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CN-224233871-U - Control circuit for sectional type LED driving and sectional type LED driving circuit

CN224233871UCN 224233871 UCN224233871 UCN 224233871UCN-224233871-U

Abstract

The utility model provides a sectional type LED driving circuit and a control circuit thereof. The control circuit comprises N first subtracting circuits, N second subtracting circuits and N operational amplifying circuits, wherein each first subtracting circuit receives voltage detection signals of two adjacent LED node voltages and provides compensation signals, each second subtracting circuit receives reference signals and one compensation signal and provides compensated reference signals, each operational amplifying circuit receives the compensated reference signals and current detection signals, the output end of each operational amplifying circuit is coupled with a corresponding transistor, the transistor is coupled between the corresponding LED module and the first end of the current detection resistor, the second end of the current detection resistor is grounded, and the first end of the current detection resistor provides current detection signals. The sectional type LED driving circuit and the control circuit thereof provided by the utility model can eliminate the unbalanced phenomenon of compensation in the control of the sectional type LED lamp and realize self-adaptive power compensation.

Inventors

  • WANG SHUGUANG

Assignees

  • 厦门市必易微电子技术有限公司

Dates

Publication Date
20260512
Application Date
20250328

Claims (7)

  1. 1. A control circuit for segmented LED driving, the control circuit comprising: N first subtracting circuits, wherein each first subtracting circuit receives voltage detection signals representing node voltages of two adjacent LED nodes in N LED modules and provides a compensation signal, and N is an integer greater than or equal to 2; N second subtracting circuits, each of which receives the reference signal and a corresponding compensation signal to provide a compensated reference signal, and The first input end of each operational amplification circuit receives a corresponding compensated reference signal, the second input end of the operational amplification circuit receives a current detection signal, the output end of the operational amplification circuit is coupled with a corresponding transistor, the transistor is coupled between the corresponding LED module and the first end of the current detection resistor, the second end of the current detection resistor is grounded, and the first end of the current detection resistor provides the current detection signal.
  2. 2. A sectional type LED driving circuit, which comprises a first LED driving circuit and a second LED driving circuit, the LED driving circuit is characterized by comprising: The first output end of the rectifying circuit provides direct current bus voltage, and the second output end of the rectifying circuit is coupled with reference ground; N LED modules connected in series, wherein anodes of the plurality of LED modules connected in series are coupled to a first output end of the rectifying circuit, N being an integer greater than or equal to 2; A plurality of transistors, a first end of each transistor is coupled with the cathode of each LED module, a second end of each transistor is grounded through a current detection resistor, and The control circuit comprises a compensation signal generation unit, a compensation unit and N control units, wherein the compensation signal generation unit generates N compensation signals, the compensation signals are in direct proportion to lamp voltages at two ends of corresponding LED modules, the compensation unit receives N reference signals and N compensation signals, each compensation signal compensates the corresponding reference signal to obtain a compensated reference signal, the output end of each control unit is coupled with the control end of the corresponding transistor, and each control unit receives the corresponding compensated reference signal and controls the corresponding LED module.
  3. 3. The LED driving circuit of claim 2, wherein the control unit comprises an operational amplifier circuit, a first input terminal of the operational amplifier circuit is coupled to the compensated reference signal, a second input terminal of the operational amplifier circuit receives the current detection signal, wherein the current detection signal is a voltage difference across the current detection resistor, and an output terminal of the operational amplifier circuit is coupled to the control terminal of the corresponding transistor.
  4. 4. The LED driving circuit of claim 2, wherein the control circuit further comprises a voltage detection circuit for detecting node voltages on n+1 LED nodes corresponding to the N LED modules to obtain n+1 node detection signals, wherein: the compensation signal generation unit comprises N first subtracting circuits, and each first subtracting circuit subtracts two node detection signals of adjacent LED nodes to obtain a compensation signal; The compensation unit comprises N second subtracting circuits, and the reference signal subtracts the compensation signal to form a compensated reference signal.
  5. 5. A control circuit for segmented LED driving, the control circuit comprising: The input end of the compensation signal generation unit is coupled with the LED module to obtain node voltage of the corresponding LED module, the output end of the compensation signal generation unit provides a plurality of compensation signals, and each compensation signal is proportional to the lamp voltage of the two ends of the corresponding LED module, wherein N is an integer greater than or equal to 2; A compensation unit having an input coupled to the output of the compensation signal generation unit for receiving the N compensation signals, each compensation signal compensating the corresponding reference signal to obtain a compensated reference signal, and And N control units, wherein each control unit receives a corresponding compensated reference signal and a corresponding current detection signal, the output end of each control unit is coupled with the control end of the corresponding transistor and used for controlling the corresponding LED module, and the current detection signal is the voltage difference between two ends of the current detection resistor.
  6. 6. The control circuit of claim 5, wherein the control unit comprises an operational amplifier circuit, a first input terminal of the operational amplifier circuit is coupled to the compensated reference signal, a second input terminal of the operational amplifier circuit receives the current detection signal, and an output terminal of the operational amplifier circuit is coupled to the control terminal of the corresponding transistor.
  7. 7. The control circuit of claim 5, wherein the control circuit further comprises a voltage detection circuit that detects node voltages of n+1 LED nodes in the N LED modules to obtain n+1 node detection signals, wherein: The compensation signal generation unit comprises N first subtracting circuits, wherein the first subtracting circuits subtract the node detection signals of adjacent nodes to obtain compensation signals proportional to the lamp voltages at the two ends of the corresponding LEDs; the compensation unit comprises N second subtracting circuits, and the second subtracting circuits subtract the corresponding compensation signals from the corresponding reference signals to form compensated reference signals.

