LED power supply circuit

Abstract

The utility model relates to the technical field of illumination, and discloses an LED power supply circuit, in which a feedback end of a switch voltage stabilizing circuit is connected with an output end of a switching circuit; the first input end of the switching circuit is connected with the output end of the low-voltage configuration circuit, the second input end of the switching circuit is connected with the output end of the normal work configuration circuit, an external control signal is connected to the third input end of the switching circuit, and the low-voltage configuration circuit is used for configuring the output voltage of the switching voltage stabilizing circuit to be smaller than the starting voltage of an LED. When the LED needs to be turned off, the low-voltage configuration circuit is switched to be connected through the switching circuit, the normal working configuration circuit is turned off, the switching voltage stabilizing circuit is configured to be low output voltage, and the switching voltage stabilizing chip is in a normal operation state while the LED does not work. Therefore, the influence of the soft start time of the chip is avoided during next start, and quick start is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of lighting, in particular to an LED power supply circuit. Background Art

[0002] In the prior art, LEDs are widely used in various occasions, such as endoscope systems, due to their advantages such as high efficiency and energy saving, long life, and low voltage controllability. When the same-screen display of the endoscope system needs to quickly switch between different modes of spectrum, the LED needs to be quickly started. At this time, the following methods are generally used to quickly start the LED: (1) through the enable function of the switching regulator chip; (2) by adding an electronic switch in the power supply circuit. However, due to the soft start time of the switching regulator chip, it is difficult to achieve rapid startup of the circuit through the enable function of the chip itself in method (1), thereby failing to meet the application requirements. Method (2) uses an electronic switch in series in the power supply circuit. Although it can meet the requirements of rapid startup, it will reduce the efficiency of the circuit, which becomes more obvious as the power supply current of the LED increases. Utility Model Content

[0003] In view of this, the utility model provides an LED power supply circuit to solve the problem that it is difficult to achieve rapid start-up of the LED.

[0004] The utility model provides an LED power supply circuit, including: a switch voltage stabilizing circuit, a switching circuit, a normal working configuration circuit and a low voltage configuration circuit, wherein:

[0005] The input end of the switching voltage stabilizing circuit is connected to an external DC power supply, the output of the switching voltage stabilizing circuit is connected to an LED, and the feedback end of the switching voltage stabilizing circuit is connected to the output end of the switching circuit;

[0006] The first input terminal of the switching circuit is connected to the output terminal of the low-voltage configuration circuit, the second input terminal of the switching circuit is connected to the output terminal of the normal working configuration circuit, and the third input terminal of the switching circuit is connected to an external control signal. The low-voltage configuration circuit is used to configure the output voltage of the switching voltage regulator circuit to be lower than the start-up voltage of the LED.

[0007] In an optional embodiment, the switching voltage regulator circuit includes a switching voltage regulator chip and a peripheral configuration circuit, the input voltage pin of the switching voltage regulator chip is connected to an external DC power supply, the switching voltage regulator chip is connected to the LED through the peripheral configuration circuit, and the feedback pin of the switching voltage regulator chip is connected to the signal output end of the switching circuit.

[0008] In an optional implementation, the low voltage configuration circuit includes: a first resistor and a second resistor, wherein:

[0009] One end of the first resistor is connected to the output voltage of the switching voltage regulator circuit, the other end of the first resistor is respectively connected to the first input end of the switching circuit and one end of the second resistor, and the other end of the second resistor is grounded.

[0010] In an optional implementation, the low voltage configuration circuit includes: a first resistor and a second resistor, wherein:

[0011] One end of the first resistor is connected to the output voltage of the switching voltage regulator circuit, and the other end of the first resistor is connected to the first input end of the switching circuit;

[0012] One end of the second resistor is connected to the feedback pin of the switching voltage regulator chip, and the other end of the second resistor is grounded.

