TWM430783U - LED driving circuit - Google Patents

Description

M430783 V. New Description: [New Technology Field] The present invention relates to the field of circuits, and more particularly to a light-emitting diode (LED) driving circuit. [Prior Art]

Lu Currently, LED technology has matured. Due to the high luminous efficiency and long service life of LEDs, it is imperative to replace traditional incandescent lamps in the field of lighting. However, in the switching power supply schemes used in existing low-power LEDs such as lamp cups and lamps, there are generally disadvantages such as low power factor, low current accuracy, and large printed board size. The low power factor leads to problems such as large harmonic energy in the power grid, low energy utilization, and large transmission loss, which will increase the burden on the grid; on the other hand, low current accuracy will affect the service life of the LED. [New Content] In view of one or more of the problems described above, the present invention provides a novel LED driver circuit. The LED driving circuit according to the novel embodiment includes an AC power input rectification and electromagnetic interference filter circuit, a buck structure switching circuit, a control circuit, and a driving circuit. The voltage-reduction structure switching circuit includes a step-down inductor, a switching metal oxide semiconductor field effect transistor, a freewheeling body, a wave capacitor, a current sampling resistor, and an output dummy load. In the buck structure switch power =, one end of the freewheeling diode is connected to the switch metal oxide semiconductor field effect transistor and the current sampling resistor, and the other end is grounded. The control circuit comprises a pulse width modulation control chip, and the pulse width modulation control chip comprises a crystal feedback wheel input pin, a loop compensation setting pin, a multiplier input pin, a peak current detection input pin, and a zero current detection input connection. Foot, wafer reference ground, wafer drive output pin, and chip power input pin. The chip feedback input pin is connected to the metal oxide layer semiconductor field effect transistor, the current sampling capacitor, and the 嵫2 pole body through a resistor or directly to the step-down junction=off circuit towel. The chip power input pin is connected to the differential mode filter inductor and the filter capacitor in the AC power input rectification and electrical interference filter circuit through a resistor, and is connected to the output end of the LED drive circuit through the Zener diode and the diode 3 M430783 body, and Through the zero current inspector to pick up the power _ LED (four) circuit is connected. According to the handle, the coffee_circuit has high discrimination and low cost, and is compatible with various safety silk counties. L again, [Embodiment]

"The features and exemplary implementations of various aspects of the present invention will be described in detail below. The following covers a lot of H details, and the reading provides a comprehensive turn for this new rhyme. But for the secret: it is obvious that 'this new type can be needed In the specific details, the details are as follows: The following description of the embodiments is merely intended to provide a clearer understanding of the present invention by showing the present invention. The present disclosure is not limited to any of the following. It has been set up to cover the modification, replacement and improvement of related elements or components without departing from the spirit of the present invention. The purpose of the present invention is to overcome the current technical bottleneck and provide a high power factor, high current accuracy, And a light-emitting diode (LED) driving circuit of a step-down structure. Fig. 1 is a circuit diagram of an LED driving circuit according to an embodiment of the present invention. As shown in Fig. 1, the implementation of the _LED_includes money Power supply (AQ input rectification and electromagnetic interference (EMI) filter circuit 1, buck structure switching circuit 2, control circuit 3, and drive circuit 4.

In the embodiment shown in Fig. 1, the AC input rectification and EMI filter circuit includes: fuse (FUSE), varistor (MOV), common mode filter inductor LI, X capacitor CX1 and CX2, rectifier bridge BD1, and difference Mode filter inductor L2 and filter capacitor ci. In the embodiment shown in FIG. 1, the buck structure switching circuit 2 includes: a buck inductor, a switch metal oxide semiconductor field effect transistor (MOSFET) Q1, a freewheeling diode D1, a chopper capacitor C2, and a current. The sampling resistor R7 and the output dummy load R6. In the embodiment shown in Fig. 1, the control circuit 3 includes a pulse width modulation (PWM) control chip U1 as a main component of the control circuit 3 and a necessary external auxiliary component, which includes a total of eight functional connections. The feet are: 4 M430783 FB pin: the chip feedback input pin, the ii over resistor R8 is connected with the current sampling resistor R7, the M0SFET transistor _, and the freewheeling diode in the buck structure switching circuit 2, and Connected to the chip ground through capacitor C6; COMP pin: ring compensation set pin, through Wei Rong C4 touch the chip ground; mult pin: multiplier input pin, through the resistor R3, R4 and ac rectification input and EMU The differential mode ship inductor L2 in the wave circuit 1 is connected to the slave capacitor ,, and is connected to the ground of the wafer through the resistor R5 and the capacitor C5; CS pin: the buzzer current detecting input pin, through the resistor and the buck structure switching circuit The current sampling resistor R7 and the MOSFET electric crystal in 2 are connected with the freewheeling diode m;

ZCD pin ·· zero current detection input pin, connected to the output through the resistor and the output; GND pin: the chip reference ground, and the current sampling resistor R7 and the buck inductor L3 node in the buck structure switching circuit 2 GD pin: The chip drive output pin is connected to the MOSFET transistor Q1 in the buck structure switching circuit 2 through the driving circuit 4; VCC pin: the chip power input pin, through the resistor long R and R2 The differential mode filter inductor L2 and the filter capacitor C1 in the Ac input rectification and EM filter circuit 1 are connected, and are connected to the output terminal Vout through the Zener diode Z1 and the diode 〇2, and are connected to the chip ground through the capacitor C3. .

