Resonant hybrid flyback converter with overcurrent detection

Abstract

A resonant hybrid flyback converter (100) with overcurrent detection and / or protection for an LED lighting device (34) is provided. The resonant hybrid flyback converter (100) comprises a half-bridge (10) and a flyback resonant tank (20) comprising a transformer having a primary side (61) and a secondary side (62). In this case, the half-bridge (10) is configured to supply power to the primary side (61). In addition to this, the resonant hybrid flyback converter (100) comprises a control unit (70) that controls the operation of the switches (11, 12) of the half-bridge (10) and is supplied with a feedback signal (sense) from a sense circuit (Rshunt) configured to sense a primary side current in the flyback resonant tank (20).

Description

[0001] The present invention relates to a resonant hybrid flyback converter with over-current detection and / or protection.

[0002] "Hybrid flyback" should be understood as "a half-bridge circuit feeding a flyback resonant tank".

[0003] Generally, with the increasing use of LED (light emitting diode) lighting devices in many different areas of life, there is also an increasing demand for resonant hybrid flyback converters with overcurrent detection and / or protection for LED lighting devices and systems including such resonant hybrid flyback converters with overcurrent detection and / or protection and LED lighting devices, so as to ensure efficient and reliable power supply to the LED lighting devices.

[0004] However, there is no resonant hybrid flyback converter that can protect both the LED lighting device as a whole and the corresponding pre-circuit from potential damage, especially damage caused by overcurrent.

[0005] Therefore, an object of the present invention is to provide a resonant hybrid flyback converter with overcurrent detection and / or protection for an LED lighting device, and a system including such a resonant hybrid flyback converter with overcurrent detection and / or protection and an LED lighting device, thereby ensuring high efficiency and reliability.

[0006] This object is achieved by the features of a resonant hybrid flyback converter with overcurrent detection and / or protection for an LED lighting device according to claim 1 and by the features of a system comprising such a resonant hybrid flyback converter with overcurrent detection and / or protection and an LED lighting device according to claim 15. The dependent claims contain further developments.

[0007] According to a first aspect of the present invention, a resonant hybrid flyback converter (for LED lighting device) with overcurrent detection and / or protection is provided. The resonant hybrid flyback converter comprises a half-bridge and a flyback resonant tank, the flyback resonant tank comprising a transformer having a primary side and a secondary side. In this case, the half-bridge is configured to supply power to the primary side. In addition, the resonant hybrid flyback converter comprises a control unit, which controls the operation of the switches of the half-bridge and is supplied with a feedback signal from a sensing circuit, which is configured to sense the primary side current in the flyback resonant tank. Advantageously, in the event of an overcurrent event, the half-bridge, the entire circuit and the load or LED lighting device are protected from potential damage in a particularly efficient and reliable manner.

[0008] According to a first preferred specific implementation form of the first aspect of the present invention, the switch of the half-bridge comprises a high-side switch and a low-side switch, the high-side switch is preferably a first transistor, more preferably a first field effect transistor, and the low-side switch is preferably a second transistor, more preferably a second field effect transistor. Advantageously, for example, complexity can be reduced, thereby improving efficiency. Further advantageously, the current sensing of the present invention captures both the corresponding magnetizing current, especially through the high-side switch, and the corresponding resonant current, especially through the low-side switch.

[0009] According to a second preferred specific implementation form of the first aspect of the present invention, the primary side comprises a series connection of an optional inductance, a corresponding transformer main inductance and a capacitor, the optional inductance is preferably an optional leakage inductance, more preferably an optional resonant choke, most preferably a resonant choke implemented in a transformer or as a separate component, and the capacitor is preferably a resonant capacitor. In this case, the corresponding primary side current flows in particular through the series connection. Advantageously, for example, simplicity can be ensured, thereby achieving high efficiency.

[0010] According to another preferred specific implementation form of the first aspect of the present invention, in particular in the case where the corresponding primary side current is sensed, the flyback resonant tank, in particular the primary side, comprises a resistor, which is preferably a shunt resistor, more preferably a shunt resistor providing a sensing voltage, most preferably a shunt resistor providing a sensing voltage according to the corresponding primary side current. Advantageously, for example, current sensing can be achieved in a simple and therefore cost-effective manner.

