LED driving circuit with voltage regulation function and control method

Abstract

The present invention provides an LED driving circuit and a control method with a voltage regulation function. The LED driving circuit includes a control circuit and a voltage regulation circuit. The voltage regulation circuit includes a filter circuit, a detection circuit and a boost circuit. The voltage regulation circuit is electrically connected to the control circuit. The detection circuit is electrically connected to the filter circuit. The boost circuit is electrically connected to the filter circuit and the detection circuit. The control circuit is used to control the sub-circuit of the voltage regulation circuit. The detection circuit is used to detect the voltage level of the input voltage. The control circuit controls the boost circuit to perform staged boosting according to the voltage level of the input voltage detected by the detection circuit. The LED driving circuit provided by the present invention can perform staged boosting according to the voltage level of the detected input voltage, wherein the voltage regulation function is completed by staged boosting to increase the power conversion efficiency.

Description

Technical Field

[0001] The present invention relates to the field of electronic circuits, and in particular to an LED driving circuit with a voltage regulation function and a control method thereof. Background Art

[0002] With the development of high-power LED driver power supplies, due to the requirements of laws and regulations on harmonics, a PFC circuit is generally required in the front stage. In a non-isolated LED driver power supply with a Boost PFC boost in the front stage and a Buck step-down in the back stage, according to the traditional practice, the input AC voltage is first rectified and boosted to a DC voltage of about 400V, and then the voltage is reduced to a lower DC load voltage through the Buck step-down voltage in the back stage. In this way, when the network input is low, the conversion efficiency decreases due to the large step-up ratio of the front-stage PFC circuit. The back-stage Buck step-down circuit also reduces the conversion efficiency due to the large step-down ratio. The reduced efficiency means that the components generate high heat. Under the condition of limited heat dissipation conditions, the temperature rise of the components is difficult to meet the requirements. Summary of the invention

[0003] In view of the above problems, the present invention provides an LED driving circuit with voltage regulation function and a control method, which can effectively solve the problem of reduced efficiency.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] In a first aspect, the present invention provides an LED driving circuit with a voltage regulation function, the LED driving circuit comprising:

[0006] Control circuit;

[0007] A voltage regulating circuit, which is electrically connected to the control circuit, the control circuit is used to control the sub-circuit of the voltage regulating circuit, and the voltage regulating circuit includes:

[0008] A filter circuit, wherein the filter circuit is used to filter the input voltage;

[0009] a detection circuit, which is electrically connected to the filter circuit, and is used to detect the voltage level of the input voltage;

[0010] A boost circuit is electrically connected to the filter circuit and the detection circuit, wherein the control circuit controls the boost circuit to perform phased boosting according to the voltage level of the input voltage detected by the detection circuit.

[0011] As an optional implementation, when the voltage level of the input voltage detected by the detection circuit is higher than the preset voltage level, the control circuit controls the boost circuit to perform a first-stage boost on the voltage level of the input voltage and transmit the first output voltage; when the voltage level of the input voltage detected by the detection circuit is lower than the preset voltage level, the control circuit controls the boost circuit to perform a second-stage boost on the voltage level of the input voltage and transmit the second output voltage;

[0012] The voltage level of the first output voltage is higher than the voltage level of the second output voltage.

[0013] As an optional implementation, the detection circuit includes:

[0014] An RC filter circuit comprises a first end and a second end, wherein the second end of the RC filter circuit is grounded;

[0015] A Zener diode, comprising a first end, a second end and a third end, wherein the first end of the Zener diode is connected to the first end of the RC filter circuit, and the second end of the Zener diode is grounded;

[0016] A diode, comprising a first end and a second end, wherein the first end of the diode is connected to the third end of the Zener diode;

[0017] A resistor, comprising a first end and a second end, wherein the first end of the resistor is connected to the second end of the diode, and the second end of the resistor is connected to the equal pressure point;

[0018] Among them, when the voltage level of the input voltage detected by the detection circuit is higher than the preset voltage level, the line from the Zener diode to the isobaric point is in a conducting state, the isobaric point is at a high potential, and the first end of the Zener diode has a first voltage level; when the voltage level of the input voltage detected by the detection circuit is lower than the preset voltage level, the line from the Zener diode to the isobaric point is in a non-conducting state, the isobaric point is at a low potential, and the first end of the Zener diode has a second voltage level; the first voltage level of the first end of the Zener diode is higher than the second voltage level.

