DE102019117412A1 - Driver, driver control method, and lighting module - Google Patents

Abstract

The present invention relates to a driver (100) for a lighting module, to a method for controlling such a driver and to a lighting module with such a driver (100) and a light-emitting element (300). The driver has inputs (101, 102) for receiving a supply voltage from an input unit (200) and driver outputs (301, 302) for supplying power in order to effect a light-emitting element (300) for generating light. The driver also has a power switching transistor (135) for controlling the power supplied to the driver outputs (301, 302). A controller (130) controls the power switching transistor (135) in order to operate the driver (100) alternately as a step-up converter or as a step-down converter depending on the supply voltage. The controller (130) includes an error detection input (147) which is adapted to detect both an error state of the zero current detection (ZCD) and an error state of the overvoltage protection (OVP). The driver (100) also includes a stabilization block (140) to prevent the OVP fault condition from being triggered incorrectly when the driver (100) is operated as a buck converter, or to prevent the ZCD fault condition from being triggered incorrectly when the driver (100) is operated as a step-up converter.

Description

Technical part

The invention relates to a driver for a lighting module, a method for controlling a driver, and a lighting module that includes the driver.

Technical background

With the introduction of light-emitting diode (LED) lamps, more efficient and long-lasting lamps are available than incandescent and fluorescent lamps. Materials of LED lamps are safer compared to fluorescent lamps because, for example, no mercury is required. Therefore, there is a need to adapt existing lights for fluorescent and incandescent lamps to accommodate LED lamps, preferably without having to change the entire light or the lamp holder.

Lamp sockets currently available can simply include an AC line to operate an incandescent lamp that is received in the lamp socket. Other lamp holders currently available can include an electronic ballast (also referred to as an electronic control gear, abbreviated ECG) for supplying a fluorescent lamp accommodated in the lamp holder. Such ECGs regulate and limit the current that is fed to the fluorescent lamp.

An LED retrofit lamp is an LED lamp that is used as a replacement for an incandescent, fluorescent or halogen lamp. Therefore, LED retrofit lamps may need to be compatible with AC power lines or an ECG device in the luminaire.

With some ECGs, the output voltage ranges from 24-100V. With some AC power supplies, the output voltage ranges from 198-264VAC. Therefore, a driver for an LED retrofit lamp that is compatible with both ECG and AC power supplies must be compatible with a wide range of possible voltages.

In order to be able to use only one driver for both operating modes (ECG and AC), the driver must be able to act as both a step-up and a step-down converter. On the one hand, if the input voltage is higher than the output voltage, the driver converter should automatically switch to downconversion (also called "buck conversion"). On the other hand, if the input voltage is less than the output voltage, the driver's converter should switch to boost conversion.

shows a retrofit driver for an ECG or AC light module, as is known in the prior art. The driver 100 includes the voltage inputs 101 . 102 for receiving a supply voltage from an ECG and a filament circuit or from the AC network.

The driver inputs 101 . 102 of the driver 100 are on a bridge 110 , alternatively referred to as a "Boost" converter, for converting or rectifying the driver inputs 101 . 102 applied voltage is provided. The bridge 110 in conjunction with one parallel to the bridge 110 provided filter capacitor 120 contributes to the achievement of ECG compatibility.

The driver 100 generates a first driver output 301 and a second driver output 302 , A light-emitting element can be placed between the outputs 300 , such as an LED lamp, can be provided.

The driver 100 also includes an integrated circuit (IC) controller 130 , Together with the adjacent circuit, the IC controller controls 130 both the down conversion and the up conversion of the driver 100 , In particular, the IC controller 130 a control output 137 on which is a gate of a power switching transistor 135 controls. The power switching transistor 135 controls the turn-on time of a transformer coming from the primary coil 132A and the auxiliary coil 132B of the transformer. This will make the driver outputs 301 . 302 to supply the light-emitting element 300 rated power.

• Überspannungsschutz (OVP) und Nullstromerkennung (ZCD). Ein einzelner Transformator, der in der IC-Steuerung 130 vorgesehen ist, wird verwendet, um sowohl OVP- als auch ZCD-Fehlerzustände zu erfassen.

