CN209824089U - LCC circuit and LEDset2.0 settable current circuit - Google Patents

Abstract

The utility model discloses a LCC circuit adds LEDset2.0 settable current circuit, include: the circuit comprises an alternating current-direct current pre-stage filter rectifying circuit, an LCC half-bridge resonant cavity circuit, an IC control circuit, a secondary rectifier filtering circuit, an LEDset circuit and a load; the alternating current-direct current pre-stage filter rectification circuit is electrically connected with the LCC half-bridge resonant cavity circuit; the LCC half-bridge resonant cavity circuit is electrically connected with the IC control circuit and the secondary rectifying and filtering circuit; the IC control circuit is electrically connected with the LEDset circuit; the secondary rectifying and filtering circuit is connected with a load. This utility model has the following advantages: (1) the accuracy is as follows: the LEDset circuit is matched with the optocoupler to transmit signals, and as the number of heating devices is small, the influence of temperature is reduced, and the signals can be transmitted more accurately; (2) stability: ripple waves are output when low load voltage and large current are output, and the efficiency is kept in a required range; (3) the simplicity is as follows: only one control IC is used, the LEDset circuit is matched with the optocoupler to realize the setting of the output current, the number of peripheral devices is small, and the design is simple.

Description

LCC circuit and LEDset2.0 settable current circuit

Technical Field

The utility model relates to a dimming circuit technical field, more specifically says so and relates to a LCC circuit adds LEDset2.0 can set for the electric current circuit.

Background

The existing general single-stage PFC plus ripple plus LED set circuit has: high PF value, simple circuit, no large electrolytic capacitor, high power density and small size.

The prior art has the following disadvantages: the single-stage PFC plus ripple-removal plus LEDset circuit 100HZ has large power frequency ripple, is not suitable for low-voltage and wide-load current output, has large stress on an MOS tube, has the stroboscopic problem when being used as an LED driving power supply because lightning stroke surge of an input-free electrolytic capacitor is difficult to pass and the retention time is short, and has the large requirement on the capacity of an output electrolytic capacitor and the cost increase because the ripple-removal circuit is required to be added for realizing low ripple of the single-stage PFC circuit.

Therefore, a need exists in the art to provide a settable current line for LCC line plus ledset2.0 that has the characteristics of accurate transmission, stable voltage, simple design, and low cost.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model provides a LCC circuit adds LEDset2.0 can set for the electric current circuit with characteristics such as transmission is accurate, voltage is stable, the design is succinct, with low costs.

In order to achieve the above object, the utility model provides a following technical scheme:

an LCC circuit plus ledset2.0 settable current circuit, comprising: the circuit comprises an alternating current-direct current pre-stage filter rectifying circuit, an LCC half-bridge resonant cavity circuit, an IC control circuit, a secondary rectifier filtering circuit, an LEDset circuit and a load; the alternating current-direct current pre-stage filter rectification circuit is electrically connected with the LCC half-bridge resonant cavity circuit; the LCC half-bridge resonant cavity circuit is electrically connected with the IC control circuit and the secondary rectifying and filtering circuit; the IC control circuit is electrically connected with the LEDset circuit; the secondary rectifying and filtering circuit is connected with a load.

Preferably, in the LCC line plus ledsett 2.0 settable current line, the ac-dc pre-filter rectifying circuit is a filter circuit formed by an ac input, L and N connections passing through a fuse F1, an NTC thermistor and a varistor VR1 connected in parallel, a regulation capacitor C1 and a common mode inductor L2, a differential mode inductor L1, and a regulation capacitor C2.

Preferably, in the LCC circuit plus ledset2.0 settable current circuit, the LCC half-bridge resonant cavity circuit is composed of a resonant inductor L4, a transformer T2, a driving transformer T1, two triodes Q1 and Q2, a resonant capacitor C4, a large energy storage filter electrolytic capacitor C5, and a secondary resonant capacitor C19.

Preferably, in the LCC line plus ledsett 2.0 settable current line, the IC control circuit mainly comprises a 1-pin VFB for detecting the output voltage, a 2-pin DIM for receiving the dimming signal, a 3-pin TX1 and a 4-pin TX2 for controlling the driving of the driving transformer T1 and the on and off of the transistors Q1 and Q2, a 5-pin RC for detecting and adjusting the starting frequency, a 6-pin VDD for the power supply pin of the IC, a 7-pin GND for the ground pin of the IC, and an 8-pin CS for detecting the output current.

