Feedback circuit and control circuit for lamp load

Abstract

The utility model relates to a feedback circuit and a control circuit for a lamp load, the feedback circuit is connected with a driving circuit of the lamp load, the driving circuit comprises a non-dimming chip, a semiconductor switching device and a sampling resistor, the semiconductor switching device comprises a grid electrode, a source electrode and a drain electrode, the drain electrode is connected to a negative electrode of the lamp load, and the sampling resistor is connected with the grid electrode. The sampling resistor is connected between the source electrode and the ground, the non-dimming chip comprises a first output terminal and a voltage feedback terminal, the first output terminal is connected to the grid electrode, the feedback circuit comprises a first divider resistor and a second divider resistor which are connected in series, the first end of the first divider resistor is connected to the negative electrode of the lamp load, and the second end of the second divider resistor is connected to the negative electrode of the lamp load. The first end of the first divider resistor is connected to the first end of the first divider resistor, the second end of the first divider resistor is connected to the source electrode, the second end of the second divider resistor is connected to the source electrode, and the voltage feedback terminal is connected to the second end of the first divider resistor, so that the technical effect that the power difference of the driving circuit under different input voltages is reduced in a low-cost and simple mode is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to a driving circuit including a non-dimming chip for a lamp load, and more particularly, to a feedback circuit capable of reducing power difference of a constant current driving circuit including a non-dimming chip under different operating voltages and a control circuit for a lamp load including the same. BACKGROUND

[0002] For a lamp load, when a constant current driving circuit including a non-dimming chip is used, since the output current of the circuit cannot be adjusted according to voltage variation, the operating power of the lamp load under different AC voltage conditions (e.g., 108 Vac, 120 Vac, 132 Vac) can be significantly different. Generally, in order to ensure that the driving circuit can operate normally under the 132 Vac condition, the actual operating power of the driving circuit under the 120 Vac nominal operating condition is reduced, which in turn causes the power usage efficiency of the driving circuit to decrease. The problem of power difference under different voltage conditions can be solved by using a constant current driving circuit including a dimming chip. However, using a dimming chip can significantly increase the cost of the circuit.

[0003] In view of this, there is a need for a low-cost method to reduce the power difference of a constant current driving circuit including a non-dimming chip for a lamp load under different operating voltages. SUMMARY

[0004] The present application is proposed in view of the above problems, and the main purpose of the present application is to provide a feedback circuit for a constant current driving circuit including a non-dimming chip for a lamp load, so as to solve the technical problem that the power difference of the constant current driving circuit including a non-dimming chip under different operating voltages is difficult to be solved in a low-cost manner in the prior art, thereby reducing the power difference of the driving circuit under different input voltages in a low-cost and simple manner, improving the power usage efficiency of the driving circuit of the lamp load, and reducing the overall power consumption and temperature rise of the circuit.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a feedback circuit for a lamp load is provided, which is connected to a driving circuit of the lamp load, the driving circuit including a non-dimming chip, a semiconductor switching device, and a sampling resistor, the semiconductor switching device including a gate, a source, and a drain, the drain of the semiconductor switching device being connected to a negative electrode of the lamp load, the sampling resistor being connected between the source of the semiconductor switching device and the ground, the non-dimming chip including a first output terminal and a voltage feedback terminal, the first output terminal being connected to the gate of the semiconductor switching device, the feedback circuit including: a first voltage dividing resistor and a second voltage dividing resistor connected in series, a first end of the first voltage dividing resistor being connected to the negative electrode of the lamp load, a second end of the first voltage dividing resistor being connected to a first end of the second voltage dividing resistor, a second end of the second voltage dividing resistor being connected to the source of the semiconductor switching device, wherein the voltage feedback terminal is connected to the second end of the first voltage dividing resistor.

[0006] In this way, when the input voltage of the power input end increases, the voltage drop on the second voltage dividing resistor will increase, which leads to a decrease in the voltage drop on the sampling resistor, and thus a decrease in the current flowing through the lamp load, the semiconductor switching device and the sampling resistor, so as to reduce the circuit power difference caused by different input voltages when the input voltage fluctuates, keep the circuit power consumption stable under different input voltages, and reduce the overall power consumption and temperature rise of the circuit.

[0007] Further, according to an embodiment of the present application, the non-dimming chip further comprises a first input terminal and a ground terminal, the first input terminal being connected to the power input end, and the driving circuit further comprises a first capacitor and a second capacitor, the first capacitor being connected in parallel to the lamp load, and the two ends of the second capacitor being connected to the first input terminal and the ground terminal respectively.