The IC control 130 typically has a single fault detection pin 147 , which is used for two error detection functions at the same time:

• Surge protection (OVP) and zero current detection (ZCD). A single transformer in the IC control 130 is used to capture both OVP and ZCD error conditions.

Summary

The in The prior art shown has the disadvantage that operation in the different conversion modes of the downconversion and upconversion can lead to a conflict between the error conditions OVP and ZCD.

If the driver 100 performs a downconversion, the voltage of the driver outputs 301 . 302 be high enough for a high voltage on the transformer auxiliary coil 132B build. The high voltage on the transformer auxiliary coil 132B in turn causes the voltage across the resistor 142 (which detects the voltage on the error detection pin 147 determined) to such a high level that the IC control 130 incorrectly recognizes an overvoltage protection (OVP) fault condition.

If the driver 100 performs an upconversion, the voltage gap between the driver inputs 101 . 102 and the driver outputs 301 . 302 be so low that the voltage across the resistor 142 (which detects the voltage on the error detection pin 147 determined) to such a low level that the IC control 130 incorrectly detects an error state of the zero current detection (ZCD).

In both of the above scenarios, IC control goes 130 in error mode (also called protection mode) and stops the energy transfer to the driver outputs 301 . 302 ,

The error state when the driver 100 of 1 downconverting is in the 2 and 3 shown.

In particular shows the voltage V _DS over the power switching transistor 135 , The value fluctuates between approx. 0V and 320V. The value V _DS represents the voltage difference between the drain and the source of the power switching transistor 135 the who in is designed as a MOSFET.

shows the tension V ₁₄₇ on the error detection pin 147 the IC control 130 , How out can be seen is the voltage at the error detection pin 147 in the range of approximately -5V to + 2V very high, which leads to the IC control 130 recognizes an overvoltage protection (OVP) fault condition. This is the IC control 130 in protection mode to damage the power switching transistor 135 to avoid. Operation of the IC controller 130 is not normal.

In view of these drawbacks, one aim is to provide a driver for an LED lamp to retrofit an existing lighting module, such as a currently available incandescent lamp that is connected to an AC power supply, or a currently available fluorescent lamp lamp with an ECG to the existing lighting module to make it compatible with the LED lamp.

The driver is designed to offer the advantage of fault resistance when operating as a step-down converter and as a step-up converter. In other words, operation of either type of voltage conversion can be achieved without a fault condition being triggered incorrectly. In particular, the driver is preferably designed such that operation as a step-down converter does not incorrectly trigger an OVP error state. In addition, the driver is preferably designed so that operation as a step-up converter does not erroneously trigger a ZCD error state.

In addition, the driver can offer one or more of the following additional advantages: good compatibility with both types of power sources (namely AC and ECG), simple control, good performance and / or low cost.

One or more of the above advantages are provided by a driver for a lighting module according to the independent claim. Preferred embodiments result from the dependent claims, the description and the drawings.

Accordingly, a driver for a lighting module is provided which has inputs for receiving a supply voltage from an input unit and driver outputs for the power supply in order to effect a light-emitting element for generating light. The driver comprises a power switching transistor for controlling the power supplied to the driver outputs and a controller for controlling the power switching transistor in order to operate the driver alternately as a step-up converter or as a step-down converter depending on the supply voltage. The control includes an error detection input, which is adapted to detect an error state of the zero current detection (ZCD) as well as an error state of the overvoltage protection (OVP). The driver also includes a stabilization block to prevent an OVP fault condition from being triggered incorrectly when the driver is operated as a buck converter.

The driver can be used to operate an LED lighting module, e.g. an LED retrofit lamp or tube.

Alternatively or additionally, the stabilization block can prevent the ZCD fault condition from being incorrectly triggered when the driver is operated as a step-up converter.

In a first aspect, a driver is proposed that further comprises a transformer that is connected to the power switch transistor and the driver outputs, so that the power switch transistor controls the power supplied by the transformer to the driver outputs.

According to a further aspect, a driver is proposed which further comprises a conversion signaling unit. The conversion signaling unit generates a down signal to causing the driver to act as a down converter and / or an up signal to cause the driver to operate as a step up converter. In this way, the driver can be used for a wide range of voltage inputs and is compatible with both ECGs as input units and AC networks as input units.

