CN214627429U - Non-isolated AC-DC constant current driver and LED lighting equipment - Google Patents
Non-isolated AC-DC constant current driver and LED lighting equipment Download PDFInfo
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Abstract
The application discloses a non-isolated AC-DC constant current driver and LED lighting equipment, wherein the non-isolated AC-DC constant current driver comprises a non-isolated PFC main converter and a DC-DC auxiliary converter; the non-isolated PFC main converter comprises a main input port, a PFC power conversion unit, a voltage converter and a main output port, wherein the voltage converter comprises a main winding and an auxiliary winding; the DC-DC auxiliary converter comprises an auxiliary input port and an auxiliary output port; the input end of the PFC power conversion unit is connected with the main input port, and the output end of the PFC power conversion unit is connected with one end of the main winding; the other end of the main winding is connected with the main output port; the auxiliary winding is connected with the auxiliary input port; the auxiliary output port and the main output port are connected in series. In this application, only a part of electric energy provides to the load through the two-stage transform, compares in the condition that full power all passes through the two-stage transform, has reduced the consumption, has improved whole conversion efficiency.
Description
Technical Field
The present disclosure relates to circuit technologies, and particularly to a non-isolated AC-DC (alternating current-direct current) constant current driver and a Light Emitting Diode (LED) lighting device.
Background
The LED is applied to lighting devices, and has the advantages of wide color gamut, high brightness, large viewing angle, low power consumption, long service life, and the like, so that the LED lighting devices are widely applied to various lighting display fields. Such as the common stock exchange and financial information display, airport flight dynamic information display, port and station passenger guidance information display, stadium information display, road traffic information display, electric power scheduling, vehicle dynamic tracking and other scheduling command center information display, market shopping center and other service fields business propaganda information display, advertising media products and the like.
Generally, a driving power source is required to drive an LED lighting device in normal operation, the driving power source is generally a constant current driver, and when the power of the LED lighting device is relatively high, the constant current driver needs to have a Power Factor Correction (PFC) function.
The current constant current driver comprises a single stage and a plurality of stages. Although the single-stage constant-current driver has a simple structure and low cost, the single-stage constant-current driver cannot simultaneously give consideration to input high power factor and output low ripple, and even the power tube still has overhigh voltage or current stress. Therefore, a multi-stage constant current driver is generally selected in the industry, wherein two stages are common, and in the two-stage constant current driver, a front-stage PFC converter is used for adjusting an input power factor and balancing input and output energy; and the rear-stage direct current (DC-DC) auxiliary converter is used for adjusting the output voltage and reducing the output ripple voltage or current.
However, the ac output of the two-stage constant current driver can obtain the total output after the two-stage full power conversion, and the power consumption is relatively high, resulting in low overall conversion rate.
SUMMERY OF THE UTILITY MODEL
The application aims to provide a non-isolated AC-DC constant current driver and an LED lighting device, which are low in power consumption and high in overall conversion efficiency.
A first aspect of the present application provides a non-isolated AC-DC constant current driver, including: the non-isolated PFC main converter and the DC-DC auxiliary converter; the non-isolated PFC main converter comprises a main input port, a PFC power conversion unit, a voltage converter and a main output port, wherein the voltage converter comprises a main winding and an auxiliary winding; the DC-DC auxiliary converter comprises an auxiliary input port and an auxiliary output port; the input end of the PFC power conversion unit is connected with the main input port, and the output end of the PFC power conversion unit is connected with one end of the main winding; the other end of the main winding is connected with the main output port; the auxiliary winding is connected with the auxiliary input port; the auxiliary output port is connected with the main output port in series; the PFC power conversion unit is used for: converting alternating current input through the main input port into direct current and transmitting the direct current to the voltage converter; the voltage converter is used for: transmitting the received direct current to a main output port through a main winding, and transmitting the received direct current to a DC-DC auxiliary converter through an auxiliary winding and an auxiliary input port; the DC-DC auxiliary converter is used for: and transmitting the received direct current to an auxiliary output port after processing.
In one embodiment, the non-isolated AC-DC constant current driver further comprises: a PFC controller; the non-isolated PFC main converter further comprises: a main power switch tube; the main power switch tube is connected between the output end of the PFC power conversion unit and one end of the main winding; or the main power switch tube is connected with the other end of the main winding; the PFC controller comprises a main feedback port, a first main acquisition port, a main control port, a main reference voltage port and a main reference sawtooth wave signal port; the main feedback port is connected with the main output port, the first main acquisition port is connected with the auxiliary winding, and the main control port is connected with the control end of the main power switch tube; the PFC controller is used for: the main voltage of a main output port is received through a main feedback port, the voltage of an auxiliary winding is received through a first main acquisition port, the main reference voltage is received through a main reference voltage port, and a main reference sawtooth wave signal is received through a main reference sawtooth wave signal port; and then the main voltage of the main output port, the voltage of the auxiliary winding, the main reference voltage and the main reference sawtooth wave signal are utilized to control the on and off of the main power switch tube.
In one embodiment, the PFC controller further comprises a second primary acquisition port; the second main acquisition port is connected with the main power switch tube; the PFC controller is further configured to: and receiving the voltage of the main power switch tube through the second main acquisition port.
In one embodiment, the non-isolated PFC main converter further comprises: a first main collecting part and a second main collecting part; the first main acquisition part is connected between the second main acquisition port and the main power switch tube, and the second main acquisition part is connected between the first main acquisition port and the auxiliary winding; the second main acquisition port acquires the voltage of the main power switch tube through the first main acquisition part, and the first main acquisition port acquires the voltage of the auxiliary winding through the second main acquisition part.