[0008] In this way, the non-dimming chip and the semiconductor switching device can keep the sum of the voltage drop on the sampling resistor and the voltage drop on the second voltage dividing resistor at a preset fixed threshold, so that the current flowing through the sampling resistor can decrease with the increase of the input voltage.

[0009] Further, according to an embodiment of the present application, the semiconductor switching device is a metal oxide semiconductor field effect transistor.

[0010] In this way, the on-off degree of the semiconductor switching device can be adjusted according to the difference between the sampling voltage and the preset threshold voltage, and thus the size of the current flowing through the sampling resistor can be adjusted.

[0011] Further, according to an embodiment of the present application, any one of the first voltage dividing resistor and the second voltage dividing resistor is composed of one or more resistors.

[0012] In this way, fixed resistors can be flexibly combined to realize the first voltage dividing resistor and the second voltage dividing resistor with desired resistance values.

[0013] Further, according to an embodiment of the present application, the non-dimming chip is built-in with a voltage comparator and a control loop, the voltage comparator being configured to compare the sampling voltage input from the voltage feedback terminal with a preset threshold voltage and output a comparison result, and the control loop being configured to adjust the voltage at the first output terminal by using the comparison result.

[0014] According to another aspect of the present application, there is provided a feedback circuit for a lamp load, connected to a driving circuit of the lamp load, the driving circuit comprising a non-dimming chip, a semiconductor switching device and a sampling resistor, the semiconductor switching device comprising a gate, a source and a drain, the drain of the semiconductor switching device being connected to a negative pole of the lamp load, a positive pole of the lamp load being connected to a power input, the sampling resistor being connected between the source of the semiconductor switching device and ground, the non-dimming chip comprising a first output terminal and a voltage feedback terminal, the first output terminal being connected to the gate of the semiconductor switching device, the feedback circuit comprising: a first voltage dividing resistor and a second voltage dividing resistor, a first end of the first voltage dividing resistor being connected to the power input, a second end of the first voltage dividing resistor being connected to the positive pole of the lamp load, a first end of the second voltage dividing resistor being connected to the drain of the semiconductor switching device, a second end of the second voltage dividing resistor being connected to the source of the semiconductor switching device, wherein the voltage feedback terminal is connected to the second end of the first voltage dividing resistor.

[0015] In this way, when the input voltage of the power input increases, the voltage drop across the second voltage dividing resistor will increase, which results in a decrease of the voltage drop across the sampling resistor, and thus a decrease of the current flowing through the lamp load, the semiconductor switching device and the sampling resistor, so as to achieve a decrease of the circuit power difference caused by different input voltages when the input voltage fluctuates, so as to keep the circuit power consumption stable under different input voltages, and to reduce the overall power consumption and temperature rise of the circuit.

[0016] Further, according to an embodiment of the present application, the non-dimming chip further comprises a first input terminal and a ground terminal, the first input terminal being connected to the power input, the driving circuit further comprising a first capacitor and a second capacitor, the first capacitor being connected in parallel to the lamp load, the second capacitor having two ends connected to the first input terminal and the ground terminal respectively.

[0017] According to yet another aspect of the present application, there is provided a control circuit for a lamp load, the control circuit comprising: the above-mentioned feedback circuit for a lamp load; and the above-mentioned driving circuit for a lamp load, connected to the feedback circuit.

[0018] In the embodiment of the present application, a feedback circuit for a lamp load is provided, which is connected with a driving circuit of the lamp load, the driving circuit comprising a non-dimming chip, a semiconductor switching device and a sampling resistor, the semiconductor switching device comprising a gate, a source and a drain, the drain of the semiconductor switching device being connected to a negative electrode of the lamp load, the sampling resistor being connected between the source of the semiconductor switching device and the ground, the non-dimming chip comprising a first output terminal and a voltage feedback terminal, the first output terminal being connected to the gate of the semiconductor switching device, the feedback circuit comprising: a first voltage dividing resistor and a second voltage dividing resistor connected in series, a first end of the first voltage dividing resistor being connected to the negative electrode of the lamp load, a second end of the first voltage dividing resistor being connected to a first end of the second voltage dividing resistor, a second end of the second voltage dividing resistor being connected to the source of the semiconductor switching device, wherein the voltage feedback terminal is connected to the second end of the first voltage dividing resistor, so as to at least solve the technical problem that it is difficult to solve the power difference of the constant current driving circuit comprising the non-dimming chip under different working voltages in a low-cost manner in the prior art, thereby achieving the technical effects of reducing the power difference of the driving circuit under different input voltages in a low-cost and simple manner, improving the power use efficiency of the driving circuit of the lamp load, and reducing the overall power consumption and temperature rise of the circuit. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application, and are used to interpret the illustrative embodiments of the present application and their descriptions, and do not constitute improper limitations to the present application. In the drawings:

