (also referred to as a ground reference). Those skilled in the art will appreciate that this is not required or possible in all configurations. When the power regulator 3 is, for example, a buck converter, the load 3 is not coupled to the ground reference. Therefore, depending on whether the configuration requires a ground reference, the ground reference to the load 3 can be omitted.

[0059] In the example provided, the power regulator 5 is shown as a buck converter, and those skilled in the art will understand that any type of converter may be used for the function of the power regulator 5, such as a boost converter, a buck converter, a buck-boost converter, a flyback converter, a resonant converter, or a linear current regulator. In its simplest form, a linear current regulator may be a switching element in series with a current limiting resistor.

[0060] In the example provided, 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.

[0061] Other variations to the disclosed embodiments may be understood and effected by those skilled in the art in practicing the claimed invention by studying the drawings, the present disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The fact that certain measures are cited 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 construed as limiting the scope.

Claims

1. A load module (2) for connecting to a power source (1) having a maximum power capability, the load module (2) comprising: An input (IN) for receiving an input voltage from the power supply (1); a power regulator (5) adapted to receive the input voltage and adapted to provide regulated power to the load (3, LED); A current sensor (R1, R5) for sensing a current provided by the power supply (1); A voltage sensor (6), used for sensing the input voltage; as well as A controller (4) for controlling the power regulator, wherein the controller (4) is arranged to operate in a configuration mode, wherein the controller (4) is arranged to control the power regulator (5) to draw a current from the input (IN), the current gradually increasing until the input voltage drops, wherein the current when the input voltage drops is indicative of the maximum power capability of the power supply (1), wherein the controller (4) is arranged to determine the maximum power capability of the power supply (1) based on the sensed current and the sensed input voltage near the event of the input voltage dropping, The power regulator (5) comprises a current drawing circuit adapted to draw the current from the input (IN), the current gradually increasing until the input voltage drops, so that no current flows through the load (3, LED) during the configuration mode.

2. A load module (2) according to any one of the preceding claims, wherein the controller (4) is arranged to set the maximum power that the load module (2) can draw to 80% of the maximum power capability of the power supply (1).

3. The load module (2) according to any of the preceding claims, wherein the controller (4) is arranged to operate in the configuration mode when the power supply (1) starts to provide the input voltage to the load module (2).

4. The load module (2) according to claim 1, wherein the current sinking circuit comprises a variable resistor between the input (IN) and a return path (RETURN) to the power source (1).

5. A load module (2) according to claim 4, wherein the controller (4) is arranged to control the resistance of the variable resistor during the configuration mode, and wherein the controller (4) is adapted to prevent any current from flowing through the variable resistor when the controller (4) operates in a normal operation mode.

6. A load module (2) according to any one of claims 1 to 3, wherein the power regulator (5) is adapted to draw a current from the input (IN) during the configuration mode, the current gradually increasing until the input voltage drops, wherein the current flows through the load (3, LED).

7. The load module (2) according to claim 6, wherein the load (3, LED) has a maximum current handling capability, wherein the controller (4) is arranged to stop increasing the current when the current exceeds the maximum current handling capability of the load (3, LED).

8. The load module (2) according to any of the preceding claims, wherein the controller (4) comprises a memory adapted to store the maximum power capability of the power supply (1).

9. The load module (2) according to any one of the preceding claims, further comprising the load (3).

10. The load module (2) according to claim 9, wherein the load (3, LED) is a lighting load.

11. The load module (2) according to claim 10, wherein the lighting load is a semiconductor lighting load.

12. A system comprising a load module (2) according to any one of the preceding claims and the power supply (1).

13. A method for determining the maximum power handling capability of a power supply (1), comprising the steps of: coupling a load module (2) to the power source (1) such that the load module (2) is adapted to receive power from the power source (1); drawing current from the power source (1); gradually increasing the current until the voltage provided by the power source (1) drops below a threshold; determining the voltage and the current provided by the power supply (1) when the voltage drops to determine the maximum power handling capability of the power supply (1), The current drawn therein gradually increases until the input voltage from the power supply (1) drops, so that no current flows from the power regulator (5) through the load (3, LED) during the configuration mode.

14. The method of claim 13, wherein the power consumption of the load module (2) is prevented from exceeding the maximum power handling capability of the power supply (1).

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