According to a further aspect, a driver is proposed which further comprises an OVP detection block in order to override the stabilization block when the OVP error state actually occurs and to recognize the OVP error state at the input for error detection.

According to a further aspect, a driver is proposed, which further comprises a power supply block that supplies a Vcc voltage to the controller. The power supply block includes a low drop-out regulator (LDO) to limit the Vcc voltage. This counteracts an increase in Vcc voltage, which is a side effect of increasing the voltage of an auxiliary coil of the transformer. The increased voltage of the auxiliary coil of the transformer, which is provided in the stabilization block, is necessary to avoid false tripping of the ZCD fault condition.

It is another object of the present invention to provide a method for controlling a driver for a light emitting element. In a first step, an input unit is provided that is coupled to the driver. The input unit generates a supply voltage. In a second step, the controller alternately operates the driver either as a step-down converter or as a step-up converter, depending on the voltage level. In a third step, a control system detects a power level supplied to the light-emitting element without erroneously triggering the OVP error state or the ZCD error state. The controller includes an error detection input to detect an OVP fault condition and a ZCD fault condition.

It is another object of the present invention to provide a lighting module comprising a driver according to one of the previous aspects and a light emitting element. The light emitting element is coupled to the driver outputs of the driver.

The driver is preferably the driver as described above. That is, all features that are disclosed in connection with the driver are also disclosed in connection with the lighting module and vice versa.

The light-emitting element preferably has a light-emitting diode (LED) or is a light-emitting diode. The lighting module can be adapted for installation in an LED lamp.

list of figures

• 1 eine schematische Darstellung eines Nachrüstungstreibers für ein Beleuchtungsmodul, wie dieser im Stand der Technik bekannt ist,
• 2 ist ein Diagramm einer Spannung über einem Leistungsschalttransistor des Nachrüstungstreibers von 1, das die Auswirkungen eines Überspannungsschutz-Fehlerzustands veranschaulicht,
• 3 ist eine Grafik einer Spannung an einem Fehlererkennungspin einer IC-SteuerungIC-Steuerung des Nachrüstungstreibers von 1, die die Bedingungen veranschaulicht, die zu einem Fehlerzustand Überspannungsschutz führen,
• 4 ist ein Schaltplan, der eine exemplarische Ausführungsform eines Treibers für ein Beleuchtungsmodul zeigt,
• 5 ist ein Diagramm einer Spannung über einem Leistungsschalttransistor des Treibers von 4, wenn der Treiber als Abwärtswandler arbeitet,
• 6 ist eine Grafik einer Spannung an einem Fehlererkennungspin einer IC-SteuerungIC-Steuerung des Treibers von 4, wenn der Treiber als Abwärtswandler arbeitet,
• 7 ist ein Diagramm einer Spannung über einem Leistungsschalttransistor des Treibers von 4, wenn der Treiber als Aufwärtswandler arbeitet, und
• 8 ist eine Grafik einer Spannung an einem Fehlererkennungspin einer IC-SteuerungIC-Steuerung des Treibers von 4, wenn der Treiber als Aufwärtswandler arbeitet.

The present disclosure will be more readily understood by reference to the following detailed description in conjunction with the accompanying figures, in which:

• 1 1 shows a schematic illustration of a retrofit driver for a lighting module, as is known in the prior art,
• 2 FIG. 10 is a diagram of a voltage across a power switching transistor of the retrofit driver of FIG 1 that illustrates the effects of a surge protection fault condition
• 3 FIG. 4 is a graph of a voltage on an IC controller IC controller fault detection pin of the retrofit driver of 1 that illustrates the conditions that lead to a surge protection fault condition,
• 4 10 is a circuit diagram showing an exemplary embodiment of a driver for a lighting module,
• 5 10 is a diagram of a voltage across a power switching transistor of the driver of FIG 4 if the driver works as a buck converter,
• 6 is a graph of a voltage on an error detection pin of an IC controller of the driver of 4 if the driver works as a buck converter,
• 7 10 is a diagram of a voltage across a power switching transistor of the driver of FIG 4 if the driver works as a step-up converter, and
• 8th is a graph of a voltage on an error detection pin of an IC controller of the driver of 4 if the driver works as a step-up converter.