[0019] As an optional implementation, the boost circuit includes:

[0020] an inductor, which is electrically connected to the control circuit, and the inductor receives a boost signal transmitted by the control circuit to boost the input voltage;

[0021] The voltage divider circuit is electrically connected to the control circuit and the inductor. The voltage divider circuit is connected to the equal voltage point. The control circuit controls the boost circuit to perform step-by-step voltage boosting according to the voltage level of the equal voltage point.

[0022] As an optional implementation, the LED driving circuit further includes:

[0023] A rectifier circuit is electrically connected to the filter circuit, and the rectifier circuit rectifies the input voltage.

[0024] As an optional implementation, the LED driving circuit further includes:

[0025] The input circuit is electrically connected to the rectifier circuit, and the input circuit is used to transmit the input voltage to the rectifier circuit.

[0026] As an optional implementation, the LED driving circuit further includes:

[0027] An EMI circuit is electrically connected to the input circuit and the rectifier circuit, and the EMI circuit is used to protect the input voltage from electromagnetic interference.

[0028] In a second aspect, the present invention provides a control method, which is applied to an LED driving circuit with a voltage regulation function, wherein the LED driving circuit includes a control circuit and a voltage regulation circuit, wherein the voltage regulation circuit includes a filter circuit, a detection circuit and a boost circuit, wherein the control circuit is used to control a subcircuit of the voltage regulation circuit, and wherein the control method includes:

[0029] Setting the filter circuit to filter the input voltage;

[0030] Setting the detection circuit to detect the voltage level of the input voltage;

[0031] The control circuit is configured to control the boost circuit to perform step-by-step boosting according to the voltage level of the input voltage detected by the detection circuit.

[0032] As an optional implementation, when the voltage level of the input voltage detected by the detection circuit is higher than the preset voltage level, the control circuit controls the boost circuit to perform a first-stage boost on the voltage level of the input voltage and transmit the first output voltage; when the voltage level of the input voltage detected by the detection circuit is lower than the preset voltage level, the control circuit controls the boost circuit to perform a second-stage boost on the voltage level of the input voltage and transmit the second output voltage;

[0033] The voltage level of the first output voltage is higher than the voltage level of the second output voltage.

[0034] As an optional implementation manner, the detection circuit includes a Zener diode, and the control method includes:

[0035] When the voltage level of the input voltage detected by the detection circuit is higher than the preset voltage level, the line from the Zener diode to the isovoltage point is in a conducting state, the isovoltage point is at a high potential, and the first end of the Zener diode has a first voltage level; when the voltage level of the input voltage detected by the detection circuit is lower than the preset voltage level, the line from the Zener diode to the isovoltage point is in a non-conducting state, the isovoltage point is at a low potential, and the first end of the Zener diode has a second voltage level; the first voltage level of the first end of the Zener diode is higher than the second voltage level.