In one embodiment, a PFC controller includes a main reference voltage source, a main reference sawtooth signal source, a first main comparator, a second main comparator, a third main comparator, and a flip-flop; the trigger is provided with an S port, a Q port and an R port; the negative input end of the first main comparator is connected with the main feedback port, the positive input end of the first main comparator is connected with a main reference voltage source through a main reference voltage port, and the output end of the first main comparator is connected with the positive input end of the second main comparator; the negative input end of the second main comparator is connected with the second main acquisition port, and the output end of the second main comparator is connected with the positive input end of the third main comparator; the negative input end of the third main comparator is connected with the main reference sawtooth wave signal source through a main reference sawtooth wave signal port, and the output end of the third main comparator is connected with the R port; the Q port is connected with the main control port, and the S port is connected with the first main acquisition port.
In one embodiment, the non-isolated AC-DC constant current driver further comprises: a DC-DC controller; the DC-DC auxiliary converter further includes: an auxiliary power switch tube; the DC-DC controller comprises an auxiliary feedback port, an auxiliary control port, an auxiliary reference current port and an auxiliary reference sawtooth wave signal port; the auxiliary feedback port is connected with the auxiliary output port, and the auxiliary control port is connected with the control end of the auxiliary power switch tube; the DC-DC controller is used for: receiving a current provided by the auxiliary output port and the main output port after being connected in series through an auxiliary feedback port, receiving an auxiliary reference current through an auxiliary reference current port, and receiving an auxiliary reference sawtooth wave signal through an auxiliary reference sawtooth wave signal port; and then the current, the auxiliary reference current and the auxiliary reference sawtooth wave signal which are provided after the auxiliary output port and the main output port are connected in series are utilized to control the on and off of the auxiliary power switch tube.
In one embodiment, the DC-DC auxiliary converter further comprises: an auxiliary collecting member; the auxiliary acquisition part is connected between the auxiliary output port and the auxiliary feedback port; the auxiliary output port collects current provided by the auxiliary output port and the main output port after being connected in series through the auxiliary collecting piece.
In one embodiment, a DC-DC controller includes: the auxiliary reference current source comprises a first auxiliary comparator, a second auxiliary comparator, an auxiliary reference current source and an auxiliary reference sawtooth wave signal source; the negative input end of the first auxiliary comparator is connected with the auxiliary output port, the positive input end of the first auxiliary comparator is connected with the auxiliary reference current source through the auxiliary reference current port, and the output end of the first auxiliary comparator is connected with the positive input end of the second auxiliary comparator; the negative input end of the second auxiliary comparator is connected with the auxiliary reference sawtooth wave signal source through an auxiliary reference sawtooth wave signal port, and the output end of the second auxiliary comparator is connected with the auxiliary control port.
In one embodiment, the non-isolated PFC main converter comprises one of a buck converter, a boost converter, a buck-boost converter, a single-ended primary inductive converter, and a zero-voltage switching converter; the DC-DC auxiliary converter comprises one of a buck converter, a boost converter, a buck-boost converter, a flyback converter, a forward converter, a Cuk converter, a single-ended primary inductance type converter and a zero-voltage switch converter.
A second aspect of the application provides an LED lighting device comprising a non-isolated AC-DC constant current driver according to any one of the first aspects of the application.
In this application, when the non-isolated AC-DC constant current driver provided in the above embodiment is applied, the main input port is connected to the AC power supply, and the main output port and the auxiliary output port are connected in series and then connected to the load. Part of electric energy provided by the alternating current power supply is transmitted to the load through single conversion, and part of electric energy is transmitted to the load through primary and secondary conversion. That is, only a part of electric energy is provided to the load through two-stage conversion, and compared with the condition that the full power is converted through two stages, the power consumption is reduced, and the overall conversion efficiency is improved.
Drawings
In order to more clearly explain the technical solution of the present application, the drawings used in the embodiments will be briefly described below.
Fig. 1 is a schematic diagram of a non-isolated AC-DC constant current driver provided in one embodiment of the present application;
fig. 2 is a schematic diagram of a non-isolated AC-DC constant current driver provided in another embodiment of the present application;
fig. 3 is a schematic diagram of a non-isolated AC-DC constant current driver provided in another embodiment of the present application;
fig. 4 is a schematic diagram of a non-isolated AC-DC constant current driver provided in another embodiment of the present application;
fig. 5 is a schematic diagram of a non-isolated PFC main converter provided in an alternative embodiment of the present application;
fig. 6 is a schematic diagram of a non-isolated PFC main converter provided in an alternative embodiment of the present application;
FIG. 7 is a schematic diagram of a DC-DC auxiliary converter provided in an alternative embodiment of the present application;
FIG. 8 is a schematic diagram of a DC-DC auxiliary converter provided in an alternative embodiment of the present application;
FIG. 9 is a schematic diagram of a DC-DC auxiliary converter provided in an alternative embodiment of the present application;
fig. 10 is a schematic diagram of a DC-DC auxiliary converter provided in an alternative embodiment of the present application.
Description of reference numerals:
the power factor correction circuit comprises a non-isolated PFC main converter 10, a PFC power conversion unit 11, a voltage converter 12, a main winding 121, an auxiliary winding 122, a DC-DC auxiliary converter 20, a PFC controller 30, a DC-DC controller 40, an alternating current power supply 50, a load 60, main input ports 1 and 2, main output ports 3 and 4, auxiliary input ports 5 and 6 and auxiliary output ports 7 and 8.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.
Referring to fig. 1 to 10, the present application provides a non-isolated AC-DC constant current driver, which includes a non-isolated PFC main converter 10 and a DC-DC auxiliary converter 20.
