CN212413061U - Intrinsic safety type power supply constant current supply circuit and display device - Google Patents

Abstract

The embodiment of the utility model discloses an intrinsic safety type power supply constant current power supply circuit and a display device, which comprises a voltage conversion circuit, an energy-saving control circuit, a first voltage control circuit and a drive circuit; the voltage conversion circuit is used for converting the direct-current voltage output by the intrinsic safety type power supply into alternating-current voltage and outputting the alternating-current voltage from an output end of the voltage conversion circuit; the input end of the energy-saving control circuit is electrically connected with the output end of the voltage conversion circuit, and the output end of the energy-saving control circuit is electrically connected with the LED; the driving circuit is used for generating a driving control signal to drive the LED to emit light; the input end of the first voltage control circuit is electrically connected with the output end of the driving circuit, and the output end of the first voltage control circuit is electrically connected with the control end of the energy-saving control circuit. The embodiment of the utility model provides a technical scheme has solved the unable problem to the power supply of jumbo size LED display screen of this ampere of type power, and can reduce the consumption under the condition that does not reduce the display effect through energy-conserving control circuit.

Description

Intrinsic safety type power supply constant current supply circuit and display device

Technical Field

The embodiment of the utility model provides a relate to power electronic technology field, especially relate to an intrinsic safety type power supply constant current supply circuit and display device.

Background

With the rapid development of display technologies, large-size LED display screens are receiving more and more attention from people, and share of the large-size LED display screens in the market is increasing.

At present, the standard power supply of the boosting constant-current driving board of the large-size LED display screen is based on the input direct current +24V, and the standard is very common in the use of some products, so that the standard is adopted in the upstream and the downstream of the industry. However, in the display panel of which the input power supply is the intrinsically safe explosion-proof power supply, the voltage required by the constant current board of the large-size display panel cannot be achieved by the method.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model provides an intrinsic safety type power supply constant current supply circuit and display device to realize that intrinsic safety type power supply reduces the consumption under the condition that does not reduce the display effect to the drive control of constant current drive plate.

In a first aspect, an embodiment of the present invention provides an intrinsically safe power supply constant current power supply circuit, including: the energy-saving control circuit comprises a voltage conversion circuit, an energy-saving control circuit, a first voltage control circuit and a driving circuit;

the voltage conversion circuit comprises an input end and an output end, the input end of the voltage conversion circuit is electrically connected with the intrinsic safety type power supply, and the voltage conversion circuit is used for converting direct-current voltage output by the intrinsic safety type power supply into alternating-current voltage and outputting the alternating-current voltage from the output end of the intrinsic safety type power supply;

the energy-saving control circuit comprises an input end, an output end and a control end, wherein the input end of the energy-saving control circuit is electrically connected with the output end of the voltage conversion circuit, and the output end of the energy-saving control circuit is electrically connected with the LED;

the driving circuit comprises a power end and an output end, the power end of the driving circuit is electrically connected with the intrinsic safety type power supply, and the driving circuit is used for generating a driving control signal to drive the LED to emit light;

the first voltage control circuit comprises an input end and an output end, the input end of the first voltage control circuit is electrically connected with the output end of the driving circuit, and the output end of the first voltage control circuit is electrically connected with the control end of the energy-saving control circuit.

Optionally, the voltage conversion circuit comprises a fuse, a first capacitor and a transformer;

the first end of the protective tube is electrically connected with the intrinsic safety type power supply, the second end of the protective tube is electrically connected with the input end of the transformer, the output end of the transformer is electrically connected with the input end of the energy-saving control circuit, the first end of the first capacitor is electrically connected with the input end of the transformer, and the second end of the first capacitor is grounded.