Detailed description

The exemplary embodiment of the driver and the lighting module is explained in more detail below with reference to the attached figures. The same or similar elements or elements with the same effect are identified by the same reference numerals, and a repeated description can be omitted to avoid redundancies. The numbers and proportions the elements shown one below the other in the figures are not to be regarded as scalable. Rather, individual elements can be represented with an exaggerated size in order to enable a better representation and / or a better understanding.

In 4 Figure 4 is an exemplary embodiment of a driver 100 shown for a light-emitting element. The driver 100 includes the voltage inputs 101 . 102 for receiving a supply voltage from a unit 200 which can be an AC network or an electronic ballast (ECG).

The driver 100 can be used to operate an LED lighting module, e.g. an LED retrofit lamp or tube.

The unit 200 can simply be a power supply such as an AC power supply or a DC power source.

Alternatively, the unit 200 also be an ECG and filament circuit. The filament circuit can supply an electromagnetically compatible circuit (EMC) to the driver 100 the entrances 101 . 102 provides. Alternatively, the EMC circuit and the driver inputs can be omitted 101 . 102 can be supplied directly from the filament circuit. The ECG can be operated with a standard AC power supply with 230V. Alternatively, the ECG can also be designed for another type of power supply, such as a DC power supply or an AC power supply that is operated with a different voltage and / or frequency.

In any case, if the driver 100 to a unit 200 connected, which is an AC power line, the driver should 100 work in an AC mode. If the driver 100 with one unit 200 connected, which is an ECG and filament circuit, is the driver 100 work in an ECG mode.

The unit generates for both operating modes 200 a pair of driver inputs 101 . 102 , The driver inputs 101 . 102 of the driver 100 are on a bridge 110 intended. The rectified voltage output of the bridge 110 over the bridge exits 110A . 110B is through an input filter capacitor 120 filtered.

The driver 100 further comprises a transformer with a primary coil 132A and an auxiliary coil 132B , The driver 100 also includes a power switching transistor 135 and a controller implemented as an integrated circuit (IC) 130 , A gate of the power switching transistor 135 is with a control signal 137 connected and controlled by this by the IC controller 130 is issued. The IC control 130 regulates the power switching transistor 135 to control the switch-on time of the transformer 132 , The IC control thus regulates 130 that of the transformer 132 current supplied for a driver 100 attached light-emitting element 300 ,

The light emitting element 300 is via a first driver output 301 and a second driver output 302 with the driver 100 connected. Preferably the light emitting element is 300 provided as a removable component by the driver 100 separated and at the first and second driver outputs 301 . 302 can be attached.

The first and second driver outputs 301 . 302 are through a filter capacitor 180 separated, which is parallel to the light-emitting element 300 is arranged. Between the primary coil 132A of the transformer and the filter capacitor 180 is also a free-wheeling diode 185 intended. The filter capacitor 180 and the freewheeling diode 185 help the the light emitting element 300 stabilize supplied voltage. If the primary coil 132A has discharged the transformer, current flows through the freewheeling diode 185 to the filter capacitor 180 and the light-emitting element 300 , If the transformer is no longer discharged, the filter capacitor supplies 180 the light emitting element 300 while the freewheeling diode 185 prevents the charge from the filter capacitor 180 back to the power switching transistor 135 flows.

A conversion signaling unit 150 detects an input voltage 101 . 102 and puts the switches 155 . 165 an up or down signal is available. This signal causes the driver 100 , between the up-voltage conversion (with switch 165 open and switch 155 closed) and the step-down voltage conversion (with switch 165 closed and switch 155 open).

The driver 100 is designed to offer the benefit of fault resistance when operating as a step-down converter and as a step-up converter. Operation as a voltage converter of both types is possible without an error condition being triggered incorrectly. This is done by providing a stabilization block 140 , a modified OVP recognition block 160 and a modified power supply block 170 reached.