[0011] According to another preferred specific implementation form of the first aspect of the present invention, the series connection further comprises a resistor, which is preferably a shunt resistor, more preferably a shunt resistor providing a sensing voltage, and most preferably a shunt resistor providing a sensing voltage according to a corresponding primary side current. Advantageously, for example, complexity can be further reduced, thereby improving efficiency.

[0012] According to another preferred specific implementation form of the first aspect of the present invention, the first terminal of the resistor is connected to the terminal of the capacitor, the resistor is preferably a shunt resistor, more preferably a shunt resistor providing a sensing voltage, most preferably a shunt resistor providing a sensing voltage according to the corresponding primary side current, and the capacitor is preferably a resonant capacitor. In addition or as an alternative, the second terminal of the resistor is connected to a voltage potential, preferably to the ground, the resistor is preferably a shunt resistor, more preferably a shunt resistor providing a sensing voltage, most preferably a shunt resistor providing a sensing voltage according to the corresponding primary side current. Advantageously, for example, simplicity can be further improved, thereby reducing inefficiency.

[0013] According to another preferred specific implementation form of the first aspect of the present invention, the first terminal of the resistor is connected to the sensing terminal, and the resistor is preferably a shunt resistor, more preferably a shunt resistor providing a sensing voltage, and most preferably a shunt resistor providing a sensing voltage according to the corresponding primary side current. Advantageously, for example, the sensing voltage for further processing can be provided in a simple manner, thereby improving efficiency.

[0014] According to another preferred specific implementation form of the first aspect of the present invention, the resonant hybrid flyback converter is further configured to compare the sensed corresponding primary side current with a reference, preferably by means of a comparator, in particular comprised by the resonant hybrid flyback converter. Advantageously, for example, the reference can preferably define the maximum allowed current in an efficient and reliable manner. It should be noted that, in the case where the sensed signal exceeds the reference, an overcurrent event occurs.

[0015] According to another preferred specific implementation form of the first aspect of the present invention, based on the comparison result between the sensed corresponding primary side current and the reference, preferably when the sensed corresponding primary side current exceeds the reference, the resonant hybrid flyback converter is further configured to enter the constant off-time mode of the half-bridge according to the corresponding timing trigger of the corresponding overcurrent event, especially to deactivate, preferably to enter the constant off-time mode of the high-side switch and / or the low-side switch, and more preferably to enter the constant off-time mode of the high-side switch and / or the low-side switch. Advantageously, for example, the half-bridge can be completely shut down in an efficient manner, so that particularly reliable overcurrent protection can be achieved.

[0016] According to another preferred specific implementation form of the first aspect of the present invention, based on the comparison result between the sensed corresponding primary side current and the reference, preferably when the sensed corresponding primary side current exceeds the reference, the resonant hybrid flyback converter is further configured to trigger the constant on-time mode of the half bridge, preferably the constant on-time mode of the high-side switch and / or the low-side switch. Advantageously, for example, the high-side switch and the low-side switch can be switched separately in an efficient manner.

[0017] According to another preferred specific implementation form of the first aspect of the present invention, based on the comparison result between the sensed corresponding primary side current and the reference, preferably when the sensed corresponding primary side current exceeds the reference, the resonant hybrid flyback converter is further configured to trigger the entry into the burst mode of the relevant half bridge, preferably the burst mode of reducing the corresponding frequency of the corresponding drive signal of the high side switch and / or the low side switch. Advantageously, for example, such a burst mode enables particularly efficient and reliable overcurrent protection.

[0018] According to another preferred specific implementation form of the first aspect of the present invention, the resonant hybrid flyback converter is further configured to trigger entering the operating mode preferably after a defined time and / or in response to a trigger signal. Advantageously, for example, the operating mode may preferably be a conventional operating mode or an operating mode according to a corresponding operating mode before an overcurrent event occurs.