[0036] According to the present invention, an LED driving circuit and a control method with a voltage regulation function are provided. The LED driving circuit includes a control circuit and a voltage regulation circuit. The voltage regulation circuit includes a filter circuit, a detection circuit and a boost circuit. The voltage regulation circuit is electrically connected to the control circuit. The detection circuit is electrically connected to the filter circuit. The boost circuit is electrically connected to the filter circuit and the detection circuit. The control circuit is used to control the sub-circuit of the voltage regulation circuit. The detection circuit is used to detect the voltage level of the input voltage. The control circuit controls the boost circuit to perform stage-by-stage boosting according to the voltage level of the input voltage detected by the detection circuit. The LED driving circuit provided by the present invention can perform stage-by-stage boosting according to the voltage level of the detected input voltage, wherein the voltage regulation function is completed by stage-by-stage boosting to increase power conversion efficiency. In addition, when the voltage level of the detected input voltage is higher / lower than the preset voltage level, the first / second output voltage is transmitted after multi-stage boosting to complete multi-stage power supply and increase flexibility. In addition, the voltage level of the isobaric point is controlled by the clamping function of the Zener diode to increase the accuracy of controlling the output voltage. Generally speaking, at low grid input (which can be regarded as the voltage level of the input voltage being lower than the preset voltage level), the PFC (which can be regarded as the LED driving circuit) output is only increased to a relatively low voltage, such as 250V. In this way, the conversion efficiency of the front-stage PFC boost circuit can be improved, and the conversion efficiency of the rear-stage buck circuit can also be improved. In the end, the overall conversion efficiency will be relatively high. Compared with the traditional design of increasing to a fixed voltage point, the efficiency is improved by 1%-2% at low grid input. The application of the LED driving circuit of the present invention in high-power LED power supplies has great significance.

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope of the present invention.

[0039] Figure 1 is a schematic block diagram of an LED driving circuit with a voltage regulation function provided in Embodiment 1 of the present invention;

[0040] Figure 2 is a partial circuit diagram of a detection circuit provided in Embodiment 2 of the present invention;

[0041] Figure 3 is a partial circuit diagram of a boost circuit provided by Embodiment 3 of the present invention;

[0042] Figure 4 It is a method flow chart of the control method provided in Example 4 of the present invention.

[0043] Description of main component symbols:

[0044] 100-led driving circuit;

[0045] 110- control circuit;

[0046] 120-voltage regulating circuit;

[0047] 121-filter circuit;

[0048] 122- detection circuit;

[0049] 123-boost circuit;

[0050] RC-RC filter circuit;

[0051] Z-Zener diode;

[0052] D-diode;

[0053] R-resistance;

[0054] L-inductor;

[0055] FC-voltage divider circuit;

[0056] EV - isobaric point. DETAILED DESCRIPTION

[0057] The embodiments of the present invention are described in detail below, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions.

[0058] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0059] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0060] Example 1

[0061] See also Figure 1 , Figure 1 1 is a schematic block diagram of an LED driving circuit with a voltage regulation function (hereinafter referred to as “LED driving circuit”) provided in Embodiment 1 of the present invention. The LED driving circuit 100 includes a control circuit 110 and a voltage regulation circuit 120. Specifically, the voltage regulation circuit 120 includes a filter circuit 121, a detection circuit 122 and a boost circuit 123.

[0062] The voltage regulating circuit 120 is electrically connected to the control circuit 110. For example, the control circuit 110 may be a central processor unit (CPU), including a plurality of pins, each of which is used to send and receive signals, and control the LED driving circuit 100 to send an output signal to control its dimming function. In other words, the control circuit 110 is used to control the sub-circuit of the voltage regulating circuit 120. The sub-circuit of the voltage regulating circuit 120 includes at least a filter circuit 121, a detection circuit 122, and a boost circuit 123.

[0063] The filter circuit 121 is used to filter the input voltage. For example, the filter circuit 121 can filter out extremely high frequency and extremely low frequency input voltages. The detection circuit 122 is electrically connected to the filter circuit 121. The detection circuit 122 is used to detect the voltage level of the input voltage. For example, the voltage level of the input voltage can include at least a high grid voltage level (220V) and a low grid voltage level (110V). The voltage regulating circuit 120 adjusts the output signal according to the detected high grid voltage level or low grid voltage level to control the dimming function of the LED driving circuit 100.

