AT15900U1 - Converter module for bulbs with load detection function - Google Patents

Abstract

The invention provides a converter module (KM) for operating a load in the form of at least one light source, preferably at least one LED, with a potential-separated clocked converter, which is controlled on the primary side by a control unit (SE), the converter (W). on the primary side starting from a supply voltage, preferably an AC voltage, can be supplied, and wherein starting from the secondary side of the converter, the light source can be supplied, wherein the converter module (KM) further primary side a load identification circuit (LI), which designed is, depending on a load that can be supplied from the secondary side to select an operating mode of the control unit (SE) by means of only primary-side signals, and which is set up; detect a primary-side current and an applied supply voltage, and relate the detected current and the detected supply voltage, and select the operation mode depending on the relationship.

Description

description

CONVERTER MODULE FOR LUMINAIRES WITH LASER DETECTION FUNCTION The invention relates to a converter module for lamps, in particular for operating at least one LED, or an LED string, which enables dimmable operation of lamps. The invention preferably relates to a converter module for use in ballasts or luminaires, with which in particular the illuminant to be operated can be connected. The illuminants can be dimmed using a phase dimmer or triac, as is still widely used as an infrastructure for dimming incandescent lamps.

The converter module can be used to operate at least one LED lamp, e.g. an LED retrofit lamp (LED retrofit lamp). Alternatively or additionally, the converter module can also be part of an LED lamp, for example as a module integrated in the lamp. The converter module according to the invention can in particular be a driver module for LED retrofit lamps, in particular for retrofit lamps of the MR16 type.

The converter module according to the invention preferably has a clocked potential-isolating converter (flyback converter, flyback converter), which galvanically or potential-separates a primary side of the converter module from a secondary side of the module. The converter is clocked on the primary side by means of a switch and can be supplied from a mains voltage. The at least one illuminant can be operated / supplied from the secondary side. The switch can be controlled by a control unit, for example a microcontroller, an ASIC or an IC, and can be provided either in the control unit or separately therefrom.

The starting point of the invention is the desire to be able to operate different loads on a converter module. The possibility of operating different loads allows the lamps used to be selected flexibly, but on the other hand also easy to deal with forward voltage tolerances. These problems exist in particular in the case of converter modules for retrofit lamps, in particular in the case of MR16 operating modules, since a user can connect a different number of lamps to the converter module, these having different power values or belonging to different power classes , Furthermore, lamps can be freely connected and removed by the user, and it is important that the remaining lamps continue to operate properly even when dimmed down.

However, a variable load is a problem in many dimming applications, especially for low-cost dimming solutions with phase cut dimming. This problem results from the fact that known dimming techniques reduce the peak current on the primary side in order to achieve dimming of the illuminant, that is to say to reduce the light output emitted by the illuminant.

However, the resultant effect is that the power output by the module is reduced instead of the output current when dimming down. Therefore, if the current load is less than the maximum load, the load is always operated with reduced power because the forward voltage is lower. On the one hand, a dimmer must first be dimmed to a certain degree before the module output drops to such an extent that the non-maximum load is actually dimmed.

On the other hand, the minimum dimming value to be achieved is higher than that which could be achieved when the maximum load was applied. This means that when the load is reduced, it cannot be dimmed down as far as would be possible at maximum load. This results in an undesirable reduced dimming range, since the lower limit for the adjustable dimming value is raised.

[0008] LED drivers are known from the prior art which have different power levels

AT15 900U1 2018-08-15 Austrian

Provide the patent office. However, each of these must be selected manually, using a jumper, a switch or via separate output connections. This is cumbersome and requires user intervention.

It is now the aim of the invention to overcome these disadvantages and to automatically select a range for the output power depending on the supplied load.

[0010] The problem is solved according to the invention by a device and a method according to the independent claims. Further forms of the invention are the subject of the dependent claims.

In a first aspect, the invention provides a converter module for operating a load in the form of at least one lamp, preferably at least one LED, with a potential-separated clocked converter which is controlled on the primary side by a control unit, the converter starting on the primary side can be supplied by a supply voltage, preferably an AC voltage, and wherein the illuminant can be supplied starting from the secondary side of the converter, the converter module further comprising a load identification circuit on the primary side, which is designed to be dependent on one of the Secondary-side load selectable by means of only primary-side signals an operating mode of the control unit, and which is set up to detect a primary-side current and an applied supply voltage and to relate the detected current and the detected supply voltage and depending on the reference to select the operating mode.

A signal can be generated by relating the operating load to the secondary side of the clocked isolated converter.

