CN211509381U

CN211509381U - Multi-path constant-current LED driving power supply

Info

Publication number: CN211509381U
Application number: CN202020175854.4U
Authority: CN
Inventors: 董刚
Original assignee: Shenzhen Jinyipai Technology Co ltd
Current assignee: Shenzhen Jinyipai Technology Co ltd
Priority date: 2020-02-17
Filing date: 2020-02-17
Publication date: 2020-09-15
Anticipated expiration: 2030-02-17

Abstract

The utility model provides a multi-channel constant current LED driving power supply, which comprises a constant current conversion module for providing proper power supply for LEDs, switch tubes Qi arranged between the constant current conversion module and each channel of LEDs, and a PWM signal generator for generating PWM signals for controlling each switch tube Qi; the phase shifter i is used for shifting the phase of a PWM signal output end of the PWM signal generator and then connecting the PWM signal output end of the PWM signal generator with a control end of a corresponding switching tube Qi; the phase shifting angles of the phase shifters i are (i-1) 360/N respectively, N is a natural number representing the number of the LED paths, i is a natural number smaller than or equal to N, and the maximum duty ratio of the PWM signal is 1/N. The utility model discloses in, the mode that adopts to move the phase converts a PWM signal to the PWM signal that is effective signal at most only one at the same moment, realizes that power work is added during each way LED.

Description

Multi-path constant-current LED driving power supply

Technical Field

The utility model relates to a LED drive power supply field, especially a multichannel constant current LED drive power supply.

Background

Because a constant current source drives a plurality of paths of LED lamps, a balancing circuit is generally adopted to equally divide the current output by a driving power supply to each path of LED lamp, but the equal division requires the same resistance for a load (here, an LED), and thus, proper current can be distributed. The time-sharing multi-path constant-current driving LED lamp comprises a plurality of LED particles and a driving power supply for driving the LED particles to emit light, wherein the LED particles belong to a plurality of LED groups, each LED group comprises at least one LED particle, the driving power supply comprises a constant-current conversion module capable of outputting constant current and a scheduling module connected to the output end of the constant-current conversion module, and the scheduling module comprises a controller for generating a plurality of PWM signals and a plurality of on-off devices which are controlled by the PWM signals generated by the controller and directly drive the LED groups; and the product of the current value of the output current of the constant current conversion module and the duty ratio of the PWM signal input to the on-off device is the driving current required by the LED group. The phases of the PWM signals are not equal, and the phase differences of all adjacent PWM signals are equal. The number of PWM signals is the same as the number of the LED groups and the number of the on-off devices, and each PWM signal drives on and off of one of the LED groups through the on-off device.

The power supply for driving the LED by the time-sharing multi-path constant current only adopts one constant current unit, compared with the power supply with a plurality of traditional constant current units, the power supply reduces the electric signal interference between the adjacent constant current units, and the output current of the power supply is purer.

However, the number of PWM signals of such time-division multiplexing constant-current driving LEDs is the same as the number of the LED groups and the number of the on-off switches, and each of the PWM signals drives on and off of one of the LED groups through the on-off switch. It can be difficult to synchronize the different PWM signals, which can increase the cost in order to synchronize them.

Disclosure of Invention

The utility model discloses to present timesharing multichannel constant current drive LED's power PWM signal the quantity with the quantity of LED group with the quantity homogeneous phase of on-off ware, every the PWM signal all passes through on-off ware drive one the opening and closing of LED group. Can make the synchronous difficulty of different PWM signals, in order to make it synchronous, can increase the cost, the utility model provides a multichannel constant current LED drive power supply adopts the same PWM signal of the same way, realizes the power supply to multichannel LED through the delay of difference.

The utility model discloses realize that its technical purpose technical scheme is: a multi-path constant current LED driving power supply comprises a constant current conversion module for providing proper power supply for LEDs, switching tubes Qi arranged between the constant current conversion module and each path of LEDs, and a PWM signal generator for generating PWM signals for controlling each switching tube Qi; the phase shifter i is used for shifting the phase of a PWM signal output end of the PWM signal generator and then connecting the PWM signal output end of the PWM signal generator with a control end of a corresponding switching tube Qi; the phase shifting angles of the phase shifters i are (i-1) 360/N respectively, N is a natural number representing the number of the LED paths, i is a natural number smaller than or equal to N, and the maximum duty ratio of the PWM signal is 1/N.

The utility model discloses in, the mode that adopts to move the phase converts a PWM signal to the PWM signal that is effective signal at most only one at the same moment, realizes that power work is added during each way LED.