[0020] Figure 1 is a schematic diagram of a conventional constant current driving circuit for a lamp load comprising a non-dimming chip;

[0021] Figure 2 is Figure 1 is a schematic diagram of the input voltage and current in the constant current driving circuit shown in

[0022] Figure 3 is a schematic diagram of a feedback circuit for a lamp load according to the first embodiment of the present application and a control circuit comprising the same;

[0023] Figure 4 is Figure 3 is a schematic diagram of the input voltage and current in the control circuit for a lamp load shown in

[0024] Figure 5 is a schematic diagram of a feedback circuit for a lamp load according to the first exemplary embodiment of the present application and a control circuit comprising the same;

[0025] Figure 6 is shown in Figure 5Measurement results of voltage waveforms at nodes of the control circuit shown in the case of the constant current drive circuit;

[0026] Figure 7 Actual measurement results of the circuit power consumption in the case of the constant current drive circuit shown in Figure 1 Actual measurement results of the circuit power consumption in the case of the control circuit shown in Figure 5 Actual measurement results of the circuit power consumption in the case of the control circuit shown in

[0027] Figure 8 is a schematic diagram of a feedback circuit for a lamp load according to the second embodiment of the present application and a control circuit comprising the same.

[0028] In the above drawings, reference signs include the following:

[0029] 100': constant current drive circuit

[0030] 100, 100": drive circuit

[0031] 110: non-dimming chip

[0032] 1101: first output terminal

[0033] 1102: voltage feedback terminal

[0034] 1103: first input terminal

[0035] 1104: ground terminal

[0036] 120: semiconductor switching device

[0037] 120D: drain

[0038] 120G: gate

[0039] 120S: source

[0040] 130: sampling resistor

[0041] 140: first capacitor

[0042] 150: second capacitor

[0043] 200: lamp load

[0044] 300, 300": feedback circuit

[0045] 310: first voltage dividing resistor

[0046] 320: second voltage dividing resistor

[0047] 400, 400": control circuit

[0048] Vin: input voltage

[0049] VF: forward voltage

[0050] Vth, Vth': threshold voltage

[0051] Vsa: sampling voltage

[0052] V_130: voltage drop on sampling resistor

[0053] V_200_C: voltage at the negative pole of the lamp load

[0054] V_320: voltage drop on the second voltage dividing resistor DETAILED DESCRIPTION

[0055] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other without conflict, unless otherwise specified. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0056] It should be noted that, unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0057] In the present application, unless otherwise specified, the orientation words such as "upper", "lower", "top", "bottom" are generally directed to the direction shown in the drawings, or are directed to the vertical, perpendicular or gravity direction of the components themselves; similarly, for the convenience of understanding and description, "inner" and "outer" refer to the inner and outer relative to the contour of the components themselves, but the above orientation words are not used to limit the present application.

[0058] First, refer to Figure 1 and Figure 2 Explain the conventional constant current driving circuit 100' for lamp load including non-dimming chip. As Figure 1 shown, the conventional constant current driving circuit 100' includes a non-dimming chip 110, a semiconductor switching device (such as MOS tube) 120 and a sampling resistor 130. The drain of the semiconductor switching device 120 is connected to the negative pole of the lamp load 200 (such as one or more LEDs), and the sampling resistor 130 is connected between the source of the semiconductor switching device 120 and the ground. The non-dimming chip 110 includes a first output terminal 1101 and a voltage feedback terminal 1102, the first output terminal 1101 is connected to the gate of the semiconductor switching device 120, and the voltage feedback terminal 1102 is connected between the sampling resistor 130 and the source of the semiconductor switching device 120. In addition, the positive pole of the lamp load 200 is also connected to the power input end (such as via a rectifier and a driver), and the lamp load 200 is also connected in parallel with a first capacitor 140, and the two ends of a second capacitor 150 are connected to a first input terminal 1103 and a ground terminal 1104 of the non-dimming chip 110, respectively.

