Driver unit, driver and LED light source with one driver

Abstract

Driver unit for programming an output current of a driver (4) with an output stage (5) for providing the output current and with a primary control stage (6) with a control input (7) for controlling the output current, wherein the driver unit (8) comprises: - a programmable memory unit (9) for storing data corresponding to a setpoint of the output current, - a programming signal circuit (10) configured to provide electrical signals for writing data to the programmable memory unit (9), - a control circuit (11) with a controller (14) which is operationally connected to the programmable memory unit (9), wherein the controller (14) is configured to read the data stored in the programmable memory unit (9) and generates a controller output signal at a controller output for setting the output current of the driver (4) based on the data stored in the programmable memory unit (9), wherein the programming signal circuit (10) includes a terminal (16) which can be connected to the output stage (5) of the driver, and wherein the programming signal circuit (10) is configured such that the electrical signals for writing the data to the programmable memory unit (9) can be deactivated by applying a voltage to the terminal (16).

Description

[0001] The technical field of this disclosure relates generally to drivers for controlling loads. In particular, this disclosure relates to a driver unit, a driver, and an LED (light-emitting diode) light source with a driver.

[0002] Drivers for providing an output current to drive loads are known. Furthermore, drivers with adjustable output current are known, allowing the driver current to be set by external elements such as resistors, jumpers, or switches. However, such drivers offer only a limited selection of output current values, while drivers with greater adjustment options for the output current are complex, prone to failure, and expensive.

[0003] Documents DE102013107771A1 and WO 2005 / 084 085 A1 describe an electrical power converter for providing an output current, wherein the power converter includes an integrated interface component for programming and controlling the output current.

[0004] One objective of the present application is to provide a driver unit for programming an output current of a driver that is particularly robust and cost-effective.

[0005] According to a first aspect, a driver unit is provided for programming the output current of a driver with a power stage for providing the output current and a primary control stage with a control input for controlling the output current. The driver unit includes a programmable, in particular electrically programmable, memory unit for storing data that corresponds to or represents a setpoint or setpoint level of the output current. The driver unit further includes a programming signal circuit configured to provide electrical signals for writing the data to the programmable memory unit, and a control circuit with a controller or microcontroller unit that is operationally connected to the programmable memory unit.The controller is configured to read the data stored in the programmable memory unit and, based on this data, generate a controller output signal to adjust the driver's output current. Specifically, a control signal can be provided based on the controller output signal to feed into the driver's primary control stage, thus creating a control loop to adjust the driver's output current according to the data stored in the programmable memory unit.

[0006] By feeding the control signal into the control input of the driver's primary control stage, the driver output current can be easily adjusted according to the data stored in the programmable memory unit. In this way, the driver unit can be used to provide a programmable driver that allows the output current to be set and regulated to a desired value.

[0007] The programming signal circuit includes a connection that can be connected to the output stage of the driver or the driver bus. Furthermore, the programming signal circuit is configured such that the electrical signals for writing data to the programmable memory unit can be switched off by applying a voltage to the connection, particularly relative to a ground potential.

[0008] The programming signal circuit can be connected to the driver's output stage in such a way that, during driver operation, an electrical potential is present at the connection, which disables the electrical signals for writing data to the programmable memory unit. Therefore, programming such a driver is only possible when the driver is offline or switched off. This offline programming function makes the driver particularly convenient and safe for the user, as programming such a driver requires switching it off, and the user has no reason to interact with the driver for programming while it is running.

[0009] The programming signal circuit can include an activation switch to enable the electrical signals for writing data to the programmable memory unit. Specifically, the programming signal circuit can have an output circuit, and the activation switch can be configured so that closing the activation switch also closes the output circuit. Therefore, to program the programmable memory unit, the activation switch, which is otherwise open, must be closed. In the normal state, when the programmable memory unit is not being programmed, the output circuit is open, and the signal circuit for programming is deactivated. Consequently, the programming signal circuit consumes very little power. Furthermore, unintentional writing or erasing of data in memory due to a faulty signal can be prevented.

[0010] The programming signal circuit can further include a disable switch to deactivate the electrical signals for writing data to the programmable memory unit, specifically by opening the enable switch when a voltage is applied to the terminal. Therefore, regardless of whether the driver is operating or not, the programming signal circuit is always disabled unless it is being used to program the programmable memory unit. This reduces the power consumption of the programming signal circuit.