[0019] According to another preferred specific implementation form of the first aspect of the present invention, the resonant hybrid flyback converter also includes the above-mentioned comparator. In this case, the first input terminal of the comparator is supplied with a corresponding voltage of the relevant resistor, which is preferably a shunt resistor, more preferably a shunt resistor providing a sensing voltage, and most preferably a shunt resistor providing a sensing voltage according to the corresponding primary side current. In addition, the second input terminal of the comparator is supplied with a reference voltage. In addition, the output terminal of the comparator is particularly used to trigger entering different modes of the resonant hybrid flyback converter. Advantageously, for example, the first input terminal can be powered by or connected to the above-mentioned sensing terminal, thereby reducing complexity and thus improving efficiency.

[0020] According to another preferred specific implementation form of the first aspect of the present invention, the resonant hybrid flyback converter further includes a power supply device, which is configured to be powered by the secondary side and to supply power to the LED lighting device as a load. In addition, the power supply device includes a switch and / or a diode and / or a capacitor, which is preferably a capacitor. In addition, the capacitor, preferably a capacitor, is especially connected in parallel to the load. Further in addition to this, the switch and / or the diode is especially connected in series to the load. Advantageously, for example, not only the overcurrent protection of the two switches of the half bridge is achieved, but also the overcurrent protection of all components in the power supply device and the load is achieved.

[0021] According to a second aspect of the present invention, a system is provided. The system comprises a resonant hybrid flyback converter according to the first aspect of the present invention or any preferred specific implementation form of the first aspect of the present invention, and an LED lighting device powered by the resonant hybrid flyback converter. Advantageously, in the event of an overcurrent event, the half-bridge, the entire circuit and the load or the LED lighting device are protected from potential damage in a particularly efficient and reliable manner.

[0022] Exemplary embodiments of the present invention will now be further explained by way of example only and not limitation with reference to the accompanying drawings. In the drawings:

[0023] Figure 1 An exemplary embodiment of the first aspect of the present invention combined with the second aspect of the present invention is shown;

[0024] Figure 2 An exemplary embodiment of a comparator in the context of the present invention is shown; and

[0025] Figure 3 An exemplary time-voltage diagram is shown for an overcurrent event in the sense of the present invention.

[0026] first, Figure 1 An exemplary embodiment of the resonant hybrid flyback converter 100 of the present invention with over-current detection and / or protection for an LED lighting device 34 is illustrated.

[0027] In addition, it should be noted that Figure 1 An exemplary embodiment of a system 200 of the present invention is also depicted, the system comprising the above-described resonant hybrid flyback converter 100 and the above-described LED lighting device 34 , which is exemplarily illustrated as a load and is powered by the resonant hybrid flyback converter 100 .

[0028] As from Figure 1 It can be seen that the resonant hybrid flyback converter 100 includes a half-bridge 10 and a flyback resonant tank 20 including a resonant capacitor 23 and a transformer having a primary side 61 and a secondary side 62 .

[0029] In this case, the half bridge 10 is configured to supply power to the primary side 61 . Furthermore, the resonant hybrid flyback converter 100 is configured to sense the primary side current in the flyback resonant tank 20 .

[0030] Specifically, for the sensing, especially in case of overcurrent protection, the resonant hybrid flyback converter 100 comprises a control unit 70 which controls the operation of the switches 11, 12 of the half bridge 10 and is supplied with the sensing circuits (R shunt or reference numeral 24 ), the sensing circuit being configured to sense the primary side current in the flyback resonant tank 20 .

[0031] For the control unit 70, it should be noted that the control unit may also be a control unit and / or a processing unit. In the following, the term "control unit and / or processing unit" will be used, wherein corresponding features may be applied to the control unit 70 in a similar manner. However, in addition to the control unit 70, such control units and / or processing units may also be used.

[0032] The above-mentioned half-bridge 10 comprises a high-side switch 11 exemplarily in the form of a first field effect transistor and a low-side switch 12 exemplarily in the form of a second field effect transistor.

[0033] For the sake of completeness, it should be noted that, with respect to the field effect transistors 11 and 12 , the transistors are exemplarily of n-channel enhancement type.