[0013] In an optional implementation, the low voltage configuration circuit includes: a voltage stabilizing diode and a second resistor, wherein:

[0014] One end of the voltage regulator diode is connected to the output voltage of the switching voltage regulator circuit, the other end of the voltage regulator diode is respectively connected to the first input end of the switching circuit and one end of the second resistor, and the other end of the second resistor is grounded.

[0015] In an optional implementation, the switching circuit is an integrated electronic switch or a switching circuit composed of discrete components.

[0016] In an optional embodiment, the switching circuit is an integrated electronic switch, an enable pin of the integrated electronic switch is connected to an external control signal, a first input pin of the integrated electronic switch is connected to the low-voltage configuration circuit, a second input pin of the integrated electronic switch is connected to the normal working configuration circuit, and an output pin of the integrated electronic switch is connected to a feedback pin of the switching voltage regulator chip.

[0017] In an optional implementation, the switching voltage regulator chip is a boost voltage regulator chip or a buck voltage regulator chip.

[0018] In an optional implementation, an input voltage pin of the integrated electronic switch is connected to an external power supply, and the input voltage pin is also grounded via a first capacitor.

[0019] In an optional implementation, a ground pin of the integrated electronic switch is grounded.

[0020] The utility model provides an LED power supply circuit, including: a switching voltage regulator circuit, a switching circuit, a normal working configuration circuit and a low voltage configuration circuit, wherein the input end of the switching voltage regulator circuit is connected to an external DC power supply, the output of the switching voltage regulator circuit is connected to an LED, and the feedback end of the switching voltage regulator circuit is connected to the output end of the switching circuit; the first input end of the switching circuit is connected to the output end of the low voltage configuration circuit, the second input end of the switching circuit is connected to the output end of the normal working configuration circuit, the third input end of the switching circuit is connected to an external control signal, and the low voltage configuration circuit is used to configure the output voltage of the switching voltage regulator circuit to be less than the starting voltage of the LED. When the LED needs to be turned off, the switching circuit is switched to the low voltage configuration circuit, the normal working configuration circuit is disconnected, and the switching voltage regulator circuit will be configured to a lower output voltage, so that the LED is not working while the switching voltage regulator chip is in a normal operating state, thereby avoiding the influence of the chip soft start time at the next startup, and then realizing a fast startup. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 This is a principle block diagram of an LED power supply circuit according to an embodiment of the utility model;

[0023] Figure 2 It is a schematic diagram of the structure of an LED power supply circuit according to an embodiment of the utility model. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0025] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0026] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0027] The utility model provides an LED power supply circuit, which provides a quick start solution for the LED. Figure 1 As shown, the LED power supply circuit includes: a switching voltage regulator circuit 1, a switching circuit 2, a normal working configuration circuit 3 and a low voltage configuration circuit 4. Among them, the input end of the switching voltage regulator circuit 1 is connected to an external DC power supply, the output of the switching voltage regulator circuit 1 is connected to the LED, and the feedback end of the switching voltage regulator circuit 1 is connected to the output end of the switching circuit 2. The first input end of the switching circuit 2 is connected to the output end of the low voltage configuration circuit 4, the second input end of the switching circuit 2 is connected to the output end of the normal working configuration circuit 3, the third input end of the switching circuit 2 is connected to an external control signal, the input end of the low voltage configuration circuit 4 and the input end of the normal working configuration circuit 3 are both connected to the output voltage of the switching voltage regulator circuit 1, and the low voltage configuration circuit 4 is used to configure the output voltage of the switching voltage regulator circuit 1 to be less than the start-up voltage of the LED.

[0028] Specifically, when the LED power supply circuit is started for the first time, the switching voltage regulator chip in the switching voltage regulator circuit 1 has not yet been powered on and initialized, so a soft start delay is required. After the LED power supply circuit completes the first startup, the switching voltage regulator chip will always be in a working state and no initialization is required, and there will be no subsequent soft start delay.