[0011] In some embodiments, the activation and deactivation switches can be transistor switches based on MOSFETs (metal-oxide-semiconductor field-effect transistors), each MOSFET having a source, a drain, and a gate. The gate of the activation switch is connected to the drain of the deactivation switch, and the gate of the deactivation switch is electrically connected to the terminal of the programming signal circuit. MOSFETs are suitable switches due to their robustness and low power consumption.

[0012] The programmable memory unit can include a single-wire programmable memory. Programming a single-wire programmable memory requires only an electrical connection. This eliminates the need for a complex interface for programming the programmable memory unit. In particular, any wireless interface, such as those based on NFC (Near Field Communication), BLE® (Bluetooth Low Energy), or WiFi® protocols, can be avoided. Furthermore, wireless interfaces require antennas, which are unsuitable for applications in metal enclosures and incur additional costs for waterproofing and standby power losses during programming. Additionally, a connecting wire can be used for programming communication between the programmer and the programmable memory unit, linking the driver's output stage to the load.The programmable memory unit using one-wire technology thus makes it possible to keep the circuit of the programmable driver simple and compact.

[0013] The programmable memory unit may include an EEPROM (electrically erasable programmable read-only memory), in particular a one-wire programmable EEPROM, which is a readily available, inexpensive standard component.

[0014] The output circuit of the programming signal circuit can include an inductive element configured to inductively couple the electrical signals for writing data to the programmable memory unit. The inductive coupling between the programming signal circuit and the programmable memory unit can be used as a low-pass filter or surge arrester to suppress interference signals.

[0015] The control circuit can be operationally connected to the driver's output stage, so that data communication between the control circuit and the programmable memory unit is blocked when the driver is switched off. In particular, the control circuit can include a connection that can be connected to the driver's output stage, and the control circuit can be configured so that data communication between the control circuit and the programmable memory unit can be disabled by applying a voltage to this connection. Disabling data exchange between the programmable memory unit and the controller, in particular, avoids the power dissipation caused by data communication between the programmable memory unit and the controller in standby mode.

[0016] The driver unit can include an output section that is connectable to the driver's output stage and configured to generate the control signal based on the controller output signal and a current value of the output current. Specifically, the output section of the driver unit can be configured to generate the output signal in accordance with, or matching, the control input of the driver.

[0017] The output stage can include an error amplifier or differential amplifier, whose first input can be connected to the driver's output stage to sample the output current, and whose second input is electrically connected to the controller output to provide a reference for the error amplifier. The error amplifier's output signal reflects the difference between the actual output current and the target output current. The differential signal at the error amplifier's output can be used to essentially maintain the driver's output current at the target level.

[0018] In some embodiments, the controller is configured so that the controller output signal is a PWM (pulse-width modulation) signal with a duty cycle that depends on the data stored in the programmable memory unit. Controllers or microcontroller units that provide a variable-duty-cycle PWM signal are readily available, inexpensive, and standard components.

[0019] The driver unit can include a controller output circuit with an RC filter to provide a DC (direct current) reference voltage for the error amplifier. Specifically, the RC filter filters the controller output signal so that the reference voltage level at the second input of the error amplifier reflects the characteristics, particularly the duty cycle, of the controller output signal and thus the data stored in the memory unit. Therefore, if a voltage reflecting the current value of the output current is present at the first input of the error amplifier, the error amplifier can provide a correction signal as an input for the control input of the driver, adjusting the output current to the setpoint. Consequently, analog control for adjusting the output current, particularly without PWM flickering, can be achieved.

[0020] According to another aspect, a driver is provided with a driver output stage or driver bus for supplying an output current, a primary control stage with a control input for controlling the output current, and a driver unit, as described in the first aspect, for programming the driver's output current. The output stage of the driver unit is connected to the driver's control input in such a way that the output current is essentially adjustable to the setpoint based on the data stored in the driver unit's programmable memory. The driver is particularly reliable, cost-effective, and easy to program.

[0021] The programming signal circuit of the driver unit can be connected to the driver's output stage, so that the programming signal circuit is deactivated when the driver is switched on. By deactivating the programming signal circuit, programming the driver is not possible when the driver is switched on. Therefore, such a driver is also safe for the user.