Preferably, in the LCC circuit plus ledsett 2.0 settable current circuit, the secondary rectifying and smoothing circuit is composed of two diodes D10, D11 and an electrolytic capacitor C18; in the circuit, R24 is a discharge resistor.

Preferably, in the LCC line plus LEDset2.0 settable current line, the LEDset circuit mainly comprises a rectifying filter D12, R43, C24, linear voltage regulators R31, Q3, ZD1, a control chip U3, an LEDset circuit ZD3, Q5, R39, R40, R41, an optical coupler, a zener diode ZD4, voltage dividing resistors R27, R28, RC integrators R26, C21; wherein, D12 is rectifier diode, Q3 is PNP triode, ZD1 is a zener diode of 18V.

Through foretell technical scheme, compare with prior art, the utility model has the following advantage:

(1) the accuracy is as follows: different from a single-stage PFC plus ripple removal plus LEDset matched with an optical coupler for setting current, an LEDset circuit and the optical coupler are devices greatly influenced by temperature, and the designed output current precision is poor due to the influence of the temperature and the stability of a ripple removal circuit; the circuit transmits signals by matching an LEDset circuit with an optocoupler, and can transmit signals more accurately due to less heating devices and less temperature influence;

(2) stability: the current setting circuit is different from a single-stage PFC (power factor correction) circuit which is added with ripple removal and LEDset and matched with an optical coupler to set current, the ripple removal chip is limited by the lowest working voltage when the ripple removal circuit is in low-load voltage, the ripple removal chip does not work when the ripple removal circuit is lower than the lowest working voltage of the chip, the output ripple is very large, and the ripple removal MOS loss is increased. In addition, a large output current is not suitable for a ripple removing circuit, because the large output current means that an output electrolytic capacitor needs to be enlarged, the capacity of the electrolytic capacitor cannot be infinitely increased (limited by practical use and cost), and the ripple voltage is increased, so that the loss on a ripple removing MOS is increased, the temperature and the efficiency cannot meet the requirements. The circuit outputs ripples when the load voltage is low and the heavy current is output, and the efficiency is kept in the required range;

the circuit has the advantages that a plurality of peripheral devices are arranged for setting the current by the aid of the single-stage PFC, the ripple wave removal, the LEDset and the optical coupler, the circuit is complex in design, only one control IC is used for the circuit, the LEDset circuit is matched with the optical coupler to set the output current, the number of the peripheral devices is small, and the design is simple.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a schematic diagram of the dimming circuit of the present invention.

Fig. 2 is a functional module frame diagram of the dimming circuit of the present invention.

Fig. 3 is a diagram of the filtering and rectifying circuit for converting the preceding-stage ac to the dc of the present invention.

Fig. 4 is a circuit diagram of the LCC half-bridge resonant cavity of the present invention.

Fig. 5 is a block diagram of the IC control circuit according to the present invention.

Fig. 6 is a circuit diagram of the secondary rectifying and filtering circuit of the present invention.

The attached figure of fig. 7 is the LEDset2.0 control circuit diagram of the present invention.

Wherein: 1-alternating current-direct current preceding stage filter rectification circuit; 2-LCC half-bridge resonant cavity circuit; 3-IC control circuit; 4-a secondary rectifying and filtering circuit; 5-LEDset circuit; 6-load.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

The embodiment of the utility model discloses LCC circuit adds LEDset2.0 can set for the electric current circuit with characteristics such as transmission is accurate, voltage stability, design are succinct, with low costs.

Referring to fig. 1-7, for the present invention discloses an LCC circuit and ledset2.0 settable current circuit, which specifically includes:

the circuit comprises an alternating current-direct current (AC-DC) preceding stage filter rectifying circuit 1, an LCC half-bridge resonant cavity circuit 2, an IC control circuit 3, a secondary stage rectifier filtering circuit 4, an LEDset circuit 5 and a load 6; the alternating current-direct current preceding stage filter rectification circuit 1 is electrically connected with the LCC half-bridge resonant cavity circuit 2; the LCC half-bridge resonant cavity circuit 2 is electrically connected with the IC control circuit 3 and the secondary rectifying and filtering circuit 4; the IC control circuit 3 is electrically connected with an LEDset circuit 5; the secondary rectifying and filtering circuit 4 is connected with a load 6.