The stabilization block 140 is provided to the voltage at the error detection pin 147 stabilize when the driver 100 works as a step-down converter to prevent the OVP Avoid fault condition during down conversion.

In the transformer auxiliary coil 132B the number of windings is increased in order to achieve a reduction in the ratio of the windings N _primary / N _auxiliary . In this way, the stabilization block prevents 140 an incorrect triggering of a ZCD error state when the driver 100 works as a step-up converter.

Also within the stabilization block 140 is a zener diode 143 provided the voltage across the voltage dividing resistors 142 . 144 limit and thereby stabilize. The zener diode 143 has a breakdown voltage that ensures that the fault detection pin 147 that is between the voltage dividing resistors 142 . 144 an appropriate level of tension is maintained. That is, the voltage at the error detection pin 147 is from the Zener diode 143 and the resistors 142 . 144 maintained at a level lower than the OVP level to prevent the OVP fault condition from being triggered incorrectly. This prevents the stabilization block 140 an incorrect triggering of an OVP error condition when the driver 100 works as a down converter.

The OVP recognition block 160 includes a zener diode 162 and a diode 164 that are biased in opposite directions. The voltage at the light-emitting element increases 300 , there is a corresponding increase in the voltage of the transformer auxiliary coil 132B , When the voltage on the transformer auxiliary coil 132B the breakdown voltage of the zener diode 162 exceeds, current flows through the OVP detection block 160 , This increases the voltage on the error detection pin 147 until it has an OVP fault condition within the IC controller 130 triggers. The IC control 130 then goes into protection mode and switches the circuit breaker transistor 135 from. By providing the OVP recognition block 160 is the driver 100 despite the effects of the stabilization block 140 still able to detect an OVP error condition and switch to protection mode.

The power supply block 170 makes sure that the via the Vcc pin 149 the IC control 130 supplied power does not exceed a nominal level. By reducing the ratio of the windings N _primary / N _auxiliary within the transformer 132 the voltage on the auxiliary coil 132B elevated. Therefore, the power supply block includes 170 a low dropout controller (LDO) 176 to the voltage on the Vcc pin 149 down convert so that the IC control 130 can work normally.

Operation of the driver 100 when operating as a buck converter is in the 5 and 6 shown.

Specifically shows 5 the voltage V _DS on the power switching transistor 135 of 4 , which is designed as a MOSFET. The voltage V _DS ranges from approx. 0V to approx. 500V.

6 shows the tension V ₁₄₇ on the error detection pin 147 the IC control 130 , The voltage V ₁₄₇ lies between approx. 0V and 1V. How out 6 can be seen, the voltage on the error detection pin is released 147 no OVP error condition from when the driver 100 works as a down converter. The IC control 130 continues to work normally.

Operation of the driver 100 when operating as a boost converter is in the 7 and 8th shown.

In particular shows 7 the voltage V _DS over the power switching transistor 135 of 4 , The voltage V _DS lies between approx. 0V and 130V.

8th shows the tension V ₁₄₇ on the error detection pin 147 the IC control 130 , The voltage V ₁₄₇ lies between approx. 0V and 1V. How out 8th can be seen, the voltage remains at the error detection pin 147 so high that the IC control 130 does not mistakenly detect a ZCD error state when the driver 100 works as a step-up converter. The IC control 130 continues to work normally.

In some embodiments, the switches and transistors can be inside the driver 100 , including the power switching transistor 135 and the switch 155 and 165 , can be provided as MOSFETs, such as n-channel MOSFETs. However, alternative designs can use other types of transistors, such as bipolar junction transistors (BJTs), to implement these switches.

In the illustrated embodiment, the IC controller 130 implemented with an IC, but in alternative embodiments, analog circuit components can be used in addition to or instead of an IC.

Even though 4 shows that the driver 100 a light emitting element 300 includes, the light emitting element 300 separately or detachable from the driver 100 to be provided. For example, at the first and second driver outputs 301 . 302 Lanyards such as sockets or clamps are provided to separate a light-emitting element 300 take.