[0022] According to a third aspect, an LED light source is provided. The LED light source comprises at least one LED for light generation and a driver, as described above, which is connected to the LED so that the LED can be controlled by the driver. The programmable output current of the driver allows the user to easily program the current flowing through the LED and thus the light output of the light source. Furthermore, such a programmable light source is particularly cost-effective and safe for the user.

[0023] The following description provides details for describing the embodiments of this specification. However, it should be apparent to a person skilled in the art that the embodiments can also be used without such details.

[0024] Some parts of the embodiments have similar parts. The similar parts may have the same names or similar part numbers. The description of one part may, where appropriate, apply to another similar part by reference, thereby reducing text repetition without limiting the disclosure. Fig. Figure 1 shows a schematic circuit diagram of an LED light source with a driver and a driver unit according to one embodiment.

[0025] Fig. Figure 1 shows a schematic circuit diagram of an LED light source with a driver and a driver unit according to one embodiment. The LED light source 1 comprises an LED module 2 with a number of LEDs 3. The LED light source 1 further comprises a driver 4 with a driver output stage 5 for providing an output current, a primary control stage 6 (shown schematically) with a control input 7 for controlling the output current of the driver 4, and a driver unit 8 for programming the output current of the driver 4.

[0026] In the embodiment of Fig. The driver unit 8 consists of a programmable memory unit 9, a programming signal circuit 10, a control circuit 11, and an output section 12. The programmable memory unit 9 includes a programmable memory 13 for storing data corresponding to or representing a setpoint of the output current. The programming signal circuit 10 is configured to provide electrical signals for writing the data to the programmable memory 13 of the programmable memory unit 9. The control circuit 11 includes a controller 14, which is operationally coupled to the programmable memory 13 and configured to read the data stored in the programmable memory 13 and generate a controller output signal for adjusting the output current of the driver 4 based on the data stored in the programmable memory 13.

[0027] The programming signal circuit 10 includes a transformer 15 for inductive coupling of the programming signal circuit 10 with the programmable storage unit 9.

[0028] The programming signal circuit 10 further comprises an activation switch Q1 for activating the electrical signals for writing data to the programmable memory 13 and a deactivation switch Q2 for deactivating the electrical signals for writing data to the programmable memory 13. The programming signal circuit 10 also includes a terminal 16, which is electrically connected to a control input of the deactivation switch Q2. In the present embodiment, the switches Q1 and Q2 are MOSFETs (metal-oxide-semiconductor field-effect transistors), each having a source, a drain, and a gate, wherein the gate of the activation switch Q1 is connected to the drain of the deactivation switch Q2, and the gate of the deactivation switch Q2 is electrically connected to the terminal 16 of the programming signal circuit 10. In the embodiment of Fig. 1 are the MOSFETs n-channel MOSFETs of the enhancement type. Fig. Figure 1 also shows a gate resistance Rg of Q1, a high-side resistance RH and a low-side resistance RL of Q2.

[0029] The programmable memory 13 according to the embodiment of the Fig. 1 is a single-wire programmable EEPROM (electrically erasable programmable read-only memory) with a single programming input, which is electrically connected to the secondary coil of transformer 15. The single-wire programmable EEPROM is a readily available, inexpensive standard component.

[0030] The controller 14 is configured to provide a PWM (pulse width modulation) signal with a duty cycle that depends on the data stored in the programmable memory unit 9.

[0031] The output section 12 of the driver unit 8 comprises an error amplifier 17 or differential amplifier with a first input 18 for detecting an output voltage of the output stage 5 of the driver 4 and with a second input 19 for inputting a reference voltage and with an output 20. The output section 12 further includes an RC filter 21 with a resistor Rc and a capacitance Ct for providing a DC reference voltage for the error amplifier 17.

[0032] The output stage 5 of the driver 4 comprises a transformer T coupled to the output of the primary control stage 6, and a rectifier circuit with a first diode D1, a second diode D2, and an electrolytic capacitor C. The output stage 5 further comprises a sense resistor Rs for measuring or sampling the output current of the driver 4 by measuring a voltage drop across the sense resistor Rs. The output stage 5 also includes a terminal 22 for sensing an output voltage of the driver output stage 5.