Further, in the multi-path constant current LED driving power supply: the switching tubes Qi are all MOS tubes, the grids of the switching tubes Qi are connected with corresponding phase shifters i, and D-S poles of the switching tubes Qi are respectively connected between the LEDs and the ground.

Further, in the multi-path constant current LED driving power supply: the constant current conversion module comprises: the direct current output by the filtering current is grounded through each path of LEDi, the switching tube Qi and the current detecting resistor R1; the current detection resistor R1 is connected with two ends of a source side of the optical coupler U1 respectively, an output end of the optical coupler U1 is connected with a control end of the second PWM signal generator U2, the second PWM signal generator U2 generates PWM with at least two duty ratios and is connected with a grid electrode of the switching tube Q0, and when a signal of the control end of the second PWM signal generator U1 is effective, a PWM signal with a low duty ratio is output and is connected with a grid electrode of the switching tube Q0.

Further, in the multi-path constant current LED driving power supply: the source side of the switching transformer T1 further includes a PFC controller U3, and the mains supply is connected to both ends of the primary winding of the switching transformer T1 after passing through the PFC controller U3.

Further, in the multi-path constant current LED driving power supply: the current detecting resistor R1 is a resistor with adjustable resistance.

The present invention will be described in more detail with reference to the accompanying drawings and examples.

Drawings

Fig. 1 is the utility model discloses multichannel constant current LED drive power supply functional block diagram.

Fig. 2 is the utility model discloses constant current module circuit schematic diagram among multichannel constant current LED drive power supply.

Detailed Description

The embodiment is a multi-path constant current LED driving power supply for driving a plurality of paths of LEDs by a constant current power supply module in a time-sharing manner, and in the embodiment, a constant current module is used for driving 6 paths of LEDs, as shown in fig. 1: the circuit comprises a constant current conversion module for providing proper power supply for LEDs, a switching tube Q1 arranged between the constant current conversion module and the LEDs 1, a switching tube Q2 arranged between the constant current conversion module and the LEDs 2, a switching tube Q3 arranged between the LEDs 3, a switching tube Q3 arranged between the LEDs 3, a switching tube Q4 arranged between the LEDs 4, a switching tube Q5 arranged between the LEDs 5, a switching tube Q6 arranged between the LEDs 6 and a PWM signal generator for generating PWM signals for controlling the switching tubes Qi; the phase shifter for shifting the phase of the PWM signal further comprises phase shifters 1-6, the phase shifting angle of each phase shifter is 0, 60, 120, 180, 240, 300, and the duty cycle of the PWM signal is not more than 1/6, in this embodiment, the duty cycle of the PWM signal is 1/6. In this way, the switching tubes of the six LEDs are turned on in sequence, but only one switching tube Qi is turned on at any time, and in this embodiment, the switching tubes Qi are MOS tubes Q1 and Q2-Q6, respectively. Certainly, in practice, there may be any path of LEDs, that is, N paths, and the PWM signal output end of the PWM signal generator is connected to the control end of the corresponding switching tube Qi after being phase-shifted by the phase shifter i, respectively; the phase shifting angles of the phase shifters i are 360/N (i-1), N is a natural number representing the number of the LED channels, i is a natural number smaller than or equal to N, and the maximum duty ratio of the PWM signal is 1/N.

The constant current conversion module in this embodiment is a high-power lighting LED switch power supply, as shown in fig. 2, which is a switch power supply for a high-power LED lighting fixture used in wide areas such as squares and halls, the LED for lighting is formed by connecting a known number of LEDs in series to form an LED unit, and a plurality of such units are connected in series to form a dashed line frame as shown in fig. 1, the number of the LEDs connected in series is determined according to the working voltage of a single LED, the number of the LEDs connected in series is determined according to the dc voltage generated after rectification and filtering of the mains supply, if the number of the LEDs is small, a transformer T1 is added when the mains supply is connected, so as to transform the mains supply into a voltage matched with the number of the LEDs, at present, rectification can be performed by adopting a half-wave rectification, so that a high-current diode D1 rectifies an ac signal induced by a secondary coil of the switch transformer, therefore, larger power can be output, other rectification modes such as a full-wave rectification mode or a bridge rectification mode can also be adopted, and some silicon controlled rectifiers on the market can output quite large current of several watts of output power. The filter circuit may be implemented by using an electrolytic capacitor as the filter capacitor C1, or other filter circuits may be used in practice. As shown in fig. 1, the N-stage and L-line of the utility power are respectively connected to two ends of the PFC controller to form a source side of a dc output access switching transformer T1, a switching tube Q0 is added between the source side of the switching transformer T1 and the ground, a gate of the switching tube Q0 is controlled by a PWM signal generator U2, and the control of the magnitude of the secondary power supply is realized by the duty ratio of the PWM signal, in this embodiment, the PWM signal generating device generates PWM signals of at least two duty ratios, and the default output is the PWM signal with a higher duty ratio and is output to the gate of the switching tube Q1.