The non-isolated PFC main converter 10 comprises a main input port, a PFC power conversion unit 11, a voltage converter 12 and a main output port, wherein the voltage converter 12 comprises a main winding 121 and an auxiliary winding 122; the DC-DC auxiliary converter 20 includes an auxiliary input port and an auxiliary output port. The input end of the PFC power conversion unit 11 is connected with the main input port, and the output end of the PFC power conversion unit 11 is connected with one end of the main winding 121; the other end of the main winding 121 is connected with the main output port; the auxiliary winding 122 is connected with the auxiliary input port; the auxiliary output port and the main output port are connected in series.
Specifically, the PFC power conversion unit 11 converts ac power input through the main input port into dc power and transmits the dc power to the voltage converter 12; the voltage converter 12 transmits the received direct current to the main output port via the main winding 121, and transmits the received direct current to the DC-DC auxiliary converter 20 via the auxiliary winding and the auxiliary input port; the DC-DC auxiliary converter 20 processes the received DC power and transmits the processed DC power to the auxiliary output port.
Then, when the non-isolated AC-DC constant current driver provided in the above embodiment is applied, the main input port is connected to the AC power supply 50, and the main output port and the auxiliary output port are connected in series and then connected to the load 60. Of course, the load 60 may be any device that needs to be powered, and in the embodiment of the present application, for convenience of description, a string of LEDs is used as the load 60. The main output port provides the main voltage Vo1 to the load 60 and the auxiliary output port provides the auxiliary voltage Vo2 to the load 60, so that the total voltage of the load 60 is the sum of the main voltage Vo1 and the auxiliary voltage Vo 2. The main output port forms a direct current bus.
After the alternating current power supply 50 and the LED lamp string are connected, wherein the current provided by the alternating current power supply 50 is directly output to the LED lamp string from the main output port in the form of the main voltage Vo1 after passing through the PFC power conversion unit 11 and the main winding 121; the current provided by the ac power source 50 is converted into a voltage by the PFC power conversion unit 11 and the auxiliary winding 122, and then output to the DC-DC auxiliary converter 20 in the form of an auxiliary voltage Vo2 from the auxiliary output port, and the DC-DC auxiliary converter 20 adjusts the voltage and then outputs the voltage to the LED string.
As can be seen from the above, the PFC power conversion unit 11 only performs a single-stage conversion on part of the output power to the load 60. Since the DC-DC auxiliary converter 20 provides the load 60 with a part of power through two-stage conversion, that is, only a part of power is converted through two-stage conversion as a whole, power consumption can be reduced by performing the part of power through two-stage conversion as compared with a method in which all output power is converted through two-stage conversion.
In an alternative embodiment, the resistance of the main winding 121 is smaller than that of the auxiliary winding 122, so that the voltage of the main winding 121 is larger than that of the auxiliary winding 122 under the condition of the same current, that is, the main voltage is larger than the auxiliary voltage, and the output power of the main output port is larger than that of the auxiliary output port. Therefore, the conversion efficiency can be improved better.
Specifically, assume that the conversion efficiency of the non-isolated PFC main converter 10 is ηPFCConversion efficiency of the DC-DC auxiliary converter 20 is etaDC-DC，PPFC、PDC-DC、PoutThe output power of the non-isolated PFC main converter 10, the output power of the DC-DC auxiliary converter 20, and the overall output power, respectively, the overall efficiency is:
let PDC-DC＝10％xPoutAnd then:
is additionally provided with etaDC-DC90%, the overall conversion efficiency ηtotal＝98.9％xηPFC。
From the above, it can be seen that if the output power ratio of the DC-DC auxiliary converter 20 is set toAt 10%, even if the conversion efficiency of the DC-DC auxiliary converter 20 is as low as 90%, the overall efficiency ηtotalClose to 99%, very close to the conversion efficiency of a pure single stage converter directly provided to the LED string. Therefore, the non-isolated AC-DC constant current driver provided by the embodiment of the application has lower power loss and can improve the overall efficiency.
It can be seen that the PFC power conversion unit 11 provides most of the output power to the LED string and is only a single stage power conversion. The DC-DC auxiliary converter 20 provides a small portion of the output power to the string, and although the power provided by the DC-DC auxiliary converter 20 is converted in two stages, it only processes a small portion of the output power, i.e., only a small portion of the output power is converted in two stages.
In the embodiment of the application, most of the electric energy provided by the ac power supply 50 is transmitted to the LED light string through single conversion, and a small part of the electric energy is transmitted to the LED light string through primary and secondary conversion. Therefore, the power consumption is reduced, and the overall conversion efficiency is improved. In addition, because the DC-DC auxiliary converter 20 only converts a small part of electric energy, the voltage and current stress of the internal devices is also small, and the cost of the components can be reduced.
The voltage converter 12 may be a transformer or inductor L1 of the dual winding type having a primary winding 121 and a secondary winding 122.
In an alternative embodiment, referring to fig. 2, the non-isolated AC-DC constant current driver further includes a PFC controller 30; the non-isolated PFC main converter 10 also includes a main power switch Q1.
The main power switching tube Q1 is connected between the output end of the PFC power conversion unit 11 and one end of the main winding 121; alternatively, the main power switch Q1 is connected to the other end of the main winding 121.
The PFC controller 30 includes a main feedback port a1, a first main acquisition port a2, a main control port a3, a main reference voltage port a4, and a main reference sawtooth signal port a 5; the main feedback port a1 is connected with the main output port, the first main collecting port a2 is connected with the auxiliary winding 122, and the main control port a3 is connected with the control end of the main power switch tube Q1.