Regarding the embodiment of 4 it was described that the number of windings in the transformer auxiliary coil 132B is increased in order to achieve a reduction in the ratio of the windings N _primary / N _auxiliary (primary / shunt). However, it will be appreciated that the same reduction in the ratio alternatively or additionally by reducing the number of windings in the primary coil 132A of the transformer could be reached.

It will be apparent to a person skilled in the art that the illustrated embodiment represents only one example from a multitude of possibilities. Therefore, the embodiments discussed here should not be construed to limit these features and configurations. Any possible combination and configuration of the described features can be chosen in accordance with the scope of the invention.

LIST OF REFERENCE NUMBERS

100

driver

101, 102

First and second input of the driver

110

bridge

110A, 110B

bridge outputs

120

Input filter capacitor

130

Control IC

132A

Transformer primary coil

132B

Transformer auxiliary coil

135

Power switching transistor

137

Gate control signal

138

control input

139

resistance

140

stabilizing block

141

capacitor

142

First voltage dividing resistor

143

Zener diode

144

Second voltage dividing resistor

146

resistance

147

Error detection spin

148

diode

149

Vcc voltage

150

Conversion signaling unit

155

switch

160

Surge protection (OVP) detection block

162

Zener diode

164

diode

165

switch

170

Control power supply block

171

resistance

172

diode

174

capacitor

176

Low drop-out controller (LDO)

178

capacitor

180

filter capacitor

185

Freewheeling diode

300

Light emitting element

301

First driver output

302

Second driver output

Claims (9)

A driver (100) for a lighting module, comprising: - inputs (101, 102) for receiving a supply voltage from an input unit (200); - driver outputs (301, 302) for power supply to effect a light emitting element (300) for generating light; - a power switching transistor (135) for controlling the power supplied to the driver outputs (301, 302); - a controller (130) for controlling the power switching transistor (135) to operate the driver (100) alternately as a step-up converter or as a step-down converter depending on the supply voltage; wherein the controller (130) comprises an error detection input (147) which is adapted to detect both an error state of the zero current detection (ZCD) and an error state of the overvoltage protection (OVP); characterized by - a stabilization block (140) to prevent the OVP fault condition from being incorrectly triggered when the driver (100) is operated as a step-down converter. Driver (100) after Claim 1 wherein the stabilization block (140) prevents the ZCD fault condition from being erroneously triggered when the driver (100) is operated as a step-up converter. Driver (100) after Claim 1 or 2 , further comprising a transformer (132A, 132B) connected to is connected to the power switching transistor (135) and the driver outputs (301, 302) such that the power switching transistor (135) controls the power supplied by the transformer (132A, 132B) to the driver outputs (301, 302). A driver (100) according to any previous claim, further comprising a conversion signaling unit (150), - wherein the conversion signaling unit (150) generates a down signal to cause the driver (100) to operate as a down converter, and / or - wherein the conversion signaling unit (150) generates an up signal to cause the driver (100) to operate as an up converter. Driver (100) according to a previous claim, wherein the driver (100) is compatible with the input unit (200) provided as an ECG and wherein the driver (100) is also compatible with the input unit (200) provided as an AC power line. A driver (100) according to any previous claim, further comprising an OVP detection block (160) to override the stabilization block (140) and to detect the OVP fault condition at the fault detection input (147) when the OVP fault condition actually occurs. A driver (100) according to any previous claim, further comprising a power supply block (170) supplying the controller (130) with a Vcc voltage (149), the power supply block (170) including a low drop-out regulator (LDO, 176) to limit Vcc voltage (149). A method of controlling a driver (100) for a light emitting element (300), the method comprising: - Providing an input unit (200) coupled to the driver (100), the input unit (200) generating a supply voltage; and - in a controller (130) detecting a voltage level which is supplied to the light-emitting element (300), the controller (130) comprising an error detection input (147) for detecting an OVP error state and a ZCD error state; and - Operating the controller (130) in order to operate the driver (100) alternately either as a step-down converter or as a step-up converter, depending on the voltage level, without triggering the OVP error state or the ZCD error state incorrectly. Lighting module with a driver (100) according to one of claims 1 to 6 and a light-emitting element (300), wherein the light-emitting element (300) is coupled to the driver outputs (301, 302) of the driver (100).

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