Hybrid multi-output power supply and regulating method thereof

Abstract

The invention provides a hybrid multi-output power supply and a regulating method thereof. The hybrid multi-output power supply is used for generating a constant-voltage output to drive a load and generating a constant-current output to drive a light-emitting diode (LED) and comprises a primary voltage regulating circuit, a secondary voltage regulating circuit and a driving circuit. Only a primary voltage converting circuit is required to acquire driving voltage which is required to support a sequent LED, so that an implementing circuit and a control scheme of the hybrid multi-output power supply are relatively simple, the structure of the circuit is simplified, and the implementing cost is reduced; and furthermore, first regulating voltage can be regulated according to change of the current of the LED, so that the numerical value of the first regulating voltage can be always kept the minimum voltage value capable of driving all the circuits of the LED along with the change of the current of the LED, and the power converting efficiency is improved to the maximum extent.

Description

technical field [0001] The present invention relates to the field of electronic technology, and more specifically, relates to a power supply with multiple outputs and an adjusting method thereof applied to an LED device, a driving circuit and a driving method thereof. Background technique [0002] With the continuous innovation of liquid crystal display technology and the increase of application products, LED backlight has developed rapidly due to the advantages of energy saving, environmental protection and light and thin volume. However, since the brightness of an LED lamp is related to the light output intensity parameter, it is directly proportional to its current and forward voltage drop, and changes with temperature. Therefore, the driving of LED requires a constant current power supply to ensure the safety of LED use and achieve ideal luminous intensity at the same time. It can be seen that it is very important to choose the correct LED driver. Without a good LED dr...

AI Technical Summary

Problems solved by technology

[0007] By combining the above figure 1 From the description of the technical solution of the existing LED driving power supply, it can be seen that in order to provide driving voltage for the LED and controller systems at all levels, three sets of secondary windings and three sets of corresponding diodes, capacitors, and EMI electromagnetic interference circuits are required. The rectifier circuit composed of the suppression circuit has a very complicated implementation circuit, a large number of components, a complicated circuit control scheme, and a correspondingly high implementation cost.

[0008] In addition, the first output V out1 In order to provide sufficient driving voltage for the LED load, it is necessary to go through a step-up voltage regulator for step-up operation again. Such two-level voltage conversion obviously increases the conversion loss and reduces the working efficiency.

[0009] Moreover, the output power of the driving circuit part for realizing the constant current output of the LED is generally greater than the output power of the driving circuit part for realizing the constant voltage output, so the conversion efficiency of the LED driving power supply is relatively low

At the same time, the feedback of the driving circuit part that realizes the constant voltage output is usually transmitted to the controller 102 using optocouplers (IC1A and IC1B), so the transient response is relatively slow

In order to achieve a better adjustment accuracy of the output voltage, more output capacitors are required, which also leads to an increase in cost

Images