[0013] The load identification circuit can have a latch circuit with at least two switching elements.

The control unit can be in a high-power operating mode after a network reset and switch to a low-power operating mode when a load is detected that is below the maximum load.

[0015] The latch circuit can activate / deactivate a circuit part which changes a reference value supplied to the control circuit.

An unchanged reference value can be supplied to the control unit if the latch circuit is in a first state, in particular is conductive, and the control unit can operate the converter with low power in this state.

The changed reference value can be supplied to the control unit when the latch circuit is in a second state, in particular is not conductive, and the control unit can operate the converter with high power in this state.

[0018] The latch circuit can hold the first state until a network reset, in particular independently of a dimming value / a change in dimming value.

The control unit is preferably supplied with no signal from the secondary side of the converter.

The supply voltage can be detected via a detection circuit.

[0021] In another aspect, the invention provides a lamp, in particular an LED retrofit lamp, with a converter module, as described above.

In a further aspect, the invention provides a ballast for light sources, in particular at least one LED or an LED section, with a converter module, as described above.

In yet another aspect, the invention provides a luminaire with a converter module, as described above.

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In yet another aspect, the invention provides a method for operating a converter module for operating at least one light source, preferably at least one LED, a primary-side control unit controlling a potential-isolated converter, preferably on the primary side starting from a supply voltage an AC voltage, and the lamp can be supplied starting from the secondary side of the converter, a primary-side load identification circuit of the converter module depending on a load that can be supplied from the secondary side using only primary-side signals to select an operating mode of the control unit and a primary-side one Detects current and the applied supply voltage and relates the detected current and the detected supply voltage and, depending on the relationship, selects the operating mode.

The invention will now be described with reference to the figures. 1 shows schematically a block diagram of the device according to the invention.

2 shows a circuit arrangement according to the invention.

In general, the invention is aimed at enabling a smooth and flicker-free dimming, in particular in connection with the widespread leading edge dimmers. At the same time, however, the number of circuit elements required should be kept as low as possible, but operation with different control units should also be made possible.

An essential feature of the invention is that the control unit, which is arranged on the primary side of the converter, selects a lower value for the maximum power when a changed load is detected in order to provide an improved dimming behavior.

The invention now provides to show a simple circuit arrangement which can gradually switch between several operating modes depending on a detected load, for example between two operating modes, i.e. a higher power operating mode and a lower power operating mode when dimmer, i.e. the dimming value is reduced.

A load identification circuit has a detection resistor (in Fig. 2 e.g. resistor R35), on which an input side, i.e. primary current is detected. In addition, a detection circuit for the voltage present is provided (in FIG. 2 in particular the resistors R21, R39, R24 with the capacitance C11), the voltage being known to change when dimming.

If current and the supply voltage are now related, a signal can be obtained therefrom which represents the load being operated on the secondary side of the clocked floating converter.

This is illustrated in Fig. 1, which shows a converter module KM according to the invention. A voltage detection circuit VE detects the supply voltage, while a current detection circuit IE detects the current from the converter W on the primary side. A signal is fed from both detection circuits VE, IE to a load identification circuit LI, which preferably has a latch circuit, which relates the two signals. An identification then also takes place depending on threshold values set in the circuit, which e.g. by appropriate dimensioning of the resistors used or of the switching elements (transistors) of the load identification circuit LI, in particular the latch circuit. In particular, the load identification circuit LI can logically perform a subtraction / addition of the signals.

An output signal of the load identification circuit LI is then fed to the control unit SE which, based on this, selects an operating mode and, depending on the selected operating mode, then controls the switch (which can also be provided internally in the control unit SE) of the converter W. ,

The galvanically insulating barrier B, which divides the converter module KM into a primary side P and a secondary side S, is also shown schematically in FIG. 1.

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AT15 900U1 2018-08-15 Austrian Patent Office [0036] FIG. 2 shows an example of a circuit arrangement that allows the output power to be controlled / regulated in accordance with the invention.

Starting from the connections on the primary side labeled “Live and“ Neut, which denote the outer conductor (phase) and the neutral conductor, the converter module is supplied with a supply voltage, for example an alternating voltage / alternating current (AC). The supply voltage is rectified via a rectifier D1. It can also be provided that the converter module can be supplied directly by a direct voltage / direct current, so that the rectifier can be omitted.

On the secondary side, output connections are provided (denoted by OV and + 12V) from which the lamp can be supplied.

The control unit U1, which is used in the circuit arrangement in FIG. 2, is, for example, an LED driver HV LED 815 from ST Microelectronics, which is designed as a dimmable driver for LED retrofit lamps.