[0033] In the LED light source 1 of Fig.The output stage 5 of driver 4 is connected to the LED module 2 via a driver bus 23 with connectors 24 and 25 for controlling the LEDs 3. The driver unit 8 is operationally coupled to the output stage 5 and the primary control stage 6 of driver 4, so that the output current of driver 4 can be programmed by means of the driver unit 8. In particular, the output 20 of the error amplifier 17 is electrically connected to the control input 7 of the primary control stage 6 of driver 4, and the terminal 16 of the programming signal circuit 10 is electrically connected to the terminal 22 of the output stage 5 of driver 4. For the sake of simplicity, the connection between terminal 16 and terminal 22 is not shown. Furthermore, a programming input 26 of the programming signal circuit 10 is electrically connected to an output terminal 27 of the output stage 5 and the first input 18 of the error amplifier 17 is electrically coupled to the measuring resistor Rs via an input resistor Ri.The input 18 of the error amplifier 17 is electrically connected to the output stage 5 of the driver 4, so that the potential at the first input 18 of the error amplifier corresponds to the voltage drop across the sense resistor Rs of the output stage 5 of the driver 4. Since the output terminal 27 is connected to the programming input 26 of the programming signal circuit 10, the driver bus 23 can be used to program the programmable memory unit 9, in particular to write the data representing the setpoint of the output current to the programmable memory 13.

[0034] In some embodiments, the control circuit 11 can be operationally connected to the output stage 5 of the driver 4 such that data communication between the control circuit and the programmable memory unit is blocked when the driver is switched off. In particular, the control circuit 11 can include a terminal that can be connected to the output stage 5 of the driver, and the controller 14 can be configured such that data communication between the controller 14 and the programmable memory unit 9 can be disabled by applying a voltage to the terminal. In some embodiments, the controller 14 includes a power supply pin V. dd, which can be connected to the output stage 5 of the driver 4, so that when the driver is switched off, the power supply to the controller 14 is also interrupted. By switching off the data exchange between the programmable memory unit 9 and the controller 14, the energy required for data communication between the programmable memory unit and the controller can be saved.

[0035] When the LED light source 1 is operating, a positive voltage (relative to ground potential) is present at terminal 16, and switch Q2 is closed. The source electrode of Q2 is connected to the gate electrode of Q1, so that closing Q2 opens switch Q1 and thus interrupts the output circuit of the programming signal circuit 10. Therefore, programming of the driver unit 4 is disabled when the driver 4 is operating.

[0036] Since Q1 is an n-channel enhancement transistor, it is normally "off" or open. Therefore, the programming signal circuit 10 is deactivated, even when the driver 4 is not operating. To program the programmable memory unit 9 of the driver unit 8, both conditions must be met: the driver 5 should be switched off, and the programming signal circuit 10 should be activated, specifically by applying a programming voltage to the programming input 26.

[0037] Such a programmable driver is not only easy to program, but also reliable and safe for the user, since the programming signal circuit 10 must be enabled to write data to or delete data from the programmable memory unit 9, and the user is prompted to turn off the driver 4 before starting to program the driver 4.

[0038] After the output current has been set to a target value by appropriately programming the programmable memory unit 9, in particular by an external programmer connected to the driver bus 23, the output current of the driver 4 can be adjusted to the target value. Specifically, during operation of the driver 4, the controller 14 reads the data stored in the programmable memory 13, which represents the target value of the output current, and generates a PWM signal with a duty cycle that reflects or corresponds to the target value of the output current. The RC filter 21 filters the controller output signal so that the reference voltage level at the second input 19 of the error amplifier 17 reflects the duty cycle of the controller output signal.Since the potential at the first input 18 of the error amplifier 17 represents the voltage drop across the measuring resistor Rs and thus reflects the current value of the output current, the error amplifier 17 can provide a correction signal as an input for the control input 7 of the primary control stage 6 of the driver 4 to adjust the output current to the setpoint. Thus, the output current can be controlled or regulated in an analog manner without the light generated by the LED light source being degraded by PWM flickering.

