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Load driving circuit and method

A technology of load drive and load circuit, which is applied in the electronic field, and can solve problems such as output capacitor Cout explosion, output voltage reduction, LED light brightness weakening, etc.

Active Publication Date: 2015-06-10
SILERGY SEMICON TECH (HANGZHOU) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] use figure 1 In the capacitive step-down LED drive circuit shown in the prior art, the output current, that is, the LED drive current, will vary greatly with the input capacitor Cin and the AC power supply Vac, resulting in poor brightness stability of the LED lamp;
[0007] On the other hand, since the LED drive current is related to the value of the input capacitor Cin, and the capacitance of the capacitor Cin gradually decreases after use, the LED drive current will also decrease as the value of the input capacitor Cin decreases. Small, causing the brightness of the LED lamp to weaken;
[0008] On the other hand, the existing capacitive step-down LED drive circuit design scheme will lead to a significant decrease in output voltage when the load increases, which affects the stability of the load LED lamp.
When the AC power supply is overvoltage, it may cause the explosion of the output capacitor Cout;
[0009] On the other hand, because there are no protection schemes such as surge limit, output short circuit protection, and output open circuit protection, there are many safety hazards in the existing capacitive step-down LED drive circuit.

Method used

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  • Load driving circuit and method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0118] figure 2 It is a schematic flowchart of a load driving method provided in this embodiment. The load in this implementation may be an LED circuit or other loads.

[0119] see image 3 As shown, the load driving method provided in this embodiment mainly uses the rectifier bridge circuit 301 provided in this embodiment to convert an externally input AC current into a DC current, and then supplies power to the load circuit 302 . Wherein, the rectifier bridge circuit 301 of this embodiment is composed of a first rectifier circuit and a second rectifier circuit bridged to each other, the first rectifier circuit is composed of a first diode D1 connected in series and the second controllable switch Q2, The second rectifier circuit is composed of a second diode D2 connected in series and a first controllable switch Q1. An input capacitor is connected in series at the input end of the rectifier bridge circuit 301 , and an output capacitor Cout is connected in parallel with th...

Embodiment 2

[0144] Figure 9 For a schematic flowchart of a load circuit driving method provided in this embodiment, see Figure 9 As shown, the method of this embodiment mainly includes the following processes:

[0145] Step 901: Monitor the AC input to the rectifier bridge circuit in real time.

[0146] The AC input VAB input to the rectifier bridge circuit 301 is monitored in real time.

[0147] This step is the same as Step 201 in Embodiment 1.

[0148] Step 902: Monitor the load circuit in real time to determine the current load driving electrical signal.

[0149] In this embodiment, it is possible, but not limited to, to sample the sense resistor Rsense connected in series with the load, obtain the current load driving feedback voltage signal Vsense by sampling the voltage of the sense resistor Rsense, and then drive the feedback voltage signal Vsense according to the load and the The impedance of the detection resistor Rsense is determined, and the load driving feedback voltage...

Embodiment 3

[0161] Figure 10 It is a schematic structural diagram of a load driving circuit provided in this embodiment. Referring to the figure, the driving circuit mainly includes: an input capacitor Cin, a rectifier bridge circuit 301, a control circuit 1001, and an output capacitor Cout.

[0162] Wherein, for the specific structure of the rectifier bridge circuit 301, see image 3 shown.

[0163] One end of the input capacitor Cin is connected to the positive end of the AC power Vac, the other end is connected to an input end A of the rectifier bridge circuit 301, and the other input end B of the rectifier bridge is connected to the negative end of the AC power Vac.

[0164] The bridge rectification circuit 301 is composed of a first rectification circuit and a second rectification circuit. The first rectifier circuit is composed of a first diode D1 and a second controllable switch Q2. The second rectifier circuit is composed of a second diode D2 and a first controllable switch Q...

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Abstract

The invention relates to the field of electronics, and discloses a load driving circuit and a method. The method includes: monitoring the AC input to the rectifier bridge circuit in real time; turning on the second controllable switch when the AC input is in the first state, and turning on the first and second controllable switches when the AC input is in the second and fourth states , when the AC input is in the third state, the first controllable switch is turned on; the anode of the first diode in the rectifier bridge circuit is connected to the anode of the AC input, the cathode is connected to the first end of the output capacitor, and the second controllable The first end of the control switch is connected to the negative pole of the AC input, the second end is connected to the second end of the output capacitor; the positive pole of the second diode is connected to the negative pole of the AC input, and the negative pole is connected to the first end of the output capacitor The first end of the second controllable switch is connected to the positive pole of the AC input, and the second end is connected to the second end of the output capacitor. Applying the technical solution is beneficial to improving the stability of the load circuit.

Description

technical field [0001] The present invention relates to the field of electronics, in particular to a load driving circuit and method. Background technique [0002] Light Emitting Diode (LED for short), as a kind of lighting circuit load, is widely used in landscape lighting, street lighting and backlighting of electronic products due to its characteristics of energy saving, high efficiency and low cost. [0003] At present, the design of general LED drive power supply is the input of mains power. Firstly, the mains power is rectified into DC, and then the DC is converted into step-down and step-down to provide the DC required by the load LED. [0004] figure 1 It is a functional block diagram of a capacitive step-down LED drive circuit using the prior art. Using the principle of capacitive current limiting, the AC power Vac is stepped down through the input capacitor Cin, and then input to the rectifier bridge 11 . The output capacitor Cout filters the DC voltage output b...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H05B37/02H05B44/00
CPCH02M1/32H02M7/217H05B45/37Y02B20/30H02M1/0009H02M1/0085H02M7/05Y02B20/40H02M7/06
Inventor 陈伟
Owner SILERGY SEMICON TECH (HANGZHOU) CO LTD