The operating mode is selected by a load identification circuit 1.

In Fig. 2, an identification signal output by the load identification circuit 1 is used to externally switch a resistor circuit 3, so that different voltage levels U1 are supplied to the control unit and thus the reference voltage of the control unit U1 can be changed.

In a more complex embodiment, which is not shown in FIG. 2, the identification signal is supplied, for example, to the pin of the control unit (IC, ASIC, microcontroller, ...), the mode of operation or operating parameters of which can be set depending on this identification signal ,

In the embodiment shown in FIG. 2 with external circuitry (trick circuit for the control unit U1), a latch circuit is provided which also maintains this state in the event that a state with low power is detected (low power) if the dimming levels subsequently change.

The latch circuit is only reset when the supply voltage supply is switched off (network reset). When the device is switched on again, the circuit normally returns to the 'high power' state and remains in this state until a reference to the input-side current with the applied voltage triggers the switching to the mode with reduced power (low power mode).

The load identification can be evaluated in a more intelligent primary control unit (microcontroller, ASIC, IC) in different ways.

[0046] For example, it can be used to detect a lamp voltage. This has the advantage that no secondary-side illuminant voltage detection has to be carried out and thus, for example, no signal has to be routed from the secondary side to the primary side via the potential separation (for example insulating SELV barrier). Thus, the illuminant path can be operated with a specified illuminant current without secondary detection. For this purpose, the current through the primary side of the isolated converter is detected and the load identification signal is also used.

The load is identified by the load identification circuit 1 by monitoring the supply voltage at a first resistor R35, which is circled in FIG. 2.

Since the current also drops when dimming down, the voltage drop across the first resistor R35 is not compared to a fixed reference value. Instead, it is compared to a reference value that changes in proportion to the average supply voltage. This reference value is generated by a detection circuit 2 on a first voltage divider, formed by resistors R23, R39 and R24, and a capacitor C11 for forming an average value.

The load can thus be recognized when the supply current or the span 4/10

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Patentamt voltage drop across the first resistor R35 is low while the supply voltage is high.

The basic function of the circuit shown in Figure 2 is as follows:

The currently selected load condition, i.e. the operating mode for the detected load is stored by a simple latch circuit, which is formed by the switching elements Q4 and Q7. The switching elements Q4 and Q7 are designed as transistors, (bipolar transistors, FET, MOSFET) or a combination thereof.

The latch circuit can either be conductive, i.e. both switching elements Q4, Q7 can be switched on (conductive) or the LED circuit cannot be conductive if both switching elements are switched off.

After switching on (mains reset), the latch circuit is initially in a non-conductive state, as a result of which the setting for high output power is selected by the control unit. In this state, the collector of the switching element Q4 will be pulled to a voltage V _cc is turned on and thus the switching element Q6 (MOSFET, FET, bipolar transistor). The switching element Q6 is shown in the circuit part 3.

As a result, the voltage divider, which is formed by the resistors R30 and R31, is activated, thereby reducing the reference voltage signal fed back from the secondary side at the input CS (current sense) of the control unit, which is detected by the control unit via the resistor R11 becomes. The converter is then operated at full power. The connected load is monitored as described below:

The voltage drop across the resistor R35 is averaged by the resistor R34 and the capacitance C16, which results in a negative DC voltage at the emitter of the switching element Q4. This is indicated by the arrow in Fig. 2.

The positive reference voltage (proportional to the supply voltage) is added to the negative voltage by the voltage divider from the resistors R32 and R33. The switching element Q3 is connected as a diode in order to additionally add a voltage drop in the base-emitter voltage V _B e in order to compensate for the voltage drop in the base-emitter voltage at the switching element Q4. This further improves the temperature stability in a positive manner.

The resulting voltage is supplied to the base of the switching element Q4. A decrease in the supply current will increase this supplied voltage, while a reduction in the supply current will also reduce the supply voltage.

If the current is low in relation to the supply voltage, the switching element Q4 will switch the latch circuit into the conductive state.

When the latch circuit is in the conductive state, the collector of the switching element Q4 is pulled to the voltage or to a voltage close to the voltage 0V, whereby the switching element Q6 (MOSFET) is switched off. The complete feedback voltage is then detected via the current measuring resistor R11 on the control unit, and the converter is operated with reduced power.

[0061] Once the circuit arrangement is in a state with low power, the supply voltage must preferably be interrupted in order to switch back to the state with high power.

