Boost circuit and lighting equipment

Abstract

The utility model provides a boost circuit and a lighting device. The boost circuit comprises a controller, an inductor, a switch tube, a voltage sampling circuit and a current sampling circuit. The controller is electrically connected with first ends of the switching tube, the voltage sampling circuit and the current sampling circuit, the inductor is electrically connected with a power supply and a second end of the switching tube and is used for being electrically connected with an external load, and a third end of the switching tube is electrically connected with a second end of the current sampling circuit. The second end of the voltage sampling circuit is electrically connected with the inductor. Through the implementation of the utility model, the voltage sampling circuit and the current sampling circuit respectively collect the output voltage and the output current, and feed back the output voltage and the output current to the controller, so that the controller adjusts the driving control signal, thereby ensuring that the output voltage is stabilized at a set voltage value, and providing stable and reliable power supply voltage for a load.

Description

Technical Field

[0001] The utility model relates to the technical field of circuits, in particular to a boost circuit and a lighting device. Background Art

[0002] In the power supply module of emergency lighting devices, an AC-DC module is usually adopted to convert the input alternating current into direct current to supply power to the LED unit. The DC voltage output by a general AC-DC module mostly meets the requirements of standardized power supply voltage. Therefore, when a higher supply voltage is required, the voltage output by the AC-DC module will not be sufficient, so the output voltage needs to be boosted. The boost modules in related technologies usually include an inductor and a switching transistor. After setting the turns ratio of the inductor, the boost process is carried out by controlling the on-off of the switching transistor. In this structure, the output voltage may fluctuate with the input voltage, load or environmental conditions, and it is not possible to well ensure a stable boost voltage for the load device, thus affecting the normal operation of the load device. Summary of the Utility Model

[0003] The utility model provides a boost circuit and a lighting device, aiming to solve the problem of poor output voltage stability of the boost module in related technologies.

[0004] To solve the above technical problems, in a first aspect of the utility model, an oscillation counting circuit is provided, including: a controller, an inductor, a switching transistor, a voltage sampling circuit and a current sampling circuit; the controller is electrically connected to the first ends of the switching transistor, the voltage sampling circuit and the current sampling circuit respectively, the inductor is electrically connected to a power supply, the second end of the switching transistor and is used for being electrically connected to an external load, the third end of the switching transistor is electrically connected to the second end of the current sampling circuit, and the second end of the voltage sampling circuit is electrically connected to the inductor.

[0005] Further, the current sampling circuit includes a first resistor and a second resistor. One end of the first resistor is electrically connected to the third end of the switching transistor and one end of the second resistor respectively, the other end of the first resistor is grounded, and the other end of the second resistor is electrically connected to the current detection end of the controller.

[0006] Further, the voltage sampling circuit includes a third resistor, a fourth resistor, a fifth resistor and a buffer circuit; one end of the third resistor is electrically connected to the inductor and one end of the buffer circuit respectively, the other end of the third resistor is electrically connected to one end of the fourth resistor, the other end of the fourth resistor is electrically connected to one end of the fifth resistor, the other end of the buffer circuit and the feedback voltage input end of the controller respectively, and the other end of the fifth resistor is grounded.

[0007] Further, it further includes a first triode, a second triode and a seventh resistor; a first end of the first triode is electrically connected to a power supply, a second end of the first triode is respectively electrically connected to the seventh resistor and a first end of the second triode, a third end of the first triode is respectively electrically connected to a second end of the second triode and a first end of the switching tube, a third end of the second triode is grounded, and the other end of the seventh resistor is electrically connected to an output end of the controller.

[0008] Further, it further includes a rectifying and filtering circuit and a first diode. One end of the rectifying and filtering circuit is electrically connected to the inductor, and the other end of the rectifying and filtering circuit is used for being electrically connected to an external load. A positive electrode of the first diode is electrically connected to the power supply, and a negative electrode of the first diode is electrically connected to the rectifying and filtering circuit.