[0034] In this case, a first terminal (exemplarily a drain terminal) of the first field effect transistor 11 is connected to a voltage potential (exemplarily a supply voltage), while a second terminal (exemplarily a source terminal) of the first field effect transistor 11 is connected to a first terminal (exemplarily a drain terminal) of the second field effect transistor 12. Furthermore, a second terminal (exemplarily a source terminal) of the second field effect transistor 12 is connected to a voltage potential, in particular to another voltage potential, exemplarily to the ground.

[0035] Furthermore, the primary side 61 comprises a series connection of a leakage inductance 22, a corresponding transformer main inductance 21 and a capacitance 23, exemplarily a resonant capacitor, which leakage inductance may be optional or omitted, respectively. In this case, the corresponding primary side current flows in particular through the series connection.

[0036] Furthermore, in particular in the case where the corresponding primary side current is sensed, the flyback resonant tank 20 (exemplarily the primary side 61 ) includes a resistor, exemplarily a shunt resistor 24 , which provides a sense voltage according to the corresponding primary side current.

[0037] according to Figure 1 , the series connection also includes the resistor or the shunt resistor 24 which provides a sensing voltage according to the corresponding primary side current.

[0038] In addition, the first terminal (exemplarily the drain terminal) of the second field effect transistor 12 is connected to the first terminal of the leakage inductance 22, and the second terminal of the leakage inductance 22 is connected to the first terminal of the transformer main inductance 21. In the case where the leakage inductance 22 is omitted, it should be noted that the first terminal of the second field effect transistor 12 is connected to the first terminal of the transformer main inductance 21.

[0039] In addition, the second terminal of the transformer main inductor 21 is connected to the first terminal of the above-mentioned capacitor 23, and the second terminal of the capacitor 23 is connected to the first terminal of the shunt resistor 24, and the second terminal of the shunt resistor 24, which provides a sensing voltage according to the corresponding primary side current, is connected to a voltage potential, exemplarily connected to the ground.

[0040] Further in addition to this, a first terminal of the shunt resistor 24 is connected to the sensing terminal 25 .

[0041] It should also be noted that the resonant hybrid flyback converter 100 is further configured to preferably be provided with a comparator (such as the comparator described below) which may be particularly included in the resonant hybrid flyback converter 100. Figure 2 The comparator 40) compares the sensed corresponding primary side current with a reference.

[0042] It may be particularly advantageous if, based on a comparison result between the sensed corresponding primary side current and a reference, preferably when the sensed corresponding primary side current exceeds the reference, the resonant hybrid flyback converter 100 is also configured to enter a constant off-time mode of the half-bridge 10 according to a corresponding timing trigger of a corresponding over-current event, in particular to deactivate, preferably to enter a constant off-time mode of the high-side switch 11 and / or the low-side switch 12, and more preferably to enter a constant off-time mode of the high-side switch 11 and / or the low-side switch 12.

[0043] Additionally or alternatively, based on the comparison result between the sensed corresponding primary side current and a reference, preferably when the sensed corresponding primary side current exceeds the reference, the resonant hybrid flyback converter 100 can also be configured to trigger entry into a constant on-time mode of the half bridge 10, preferably into a constant on-time mode of the high side switch 11 and / or the low side switch 12.

[0044] Further in addition to this or as another alternative, based on the comparison result between the sensed corresponding primary side current and the reference, preferably when the sensed corresponding primary side current exceeds the reference, the resonant hybrid flyback converter 100 can also be configured to trigger entering a burst mode of the relevant half bridge 10, preferably entering a burst mode of reducing the corresponding frequency of the corresponding drive signal of the high side switch 11 and / or the low side switch 12.

[0045] Further additionally or further alternatively, the resonant hybrid flyback converter 100 may also be configured to be triggered to enter an operating mode, exemplarily a normal operating mode, preferably after a defined time and / or in response to a trigger signal.

[0046] In this case, the resonant hybrid flyback converter 100 may further include a control unit and / or a processing unit, which is particularly configured to generate the trigger signal. The control unit and / or the processing unit may also be configured to trigger entry into at least one of the above modes.