[0059] In the constant current driving circuit 100', when the input voltage Vin at the power input terminal is greater than the turn-on voltage VF of the lamp load, the first input terminal 1103 of the non-dimming chip 110 is connected to the power input terminal through resistive voltage division (as shown by R3 and R4), and the non-dimming chip 110 controls the voltage at the first output terminal 1101 according to the voltage at the first input terminal 1103, so the first output terminal 1101 is continuously controlled to be at high level, and the semiconductor switching device 120 is turned on. At this time, the positive voltage of the lamp load 200 is greater than the negative voltage, and the lamp load 200 is turned on. At this time, the driving current of the lamp load 200 is controlled by the sampling resistor 130 (the non-dimming chip 110 compares the sampling voltage at the voltage feedback terminal 1102 with a predetermined threshold voltage, and controls the turn-on degree of the semiconductor switching device 120 according to the voltage difference between the sampling voltage and the threshold voltage so that the voltage at the voltage feedback terminal 1102 approaches the predetermined threshold voltage, and the threshold voltage compared with the sampling voltage at the voltage feedback terminal 1102 is, for example, 0.2V, and the resistance of the sampling resistor 130 is fixed). When the input voltage Vin is less than the turn-on voltage VF of the lamp load, the non-dimming chip can continuously work due to the freewheeling of the second capacitor 150, so the first output terminal 1101 is still at high level, and the semiconductor switching device 120 is turned on. At this time, since the input voltage is insufficient to support the turn-on of the lamp load 200, the lamp load 200 is provided with a freewheeling working voltage by the first capacitor 140. In the constant current driving circuit 100', since the turn-on degree of the semiconductor switching device 120 is affected by the difference between the sampling voltage at the voltage feedback terminal 1102 and the threshold voltage, the result is that the turn-on degree of the semiconductor switching device 120 (i.e. the current flowing through it and the sampling resistor 130) is controlled so that the voltage drop on the sampling resistor 130 (i.e. the sampling voltage at the voltage feedback terminal 1102) approaches the threshold voltage, i.e. the current flowing through the semiconductor switching device 120 and the sampling resistor 130 cannot be adjusted with the change of the input voltage. In particular, when the AC input voltage is at 108Vac, 120Vac and 132Vac, the working power of the circuit under different AC voltages differs greatly, as shown in the table below. Figure 2 This is because the turn-on voltage VF of the lamp load is fixed, so compared with the 108Vac condition, under the 132Vac condition, the lamp load 200 turns on earlier and turns off later, i.e. the turn-on angle of the lamp load 200 is larger. In addition, since the working voltage under 132Vac is higher, the lamp load 200 will generate higher power under the same current. In order to ensure that the constant current driving circuit 100' can normally operate under the 132Vac condition, the actual working power of the driving circuit 100' under the 120Vac nominal working condition is usually reduced, which in turn leads to the decrease of the power usage efficiency of the driving circuit 100'.

[0060] This application aims to solve the aforementioned problems existing in conventional constant current drive circuits that include non-dimming chips. The purpose of this application is to provide a feedback circuit for a lamp load, a control circuit including the same, and a lamp including the control circuit, which can reduce the power difference of the lamp load drive circuit under different operating voltages in a low-cost and simple manner. Next, reference will be made to… Figures 3 to 7 The present application describes a feedback circuit for a lamp load and a control circuit including the same, according to a first embodiment of the present application.

[0061] Figure 3 This is a schematic diagram of a feedback circuit 300 for a lamp load and a control circuit 400 including the same, according to the first embodiment of this application. Figure 4 yes Figure 3 The diagram shown illustrates the changes in input voltage and current over time in the control circuit 400 for a lamp load. Figure 3 As shown, the feedback circuit 300 for the lamp load 200 according to the first embodiment of this application is connected to the driving circuit 100 of the lamp load 200. The control circuit 400 for the lamp load 200 according to the embodiment of this application includes the feedback circuit 300 and the driving circuit 100. The driving circuit 100 includes a non-dimming chip 110, a semiconductor switching device 120, and a sampling resistor 130. The semiconductor switching device 120 includes a gate 120G, a source 120S, and a drain 120D. The drain 120D of the semiconductor switching device 120 is connected to the negative terminal of the lamp load 200, and the positive terminal of the lamp load 200 is connected to the power input terminal. The sampling resistor 130 is connected between the source 120S of the semiconductor switching device 120 and ground. The non-dimming chip 110 includes a first output terminal 1101 and a voltage feedback terminal 1102. The first output terminal 1101 is connected to the gate 120G of the semiconductor switching device 120. The feedback circuit 300 includes a first voltage divider resistor 310 and a second voltage divider resistor 320 connected in series. The first end of the first voltage divider resistor 310 is connected to the negative terminal of the lamp load 200, the second end of the first voltage divider resistor 310 is connected to the first end of the second voltage divider resistor 320, and the second end of the second voltage divider resistor 320 is connected to the source of the semiconductor switching device 120 and the non-grounded terminal of the sampling resistor 130. The voltage feedback terminal 1102 of the non-dimming chip 110 is connected to the second end of the first voltage divider resistor 310.