[0009] A second aspect of the present utility model provides a lighting device, including the boost circuit as described in the first aspect of the present utility model.

[0010] As can be seen from the above description, in the present utility model, a drive control signal is provided for the switching tube by the controller. When the switching tube is turned on, the inductor is used to boost the voltage and output a boosted voltage to the external load. Then, the output voltage and the output current are respectively collected by the voltage sampling circuit and the current sampling circuit and fed back to the controller, so that the controller adjusts the drive control signal, thereby ensuring that the output voltage is stably maintained at a set voltage value to provide a stable and reliable power supply voltage for the load. Description of the Drawings

[0011] Figure 1 is a schematic structural diagram of a boost circuit according to an embodiment of the present utility model;

[0012] Figure 2 is a circuit schematic diagram of a first boost circuit according to an embodiment of the present utility model;

[0013] Figure 3 is a circuit schematic diagram of a voltage stabilizing circuit according to an embodiment of the present utility model;

[0014] Figure 4 is a circuit schematic diagram of a second boost circuit according to an embodiment of the present utility model. Detailed Embodiments

[0015] In order to make the objectives, technical solutions and advantages of the present utility model clearer and more understandable, the present utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model. In addition, the technical features involved in the various embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other.

[0016] In the related art, due to the problem of poor output voltage stability of the boost module, for this reason, the embodiment of the present utility model provides a boost circuit.

[0017] As Figure 1 shown is a schematic structural diagram of a boost circuit provided by an embodiment of the present utility model. The boost circuit includes: a controller 100, an inductor 200, a switching transistor 300, a voltage sampling circuit 400 and a current sampling circuit 500; the controller 100 is electrically connected to the first ends of the switching transistor 300, the voltage sampling circuit 400 and the current sampling circuit 500 respectively, the inductor 200 is electrically connected to the power supply V0 and the second end of the switching transistor 300 respectively and is used for being electrically connected to an external load 600, the third end of the switching transistor 300 is electrically connected to the second end of the current sampling circuit 500, and the second end of the voltage sampling circuit 400 is electrically connected to the inductor 200.

[0018] Specifically, in this embodiment, the controller 100 is used to output a driving signal to the switching transistor 300, so that the switching transistor 300 performs periodic switching according to the driving signal. In each switching cycle, when the switching transistor 300 is turned on, the inductor 200 stores energy to increase the output voltage. When the switching transistor Q10 is turned off, the inductor 200 releases energy and transmits the stored energy to the external load 600, such as an LED unit. The voltage sampling circuit 400 is used to collect the output voltage and transmit it to the controller 100, and compare it with the reference voltage of the error amplifier inside the controller 100 to generate a control voltage, adjust the duty cycle or pulse width of the driving signal, so as to adjust the conduction time of the switching transistor 300 to regulate the magnitude of the output voltage. The current sampling circuit 500 is used to collect the output current and convert it into a voltage, and then transmit it to the controller 100. The controller 100 adjusts the duty cycle or pulse width of the driving control signal according to the fed-back voltage. Thus, by using two sampling circuits for feedback, the output boost voltage can be stabilized at a set voltage value to provide a stable and reliable power supply voltage for the external load 600.

[0019] As Figure 2 shown is the circuit schematic diagram of the first boost circuit provided by this embodiment. Please refer to Figure 2, the current sampling circuit 500 includes a first resistor RS1 and a second resistor R58. One end of the first resistor RS1 is electrically connected to the third end of the switching transistor 300 (i.e., Q10) and one end of the second resistor R58 respectively. The other end of the first resistor RS1 is grounded, and the other end of the second resistor R58 is electrically connected to the current detection terminal of the controller 100 (i.e., U3).