The PFC controller 30 is configured to receive a main voltage Vo1 output from the main output port through a main feedback port a1, receive a voltage of the auxiliary winding 122 through a first main collecting port a2, receive a main reference voltage through a main reference voltage port a4, and receive a main reference sawtooth signal through a main reference sawtooth signal port a 5; the main power switch Q1 is then controlled to turn on and off using the main voltage Vo1 at the main output port, the voltage at the auxiliary winding 122, the main reference voltage, and the main reference sawtooth signal.
Specifically, the control process of the PFC controller 30 is as follows: upon receiving the main voltage Vo1 from the main output port of the main feedback port a1 and receiving the main reference voltage from the main reference voltage port a4, the main voltage Vo1 and the main reference voltage are compared to form a voltage error signal. After receiving the main reference sawtooth wave signal from the main reference sawtooth wave signal port a5, the main reference sawtooth wave signal is compared with the voltage error signal, and a stop pulse signal is formed according to the comparison result. After receiving the voltage of the auxiliary winding 122 from the first main collecting port a2, a start pulse signal is formed by using the voltage of the auxiliary winding 122. The stop pulse signal and the start pulse signal are used for controlling the on and off of the main power switch tube Q1.
That is, the main voltage Vo1 of the main output port is fed back to the PFC controller 30 through the main feedback port a1, the main reference voltage is supplied to the PFC controller 30 through the main reference voltage port a4, and the PFC controller 30 compares the main voltage Vo1 with the main reference voltage and then forms a voltage error signal. Then, the PFC controller 30 compares the voltage error signal with the main reference sawtooth signal to generate a stop pulse signal; the PFC controller 30 may then control the turn off of the main power switch Q1 using the stop pulse signal. The voltage of the auxiliary winding 122 is fed back to the PFC controller 30 through the first main collecting port a2, and the PFC controller 30 generates a start pulse signal by using the voltage of the auxiliary winding 122; the PFC controller 30 then uses the start pulse signal to control the turn-on of the main power switch Q1. The stop pulse signal and the start pulse signal form a Pulse Width Modulation (PWM) control signal, and the on/off of the main power switching tube Q1 can be controlled by the PWM control signal.
The control mode can control the main voltage Vo1 of the main output port in a closed loop mode, and can also realize that the input current and the output voltage are sine waves with the same frequency and the same phase so as to achieve power factor correction and better power factor and further realize zero pollution to a power grid.
In an alternative embodiment, referring to fig. 2, the PFC controller 30 further includes a second primary acquisition port a 6; the second primary collection port a6 is connected to the primary power switch Q1. The voltage of the main power switch Q1 is received through the second main acquisition port a 6. Before comparing the main reference sawtooth signal with the voltage error signal, the PFC controller 30 compares the voltage error signal with the voltage of the main power switch Q1, and then compares the comparison result with the main reference sawtooth signal. The peak current of the main power switch Q1 can thus be controlled.
In an alternative embodiment, referring to fig. 4, the non-isolated PFC main converter 10 further includes a first main collecting element and a second main collecting element; the first primary pick-up is connected between the second primary pick-up port a6 and the main power switch Q1, and the second primary pick-up is connected between the first primary pick-up port a2 and the auxiliary winding 122. The second main collecting port a6 collects the voltage of the main power switch tube Q1 through the first main collecting piece, and the first main collecting port a2 collects the voltage of the auxiliary winding 122 through the second main collecting piece. Optionally, the first main collecting element and the second main collecting element may be a resistor Ri and a resistor Rdem, respectively.
The arrangement of the first main collecting part and the second main collecting part can facilitate the PFC to control and accurately collect required signals, and improve the accuracy of the PFC controller 30 in controlling the main power switch tube Q1.
In an alternative embodiment, referring to fig. 4, the PFC controller 30 includes a main reference voltage source Vref, a main reference sawtooth signal source Vramp1, a first main comparator U1, a second main comparator U2, a third main comparator U3, and a flip-flop U4; flip-flop U4 has an S port, a Q port, and an R port.
The negative input end of the first main comparator U1 is connected with a main feedback port a1, the positive input end of the first main comparator U1 is connected with a main reference voltage source Vref through a main reference voltage port a4, and the output end of the first main comparator U1 is connected with the positive input end of the second main comparator U2; the negative input end of the second main comparator U2 is connected with the second main acquisition port a6, and the output end of the second main comparator U2 is connected with the positive input end of the third main comparator U3; the negative input end of a third main comparator U3 is connected with a main reference sawtooth wave signal source Vramp1 through a main reference sawtooth wave signal port a5, and the output end of the third main comparator U3 is connected with an R port; the Q port is connected to the primary control port a3 and the S port is connected to the first primary acquisition port a 2.
Specifically, the first master comparator U1 receives the master voltage Vo1 and the master reference voltage of the master output port, compares the master voltage Vo1 and the master reference voltage of the master output port, and then outputs a voltage error signal to the second master comparator U2. The second main comparator U2 receives the voltage error signal and the voltage of the main power switch Q1, controls the peak current of the main power switch Q1, compares the voltage error signal with the voltage of the main power switch Q1, and outputs the processed voltage error signal to the third main comparator U3. After receiving the processed voltage error signal and the main reference sawtooth wave signal, the third main comparator U3 compares the processed voltage error signal with the main reference sawtooth wave signal, and then outputs the comparison result to the R end of the contactor; the contactor generates a stop pulse signal according to the comparison result, and the stop pulse signal is output to the control end of the main power switch tube Q1 through the Q end of the contactor so as to control the turn-off of the main power switch tube Q1. After receiving the voltage of the auxiliary winding 122 through the S terminal, the contactor generates a start pulse signal by using the voltage of the auxiliary winding 122; then, the start pulse signal is output to the control terminal of the main power switch Q1 through the Q terminal to control the main power switch Q1 to be turned on.