[0062] In this way, by adding a feedback circuit 300 and changing the connection position (i.e., voltage sampling position) of the voltage feedback terminal 1102 of the non-dimming chip 110 to be connected between the first voltage divider resistor 310 and the second voltage divider resistor 320, the voltage feedback terminal 1102 samples not the voltage drop V_130 on the sampling resistor 130 in conventional technology, but the sum of the voltage drop V_130 on the sampling resistor 130 and the voltage drop V_320 on the second voltage divider resistor 320.

[0063] In the present application, the non-dimming chip 110 is configured to compare the sampling voltage Vsa input from the voltage feedback terminal 1102 with a preset threshold voltage Vth (which is a preset value, for example, 0.6V) and adjust the voltage at the first output terminal 1101 using the comparison result to control the conduction degree of the semiconductor switching device 120. Since the conduction degree of the semiconductor switching device 120 affects the current I through the loop of the lamp load, itself and the sampling resistor 130, and the conduction degree of the semiconductor switching device 120 is adjusted according to the difference between the sampling voltage Vsa and the preset threshold voltage Vth, the result of the above control is that the sampling voltage Vsa at the voltage feedback terminal 1102 is equal to the preset threshold voltage Vth, i.e., R_130*I+V_320=Vth. In the present application, the threshold voltage Vth is a fixed value preset according to requirements.

[0064] In Figure 3 In the example shown, when the input voltage Vin (which is an alternating voltage) at the power input terminal is greater than the conduction voltage VF of the lamp load 200, the lamp load 200 is turned on, and the voltage at the negative terminal of the lamp load 200 will change with the waveform of the input voltage Vin. The voltage at the negative terminal of the lamp load 200 is divided by the first voltage dividing resistor 310 and the second voltage dividing resistor 320, and the sampling resistor 130.

[0065] Since the actual input voltage at the power input terminal will fluctuate within a certain range above and below the nominal value when power is supplied, for example, in the case of a nominal 120V alternating voltage for the lamp load, the input alternating voltage can actually fluctuate between 108V and 132V, therefore, when the input voltage Vin rises, the voltage shared by the first voltage dividing resistor 310 and the second voltage dividing resistor 320 will increase. Due to the constraint of R_130*I+V_320=Vth, this results in a decrease in the voltage shared by the sampling resistor 130, and therefore a decrease in the current I flowing through the lamp load 200, the semiconductor switching device 120 and the sampling resistor 130, as shown in Figure 4 Here, considering that the resistance values of the voltage dividing resistors 310 and 320 are much greater than that of the sampling resistor 130, the currents through the first voltage dividing resistor 310 and the second voltage dividing resistor 320 are ignored. Since the current I decreases, the power consumption of the driving circuit 100 remains essentially unchanged even if the input voltage Vin rises. Correspondingly, when the input voltage Vin decreases, the voltage shared by the first voltage dividing resistor 310 and the second voltage dividing resistor 320 will decrease, resulting in an increase in the voltage shared by the sampling resistor 130, and therefore an increase in the current I flowing through the loop of the lamp load 200, the semiconductor switching device 120 and the sampling resistor 130, so that the power consumption of the driving circuit 100 remains essentially unchanged.

[0066] Thus, by using the feedback circuit 300 for the lamp load 200 as described above, the power difference of the driving circuit under different input voltages can be reduced by feedback control when the input voltage Vin fluctuates, so that the power consumption of the driving circuit under different input voltages remains stable, thereby reducing the overall power consumption and temperature rise of the driving circuit compared with conventional driving circuits. Moreover, in this way, it is not necessary to ensure that the circuit can operate normally under the condition of 132 Vac as in the traditional method, but to reduce the actual working power of the circuit under the nominal working condition of 120 Vac, thereby improving the power use efficiency of the driving circuit 100 of the lamp load. In addition, the feedback circuit 300 for the lamp load 200 is only composed of two voltage dividing resistors, so it is low in cost and simple in circuit connection structure, thereby achieving the effect of reducing the power difference of the driving circuit 100 under different input voltages in a low-cost and simple way.