[0047] As from Figure 1 It can also be seen that the resonant hybrid flyback converter 100 further includes a power supply device 30 , which is configured to be powered by the secondary side 62 and to supply power to the LED lighting device or the load 34 , respectively.

[0048] In this case, the power supply device 30 includes a switch and / or a diode (exemplarily a diode 32 ) and a capacitor (exemplarily an output capacitor 33 ).

[0049] Furthermore, the capacitor 33 is illustratively connected in parallel to the load 34 , and the diode 32 is illustratively connected in series to the load 34 .

[0050] Specifically, a first terminal of the transformer secondary inductor 31 is connected to a first terminal (exemplarily an anode terminal) of a diode 32 , and a second terminal (exemplarily a cathode terminal) of the diode 32 is connected to a first terminal of a capacitor 33 and to a first terminal of a load 34 .

[0051] In addition, a second terminal of the transformer secondary inductor 31 is connected to a second terminal of the capacitor 33 and to a second terminal of the load 34 .

[0052] As described above, if the resonant hybrid flyback converter 100 further includes a Figure 2 A comparator 40 of this type may be particularly advantageous.

[0053] In this case, if Figure 2 It can be seen that the first input terminal 41 of the comparator 40 is supplied with a corresponding voltage in relation to the above-mentioned resistor, which is exemplarily the shunt resistor 24 providing a sense voltage according to the corresponding primary-side current.

[0054] Therefore, the first input terminal 41 may be illustratively connected to the sensing terminal 25 .

[0055] In addition, if Figure 2 It can also be seen that the second input 42 of the comparator 40 is supplied with a reference or reference voltage, respectively. The reference or reference voltage, respectively, can be provided exemplarily by the above-mentioned control unit and / or processing unit.

[0056] In addition, the output terminal 43 of the comparator 40 is exemplarily used to trigger entering different modes, such as at least one of the above-mentioned modes of the resonant hybrid flyback converter 100. The output terminal 43 can be exemplarily connected to the above-mentioned control unit and / or processing unit or provided to the above-mentioned control unit and / or processing unit.

[0057] Regarding the control unit and / or processing unit, it should also be noted that if the control unit and / or processing unit is connected to Figure 1 It may be particularly advantageous if the third terminal (exemplarily the gate terminal) of the first field effect transistor 11 and / or the third terminal (exemplarily the gate terminal) of the second field effect transistor 12 is connected to the transistor 11.

[0058] at last, Figure 3 An exemplary time-voltage diagram 50 is shown for an overcurrent event 53 in the sense of the present invention, in particular Figure 2 The case of comparator 40.

[0059] according to Figure 3 , in particular the reference voltage supplied to the second input 42 of the comparator is depicted by way of example as a constant function 52 .

[0060] In addition, the sensing voltage signal is exemplarily illustrated as a linear function 51, which sensing voltage signal is exemplarily a corresponding voltage or voltage signal of the above-mentioned shunt resistor 24 that provides a sensing voltage according to the corresponding primary side current, and the corresponding voltage or voltage signal is particularly provided to the first input terminal 41 of the comparator 40.

[0061] for Figure 3 The overcurrent event 53 shown above needs to be explained that the overcurrent event 53 is exemplarily equivalent to the intersection of the linear function 51 and the constant function 52 .

Claims

1. A resonant hybrid flyback converter (100) with overcurrent detection and / or protection for an LED lighting device (34), the resonant hybrid flyback converter (100) comprising: Half Bridge (10), and A flyback resonant tank (20), comprising a transformer having a primary side (61) and a secondary side (62), The half bridge (10) is configured to supply power to the primary side (61), and The resonant hybrid flyback converter (100) comprises a control unit (70) which controls the operation of the switches (11, 12) of the half bridge (10) and is supplied with a voltage from a sensing circuit (R shunt ), the sensing circuit being configured to sense the primary side current in the flyback resonant tank (20), Characterized in that the primary side current flows through a series connection 20 of the following elements: - transformer main inductance (21), - capacitor (23) and - As a shunt resistor (R shunt ).