[0020] Further, please refer to Figure 2 , the voltage sampling circuit 400 includes a third resistor R42, a fourth resistor R44, a fifth resistor R56 and a buffer circuit; one end of the third resistor R42 is electrically connected to the inductor 200 and one end of the buffer circuit respectively. The other end of the third resistor R42 is electrically connected to one end of the fourth resistor R44. The other end of the fourth resistor R44 is electrically connected to one end of the fifth resistor R56, the other end of the buffer circuit and the feedback voltage input terminal of the controller U3 respectively. The other end of the fifth resistor R56 is grounded. The buffer circuit includes a sixth resistor R43 and a first capacitor C15. The sixth resistor R43 is electrically connected to one end of the third resistor R42 and one end of the first capacitor C15 respectively. The other end of the first capacitor C15 is electrically connected to the other end of the fourth resistor R44.

[0021] Specifically, in this embodiment, the controller U3 can adopt a controller 100 with the model UC3843. The switching transistor Q10 can be a MOS transistor, such as Figure 2 the NMOS transistor in The current sampling circuit 500 samples the current through the first resistor RS1 and the second resistor R58 and converts it into a voltage to be transmitted to the current detection terminal 3 of the controller 100. The voltage sampling circuit 400 divides and samples the output boost voltage through the third resistor R42, the fourth resistor R44, and the fifth resistor R56 and then transmits it to the feedback voltage input terminal 2 of the controller U3. After being compared and judged by the controller U3, the duty cycle or pulse width of the output drive signal is adjusted, so as to adjust the conduction time of the switching transistor Q10 and stabilize the output voltage. For example, when the potential of the feedback voltage terminal is raised, the duty cycle of the drive signal output by the controller U3 will decrease, and thus the output voltage will also decrease. The input power supply in this embodiment is V0, and the output boost voltage is 48V. In addition, it should also be noted that Figure 2 Pin 1 of the controller U3 in is the output of the error amplifier, connected to pin 2 (i.e., the feedback voltage input terminal) and the compensation network (i.e., capacitor C21, capacitor C21, resistor R50), and can be used to determine the response frequency of the control loop of the controller U3 to ensure the stability of the feedback loop; pin 4 is the oscillation terminal, connected to the fixed-frequency resistor R61 and the fixed-frequency capacitors C26, C27. Pin 5 is the ground terminal, pin 8 is the reference voltage output terminal, used to output a 5V reference voltage, and pin 7 is the power supply terminal. The input voltage V0 can be converted into the power supply voltage required by the controller U3, such as 12V, through a voltage stabilizing circuit and the power supply voltage is stabilized at 12V. The voltage stabilizing circuit is asFigure 3 As shown, the voltage stabilizing circuit includes a voltage stabilizing diode Q15 and a triode Q14. The voltage stabilizing diode is used to provide a reference voltage source and control the output of the triode according to the feedback voltage, thereby playing a role in regulating the output voltage.

[0022] Further, please refer to Figure 2 , the boost circuit further includes a first triode Q9, a second triode Q11, and a seventh resistor R48; the first end of the first triode Q9 is electrically connected to the power supply, the second end of the first triode Q9 is electrically connected to the seventh resistor R48 and the first end of the second triode Q11 respectively, the third end of the first triode Q9 is electrically connected to the second end of the second triode Q11 and the first end of the switching tube Q10 respectively, the third end of the second triode Q11 is grounded, and the other end of the seventh resistor R48 is electrically connected to the output end of the controller U3.

[0023] Further, please refer to Figure 2 , the boost circuit further includes an eighth resistor R45 and a ninth resistor R53. The eighth resistor R45 is electrically connected to the first end of the switching tube 300 respectively, the other end of the eighth resistor R45 is electrically connected to the third end of the first triode Q9, and the ninth resistor R53 is electrically connected to the first end and the third end of the switching tube Q10 respectively.