By using the PFC controller 30 with the above structure, the non-isolated PFC main converter 10 can be precisely controlled, and the PFC controller is simple to manufacture, low in cost and high in control precision.
In an alternative embodiment, referring to fig. 2 and 3, the non-isolated AC-DC constant current driver further includes a DC-DC controller 40; the DC-DC auxiliary converter 20 also includes an auxiliary power switch Q2.
Wherein the DC-DC controller 40 comprises an auxiliary feedback port b1, an auxiliary control port b2, an auxiliary reference current port b3, and an auxiliary reference sawtooth signal port b 4; the auxiliary feedback port b1 is connected with the auxiliary output port, and the auxiliary control port b2 is connected with the control end of the auxiliary power switch tube Q2. The DC-DC controller 40 is configured to: the current provided by the auxiliary output port and the main output port after being connected in series is received through an auxiliary feedback port b1, the auxiliary reference current is received through an auxiliary reference current port b3, and the auxiliary reference sawtooth wave signal is received through an auxiliary reference sawtooth wave signal port b 4; and then the current, the auxiliary reference current and the auxiliary reference sawtooth wave signal which are provided after the auxiliary output port and the main output port are connected in series are used for controlling the on and off of the auxiliary power switch tube Q2.
Specifically, the auxiliary output port and the main output port are connected in series to provide electric energy for the LED light string, so that the current provided by the auxiliary output port and the main output port in series is actually the current of the LED light string.
The DC-DC controller 40 receives the current of the LED string fed back from the auxiliary output port, and after receiving the auxiliary reference current from the auxiliary reference current port b3, compares the current of the LED string with the auxiliary reference current, and then forms a voltage error signal according to the comparison result; and then comparing the voltage error signal with the auxiliary reference sawtooth wave signal, generating a control signal of an auxiliary power switch tube Q2 according to the comparison result, and controlling the on-off of the auxiliary power switch tube Q2 by using the control signal. Therefore, the control strategy can realize the closed-loop control of the current of the LED lamp string.
In addition, the control strategy of the PFC controller 30 and the control strategy of the DC-DC controller 40 can also realize that the ripples of the main voltage Vo1 of the main output port and the auxiliary voltage Vo2 of the auxiliary output port are reversely superposed and offset each other, thereby reducing the ripple of the total output voltage Vo and reducing the ripple of the current of the LED string.
In detail, the main voltage Vo1 and the auxiliary voltage Vo2 have the purpose of reverse superposition of ripples to reduce or cancel power frequency ripples. The main voltage Vo1 of the main output port has a power frequency ripple, but is connected in series with the auxiliary voltage Vo2 of the auxiliary output port, and the reference signal in the current feedback loop of the DC-DC controller 40 of the DC-DC auxiliary converter 20 is an auxiliary reference current Iref, which is a direct current reference signal.
In addition, the switching frequency of the DC-DC auxiliary converter 20 is much higher than that of the non-isolated PFC main converter 10, so the dynamic response speed of the DC-DC auxiliary converter 20 is very fast, and theoretically, the total current io of the total output port formed by connecting the auxiliary output port and the main output port in series can be equal to Iref in real time, so the total current io is also infinitely close to a direct current value. Meanwhile, the main output port and the auxiliary output port are in series connection, so that the total current of the total output port formed by the series connection of the auxiliary output port and the main output port is equal to the current of the auxiliary output port, and the current of the auxiliary output port is a direct current value, so that the total current is also a direct current value, which is equivalent to the cancellation of power frequency ripples output by the main output port.
As can be seen from the above, the DC-DC auxiliary converter 20 is controlled in the fast loop, and the non-isolated PFC main converter 10 is controlled in the slow loop. In the application, in order to eliminate the power frequency ripple of the main output port, the main output port and the auxiliary output port are connected in series, so that the current of the main output port, the current of the auxiliary output port and the total current are equal.
The DC-DC controller 40 controls only the output current Ios, and the main voltage Vo1 or the total voltage Vo is controlled by the PFC controller 30. The reason for this is that if the amplitude of the total voltage output is smaller than the amplitude of the voltage for maintaining the normal operation of the load LED, the output DC current required by the load cannot be maintained by controlling the DC-DC controller 40 alone, so that on the one hand, the output voltage required by the load is high enough; on the other hand, when the total output voltage amplitude meets the load requirement, the DC-DC controller 40 maintains an output DC current required by the load, and the fast feedback loop of the DC-DC controller 40 makes the output current infinitely approach the DC value without the power frequency ripple. Therefore, the requirements of load working voltage and current can be met, and power frequency ripples can be eliminated.
In an alternative embodiment, referring to fig. 4, the DC-DC auxiliary converter 20 further includes an auxiliary collecting member. The auxiliary output port collects current provided by the auxiliary output port and the main output port after being connected in series through the auxiliary collecting piece. Optionally, the auxiliary collecting element may be a resistor Ro. The secondary collection element may convert the current of the LED string to a voltage that is provided to secondary feedback port b 1.
In an alternative embodiment, referring to fig. 4, the DC-DC controller 40 includes a first auxiliary comparator U5, a second auxiliary comparator U6, an auxiliary reference current source Iref, and an auxiliary reference sawtooth signal source Vramp 2. The negative input end of the first auxiliary comparator U5 is connected with the auxiliary feedback port b1, the positive input end of the first auxiliary comparator U5 is connected with the auxiliary reference current source Iref through the auxiliary reference current port b3, and the output end of the first auxiliary comparator U5 is connected with the positive input end of the second auxiliary comparator U6; the negative input end of the second auxiliary comparator U6 is connected with an auxiliary reference sawtooth wave signal source Vramp2 through an auxiliary reference sawtooth wave signal port b4, and the output end of the second auxiliary comparator U6 is connected with an auxiliary control port b 2.