Description

Control circuit for sectional type LED driving and sectional type LED driving circuit Technical Field The utility model relates to the field of electronics, in particular to a sectional type LED driving circuit and a control circuit thereof. Background In order to improve the power factor and efficiency of linear LED (light emitting diode) driving, a segment driving mode is generally adopted, and as shown in fig. 1, a typical two-segment linear constant current LED application system is formed by connecting two LED modules in series, when the input voltage Vbus gradually increases to be greater than the lamp voltage of LED1, the channel of transistor Q1 is conductive, the channel of transistor Q2 is non-conductive, the LED1 module is turned on, and LED2 is turned off. When the input voltage Vbus is greater than the sum of the lamp voltages of the LEDs 1 and 2, the transistor Q2 is turned on, the LEDs 1 and 2 are turned on at the same time, and the threshold signal Vref2 for turning on the transistor Q2 is generally set to be greater than the threshold signal Vref1 for turning on the transistor Q1, then the transistor Q1 is turned off under the closed loop control of the first operational amplifier (operational amplifier 1). When Vref1 and Vref2 are unchanged, the voltage drop and output current of each LED module are fixed, and when the input voltage Vbus increases, the on time of the LED increases, and the voltage applied to the transistors Q1 and Q2 increases, resulting in an increase in input power. In order to keep the input power unchanged with the input voltage Vbus, it is often necessary to compensate the input power. In view of this, there is a need to provide a new architecture or control method in order to solve at least some of the above problems. Disclosure of utility model At least in view of one or more problems in the background art, the present utility model provides a segmented LED driving circuit and a control circuit thereof. According to one aspect of the utility model, a control circuit for a segmented LED drive is provided, the control circuit comprising N first subtracting circuits, wherein each first subtracting circuit receives a voltage detection signal representing the voltage of two adjacent LED nodes in N LED modules, providing a compensation signal, wherein N is an integer greater than or equal to 2, N second subtracting circuits, wherein each second subtracting circuit receives a reference signal and a corresponding compensation signal, providing a compensated reference signal, and N operational amplifying circuits, wherein a first input terminal of each operational amplifying circuit receives a corresponding compensated reference signal, a second input terminal of the operational amplifying circuit receives a current detection signal, an output terminal of the operational amplifying circuit is coupled to a corresponding transistor, the transistor is coupled between the corresponding LED module and a first terminal of a current detection resistor, the second terminal of the current detection resistor is grounded, and the first terminal of the current detection resistor provides the current detection signal. According to another aspect of the utility model, an LED driving circuit is provided, which comprises a rectifying circuit, wherein two input ends of the rectifying circuit are coupled with two ports of a mains supply, a first output end of the rectifying circuit provides a direct current bus voltage, a second output end of the rectifying circuit is coupled with a reference ground, N LED modules are connected in series, anodes of the LED modules are coupled with the first output end of the rectifying circuit in series, N is an integer greater than or equal to 2, a first end of each transistor is respectively coupled with a cathode of each LED module, a second end of each transistor is grounded through a current detection resistor, and a control circuit comprises a compensation signal generating unit, a compensation unit and N control units, the compensation signal generating unit generates N compensation signals, the compensation signals are in proportion to lamp voltages at two ends of the corresponding LED modules, the compensation unit receives N reference signals and N compensation signals, each compensation signal compensates the corresponding reference signals to obtain compensated reference signals, the output end of each control unit is coupled with a control end of the corresponding transistor, and each control unit receives the corresponding compensation signals to carry out the corresponding LED modules. Optionally, the control unit includes an operational amplifier circuit, a first input terminal of the operational amplifier circuit is coupled to the compensated reference signal, a second input terminal of the operational amplifier circuit receives the current detection signal, wherein the current detection signal is a voltage difference on the current detection