[0029] Furthermore, when the normal power supply for the LED is required, the normal working configuration circuit 3 is connected through the switching circuit 2, the low voltage configuration circuit 4 is disconnected, and the feedback end of the switching voltage regulator circuit 1 is set with the parameters for the normal working of the LED. When the LED needs to be turned off, the low voltage configuration circuit 4 is connected through the switching circuit 2, and the normal working configuration circuit 3 is disconnected. The switching voltage regulator circuit 1 will be configured to a lower output voltage V0, which does not meet the requirements for lighting the LED, so the LED will not emit light, thereby realizing the shutdown of the LED power supply.

[0030] Since in the process of controlling the switching of the switching circuit 2, only the output voltage of the switching voltage regulator circuit 1 is actually changed, the switching voltage regulator chip is essentially always in a normal working state, and there is no problem of soft-start delay, so that the LED power supply can be quickly switched from off to on, and the speed can reach the us level or even the ns level, which is much faster than the ms level after soft start.

[0031] The utility model provides an LED power supply circuit, including: a switching voltage regulator circuit, a switching circuit, a normal working configuration circuit and a low voltage configuration circuit, wherein the input end of the switching voltage regulator circuit is connected to an external DC power supply, the output of the switching voltage regulator circuit is connected to an LED, and the feedback end of the switching voltage regulator circuit is connected to the output end of the switching circuit; the first input end of the switching circuit is connected to the output end of the low voltage configuration circuit, the second input end of the switching circuit is connected to the output end of the normal working configuration circuit, the third input end of the switching circuit is connected to an external control signal, and the low voltage configuration circuit is used to configure the output voltage of the switching voltage regulator circuit to be less than the starting voltage of the LED. When the LED needs to be turned off, the switching circuit is switched to the low voltage configuration circuit, the normal working configuration circuit is disconnected, and the switching voltage regulator circuit will be configured to a lower output voltage, so that the LED is not working while the switching voltage regulator chip is in a normal operating state, thereby avoiding the influence of the chip soft start time at the next startup, and then realizing a fast startup.

[0032] In an optional embodiment, if Figure 2 As shown, the switching voltage regulator circuit 1 includes a switching voltage regulator chip U1 and a peripheral configuration circuit. The input voltage pin VCC of the switching voltage regulator chip U1 is connected to an external DC power supply. The switching voltage regulator chip U1 is connected to an LED through the peripheral configuration circuit. The feedback pin FB of the switching voltage regulator chip U1 is connected to the signal output end of the switching circuit 2. Among them, the peripheral configuration circuit, the external DC power supply and the LED are not connected. Figure 2 In this embodiment, the peripheral configuration circuit includes some components such as inductors. The peripheral configuration circuit is a circuit in the prior art that can adjust the output voltage of the switching voltage regulator chip U1 and ultimately achieve a stable voltage or current to power the LED, which will not be described in detail here.

[0033] Specifically, this embodiment is based on the voltage setting function of the feedback pin FB of the switching voltage regulator chip U1. Therefore, the switching voltage regulator chip is a step-up voltage regulator chip or a step-down voltage regulator chip. In this embodiment, the chip can be used regardless of whether it is used in buck, boost or other types of switching voltage regulator power supply chips as long as the voltage can be set based on the feedback pin FB.

[0034] In an optional embodiment, if Figure 2As shown, the low voltage configuration circuit 4 includes: a first resistor R1 and a second resistor R2, wherein one end of the first resistor R1 is connected to the output voltage of the switching voltage regulator circuit 1, the other end of the first resistor R1 is respectively connected to the first input end of the switching circuit 2 and one end of the second resistor R2, and the other end of the second resistor R2 is grounded.