Specifically, the resistor Ro detects the current of the LED string and converts the current into a voltage signal, so that a total current Ios forming feedback is transmitted to the negative input end of the first auxiliary comparator U5, and after the first auxiliary comparator U5 receives the auxiliary reference current from the auxiliary reference current port b3, the total current Ios and the auxiliary reference current are compared, and then a voltage error signal formed according to the comparison result is output to the second auxiliary comparator U6; after receiving the voltage error signal and the auxiliary reference sawtooth wave signal, the second auxiliary comparator U6 compares the voltage error signal with the auxiliary reference sawtooth wave signal, generates a control signal of the auxiliary power switch Q2 according to the comparison result, and outputs the control signal to the control terminal of the auxiliary power switch Q2 to control the on and off of the auxiliary power switch Q2. The DC-DC controller 40 with the structure has the advantages of simple structure, higher control precision and lower cost. It will be appreciated that the control signal is a PWM control signal.
In an alternative embodiment, the non-isolated PFC main converter 10 comprises one of a buck converter, a boost converter, a buck-boost converter, a single-ended primary inductive converter, and a zero-voltage switching converter; the DC-DC auxiliary converter 20 includes one of a buck converter, a boost converter, a buck-boost converter, a flyback converter, a forward converter, a buck converter, a single-ended primary inductive converter, and a zero-voltage switching converter.
The non-isolated main PFC converter 10 includes PFC powerThe converter comprises a conversion unit 11, a rectifier diode D5, a rectifier diode Db, a voltage converter 12 and a main power switch tube Q1. The several units may constitute a non-isolated PFC main converter 10 of one of a buck converter, a boost converter and a buck-boost converter. The main power switch tube Q1 also has a body diode DQ1. The main input ports include main input port 1 and main input port 2. The main output port includes a main output port 3 and a main output port 4.
Specifically, referring to fig. 4, the PFC power conversion unit 11 may include an LC filter circuit, a diode full-bridge rectifier circuit, and a filter capacitor Cin. The LC filter circuit comprises a capacitor Cf and an inductor Lf, and two half-bridge circuits of a diode full-bridge rectifying circuit, wherein one half-bridge circuit is formed by connecting diodes D1 and D3 in series, the other half-bridge circuit is formed by connecting diodes D2 and D4 in series, D1 and D2 are located on the upper portion, and D3 and D4 are located on the lower portion. There is a first node between D1 and D3 and a second node between D2 and D4. One end of the inductor Lf is connected with one pole of the alternating current power supply 50 through the main input port 1, and the other end is connected with the first node; one end of the capacitor Cf is connected to the other end of the inductor Lf, and the other end of the capacitor Cf and the second node are both connected to the other pole of the ac power supply 50 through the main input port 2. The filter capacitors Cin and D2 are connected in parallel with the half bridge formed by D4. In addition, the two half bridges and the filter capacitor Cin are connected in parallel and then grounded.
Referring to fig. 4, the following details the structure of the non-isolated PFC main converter 10 of the buck converter type:
the drain of the main power switch tube Q1 is connected with one end of the filter capacitor Cin, the source of the main power switch tube Q1 is connected with the main winding 121, and the grid of the main power switch tube Q1 is connected with the Q end of the trigger U4. One end of the rectifier diode D5 is connected with the source electrode of the power switch tube, and the other end is grounded. The rectifier diode Db is connected between one end of the auxiliary winding 122 and the auxiliary input port 5, and the other end of the auxiliary winding 122 is grounded.
Referring to fig. 5, the following details the structure of the boost converter type non-isolated PFC main converter 10:
one end of the main winding 121 is connected to the filter capacitor Cin, and the other end is connected to one end of the rectifier diode D5; the other end of the rectifying diode D5 is connected with the main output port 3; one end of the auxiliary winding 122 is connected to the auxiliary input port 5 through a rectifier diode Db, and the other end of the auxiliary winding 122 is directly connected to the auxiliary input port 6. The source of the main power switch Q1 is connected to the main output port 4, the drain is connected between the main winding 121 and the rectifier diode D5, and the gate is connected to the Q terminal of the flip-flop U4.
Referring to fig. 6, the following details the structure of the buck-boost converter type non-isolated PFC main converter 10:
the source electrode of the main power switch tube Q1 is connected with the main output port 4, the drain electrode is connected with the filter capacitor Cin, and the grid electrode is connected with the Q end of the trigger U4; one end of the main winding 121 is connected between the source of the main power switch tube Q1 and the main output port 4, the other end is connected between the filter capacitor Cin and one end of the rectifier diode D5, and the other end of the rectifier diode D5 is connected with the main output port 3; the rectifier diode Db is connected between one end of the auxiliary winding 122 and the auxiliary input port 5, and the other end of the auxiliary winding 122 is connected to the auxiliary input port 6.
The DC-DC auxiliary converter 20 includes an auxiliary power switch Q2, an inductor L2 (or transformer T2), and a rectifier diode D7. Wherein the auxiliary input ports comprise an auxiliary input port 5 and an auxiliary input port 6. The auxiliary output ports include an auxiliary output port 7 and an auxiliary output port 8. The auxiliary power switch tube Q2 also has a body diode DQ2。
Referring to fig. 4, the construction of the buck converter type DC-DC auxiliary converter 20 is described in detail below:
the source of the auxiliary power switch Q2 is connected to one end of the inductor L2, the drain is connected to the auxiliary input port 5, and the gate is connected to the output of the second auxiliary comparator U6. The other end of the inductor L2 is connected to the auxiliary output port 7, one end of the rectifier diode D7 is connected between the source of the auxiliary power switch Q2 and one end of the inductor L2, and the other end of the rectifier diode D7 is connected between the auxiliary input port 6 and the auxiliary output port 8.