[0024] Specifically, in this embodiment, the first triode Q9 and the second triode Q11 are an NPN triode and a PNP triode respectively. The first triode Q9, the second triode Q11, and the seventh resistor R48 form a totem pole structure for amplifying the driving signal output by the controller U3. The eighth resistor R45 and the ninth resistor R53 can be used to provide a bias voltage for the MOS tube to ensure that the MOS tube is within the normal operating range, and can also play a role in preventing ESD static electricity, avoiding electrostatic damage when the gate and source are in a high impedance state, and ensuring the safety of the device.

[0025] As Figure 4 shown is the structural schematic diagram of the second boost circuit provided by this embodiment. Please refer to Figure 4 , the boost circuit further includes a rectifying and filtering circuit and a first diode D8. One end of the rectifying and filtering circuit is electrically connected to the inductor 200 (i.e., L3), and the other end of the rectifying and filtering circuit is used to be electrically connected to an external load. The positive electrode of the first diode D8 is electrically connected to the power supply V0, and the negative electrode of the first diode D8 is electrically connected to the rectifying and filtering circuit.

[0026] Specifically, the rectifying and filtering circuit includes a second diode D10, a second capacitor C19, a common mode inductor T2, a third capacitor C18, and a tenth resistor RS2. The positive electrode of the second diode D10 is electrically connected to the inductor L3. The negative electrode of the second diode D10 is respectively electrically connected to the first end of the common mode inductor T2 and the negative electrode of the first diode D8. One end of the second capacitor C19 is electrically connected to the negative electrode of the second diode D10, and the other end of the second capacitor C19 is grounded. The second end of the common mode inductor T2 is electrically connected to one end of the tenth resistor RS2. The third end and the fourth end of the common mode inductor T2 are both used for electrically connecting to an external load. The other end of the tenth resistor RS2 is grounded. The third capacitor C18 is respectively electrically connected to the third end and the fourth end of the common mode inductor T2. The rectifying and filtering circuit further includes a fourth capacitor C12 and an eleventh resistor R41. The eleventh resistor R41 is respectively electrically connected to the positive electrode of the second diode D10 and one end of the fourth capacitor C12. The other end of the fourth capacitor C12 is electrically connected to the negative electrode of the second diode D10.

[0027] Specifically, in this embodiment, after the boost circuit performs a boost process, it also rectifies and filters the boosted voltage before transmitting it to the external load. Among them, the second diode D10 is used to rectify the output voltage. The fourth capacitor C12 and the eleventh resistor R41 form an RC absorption circuit, which can shunt and absorb the voltage peak value to reduce the voltage peak value, thereby protecting the stability and reliability of the second diode D10; the second capacitor C19, the common mode inductor T2, the third capacitor C18, and the tenth resistor RS2 are used for filtering. In addition, it further includes a first diode D8. The first diode D8 is connected in parallel with the inductor L3 and can be used to prevent the inductor L3 from charging and saturating when the second capacitor C19 is short-circuited.

[0028] The boost circuit provided by the embodiment of the present invention provides a drive control signal for the switching tube through a controller. When the switching tube is turned on, the inductor realizes boosting and outputs the boosted voltage to the external load. Then, the voltage sampling circuit and the current sampling circuit respectively collect the output voltage and the output current and feedback them to the controller, so that the controller adjusts the drive control signal, thereby ensuring that the output voltage is stably maintained at a preset boosted voltage value to provide a stable and reliable power supply voltage for the load.

[0029] The embodiment of the present invention also provides a lighting device, which includes the above boost circuit. Among them, the lighting device can be an emergency light.

[0030] It should be noted that the various embodiments in the content of the present invention are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.

[0031] It should also be noted that in the content of the present utility model, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0032] The above description of the disclosed embodiments enables those skilled in the art to implement or use the content of the present utility model. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined in the content of the present utility model can be implemented in other embodiments without departing from the spirit or scope of the content of the present utility model. Therefore, the content of the present utility model will not be limited to these embodiments shown in the content of the present utility model, but rather to the widest scope consistent with the principles and novel features disclosed in the content of the present utility model.