[0035] Specifically, the low voltage configuration circuit 4 is used to configure the output voltage of the switching voltage regulator circuit 1 to be lower than the minimum startup voltage of the LED. When the LED needs to be turned off, the low voltage configuration circuit 4 is connected to the feedback pin FB of the switching voltage regulator chip U1 through the switching circuit 2, and the switching voltage regulator circuit 1 will be configured to a lower output voltage V0. The output voltage V0 does not meet the requirements for lighting the LED, so the LED will not emit light, thereby realizing the shutdown of the LED power supply. Since the output voltage V0 calculation formula is V0 = (R1 + R2) / R2 * VFB, and the output voltage V0 needs to be less than the minimum startup voltage V min , that is, V0<V min Therefore, the above conditions must be met when setting the resistance values ​​of R1 and R2, where VFB is the feedback voltage of the switching regulator chip U1.

[0036] In an optional embodiment, the low-voltage configuration circuit 4 includes: a first resistor R1 and a second resistor R2, wherein one end of the first resistor R1 is connected to the output voltage of the switching voltage regulator circuit 1, and the other end of the first resistor R1 is connected to the first input end of the switching circuit 2; one end of the second resistor R2 is connected to the feedback pin FB of the switching voltage regulator chip U1, and the other end of the second resistor R2 is grounded.

[0037] Specifically, the design of the low voltage configuration circuit 4 can also be realized by appropriate modification and deformation, such as transferring R2 to be connected in parallel between the FB pin and the ground. When the position of the second resistor R2 is changed, the parameter settings of the first resistor R1 and the second resistor R2 must also meet the above conditions, that is, to ensure that the output voltage V0 is less than the minimum startup voltage V of the LED. min .

[0038] In an optional embodiment, the low-voltage configuration circuit 4 includes: a Zener diode and a second resistor R2, wherein one end of the Zener diode is connected to the output voltage of the switching voltage regulator circuit 1, and the other end of the Zener diode is respectively connected to the first input end of the switching circuit 2 and one end of the second resistor R2, and the other end of the second resistor R2 is grounded.

[0039] Specifically, the design of the low-voltage configuration circuit 4 can also be realized by appropriate modification and deformation, such as replacing the first resistor R1 with a voltage-stabilizing diode. When the first resistor R1 is replaced with a voltage-stabilizing diode, the parameter settings of the voltage-stabilizing diode and the second resistor R2 also need to meet the above conditions, that is, to ensure that the output voltage V0 is less than the minimum starting voltage V of the LED. minThe specific structure of the normal working configuration circuit 3 is not limited here and can be set according to the application.

[0040] In an optional implementation, the switching circuit 2 is an integrated electronic switch or a switching circuit composed of discrete components.

[0041] Specifically, the switching circuit 2 can realize the switching function by an integrated electronic switch or a switching circuit composed of discrete components.

[0042] In an optional embodiment, if Figure 2 As shown, the switching circuit is an integrated electronic switch U2, that is, when the switching circuit 2 realizes the switching function through the integrated electronic switch U2, the enable pin EN of the integrated electronic switch U2 is connected to the external control signal, the first input pin B1 of the integrated electronic switch U2 is connected to the low voltage configuration circuit 4, the second input pin B2 of the integrated electronic switch U2 is connected to the normal working configuration circuit 3, and the output pin A of the integrated electronic switch U2 is connected to the feedback pin FB of the switching voltage regulator chip U1. The input voltage pin VCC of the integrated electronic switch U2 is connected to the external power supply, and the input voltage pin VCC is also grounded through the first capacitor C1. The ground pin GND of the integrated electronic switch U2 is grounded.

[0043] Specifically, when the LED needs to be turned off, the enable pin EN of the integrated electronic switch U2 is connected to a low-level signal, pin A is connected to pin B1, and disconnected from pin B2, that is, the low-voltage configuration circuit 4 is connected to the feedback pin FB of the switching regulator chip U1, and the normal working configuration circuit 3 path is disconnected, so that the switching regulator circuit 1 will be configured to a lower output voltage V0, that is, V0 = (R1 + R2) / R2 * VFB.