Referring to fig. 7, the constitution of the boost converter type DC-DC auxiliary converter 20 is described in detail below:
one end of the inductor L2 is connected to the auxiliary input port 5, and the other end is connected to one end of the rectifier diode D7. The other end of the rectifying diode D7 is connected to the auxiliary output port 7. The source of the auxiliary power switch Q2 is connected between the auxiliary input port 6 and the auxiliary output port 8, the drain is connected between the inductor L2 and the rectifier diode D7, and the gate is connected to the output of the second auxiliary comparator U6.
Referring to fig. 8, the following details the structure of the buck-boost converter type DC-DC auxiliary converter 20:
the source of the auxiliary power switch Q2 is connected to the auxiliary output port 8, the drain is connected to the auxiliary input port 5, and the gate is connected to the output of the second auxiliary comparator U6. The rectifier diode D7 is connected between the auxiliary input port 6 and the auxiliary output port 7. One end of the inductor L2 is connected between the source of the auxiliary power switch Q2 and the auxiliary output port 8, and the other end of the inductor L2 is connected between the auxiliary input port 6 and the rectifier diode D7.
Referring to fig. 9, the construction of the negative buck converter type DC-DC auxiliary converter 20 is described in detail below:
the source of the auxiliary power switch Q2 is connected to one end of the inductor L2, the drain is connected to the auxiliary input port 5, and the gate is connected to the output of the second auxiliary comparator U6. The other end of the inductor L2 is connected to the auxiliary output port 7. One end of the rectifier diode is connected between the auxiliary input port 6 and the auxiliary output port 8, and the other end is connected between the source of the auxiliary power switch tube Q2 and one end of the inductor L2.
Referring to fig. 10, the following details the configuration of the flyback converter type DC-DC auxiliary converter 20:
the transformer T2 comprises a first winding and a second winding, wherein one end of the first winding is connected with the auxiliary input port 5, and the other end of the first winding is connected with the drain electrode of the auxiliary power switch tube Q2; the source electrode of the auxiliary power switch tube Q2 is connected with the auxiliary input port 6, and the grid electrode of the auxiliary power switch tube Q2 is connected with the output end of the second auxiliary comparator U6; one end of the second winding of the transformer T2 is connected to the rectifier diode D7, the other end of the rectifier diode D7 is connected to the auxiliary output port 7, and the other end of the second winding is connected to the auxiliary output port 8.
In addition, the circuit is also provided with filter capacitors Co1, Cb and Co2, wherein the filter capacitor Co1 is connected between the main input ports 3 and 4 for filtering the output voltage of the main input ports. The filter capacitor Cb is connected between the auxiliary input ports 5 and 6, and filters the input voltage at the auxiliary input ports. The filter capacitor Co2 is connected between the auxiliary output ports 7 and 8 to filter the output voltage at the auxiliary output ports.
Embodiments of the present application further provide an LED lighting device, which includes the non-isolated AC-DC constant current driver provided in any optional embodiment of the present application.
The foregoing detailed description of the embodiments of the present application has been presented to illustrate the principles and implementations of the present application and, therefore, the above description of the embodiments may be used to help understand the method and the core concepts of the present application.
Claims (10)
1. A non-isolated AC-DC constant current driver, comprising: the non-isolated PFC main converter and the DC-DC auxiliary converter;
the non-isolated PFC main converter comprises a main input port, a PFC power conversion unit, a voltage converter and a main output port, wherein the voltage converter comprises a main winding and an auxiliary winding; the DC-DC auxiliary converter comprises an auxiliary input port and an auxiliary output port;
the input end of the PFC power conversion unit is connected with the main input port, and the output end of the PFC power conversion unit is connected with one end of the main winding; the other end of the main winding is connected with the main output port; the auxiliary winding is connected with the auxiliary input port; the auxiliary output port and the main output port are connected in series;
the PFC power conversion unit is used for: converting the alternating current input through the main input port into direct current and transmitting the direct current to the voltage converter; the voltage converter is used for: transmitting the received direct current to the main output port via the main winding, and transmitting the received direct current to the DC-DC auxiliary converter via the auxiliary winding and the auxiliary input port; the DC-DC auxiliary converter is used for: and processing the received direct current and transmitting the processed direct current to the auxiliary output port.
2. The non-isolated AC-DC constant current driver of claim 1, further comprising: a PFC controller; the non-isolated PFC main converter further comprises: a main power switch tube;
the main power switch tube is connected between the output end of the PFC power conversion unit and one end of the main winding; or the main power switch tube is connected with the other end of the main winding;
the PFC controller comprises a main feedback port, a first main acquisition port, a main control port, a main reference voltage port and a main reference sawtooth wave signal port; the main feedback port is connected with the main output port, the first main acquisition port is connected with the auxiliary winding, and the main control port is connected with the control end of the main power switch tube;
the PFC controller is configured to: receiving a main voltage output by the main output port through the main feedback port, receiving a voltage of the auxiliary winding through the first main acquisition port, receiving a main reference voltage through the main reference voltage port, and receiving a main reference sawtooth wave signal through the main reference sawtooth wave signal port; and then controlling the on and off of the main power switch tube by using the main voltage, the voltage of the auxiliary winding, the main reference voltage and the main reference sawtooth wave signal.