In the present embodiment, the in-phase terminal of the secondary winding of the transformer T1 is connected to the anode of the rectifier diode D1, i.e., the P pole, the cathode of the rectifier diode D1, i.e., the N pole, is connected to the filter, in the present embodiment, the filter is composed of an electrolytic capacitor C1, the cathode of the rectifier diode D1 is connected to the anode of the filter capacitor C1, and the cathode of the filter capacitor C1 is grounded.

The mains supply forms stable direct current to be connected with each circuit of LED string after being rectified and filtered, a filter capacitor C1, namely the anode of an electrolytic capacitor is connected with the input end of the LED string, namely the P pole of the LED, and is grounded through a current detection resistor R1. in the embodiment, because the LED lighting lamp has larger power, the current detection resistor R1 can select a smaller resistor, thus, when the current is larger, the optical coupler can not be conducted, only when the current is larger than a set value, the optical coupler U1 can be conducted, the output end of the optical coupler U1 is connected with a PWM signal generator U2, when the optical coupler U1 is conducted, the PWM signal generator U4 outputs a PWM signal with a lower duty ratio to control a switch tube Q1, therefore, the power output to the LED lighting lamp can be reduced, the voltage at the two ends of the current detection resistor R1 is not enough to conduct the U1, and a control signal output to a PWM signal generating device U2 is converted into an invalid signal, the power output by the secondary side of the switch transformer is increased, and the operation is repeated, so that the LED lighting lamp is always in high power. And realizing the constant current of the LED.

In this embodiment, the power control circuit further includes an LED lamp power adjusting circuit, and the output power of the LED can be adjusted by using the power adjusting circuit, in this embodiment, a plurality of PWM signals with different duty ratios are set in the PWM generating device U2, and when the PWM signal with a higher duty ratio is selected to control the switching tube Q1, the resistance value of the current detection resistor R1 is adjusted, in this embodiment, the current detection resistor R1 is an adjustable resistance resistor, and the resistance value of the current detection resistor R1 corresponds to the duty ratio of the PWM signal output by the PWM signal generating device U2.

Claims

1. A multi-path constant current LED driving power supply comprises a constant current conversion module for providing proper power supply for LEDs, switching tubes Qi arranged between the constant current conversion module and each path of LEDs, and a PWM signal generator for generating PWM signals for controlling each switching tube Qi; the method is characterized in that: the phase shifter i is used for shifting the phase of a PWM signal output end of the PWM signal generator and then connecting the PWM signal output end of the PWM signal generator with a control end of a corresponding switching tube Qi; the phase shifting angles of the phase shifters i are (i-1) 360/N respectively, N is a natural number representing the number of the LED paths, i is a natural number smaller than or equal to N, and the maximum duty ratio of the PWM signal is 1/N.

2. The multi-path constant-current LED driving power supply according to claim 1, characterized in that: the switching tubes Qi are all MOS tubes, the grids of the switching tubes Qi are connected with corresponding phase shifters i, and D-S poles of the switching tubes Qi are respectively connected between the LEDs and the ground.

3. The multi-path constant-current LED driving power supply according to claim 1 or 2, characterized in that: the constant current conversion module comprises: the direct current output by the filter circuit is grounded through each path of LEDi, the switch tube Qi and the current detection resistor R1; the current detection resistor R1 is connected with two ends of a source side of the optical coupler U1 respectively, an output end of the optical coupler U1 is connected with a control end of the second PWM signal generator U2, the second PWM signal generator U2 generates PWM with at least two duty ratios and is connected with a grid electrode of the switching tube Q0, and when a signal of the control end of the second PWM signal generator U1 is effective, a PWM signal with a low duty ratio is output and is connected with a grid electrode of the switching tube Q0.

4. The multi-path constant-current LED driving power supply according to claim 3, wherein: the source side of the switching transformer T1 further includes a PFC controller U3, and the mains supply is connected to both ends of the primary winding of the switching transformer T1 after passing through the PFC controller U3.

5. The multi-path constant-current LED driving power supply according to claim 4, wherein: the current detecting resistor R1 is a resistor with adjustable resistance.