[0064] The boost circuit 123 is electrically connected to the filter circuit 121 and the detection circuit 122, wherein the control circuit 110 controls the boost circuit 123 to perform a staged boost according to the voltage level of the input voltage detected by the detection circuit 122. For example, when the voltage level of the input voltage detected by the detection circuit 122 is a low grid voltage level, the control circuit 110 controls the boost circuit 123 to perform a first staged boost; when the voltage level of the input voltage detected by the detection circuit 122 is a high grid voltage level, the control circuit 110 controls the boost circuit 123 to perform a second staged boost. It is known from experiments that this can improve the power conversion efficiency of the low grid by at least 1%-2%, and relatively increase the light output rate. In another embodiment, at least one staged boost can be interpolated between the first staged boost and the second staged boost to increase the accuracy of adjusting the output voltage. The present invention is not limited to two staged boosts.

[0065] In one embodiment, when the voltage level of the input voltage detected by the detection circuit 122 is higher than the preset voltage level, the control circuit 110 controls the boost circuit 123 to perform a first-stage boost on the voltage level of the input voltage and transmit the first output voltage. For example, when the voltage level of the input voltage detected by the detection circuit 122 is higher than 160V (regarded as the preset voltage level), the control circuit 110 controls the boost circuit 123 to perform a first-stage boost on the voltage level of the input voltage and transmit an output voltage of 410V (regarded as the first output voltage).

[0066] In one embodiment, when the voltage level of the input voltage detected by the detection circuit 122 is lower than the preset voltage level, the control circuit 110 controls the boost circuit 123 to perform a second-stage boost on the voltage level of the input voltage and transmit the second output voltage. The voltage level of the first output voltage is higher than the voltage level of the second output voltage. For example, when the voltage level of the input voltage detected by the detection circuit 122 is lower than 160V, the control circuit 110 controls the boost circuit 123 to perform a second-stage boost on the voltage level of the input voltage and transmit an output voltage of 250V (regarded as the second output voltage).

[0067] Example 2

[0068] See also Figure 2 , Figure 2It is a partial circuit diagram of the detection circuit provided in Example 2 of the present invention. The detection circuit 122 includes an RC filter circuit RC, a Zener diode Z, a diode D and a resistor R. The RC filter circuit RC includes a first end and a second end, and the second end of the RC filter circuit RC is grounded. The Zener diode Z includes a first end, a second end and a third end. The first end of the Zener diode Z is connected to the first end of the RC filter circuit RC. The second end of the Zener diode Z is grounded. The Zener diode Z has a clamping function to provide a fixed voltage drop and increase the accuracy of controlling the output voltage. The diode D includes a first end and a second end. The first end of the diode D is connected to the third end of the Zener diode Z. The resistor R includes a first end and a second end. The first end of the resistor R is connected to the second end of the diode D. The second end of the resistor R is connected to the equal voltage point EV.

[0069] In one embodiment, when the voltage level of the input voltage detected by the detection circuit is higher than the preset voltage level (e.g., 2.5V), the line from the Zener diode Z to the equal voltage point EV is in a conducting state, the equal voltage point EV is at a high potential, and the first end of the Zener diode Z has a first voltage level. For example, the Zener diode Z is in a conducting state, the Zener diode Z provides a clamping voltage to maintain the equal voltage point EV at a high potential, and at this time, the voltage level of the first end of the Zener diode Z is 2.7V (regarded as the first voltage level).

[0070] When the voltage level of the input voltage detected by the detection circuit is lower than the preset voltage level, the line from the Zener diode Z to the equal voltage point EV is in a non-conducting state, and the equal voltage point EV is at a low potential. The first end of the Zener diode Z has a second voltage level (e.g., 2.3V). The first voltage level of the first end of the Zener diode Z is higher than the second voltage level.

[0071] Example 3

[0072] See also Figure 3 , Figure 3 1 is a partial circuit diagram of a boost circuit provided in Embodiment 3 of the present invention. The boost circuit 123 includes an inductor L and a voltage divider circuit FC.