3. The non-isolated AC-DC constant current driver of claim 2, wherein the PFC controller further comprises a second primary acquisition port; the second main acquisition port is connected with the main power switch tube;
the PFC controller is further configured to: and receiving the voltage of the main power switch tube through the second main acquisition port.
4. The non-isolated AC-DC constant current driver of claim 3, wherein the non-isolated PFC main converter further comprises: a first main collecting part and a second main collecting part; the first main acquisition part is connected between the second main acquisition port and the main power switch tube, and the second main acquisition part is connected between the first main acquisition port and the auxiliary winding;
the second main collecting port collects the voltage of the main power switch tube through the first main collecting part, and the first main collecting port collects the voltage of the auxiliary winding through the second main collecting part.
5. The non-isolated AC-DC constant current driver according to claim 3, wherein the PFC controller comprises a main reference voltage source, a main reference sawtooth signal source, a first main comparator, a second main comparator, a third main comparator and a trigger; the flip-flop is provided with an S port, a Q port and an R port;
a negative input terminal of the first master comparator is connected to the master feedback port, a positive input terminal of the first master comparator is connected to the master reference voltage source through the master reference voltage port, and an output terminal of the first master comparator is connected to a positive input terminal of the second master comparator; the negative input end of the second main comparator is connected with the second main acquisition port, and the output end of the second main comparator is connected with the positive input end of the third main comparator; the negative input end of the third main comparator is connected with the main reference sawtooth wave signal source through the main reference sawtooth wave signal port, and the output end of the third main comparator is connected with the R port; the Q port is connected with the main control port, and the S port is connected with the first main acquisition port.
6. The non-isolated AC-DC constant current driver of claim 1, further comprising: a DC-DC controller; the DC-DC auxiliary converter further includes: an auxiliary power switch tube;
the DC-DC controller comprises an auxiliary feedback port, an auxiliary control port, an auxiliary reference current port and an auxiliary reference sawtooth wave signal port; the auxiliary feedback port is connected with the auxiliary output port, and the auxiliary control port is connected with the control end of the auxiliary power switch tube;
the DC-DC controller is to: receiving a current provided by the auxiliary output port and the main output port after being connected in series through the auxiliary feedback port, receiving an auxiliary reference current through the auxiliary reference current port, and receiving an auxiliary reference sawtooth wave signal through the auxiliary reference sawtooth wave signal port; and then controlling the on and off of the auxiliary power switch tube by using the current provided by the auxiliary output port and the main output port after being connected in series, the auxiliary reference current and the auxiliary reference sawtooth wave signal.
7. The non-isolated AC-DC constant current driver of claim 6, wherein the DC-DC auxiliary converter further comprises: an auxiliary collecting member;
the auxiliary output port collects current provided by the auxiliary output port and the main output port after being connected in series through the auxiliary collecting piece.
8. The non-isolated AC-DC constant current driver according to claim 6, wherein the DC-DC controller comprises: the auxiliary reference current source comprises a first auxiliary comparator, a second auxiliary comparator, an auxiliary reference current source and an auxiliary reference sawtooth wave signal source;
the negative input end of the first auxiliary comparator is connected with the auxiliary feedback port, the positive input end of the first auxiliary comparator is connected with the auxiliary reference current source through the auxiliary reference current port, and the output end of the first auxiliary comparator is connected with the positive input end of the second auxiliary comparator; the negative input end of the second auxiliary comparator is connected with the auxiliary reference sawtooth wave signal source through the auxiliary reference sawtooth wave signal port, and the output end of the second auxiliary comparator is connected with the auxiliary control port.
9. The non-isolated AC-DC constant current driver of any one of claims 1 to 8, wherein the non-isolated PFC main converter comprises one of a buck converter, a boost converter, a buck-boost converter, a single-ended primary inductive converter, and a zero-voltage switching converter; the DC-DC auxiliary converter comprises one of a buck converter, a boost converter, a buck-boost converter, a flyback converter, a forward converter, a Cuk converter, a single-ended primary inductance type converter and a zero-voltage switch converter.
10. An LED lighting device comprising the non-isolated AC-DC constant current driver of any one of claims 1 to 9.
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| CN202120232558.8U CN214627429U (en) | 2021-01-27 | 2021-01-27 | Non-isolated AC-DC constant current driver and LED lighting equipment |
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| CN202120232558.8U CN214627429U (en) | 2021-01-27 | 2021-01-27 | Non-isolated AC-DC constant current driver and LED lighting equipment |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112737370A (en) * | 2021-01-27 | 2021-04-30 | 茂硕电源科技股份有限公司 | AC/DC converter |
| CN112788814A (en) * | 2021-01-27 | 2021-05-11 | 茂硕电源科技股份有限公司 | Non-isolated AC-DC constant current driver and LED lighting equipment |
-
2021
- 2021-01-27 CN CN202120232558.8U patent/CN214627429U/en not_active Withdrawn - After Issue
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112737370A (en) * | 2021-01-27 | 2021-04-30 | 茂硕电源科技股份有限公司 | AC/DC converter |
| CN112788814A (en) * | 2021-01-27 | 2021-05-11 | 茂硕电源科技股份有限公司 | Non-isolated AC-DC constant current driver and LED lighting equipment |
| CN112737370B (en) * | 2021-01-27 | 2024-06-18 | 茂硕电源科技股份有限公司 | AC/DC converter |
| CN112788814B (en) * | 2021-01-27 | 2024-06-18 | 茂硕电源科技股份有限公司 | Non-isolated AC-DC constant current driver and LED lighting equipment |
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