[0067] Figure 5 is a schematic diagram of a feedback circuit for a lamp load and a control circuit comprising the same according to the first exemplary embodiment of the present application. Figure 5 shows an exemplary embodiment of the control circuit 400 as shown in Figure 3 As shown in Figure 5 The non-dimming chip 110 can further comprise a first input terminal 1103 connected to the power input end and a ground terminal 1104 connected to the ground. The driving circuit 100 can further comprise a first capacitor 140 and a second capacitor 150, the first capacitor 140 being connected in parallel with the lamp load 200, and the first capacitor 140 can further be connected in parallel with a resistor (shown as R2 in the figure) to form a charge-discharge circuit. The two ends of the second capacitor 150 can be connected to the first input terminal 1103 and the ground terminal 1104 of the non-dimming chip 110, respectively. The voltage at the first output terminal 1101 of the non-dimming chip 110 is also positively correlated with the input voltage at the first input terminal 1103. Therefore, when the input voltage Vin of the power input end is high, the voltage provided from the first output terminal 1101 to the gate 120G of the semiconductor switching device 120 is also high, the semiconductor switching device 120 is turned on, and the degree of conduction is adjusted according to the difference between the sampling voltage Vsa and the preset threshold voltage Vth. In the present application, the first capacitor 140 and the second capacitor 150 can be electrolytic capacitors.

[0068] Furthermore, the non-dimming chip 110 may have a built-in voltage comparator and control loop (not shown). The voltage comparator is connected to the voltage feedback terminal 1102 and can be configured to compare the sampled voltage Vsa input from the voltage feedback terminal 1102 with the threshold voltage Vth and output the comparison result. The control loop can be configured to adjust the voltage at the first output terminal 1101 using the comparison result. Voltage comparators and control loops with the above functions are well known to those skilled in the art and will not be described in detail here.

[0069] Furthermore, either the first voltage divider resistor 310 or the second voltage divider resistor 320 can be composed of one or more resistors. The resistance values ​​of the first voltage divider resistor 310 and the second voltage divider resistor 320 can be adjusted according to the resistance value of the sampling resistor 130, the input voltage, the conduction voltage of the lamp load 200, the expected circuit power consumption, etc. Preferably, the resistance value of the first voltage divider resistor 310 is much larger than the resistance value of the second voltage divider resistor 320, and the resistance value of the second voltage divider resistor 320 is much larger than the resistance value of the sampling resistor 130.

[0070] In this application, the semiconductor switching device 120 includes any one of a metal-oxide-semiconductor field-effect transistor (MOS transistor), a bipolar transistor, an insulated-gate bipolar transistor, and an electrostatic discharge transistor. Figure 5 In the example, the semiconductor switching device 120 is shown as an N-type MOS transistor, but this application is not limited thereto.

[0071] Next, refer to Figure 6 and Figure 7 Description in Figure 5 The actual measurement results of voltage waveforms and circuit power consumption at each node in the control circuit 400 are shown in the case of feedback circuit 300 and control circuit 400. Figure 6 It shows in Figure 5 The measured voltage waveforms at each node of the circuit are shown in the control circuit diagram. During the test, the resistance of sampling resistor 130 was approximately 6Ω, the resistance of the first voltage divider resistor 310 was approximately 500KΩ, the resistance of the second voltage divider resistor 310 was approximately 0.75KΩ, the conduction voltage of lamp load 200 was approximately 70V, the input voltage at the power input terminal was approximately 200V, and the threshold voltage Vth was approximately 0.2V.

[0072] like Figure 6 As shown, Figure 6 (a) shows the waveform of the input voltage Vin at the power input terminal. Figure 6 (b) shows the waveform of the voltage V_200_C at the negative terminal of lamp load 200. Figure 6 (c) shows the waveform of the sampled voltage Vsa at the voltage feedback terminal 1102 of the non-dimming chip 110, and Figure 6Fig. 4 shows the waveforms of the voltage drop V_320 across the second voltage dividing resistor 320 and the voltage drop V_130 across the sampling resistor 130. From Figure 6 It can be seen that in this circuit, the sampling voltage Vsa at the voltage feedback terminal 1102 is substantially stabilized at the set threshold voltage Vth.

[0073] Figure 7 Fig. 5 shows the measured results of the input voltage Vin, the current I through the sampling resistor 130 (Irmsl), and the power consumed by the circuit (Pl) in the case of the control circuit 400 shown in Fig. 4. Figure 1 Fig. 6 shows the measured results of the input voltage Vin, the current I through the sampling resistor 130 (Irmsl), and the power consumed by the circuit (Pl) in the case of the control circuit 400 shown in Fig. 4. Figure 5 Fig. 7 shows the measured results of the input voltage Vin, the current I through the sampling resistor 130 (Irmsl), and the power consumed by the circuit (Pl) in the case of the control circuit 400 shown in Fig. 4. Figure 7 Fig. 8 shows the measured results of the input voltage Vin, the current I through the sampling resistor 130 (Irmsl), and the power consumed by the circuit (Pl) in the case of the control circuit 400 shown in Fig. 4. Figure 5 Fig. 9 shows the measured results of the input voltage Vin, the current I through the sampling resistor 130 (Irmsl), and the power consumed by the circuit (Pl) in the case of the control circuit 400 shown in Fig. 4.