Claims

1. A boost circuit, characterized in that: include: A controller, an inductor, a switch tube, a voltage sampling circuit and a current sampling circuit; the controller is electrically connected to the first ends of the switch tube, the voltage sampling circuit and the current sampling circuit respectively, the inductor is electrically connected to a power supply and the second end of the switch tube respectively and is used to be electrically connected to an external load, the third end of the switch tube is electrically connected to the second end of the current sampling circuit, and the second end of the voltage sampling circuit is electrically connected to the inductor.

2. The boost circuit according to claim 1, characterized in that: The current sampling circuit includes a first resistor and a second resistor, one end of the first resistor is electrically connected to the third end of the switch tube and one end of the second resistor respectively, the other end of the first resistor is grounded, and the other end of the second resistor is electrically connected to the current detection end of the controller.

3. The boost circuit according to claim 1, characterized in that: The voltage sampling circuit includes a third resistor, a fourth resistor, a fifth resistor and a buffer circuit; one end of the third resistor is electrically connected to the inductor and one end of the buffer circuit respectively, the other end of the third resistor is electrically connected to one end of the fourth resistor, the other end of the fourth resistor is electrically connected to one end of the fifth resistor, the other end of the buffer circuit and the feedback voltage input end of the controller respectively, and the other end of the fifth resistor is grounded.

4. The boost circuit according to claim 3, characterized in that: The buffer circuit includes a sixth resistor and a first capacitor. The sixth resistor is electrically connected to one end of the third resistor and one end of the first capacitor respectively. The other end of the first capacitor is electrically connected to the other end of the fourth resistor.

5. The boost circuit according to claim 1, characterized in that: It also includes a first triode, a second triode and a seventh resistor; the first end of the first triode is electrically connected to the power supply, the second end of the first triode is electrically connected to the seventh resistor and the first end of the second triode respectively, the third end of the first triode is electrically connected to the second end of the second triode and the first end of the switch tube respectively, the third end of the second triode is grounded, and the other end of the seventh resistor is electrically connected to the output end of the controller.

6. The boost circuit according to claim 5, characterized in that: It also includes an eighth resistor and a ninth resistor, wherein the eighth resistor is electrically connected to the first end of the switch tube, the other end of the eighth resistor is electrically connected to the third end of the first transistor, and the ninth resistor is electrically connected to the first end and the third end of the switch tube.

7. The boost circuit according to claim 1, characterized in that: It also includes a rectifier and filter circuit and a first diode, one end of the rectifier and filter circuit is electrically connected to the inductor, the other end of the rectifier and filter circuit is used to be electrically connected to an external load, the positive electrode of the first diode is electrically connected to a power supply, and the negative electrode of the first diode is electrically connected to the rectifier and filter circuit.

8. The voltage boost circuit according to claim 7, characterized in that: The rectification and filtering circuit includes a second diode, a second capacitor, a common-mode inductor, a third capacitor and a tenth resistor, wherein the anode of the second diode is electrically connected to the inductor, the cathode of the second diode is electrically connected to the first end of the common-mode inductor and the cathode of the first diode respectively, one end of the second capacitor is electrically connected to the cathode of the second diode, the other end of the second capacitor is grounded, the second end of the common-mode inductor is electrically connected to one end of the tenth resistor, the third end and the fourth end of the common-mode inductor are both used to be electrically connected to an external load, the other end of the tenth resistor is grounded, and the third capacitor is electrically connected to the third end and the fourth end of the common-mode inductor respectively.

9. The voltage boost circuit according to claim 8, characterized in that: The rectification and filtering circuit also includes a fourth capacitor and an eleventh resistor. The eleventh resistor is electrically connected to the anode of the second diode and one end of the fourth capacitor respectively. The other end of the fourth capacitor is electrically connected to the cathode of the second diode.

10. A lighting device, characterized in that: The method comprises the boost circuit as claimed in any one of claims 1 to 9.

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