2. The resonant hybrid flyback converter (100) according to claim 1, in, The switch of the half bridge (10) comprises a high-side switch (11) and a low-side switch (12), wherein the high-side switch is preferably a first transistor, more preferably a first field effect transistor; and the low-side switch is preferably a second transistor, more preferably a second field effect transistor.

3. The resonant hybrid flyback converter (100) according to claim 1 or 2, in, The series connection at the primary side (61) further comprises an inductance (22), preferably an optional leakage inductance, and the capacitance (23) is preferably a resonant capacitor.

4. The resonant hybrid flyback converter (100) according to claim 1, in, The first terminal of the shunt resistor is connected to a terminal of the capacitor (23), preferably to a terminal of the resonant capacitor, and / or Therein, a second terminal of the shunt resistor is connected to a voltage potential, preferably to the ground.

5. The resonant hybrid flyback converter (100) according to claim 4, in, A first terminal of the shunt resistor is connected to a sensing terminal (25).

6. The resonant hybrid flyback converter (100) according to any one of claims 1 to 5, in, The resonant hybrid flyback converter (100) is further configured to compare the sensed primary side current with a reference, preferably by means of a comparator (40) in particular comprised by the resonant hybrid flyback converter (100).

7. The resonant hybrid flyback converter (100) according to claim 6, in, Based on the comparison result between the sensed primary side current and the reference, preferably when the sensed primary side current exceeds the reference, the resonant hybrid flyback converter (100) is also configured to enter the constant off-time mode of the half-bridge (10), especially to deactivate, preferably to enter the constant off-time mode of the high-side switch (11) and / or the low-side switch (12), and more preferably to enter the constant off-time mode of the high-side switch (11) and / or the low-side switch (12), according to the corresponding timing trigger of the corresponding over-current event.

8. The resonant hybrid flyback converter (100) according to claim 6 or 7, in, Based on the comparison result between the sensed primary side current and the reference, preferably when the sensed primary side current exceeds the reference, the resonant hybrid flyback converter (100) is further configured to trigger entering into a constant on-time mode of the half-bridge (10), preferably entering into a constant on-time mode of the high-side switch (11) and / or the low-side switch (12).

9. The resonant hybrid flyback converter (100) according to any one of claims 6 to 8, in, Based on the comparison result between the sensed primary side current and the reference, preferably when the sensed primary side current exceeds the reference, the resonant hybrid flyback converter (100) is further configured to trigger entering a burst mode with respect to the half bridge (10), preferably entering a burst mode that reduces the corresponding frequency of the corresponding drive signal of the high side switch (11) and / or the low side switch (12).

10. The resonant hybrid flyback converter (100) according to any one of claims 7 to 9, in, The resonant hybrid flyback converter (100) is further configured to be triggered into the operating mode, preferably after a defined time and / or in response to a trigger signal.

11. The resonant hybrid flyback converter (100) according to any one of claims 1 to 10, in, The resonant hybrid flyback converter (100) further comprises the comparator (40), wherein the first input terminal (41) of the comparator (40) is supplied with a corresponding voltage of the relevant resistor (24), the resistor is preferably the shunt resistor, more preferably the shunt resistor providing a sensing voltage, and most preferably the shunt resistor providing a sensing voltage according to the primary side current, and The second input terminal (42) of the comparator (40) is supplied with a reference voltage, and The output terminal (43) of the comparator (40) is particularly used to trigger entering into different modes of the resonant hybrid flyback converter (100).

12. The resonant hybrid flyback converter (100) according to any one of claims 1 to 11, in, The resonant hybrid flyback converter (100) further comprises a power supply device (30), which is configured to be powered by the secondary side (62) and to supply power to the LED lighting device (34) as a load. The power supply device (30) comprises a switch and / or a diode (32) and / or a capacitor (33), wherein the capacitor is preferably a capacitor. wherein the capacitance (33), preferably the capacitor, is connected in parallel to the load (34), and The switch and / or the diode (32) are especially connected in series to the load (34).

13. A system (200), comprising: The resonant hybrid flyback converter (100) according to any one of claims 1 to 12, and An LED lighting device (34) powered by the resonant hybrid flyback converter (100).

Images