[0074] Fig. 10 shows the measured results of the input voltage Vin, the current I through the sampling resistor 130 (Irmsl), and the power consumed by the circuit (Pl) in the case of the control circuit 400 shown in Fig. 4. Figure 7 Fig. 11 shows the measured results of the input voltage Vin, the current I through the sampling resistor 130 (Irmsl), and the power consumed by the circuit (Pl) in the case of the control circuit 400 shown in Fig. 4. Figure 1 Fig. 12 shows the measured results of the input voltage Vin, the current I through the sampling resistor 130 (Irmsl), and the power consumed by the circuit (Pl) in the case of the control circuit 400 shown in Fig. 4.

[0075] Figure 8 Fig. 13 is a schematic diagram of a feedback circuit 300" for a lamp load and a control circuit 400" including the same according to a second embodiment of the present application. In the first embodiment of the present application, the voltage feedback terminal 1102 of the non-dimming chip 110 samples the remaining voltage after passing through the lamp load 200; while in the second embodiment of the present application, the voltage feedback terminal 1102 of the non-dimming chip 110 samples the input voltage before passing through the lamp load 200.

[0076] Fig. 14 shows the waveforms of the voltage drop V_320 across the second voltage dividing resistor 320 and the voltage drop V_130 across the sampling resistor 130. From Figure 8As shown, in the second embodiment of the present application, the driving circuit 100" for the lamp load 200 includes a non-dimming chip 110, a semiconductor switching device 120 including a gate 120G, a source 120S and a drain 120D, the drain 120D of the semiconductor switching device 120 is connected to the negative pole of the lamp load 200, a sampling resistor 130 connected between the source 120S of the semiconductor switching device 120 and the ground, the non-dimming chip 110 includes a first output terminal 1101 and a voltage feedback terminal 1102, the first output terminal 1101 is connected to the gate 120G of the semiconductor switching device 120. The feedback circuit 300" for the lamp load 200 according to the second embodiment of the present application includes a first voltage dividing resistor 310 and a second voltage dividing resistor 320, the first end of the first voltage dividing resistor 310 is connected to the power input terminal, the second end of the first voltage dividing resistor 310 is connected to the positive pole of the lamp load 200, the first end of the second voltage dividing resistor 320 is connected to the drain 120D of the semiconductor switching device 120, the second end of the second voltage dividing resistor 320 is connected to the source 120S of the semiconductor switching device 120, wherein the voltage feedback terminal 1102 of the non-dimming chip 110 is connected to the second end of the first voltage dividing resistor 310.

[0077] In this way, the voltage sampled by the voltage feedback terminal 1102 is the sum of the voltage drop V_200 on the lamp load 200, the voltage drop V_320 on the second voltage dividing resistor 320 and the voltage drop V_130 on the sampling resistor 130 (which is equal to the current I multiplied by the resistance R_130). By setting an appropriate threshold voltage Vth', when the input voltage Vin is greater than the turn-on voltage of the lamp load 200, the result after feedback control is: V_200+V_320+I×R_130=Vth'. Similarly to the first embodiment, when the input voltage Vin rises, the voltage drop V_320 on the second voltage dividing resistor 320 will increase, so the voltage drop V_130 on the sampling resistor 130 will decrease, resulting in a decrease in the current I flowing through the lamp load 200, the semiconductor switching device 120 and the sampling resistor 130. Since the current I decreases, the power consumption of the driving circuit 100" will remain substantially unchanged.

[0078] Thus, the feedback circuit 300" according to the second embodiment can also achieve the effect of reducing the circuit power difference caused by different input voltages when the input voltage Vin fluctuates, so that the circuit power consumption under different input voltages remains stable, thereby reducing the overall power consumption and temperature rise of the circuit.

[0079] Further, the present application also provides a lamp, which includes the feedback circuit according to the reference Figures 3 to 8The control circuit 400 or 400" and the lamp load 200 according to the present application. The lamp can also be able to reduce the circuit power difference caused by different input voltages when the input voltage of the power input end of the lamp fluctuates, so that the circuit power consumption under different input voltages remains stable, thereby reducing the overall power consumption and temperature rise of the circuit.