The switching element Q5 prevents triggering of the latch circuit during the start phase, i.e. after switching on or network reset. The Zener diode Z2 further prevents tripping until the voltage VCC reaches a certain voltage value, for example 15 volts, in particular 10-20 volts.

As a result, the circuit arrangement according to the invention dims in a state with low power even at a load of 20-40, preferably 30% of the maximum load in the same way

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Patent office as with maximum load in high performance mode.

In summary, the invention consequently exhibits improved dimming behavior with reduced load, i.e. Load below the maximum load value, while the circuit arrangement can be implemented inexpensively. It is to be understood that the circuit arrangement can also be operated with other control units.

For example, the invention prevents flickering of the illuminant during dimming, for example also when an LED retrofit lamp is replaced by halogen transformers.

The invention therefore allows the operation of an alternating load with a single converter module. As mentioned, the load differences can result from the connection of a different number of lamps / illuminants, so that the load can vary, for example, from 3 watts (in the case of a lamp, for example) to the maximum specification of the driver module.

Since the circuit arrangement according to the invention automatically changes between different power ranges, gentle dimming can take place in each of the power ranges.

[0068] Thus, a lamp can be operated on a specified current without secondary detection. As already mentioned, the current through the primary side of the isolated converter is recorded and the load identification signal is used.

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Patent Office

Claims (10)

Expectations 1. converter module (KM) for operating a load in the form of at least one lamp, preferably at least one LED, with a potential-isolated clocked converter (W), which is controlled on the primary side by a control unit (SE), the converter (W) can be supplied on the primary side starting from a supply voltage, preferably an AC voltage, and the illuminant can be supplied starting from the secondary side of the converter (W), - The converter module (KM) further has a load identification circuit (LI) on the primary side, which is designed to select an operating mode of the control unit (SE) depending on a load that can be supplied from the secondary side by means of signals on the primary side only, and the is set up to detect a primary-side current and an applied supply voltage and to relate the detected current and the detected supply voltage and to select the operating mode depending on the relationship. 2.2. + JSV 2. Converter module (KM) according to claim 1, wherein generated by generating a signal that reflects the operated load on the secondary side of the clocked floating converter (W). 3. Converter module (KM) according to claim 1 or 2, wherein the load identification circuit (LI) has a latch circuit with at least two switching elements. 4 (. 2 KM B Fig. 1 4. Converter module (KM) according to one of the preceding claims, wherein the control unit (SE) is after a network reset in an operating mode with high power and changes to an operating mode with lower power when a load is detected that is under the maximum load lies. 5. Converter module (KM) according to claim 3, wherein the latch circuit activates / deactivates a circuit part which changes a reference value supplied to the control circuit. 6. Converter module (KM) according to claim 3, wherein the control unit (SE) is supplied with an unchanged reference value when the latch circuit is in a first state, in particular is conductive, and the control unit (SE) in this state the converter (W) operates with low power. 7.10 AT15 900U1 2018-08-15 Austrian Patent Office 14. Method for operating a converter module (KM) for operating at least one light source, preferably at least one LED, wherein a primary-side control unit (SE) controls a potential-isolated converter (W) which on the primary side starts from a supply voltage, preferably an AC voltage , can be supplied, and the lamp can be supplied starting from the secondary side of the converter (W), a primary-side load identification circuit (LI) of the converter module (KM) depending on a load that can be supplied from the secondary side by means of signals on the primary side only Selects operating mode of the control unit (SE) and detects a primary-side current and the applied supply voltage and relates the detected current and the detected supply voltage and selects the operating mode depending on the relationship. Two sheets of drawings 7. Converter module (KM) according to claim 3, wherein the control unit (SE) is fed the changed reference value when the latch circuit is in a second state, in particular is not conductive, and the control unit (SE) in this state Converter (W) operates with high power. 8.10 AT15 900U1 2018-08-15 Austrian Patent Office 8. converter module (KM) according to claim 6, wherein the latch circuit holds the first state until a network reset, in particular regardless of a dimming value / a dimming value change. 9.10 AT15 900U1 2018-08-15 Austrian Patent Office 9. converter module (KM) according to any one of the preceding claims, wherein the control unit (SE) no signal is supplied from the secondary side of the converter (W). 10. Converter module (KM) according to one of the preceding claims, wherein the supply voltage is detected via a detection circuit. 11. Lamp with a converter module (KM) according to one of the preceding claims. 12. Ballast with a converter module (KM) according to one of the preceding claims. 13. Luminaire with a converter module (KM) according to one of the preceding claims. 10/10