[0073] The inductor L is electrically connected to the control circuit. The inductor L receives the boost signal transmitted by the control circuit to boost the input voltage. The voltage divider circuit FC is electrically connected to the control circuit and the inductor L. The voltage divider circuit FC is connected to the equal voltage point EV. The control circuit controls the boost circuit to perform staged boosting according to the voltage level of the equal voltage point EV. The equal voltage point EV of the boost circuit 123 is the same as the equal voltage point EV of the detection circuit 122 of Example 2. Therefore, the control circuit can control the boost circuit to perform staged boosting according to the equal voltage point EV generated by the input voltage.

[0074] In one embodiment, the LED driving circuit further includes an input circuit, an EMI circuit, a rectifier circuit and a start-up circuit. The rectifier circuit is electrically connected to the filter circuit, and the rectifier circuit rectifies the input voltage. The input circuit is used to transmit the input voltage to the rectifier circuit. The EMI circuit is electrically connected to the input circuit and the rectifier circuit, and the EMI circuit is used to protect the input voltage from electromagnetic interference. The start-up circuit is electrically connected to the filter circuit, the detection circuit and the boost circuit 123.

[0075] Example 4

[0076] Figure 4 : is a method flow chart of the control method provided by Example 4 of the present invention. The control method is applied to an LED driving circuit with a voltage regulation function. The LED driving circuit includes a control circuit and a voltage regulation circuit, and the voltage regulation circuit includes a filter circuit, a detection circuit and a boost circuit. The control circuit is used to control the sub-circuit of the voltage regulation circuit. The control method includes:

[0077] S401, setting a filter circuit to filter the input voltage;

[0078] S403, setting the detection circuit to detect the voltage level of the input voltage;

[0079] S405, setting the control circuit to control the boost circuit to perform phased boosting according to the voltage level of the input voltage detected by the detection circuit.

[0080] Preferably, when the voltage level of the input voltage detected by the detection circuit is higher than the preset voltage level, the control circuit controls the boost circuit to perform a first-stage boost on the voltage level of the input voltage and transmit the first output voltage; when the voltage level of the input voltage detected by the detection circuit is lower than the preset voltage level, the control circuit controls the boost circuit to perform a second-stage boost on the voltage level of the input voltage and transmit the second output voltage;

[0081] The voltage level of the first output voltage is higher than the voltage level of the second output voltage.

[0082] Preferably, the detection circuit includes a Zener diode, and the control method includes:

[0083] When the voltage level of the input voltage detected by the detection circuit is higher than the preset voltage level, the circuit from the Zener diode to the isovoltage point is in a conducting state, the isovoltage point is at a high potential, and the first end of the Zener diode has a first voltage level; when the voltage level of the input voltage detected by the detection circuit is lower than the preset voltage level, the circuit from the Zener diode to the isovoltage point is in a non-conducting state, the isovoltage point is at a low potential, and the first end of the Zener diode has a second voltage level; the first voltage level of the first end of the Zener diode is higher than the second voltage level.

[0084] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described above in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0085] Therefore, the above detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. An LED driving circuit with voltage regulation function, characterized in that: The LED driving circuit comprises: Control circuit; A voltage regulating circuit, which is electrically connected to the control circuit, the control circuit is used to control the sub-circuit of the voltage regulating circuit, and the voltage regulating circuit includes: A filter circuit, wherein the filter circuit is used to filter the input voltage; a detection circuit, which is electrically connected to the filter circuit, and is used to detect the voltage level of the input voltage; A boost circuit, which is electrically connected to the filter circuit and the detection circuit, wherein the control circuit controls the boost circuit to perform step-by-step boosting according to the voltage level of the input voltage detected by the detection circuit; When the voltage level of the input voltage detected by the detection circuit is higher than the preset voltage level, the control circuit controls the boost circuit to perform a first-stage boost on the voltage level of the input voltage and transmit a first output voltage; when the voltage level of the input voltage detected by the detection circuit is lower than the preset voltage level, the control circuit controls the boost circuit to perform a second-stage boost on the voltage level of the input voltage and transmit a second output voltage; The voltage level of the first output voltage is higher than the voltage level of the second output voltage.