[0080] It should be noted that the terms used herein are only for the purpose of describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and furthermore, it should be understood that when the terms "comprise" and / or "include" are used in the specification, there is a feature, step, work, device, component and / or combination thereof.

[0081] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0082] The above is only the preferred embodiment of the present application, and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A feedback circuit for a lamp load, connected to a driving circuit (100) of the lamp load (200), the driving circuit (100) comprising a non-dimming chip (110), a semiconductor switching device (120) and a sampling resistor (130), the semiconductor switching device (120) comprising a gate, a source and a drain, the drain of the semiconductor switching device (120) being connected to a negative pole of the lamp load (200), the sampling resistor (130) being connected between the source of the semiconductor switching device (120) and ground, the non-dimming chip (110) comprising a first output terminal (1101) and a voltage feedback terminal (1102), the first output terminal (1101) being connected to the gate of the semiconductor switching device (120), characterized in that, The feedback circuit (300) comprises: a first voltage dividing resistor (310) and a second voltage dividing resistor (320) connected in series, a first end of the first voltage dividing resistor (310) being connected to a negative pole of the lamp load (200), a second end of the first voltage dividing resistor (310) being connected to a first end of the second voltage dividing resistor (320), a second end of the second voltage dividing resistor (320) being connected to a source of the semiconductor switching device (120), wherein the voltage feedback terminal (1102) is connected to the second end of the first voltage dividing resistor (310).

2. The feedback circuit for a lamp load according to claim 1, wherein the non-dimming chip further comprises a first input terminal and a ground terminal, the first input terminal being connected to a power input terminal, the driving circuit further comprises a first capacitor and a second capacitor, the first capacitor being connected in parallel to the lamp load, two ends of the second capacitor being connected to the first input terminal and the ground terminal respectively.

3. The feedback circuit for a lamp load of claim 1, wherein, The semiconductor switching device is a metal oxide semiconductor field effect transistor.

4. The feedback circuit for a lamp load of claim 1, wherein, Any one of the first voltage dividing resistor and the second voltage dividing resistor is composed of one or more resistors.

5. The feedback circuit for a lamp load of claim 1, wherein, The non-dimming chip is built-in with a voltage comparator and a control loop, the voltage comparator being configured to compare a sampling voltage input from the voltage feedback terminal with a preset threshold voltage and output a comparison result, the control loop being configured to adjust a voltage at the first output terminal by using the comparison result.

6. A control circuit for a lamp load, characterized by The control circuit comprises: The feedback circuit for a lamp load according to any one of claims 1 to 5; and The driving circuit for a lamp load, connected with the feedback circuit.

7. A feedback circuit for a lamp load, connected to a driving circuit (100") of a lamp load (200), the driving circuit (100") comprising a non-dimming chip (110), a semiconductor switching device (120) and a sampling resistor (130), the semiconductor switching device (120) comprising a gate, a source and a drain, the drain of the semiconductor switching device (120) being connected to a negative pole of the lamp load (200), a positive pole of the lamp load (200) being connected to a power input, the sampling resistor (130) being connected between the source of the semiconductor switching device (120) and ground, the non-dimming chip (110) comprising a first output terminal (1101) and a voltage feedback terminal (1102), the first output terminal (1101) being connected to the gate of the semiconductor switching device (120), characterized in that, The feedback circuit (300”) comprises: a first voltage dividing resistor (310) and a second voltage dividing resistor (320), a first end of the first voltage dividing resistor (310) being connected to the power input terminal, a second end of the first voltage dividing resistor (310) being connected to a positive pole of the lamp load (200), a first end of the second voltage dividing resistor (320) being connected to a drain of the semiconductor switching device (120), a second end of the second voltage dividing resistor (320) being connected to a source of the semiconductor switching device (120), wherein the voltage feedback terminal (1102) is connected to the second end of the first voltage dividing resistor (310).

8. The feedback circuit for a lamp load of claim 7, wherein, The non-dimming chip further comprises a first input terminal and a ground terminal, the first input terminal being connected to the power input terminal, the driving circuit further comprises a first capacitor and a second capacitor, the first capacitor being connected in parallel to the lamp load, two ends of the second capacitor being connected to the first input terminal and the ground terminal respectively.

9. A control circuit for a lamp load, characterized by The control circuit comprises: The feedback circuit for a lamp load according to claim 7 or 8, and The driving circuit for a lamp load, connected with the feedback circuit.

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