The utility model discloses what mainly solve is that it replaces single-stage PFC with the ripple to add the LEDset line way and can not do wide voltage, wide load current output and low ripple to use the LCC circuit to add LEDset2.0 to set for the electric current circuit.

In order to further optimize the technical scheme, the alternating current-direct current pre-stage filter rectification circuit is a filter circuit which is composed of an alternating current input, an L and N connection which pass through a fuse F1, an NTC thermistor and a piezoresistor VR1 in parallel, a safety capacitor C1, a common mode inductor L2, a differential mode inductor L1 and a safety capacitor C2.

In order to further optimize the technical scheme, the LCC half-bridge resonant cavity circuit consists of a resonant inductor L4, a transformer T2(NP and NS respectively represent the primary and secondary of the transformer, the number of turns is N), a driving transformer T1, two triodes Q1 and Q2, a resonant capacitor C4, a large energy storage and filtering electrolytic capacitor C5 and a secondary resonant capacitor C19; in the circuit, the T1 is controlled by chips 3 and 4 to drive the Q1 and the Q2 to be switched on and off, the Q1 and the Q2 are two triodes which are alternately switched on and off, the T2 is used for storing energy by a transformer and transferring the energy to a secondary side, and the D6, the D7 and the C8 are half-bridge absorption circuits.

In order to further optimize the technical scheme, the IC control circuit mainly comprises a 1-pin VFB for detecting output voltage, a 2-pin DIM for receiving a dimming signal, a 3-pin TX1 and a 4-pin TX2 for controlling the driving of a driving transformer T1 and the on and off of a Q1 and a Q2 triode, a 5-pin RC for detecting and adjusting the starting frequency, a 6-pin VDD for a power supply pin of the IC, a 7-pin GND for a grounding pin of the IC and an 8-pin CS for detecting the output current; wherein, when the 1-pin VFB works: the secondary voltage is coupled to the primary auxiliary winding through a transformer, rectified and filtered through a sorting diode D8 and a chip capacitor C11, and then fed back to a 1 pin VFB after being subjected to voltage division through R16 and R17 resistors; the signal of the 2-pin DIM is a voltage signal of 0.3-1.3V, when the voltage is 0.3V, the voltage on the DIM pin is compared with the voltage on the 8-pin CS and then amplified to the IC internal regulation control duty ratio, and at the moment, the output current reaches the lowest state; when the dimming signal is 1.3V, the voltage on the DIM pin is compared with the voltage on the 8-pin CS and then amplified to the IC internal regulation control duty ratio, and at the moment, the output current reaches a full-load output state; the working principle of the 8-pin CS is as follows: when the detection voltage of the CS pin reaches a certain value, the detection voltage is fed back to the IC internal control Q1, and the Q2 is switched on and off.

In order to further optimize the technical scheme, the secondary rectifying and filtering circuit is composed of two diodes D10 and D11 and an electrolytic capacitor C18; r24 in the circuit is a discharge resistor.

In order to further optimize the technical scheme, the LEDset circuit mainly comprises rectifying filters D12, R43 and C24, linear voltage stabilizers R31, Q3 and ZD1, a control chip U3, an LEDset circuit ZD3, Q5, R39, R40 and R41, an optical coupler, a voltage stabilizer diode ZD4, voltage dividing resistors R27 and R28, RC integral R26 and RC 21; wherein, D12 is rectifier diode, Q3 is PNP triode, ZD1 is a zener diode of 18V.