[0039] Although at least one exemplary embodiment has been presented in the foregoing detailed description, it should be understood that a large number of variations exist. It should also be appreciated that the exemplary embodiment or embodiments are merely examples and are not intended to limit the scope, applicability, or configuration of the disclosure in any way. Rather, the foregoing detailed description is intended to provide the person skilled in the art with practical guidance for implementing the exemplary embodiment or embodiments. Reference symbols and numbers 1 LED light source 2 LED modules 3 LED 4 drivers 5 Output stage 6 control stage 7 Tax input 8 driver unit 9 programmable memory units 10 Programming signal circuit 11 Control circuit 12 Initial section 13 programmable memories 14 Controller 15 Transformer 16 connection 17 amplifiers 18 first entrance 19 second entrance 20 Exit 21 RC filters 22 connection 23 Driver bus 24 connectors 25 connectors 26 Programming input 27 Output port C capacitor C t Capacitor of the RC filter D1 Diode D2 diode R i Input resistance Q1 switch Q2 switch R measuring resistor R H High-side resistance R L Low-side resistance R s Measuring resistor T transformer V dd power supply

Claims

[1] Driver unit for programming an output current of a driver (4) with an output stage (5) for providing the output current and with a primary control stage (6) with a control input (7) for controlling the output current, wherein the driver unit (8) comprises: - a programmable memory unit (9) for storing data corresponding to a setpoint of the output current, - a programming signal circuit (10) configured to provide electrical signals for writing data to the programmable memory unit (9), - a control circuit (11) with a controller (14) which is operationally connected to the programmable memory unit (9), wherein the controller (14) is configured to read the data stored in the programmable memory unit (9) and generates a controller output signal at a controller output for setting the output current of the driver (4) based on the data stored in the programmable memory unit (9), wherein the programming signal circuit (10) includes a terminal (16) which can be connected to the output stage (5) of the driver, and wherein the programming signal circuit (10) is configured such that the electrical signals for writing the data to the programmable memory unit (9) can be deactivated by applying a voltage to the terminal (16). [2] Driver unit according to claim 1, wherein the programming signal circuit (10) has an activation switch (Q1) for releasing the electrical signals to write the data to the programmable memory unit (9). [3] Driver unit according to claim 2, wherein the programming signal circuit comprises a deactivation switch (Q2) for blocking the electrical signals for writing the data to the programmable memory unit (9) by opening the activation switch (Q1) when a voltage is applied to the terminal (16). [4] Driver unit according to claim 3, wherein the activation switch (Q1) and the deactivation switch (Q2) are MOSFETs, each of the MOSFETs having a source, a drain and a gate, and wherein the gate of the activation switch (Q1) is connected to the drain of the deactivation switch (Q2) and the gate of the deactivation switch (Q2) is electrically connected to the terminal (16) of the programming signal circuit (10). [5] Driver unit according to one of the preceding claims, wherein the programmable memory unit (9) comprises a programmable single-wire memory (13). [6] The driver unit according to any of the preceding claims, wherein the programming signal circuit (10) comprises an inductive element (15) configured to inductively couple the electrical signals for writing the data to the programmable memory unit (9). [7] Driver unit according to one of the preceding claims, wherein the control circuit (11) can be operationally connected to the output stage (5) of the driver (4) in such a way that data communication between the controller (14) and the programmable memory unit (9) is blocked when the driver (4) is switched off. [8] Driver unit according to one of the preceding claims, wherein the driver unit (8) further comprises an output section (12) which can be connected to the final stage (5) of the driver and is configured to form a control signal based on the controller output signal and a current value of the output current provided by the final stage (5). [9] Driver unit according to claim 8, wherein the controller (14) is configured such that the controller output signal is a PWM signal with a duty cycle that depends on the data stored in the programmable memory unit (9). [10] Driver unit according to claim 9, wherein the output section (12) comprises an error amplifier (17) with a first input (18) which can be connected to the output stage (5) of the driver (4) to sample the output current, and a second input (19) which is electrically connected to the controller output to provide a reference for the error amplifier (17). [11] Driver unit according to claim 10, wherein the driver unit (8) comprises a controller output circuit with an RC filter (21) for providing a reference DC voltage for the error amplifier (17). [12] Driver, wherein the driver (4) comprises an output stage (5) for providing an output current, a primary control stage (6) with a control input (7) for controlling the output current and a driver unit (8) according to one of the preceding claims for programming the output current of the driver (4), wherein the driver unit (8) is connected to the control input (7) of the driver (4) such that the output current can be set to the setpoint based on the data stored in the programmable memory unit (9) of the driver unit (8). [13] Driver according to claim 12, wherein the programming signal circuit (10) of the driver unit (8) is connected to the output stage (5) of the driver, such that the programming signal circuit (10) is deactivated when the driver is switched on. [14] LED light source with at least one LED (3) for generating light and a driver (4) according to claim 12 or 13, which is connected to the at least one LED (3) in such a way that the at least one LED (3) can be driven by the driver (4).

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