[0044] When the LED needs to be powered normally, the enable pin EN of the integrated electronic switch U2 is connected to a high-level signal, pin A and pin B2 are turned on, and B1 is turned off, that is, the normal working configuration circuit 3 is connected to the feedback pin FB of the switch voltage regulator chip U1, the low voltage configuration circuit 4 is turned off, and the feedback end of the switch voltage regulator circuit 1 is set with the parameters for normal operation of the LED. In an optional embodiment, the switching circuit 2, the normal working configuration circuit 3 and the low voltage configuration circuit 4 are not in the power loop, so the power consumption change generated is negligible relative to the power of the LED, that is, it does not affect the efficiency of the circuit.

[0045] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. An LED power supply circuit, characterized in that: include: Switching voltage regulator circuit, switching circuit, normal working configuration circuit and low voltage configuration circuit, wherein: The input end of the switching voltage stabilizing circuit is connected to an external DC power supply, the output of the switching voltage stabilizing circuit is connected to an LED, and the feedback end of the switching voltage stabilizing circuit is connected to the output end of the switching circuit; The first input terminal of the switching circuit is connected to the output terminal of the low-voltage configuration circuit, the second input terminal of the switching circuit is connected to the output terminal of the normal working configuration circuit, and the third input terminal of the switching circuit is connected to an external control signal. The low-voltage configuration circuit is used to configure the output voltage of the switching voltage regulator circuit to be lower than the start-up voltage of the LED.

2. The LED power supply circuit according to claim 1, characterized in that: The switching voltage regulator circuit includes a switching voltage regulator chip and a peripheral configuration circuit. The input voltage pin of the switching voltage regulator chip is connected to an external DC power supply. The switching voltage regulator chip is connected to an LED through the peripheral configuration circuit. The feedback pin of the switching voltage regulator chip is connected to the signal output end of the switching circuit.

3. The LED power supply circuit according to claim 2, characterized in that: The low voltage configuration circuit comprises: a first resistor and a second resistor, wherein: One end of the first resistor is connected to the output voltage of the switching voltage regulator circuit, the other end of the first resistor is respectively connected to the first input end of the switching circuit and one end of the second resistor, and the other end of the second resistor is grounded.

4. The LED power supply circuit according to claim 2, characterized in that: The low voltage configuration circuit comprises: a first resistor and a second resistor, wherein: One end of the first resistor is connected to the output voltage of the switching voltage regulator circuit, and the other end of the first resistor is connected to the first input end of the switching circuit; One end of the second resistor is connected to the feedback pin of the switching voltage regulator chip, and the other end of the second resistor is grounded.

5. The LED power supply circuit according to claim 2, characterized in that: The low voltage configuration circuit includes: a voltage stabilizing diode and a second resistor, wherein: One end of the voltage regulator diode is connected to the output voltage of the switching voltage regulator circuit, the other end of the voltage regulator diode is respectively connected to the first input end of the switching circuit and one end of the second resistor, and the other end of the second resistor is grounded.

6. The LED power supply circuit according to claim 2, characterized in that: The switching circuit is an integrated electronic switch or a switching circuit composed of discrete components.

7. The LED power supply circuit according to claim 2, characterized in that: The switching circuit is an integrated electronic switch, an enable pin of the integrated electronic switch is connected to an external control signal, a first input pin of the integrated electronic switch is connected to the low voltage configuration circuit, a second input pin of the integrated electronic switch is connected to the normal working configuration circuit, and an output pin of the integrated electronic switch is connected to a feedback pin of the switching voltage regulator chip.

8. The LED power supply circuit according to claim 2, characterized in that: The switch voltage stabilizing chip is a step-up voltage stabilizing chip or a step-down voltage stabilizing chip.

9. The LED power supply circuit according to claim 7, characterized in that: An input voltage pin of the integrated electronic switch is connected to an external power supply, and the input voltage pin is also grounded through a first capacitor.

10. The LED power supply circuit according to claim 9, characterized in that: A ground pin of the integrated electronic switch is grounded.

Images