In order to further optimize the technical scheme, the LEDset circuit has the working principle that: when the LEDset resistor is changed, different currents are obtained after Q3, the currents pass through two resistors which are connected in parallel to the ground through R40 and R41 to generate voltage drop, the voltage is the 5-pin DIMI voltage of U3, U3 outputs the corresponding duty ratio (3% -99%) from 6-pin DIMO through internal detection of the 5-pin DIMI voltage, and the output duty ratio changes the current of the primary side of the optical coupler, so that the opening degree of a triode on the secondary side of the optical coupler is changed; the auxiliary winding of the transformer is subjected to filtering rectification by D14, R42 and C28, then is subjected to voltage stabilization by a ZD4 voltage stabilizing diode, is subjected to voltage division by R27 and R28 after voltage stabilization, obtains a voltage of 1.3V, and then is supplied to a 2-pin DIM of U1 through an RC integral formed by R26 and C21; the voltage after voltage division is changed due to different opening degrees of the optical coupler, 2-pin DIM voltage (U12-pin DIM voltage range: 0.13-1.3V) of U1 is compared and amplified with CS and FB-pin voltage, then the voltage is processed in an IC, and the switching frequency of Q1 and Q2 is driven and controlled to be constant with the current of the primary side, so that LEDset set current is realized.

In order to further optimize the technical scheme, a pin 1 VFB of the IC control circuit is mainly used for detecting output voltage, secondary voltage is coupled to a primary auxiliary winding through a transformer, and is rectified and filtered by a sorting diode D8 and a chip capacitor C11, and then is fed back to a VFB pin of the IC after being subjected to voltage division through resistors R16 and R17; the 2-pin DIM mainly receives a dimming signal which is a voltage signal of 0.3-1.3V, when the voltage is 0.3V, the voltage on the DIM pin is compared with the voltage on the 8-pin CS and then amplified to the IC internal regulation control duty ratio, and at the moment, the output current reaches the lowest state; when the dimming signal is 1.3V, the voltage on the DIM pin is compared with the voltage on the 8-pin CS and then amplified to the IC internal regulation control duty ratio, and at the moment, the output current reaches a full-load output state; the 3, 4-pin TX1 and TX2 mainly control a driving transformer T1 to drive the on and off of a Q1 triode and a Q2 triode; the 5-pin RC mainly detects and adjusts the frequency during starting; the 6 pin VDD is mainly a power supply pin of the IC; the 7 pin GND is an IC grounding pin; the 8-pin CS mainly detects output current, and when the detection voltage of the CS pin reaches a certain value, the output current is fed back to the IC internal control Q1 and Q2 to be switched on and off.

In order to further optimize the technical scheme, the working principle of the LCC is as follows: at the time of T0-T1, when HV voltage is established, T1 drives Q1 to conduct NP which is supplied to T2 through L4, C4 charges and stores energy, NP of T2 is coupled with NS, NP voltage is clamped by NS, clamping voltage is N × NS voltage, meanwhile, resonance capacitor C19 is charged and supplied to an output end, and T1 is controlled to turn off Q1 when CS pin detection of a control chip U1 reaches threshold voltage; at the time of T1-T2, when Q1 is completely turned off, Q2 is driven to be turned on, at the time, a resonant capacitor reversely charges T2 and L4, primary NP of T2 is demagnetized and induces reverse voltage, NP of T2 is coupled with NS, NP voltage is clamped by NS, clamping voltage is N NS voltage, the resonant capacitor C19 is charged and then supplied with an output end, when the CS pin of a control chip U1 detects that threshold voltage is reached, T1 is controlled to turn off Q2, and the actions at the time of T0-T1 are repeated again after Q2 is completely turned off; the LCC changes the output gain by changing the switching frequency, so that the maximum frequency change is not too large when the output current is minimum (the frequency of the LLC changes along with the load); the principle of the LCC for realizing LEDset is that the voltage of a 5-pin DIMI of U3 is changed by changing the resistance of the LEDset, a U3 outputs a corresponding duty ratio (3% -99%) from a 6-pin DIMO through internally detecting the voltage of the 5-pin DIMI, the voltage of a 2-pin DIM of a primary side U1 (the voltage range of the U12-pin DIM is 0.13-1.3V) is compared and amplified with the voltage of a CS pin and an FB pin, the internal processing is carried out on the IC, and the switching frequency of Q1 and Q2 is driven and controlled to be constant to the current of the primary side so as to realize LEDset set current.