In the embodiment shown in Fig. 1, the connection of the drive circuit 4 (the circuit between the two points C and D in the figure) can be any one of the four connections shown in Fig. 2. The LED driving circuit according to the embodiment of the present invention has characteristics of high power factor, high current accuracy, and low cost, and conforms to various safety specification standards. The present invention has been described above with reference to the specific embodiments of the present invention, but those skilled in the art will understand that various modifications, combinations and changes can be made to the specific embodiments without departing from the appended claims or equivalents Limit the spirit and scope of this new type. In addition, any signal arrows in the figures should be considered as merely illustrative and not restrictive, unless otherwise specifically indicated. When the term is foreseen to be unclear, the component or combination It will also be considered that it has been recorded. [Simplified description of the drawings] The present invention will be described below with reference to the accompanying drawings, in which: the specific application of the present invention can be better understood. The circuit diagram of the LED driving circuit of the embodiment; and Fig. 2 shows the four connections of the driving circuit 4 shown in Fig. 1. [Main component symbol description] 1 AC power supply (AC) input rectification and electromagnetic interference (ΕΜΙ Filter circuit 2 Buck structure Switch circuit 3 Control circuit 4 Drive circuit BD1 Rectifier bridge a, C2 Filter capacitor C3, C4, C5, C6 Capacitance C) G ' CX2 X Capacitor D1 Freewheeling diode D2 Diode FUSE Fuse LI common mode filter inductor L2 differential mode filter inductor L3 step-down inductor MOV varistor Q1 transistor R1, R2, R3, R4, R5 resistor R6 output dummy load R7 current sampling resistor R8, R9, R10, R11 Resistor U1 Pulse Width Modulation (PWM) Control Wafer 6 M430783

Vout output Z1 regulator

Claims (1)

M430783 Sixth, the scope of application for patents _ input = _ circuit of the input end of the 'buck junction contact power failure wave circuit output is connected, the output is connected 'light = Γ Hi power input rectification and electromagnetic interference filtering The circuit is respectively connected to the r-connection of the switching circuit, the input end of the light-following circuit and the output end of the control circuit are connected to the metal-oxide-oxide semiconductor field effect transistor of the structure of the falling structure_' The voltage circuit includes the outline, the switch metal oxide semiconductor field effect electric B body, the life diode, the wave capacitance, the current sampling resistance, and the output dummy load, the basin fan diode - The end is connected to the switch metal oxide semiconductor field effect transistor and the current sampling resistor, and the other end is grounded, the _ terminal of the buck inductor is connected to the current sampling resistor, and the other end is connected to the filter capacitor and The output dummy load is connected; the filter capacitor is connected in parallel with the wheeled dummy load, one end is opposite to the dust-reducing inductor, and the other end is grounded. 2. The LED driving circuit of claim 1, wherein the control circuit comprises a pulse width modulation control chip, the pulse width modulation control chip comprising a wafer feedback input pin, a loop a compensation setting pin, a multiplier input pin, a peak current detecting input pin, a zero current detecting input pin, a reference grounding 'wafer driving output pin, and a wafer power input pin, wherein the chip feedback input is connected The pin is connected to the switching metal oxide semiconductor field effect transistor, the current sampling resistor, and the freewheeling diode in the buck structure switching circuit through a resistor. 3. The LED driving circuit of claim 2, wherein the chip power input pin passes through a resistor and a differential mode filter inductor and filter in the AC power input rectification and electromagnetic interference filter circuit. The capacitors are connected, connected to the output end of the LED driving circuit through a Zener diode and a diode, and connected to the ground of the wafer through a capacitor. 4. The LED driving circuit of claim 1, wherein the control circuit comprises a pulse width modulation control wafer, and the pulse width modulation control wafer comprises a wafer readback M430783. ---~ . C Λ ; -X . - 1% S. 13 Si I year w;'.",; ^ 1 Input pin, loop compensation setting pin, multiplier input pin, peak current detection a zero current detecting input pin, a chip reference ground, a chip driving output pin, and a chip power input pin, wherein the peak current detecting input pin passes through a resistor or directly with the buck structure switching circuit The switching metal oxide semiconductor field effect t crystal, the current sampling resistor, and the freewheeling diode are connected. 5. The illuminating diode driving circuit according to claim 2, wherein the zero current detecting input pin is connected to an output end of the illuminating diode driving circuit through a resistor. Μ43Ό.783 广执¢¢-:3]