2. The LED driving circuit according to claim 1, characterized in that: The detection circuit comprises: An RC filter circuit comprises a first end and a second end, wherein the second end of the RC filter circuit is grounded; A Zener diode, comprising a first end, a second end and a third end, wherein the first end of the Zener diode is connected to the first end of the RC filter circuit, and the second end of the Zener diode is grounded; A diode, comprising a first end and a second end, wherein the first end of the diode is connected to the third end of the Zener diode; A resistor, comprising a first end and a second end, wherein the first end of the resistor is connected to the second end of the diode, and the second end of the resistor is connected to the equal pressure point; Among them, when the voltage level of the input voltage detected by the detection circuit is higher than the preset voltage level, the line from the Zener diode to the equal voltage point is in a conductive state, the equal voltage point is at a high potential, and the first end of the Zener diode has a first voltage level; when the voltage level of the input voltage detected by the detection circuit is lower than the preset voltage level, the line from the Zener diode to the equal voltage point is in a non-conductive state, the equal voltage point is at a low potential, and the first end of the Zener diode has a second voltage level; the first voltage level of the first end of the Zener diode is higher than the second voltage level.

3. The LED driving circuit according to claim 2, characterized in that: The boost circuit comprises: an inductor, which is electrically connected to the control circuit, and the inductor receives a boost signal transmitted by the control circuit to boost the input voltage; The voltage divider circuit is electrically connected to the control circuit and the inductor. The voltage divider circuit is connected to the equal voltage point. The control circuit controls the boost circuit to perform step-by-step voltage boosting according to the voltage level of the equal voltage point.

4. The LED driving circuit according to claim 1, characterized in that: The LED driving circuit also includes: A rectifier circuit is electrically connected to the filter circuit, and the rectifier circuit rectifies the input voltage.

5. The LED driving circuit according to claim 4, characterized in that: The LED driving circuit also includes: The input circuit is electrically connected to the rectifier circuit, and the input circuit is used to transmit the input voltage to the rectifier circuit.

6. The LED driving circuit according to claim 5, characterized in that: The LED driving circuit also includes: An EMI circuit is electrically connected to the input circuit and the rectifier circuit, and the EMI circuit is used to protect the input voltage from electromagnetic interference.

7. A control method, characterized in that: The control method is applied to an LED driving circuit with a voltage regulation function, wherein the LED driving circuit includes a control circuit and a voltage regulation circuit, wherein the voltage regulation circuit includes a filter circuit, a detection circuit and a boost circuit, wherein the control circuit is used to control a subcircuit of the voltage regulation circuit, and wherein the control method includes: Setting the filter circuit to filter the input voltage; Setting the detection circuit to detect the voltage level of the input voltage; The control circuit is configured to control the boost circuit to perform step-by-step boosting according to the voltage level of the input voltage detected by the detection circuit; When the voltage level of the input voltage detected by the detection circuit is higher than the preset voltage level, the control circuit controls the boost circuit to perform a first-stage boost on the voltage level of the input voltage and transmit a first output voltage; when the voltage level of the input voltage detected by the detection circuit is lower than the preset voltage level, the control circuit controls the boost circuit to perform a second-stage boost on the voltage level of the input voltage and transmit a second output voltage; The voltage level of the first output voltage is higher than the voltage level of the second output voltage.

8. The control method according to claim 7, characterized in that: The detection circuit includes a Zener diode, and the control method includes: When the voltage level of the input voltage detected by the detection circuit is higher than the preset voltage level, the circuit from the Zener diode to the equal voltage point is in a conducting state, the equal voltage point is at a high potential, and the first end of the Zener diode has a first voltage level; when the voltage level of the input voltage detected by the detection circuit is lower than the preset voltage level, the circuit from the Zener diode to the equal voltage point is in a non-conducting state, the equal voltage point is at a low potential, and the first end of the Zener diode has a second voltage level; the first voltage level of the first end of the Zener diode is higher than the second voltage level.

Images