In order to further optimize the technical scheme, the LEDset circuit has the working principle that: a T2A winding is added on the secondary side of the transformer, and the secondary side of the transformer is rectified and filtered through D12 and C24, and a basically stable and unchangeable voltage is obtained through simple linear voltage stabilization consisting of R31, Q3 and ZD1 to supply power to U3 and an optical coupler and LEDset; different currents are obtained by changing an LEDset resistor through Q3, the currents are connected to the ground through two parallel resistors R40 and R41 to generate voltage drop, the voltage is the 5-pin DIMI voltage of U3, U3 outputs the corresponding duty ratio (3% -99%) from 6-pin DIMO through internally detecting the 5-pin DIMI voltage, and the output duty ratio changes the current of the primary side of the optical coupler, so that the opening degree of a triode on the secondary side of the optical coupler is changed; the auxiliary winding of the transformer is subjected to filtering rectification by D14, R42 and C28, then is subjected to voltage stabilization by a ZD4 voltage stabilizing diode, is subjected to voltage division by R27 and R28 after voltage stabilization, obtains a voltage of 1.3V, and then is supplied to a 2-pin DIM of U1 through an RC integral formed by R26 and C21; the voltage after voltage division is changed due to different opening degrees of the optical coupler, 2-pin DIM voltage (U12-pin DIM voltage range: 0.13-1.3V) of U1 is compared and amplified with CS and FB-pin voltage, then the voltage is processed in an IC, and the switching frequency of Q1 and Q2 is driven and controlled to be constant with the current of the primary side, so that LEDset set current is realized. The principle process of the LEDset part is mainly characterized in that the voltage of a DIMI pin is changed by changing LEDset resistance, different voltage DIMO pins of the DIMI pin output different duty ratios, and the voltage of the pin U1 on the primary side is changed by transmitting the voltage to the primary side through an optical coupler, so that LEDset current is set.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (6)

1. An LCC circuit plus ledset2.0 settable current circuit, comprising: the circuit comprises an alternating current-direct current pre-stage filter rectifying circuit, an LCC half-bridge resonant cavity circuit, an IC control circuit, a secondary rectifier filtering circuit, an LEDset circuit and a load; the alternating current-direct current pre-stage filter rectification circuit is electrically connected with the LCC half-bridge resonant cavity circuit; the LCC half-bridge resonant cavity circuit is electrically connected with the IC control circuit and the secondary rectifying and filtering circuit; the IC control circuit is electrically connected with the LEDset circuit; the secondary rectifying and filtering circuit is connected with a load.

2. The LCC circuit plus LEDset2.0 settable current circuit of claim 1, wherein said AC-DC pre-filter rectifying circuit is a filter circuit comprising an AC input, L, N connections through a fuse F1, an NTC thermistor connected in parallel with a voltage dependent resistor VR1, a safety capacitor C1 and a common mode inductor L2, a differential mode inductor L1, and a safety capacitor C2.

3. The LCC circuit plus LEDset2.0 settable current line according to claim 2, wherein said LCC half-bridge resonant tank circuit is composed of a resonant inductor L4, a transformer T2, a driving transformer T1, two transistors Q1, Q2, a resonant capacitor C4, a large energy storage filter electrolytic capacitor C5 and a secondary resonant capacitor C19.

4. The LCC circuit plus LEDset2.0 settable current circuit according to claim 3, wherein the IC control circuit is mainly composed of a 1-pin VFB for detecting the output voltage, a 2-pin DIM for receiving the dimming signal, a 3-pin TX1 for controlling the driving of the driving transformer T1 and the switching of the Q1, Q2 transistors, a 4-pin TX2, a 5-pin RC for detecting and adjusting the frequency at startup, a 6-pin VDD for the power supply pin of the IC, a 7-pin GND for the grounding pin of the IC, and an 8-pin CS for detecting the output current.

5. The LCC circuit plus LEDset2.0 settable current circuit according to claim 4, wherein said secondary rectifying-filtering circuit is comprised of two diodes D10, D11 and an electrolytic capacitor C18; r24 in the circuit is a discharge resistor.

6. The LCC circuit plus LEDset2.0 settable current circuit according to claim 5, wherein the LEDset circuit mainly comprises rectifying filters D12, R43, C24, linear voltage stabilizers R31, Q3, ZD1, a control chip U3, an LEDset circuit ZD3, Q5, R39, R40, R41, an optical coupler, a voltage stabilizer diode ZD4, voltage dividing resistors R27, R28, RC integral R26 and C21; wherein, D12 is rectifier diode, Q3 is PNP triode, ZD1 is a zener diode of 18V.