Switching buck type LED constant-current control circuit, system and method

A technology of constant current control circuit and LED circuit, applied in the direction of energy-saving control technology, electrical components, etc., can solve the problem of low output current accuracy of LED control loop, and achieve small LED output current, good load regulation rate, good linear regulation rate Effect

Pending Publication Date: 2021-04-23
CRM ICBG (WUXI) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a switch step-down LED constant current control circuit, system and method for solving the problem of low output current accuracy of the LED control loop in the prior art

Method used

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  • Switching buck type LED constant-current control circuit, system and method
  • Switching buck type LED constant-current control circuit, system and method
  • Switching buck type LED constant-current control circuit, system and method

Examples

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Embodiment 1

[0088] Such as image 3 As shown, this embodiment provides a switch step-down LED constant current control circuit 11, and the switch step-down LED constant current control circuit 11 includes:

[0089] An average current comparison module 111 , a peak current comparison module 112 , an adaptive clock generation module 113 , a PWM logic control module 114 and a driving module 115 .

[0090] Such as image 3 As shown, the average current comparison module 111 receives the current detection sampling signal Vcs of the step-down LED circuit, and is used to compare the current detection sampling signal Vcs with the average reference Vref1 and obtain a first comparison result Cp1.

[0091] Specifically, in this embodiment, the non-inverting input terminal of the average current comparison module 111 is connected to the current detection sampling signal Vcs, and the inverting input terminal is connected to the average reference Vref1; when the current detection sampling signal Vcs i...

Embodiment 2

[0106] like Figure 7As shown, this embodiment provides a switching step-down LED constant current control circuit 11, and the difference from Embodiment 1 is that this embodiment also adds other functional modules.

[0107] As an implementation of the present invention, the switching step-down LED constant current control circuit 11 further includes a short circuit protection module 116 . The short circuit protection module 116 receives the current detection sampling signal Vcs, compares the current detection sampling signal Vcs with the short circuit protection reference Vref3, and outputs a short circuit protection signal Short. When the current detection sampling signal Vcs is greater than the short-circuit protection reference Vref3, the power switch is turned off, wherein the short-circuit protection reference Vref3 is greater than the peak reference Vref2. In this embodiment, the non-inverting input terminal of the short-circuit protection module 116 is connected to th...

Embodiment 3

[0110] like Figure 8 As shown, this embodiment provides a switch step-down LED constant current control system 1, the switch step-down LED constant current control system 1 includes: a switch step-down LED constant current control circuit 11 and a step-down LED circuit 12.

[0111] like Figure 8 As shown, the switching step-down LED constant current control circuit 11 receives the current detection sampling signal of the step-down LED circuit 12, and outputs the driving signal of the step-down LED circuit.

[0112] Specifically, the circuit structure and working principle of the switching step-down LED constant current control circuit 11 are the same as those of the switching step-down LED constant current control circuit in Embodiment 1 or Embodiment 2, and will not be repeated here.

[0113] like Figure 8 As shown, the step-down LED circuit 12 obtains a stable output based on the control of the switching step-down LED constant current control circuit 11 .

[0114] Spe...

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Abstract

The invention provides a switching buck type LED constant-current control circuit, system and method. The switching buck type LED constant-current control circuit comprises an average current comparison module for comparing a current detection sampling signal with an average reference, a peak current comparison module which is used for comparing the current detection sampling signal with a peak reference, a self-adaptive clock generation module which is used for generating a turn-off ending signal; a PWM logic control module which is used for generating a logic control signal; and a driving module. When a current detection sampling signal rises to the average reference and exceeds the average reference, a power switch tube is switched on within the same time, and then the power switch tube is switched off; and if the current detection sampling signal is greater than a peak value benchmark, the power switch tube is turned off in advance, a turn-off reference signal is adjusted at the same time; and when a preset charging signal is greater than the turn-off reference signal, the power switch tube is turned on again, and a next new PWM period is started. According to the switching buck type LED constant-current control circuit, system and method of the invention, small current ripples and high-precision output current can be realized; and the linear adjustment rate and the load adjustment rate are good.

Description

technical field [0001] The invention relates to the field of LED constant current control, in particular to a switch step-down LED constant current control circuit, system and method. Background technique [0002] The traditional switching step-down LED controller adopts a peak current detection method with a fixed clock frequency. Due to the influence of the inductor ripple, the current accuracy of the output LED light-emitting unit is poor; and when the external power supply and load change, the inductor value needs to be adjusted to Ensure that the output inductor current works in continuous conduction mode, and the selection of the inductor value affects the accuracy and ripple of the LED current. [0003] In the traditional LED control scheme, after the power supply VDD is powered on, the current detection sampling signal is compared with the reference voltage to generate a charging end signal. The charging end signal and the clock signal are controlled by PWM logic to ...

Claims

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Application Information

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IPC IPC(8): H05B45/345H05B45/36H05B45/325
CPCY02B20/40
Inventor 谢飞尤勇卢圣晟李国成
Owner CRM ICBG (WUXI) CO LTD
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