Optionally, the energy-saving control circuit includes a first transistor, a second transistor, a first resistor, a first voltage regulator tube, a second voltage regulator tube, and a second capacitor;

a first pole of the first transistor and a first pole of the second transistor are both electrically connected with the output end of the first voltage control circuit through the first resistor, a second pole of the first transistor is electrically connected with the output end of the voltage conversion circuit, a third pole of the first transistor is grounded, a second pole of the second transistor is electrically connected with the second pole of the first transistor, and a third pole of the second transistor is grounded;

the first end of the first voltage-regulator tube is electrically connected with the second end of the second transistor, the second end of the first voltage-regulator tube is electrically connected with the LED, the second voltage-regulator tube is connected with the first voltage-regulator tube in parallel, the first end of the second capacitor is electrically connected with the second end of the first voltage-regulator tube, and the second end of the second capacitor is grounded.

Optionally, the first voltage control circuit includes a first transistor, a second transistor, and a second resistor;

a first pole of the first triode is electrically connected with the output end of the driving circuit, a second pole of the first triode is electrically connected with a first end of the second resistor, a second end of the second resistor is respectively electrically connected with a power supply end and the output end of the driving circuit, and a third pole of the first triode is electrically connected with a control end of the energy-saving control circuit;

the first pole of the second triode is grounded, the second pole of the second triode is electrically connected with the first end of the second resistor, and the third pole of the second triode is electrically connected with the control end of the energy-saving control circuit.

Optionally, the driving circuit includes a driving chip and a third resistor, and the driving chip includes a power supply terminal, a signal output terminal, a first voltage calibration terminal, and a second voltage calibration terminal;

the power end of the driving chip is electrically connected with the intrinsic safety type power supply, the signal output end of the driving chip is electrically connected with the input end of the first voltage control circuit, and the first voltage calibration end of the driving chip is electrically connected with the second voltage calibration end through the third resistor.

Optionally, the intrinsic safety type power supply constant current power supply circuit further includes an enable control circuit, and the driving circuit further includes an enable terminal;

the enabling control circuit comprises a fourth resistor, a first end of the fourth resistor is connected to an enabling control signal, and a second end of the fourth resistor is electrically connected with an enabling end of the driving circuit.

Optionally, the power supply further comprises a second voltage control circuit, the second voltage control circuit includes an input end and an output end, the input end of the second voltage control circuit is electrically connected to the intrinsic safety type power supply, and the output end of the second voltage control circuit is electrically connected to the power supply end of the driving circuit.

Optionally, the second voltage control circuit includes a fifth resistor, a sixth resistor, a third triode, and a third regulator tube;

a first end of the fifth resistor is electrically connected with the intrinsic safety type power supply, a second end of the fifth resistor is electrically connected with a first electrode of the third triode, a second electrode of the third triode is electrically connected with the intrinsic safety type power supply through the sixth resistor, and a third electrode of the third triode is electrically connected with a power supply end of the driving circuit;

and the first end of the third voltage-stabilizing tube is electrically connected with the second pole of the third triode, and the second end of the third voltage-stabilizing tube is grounded.

Optionally, the energy-saving control circuit further comprises a dimming circuit, the dimming circuit comprises an input end and an output end, the input end of the dimming circuit is connected with a dimming control signal, and the output end of the dimming circuit is electrically connected with the output end of the energy-saving control circuit; the dimming circuit comprises a first diode, a seventh resistor, a second diode, a third capacitor and an eighth resistor;

the first end of the first diode is connected to the dimming control signal, the second end of the first diode is electrically connected with the first end of the second diode through the seventh resistor, the second end of the second diode is electrically connected with the output end of the energy-saving control circuit, the first end of the third capacitor is electrically connected with the second end of the second diode, the second end of the third capacitor is grounded, and the eighth resistor is connected with the third capacitor in parallel.

In a second aspect, the embodiment of the present invention further provides a display device, which includes the first aspect of the present safety type power supply constant current power supply circuit.

The embodiment of the utility model provides a pair of this ampere of type power supply constant current supply circuit, through voltage conversion circuit 10 convert the standard DC voltage of this ampere of type power supply 100 output into the required AC voltage of jumbo size LED display screen, drive circuit 40 combines first voltage control circuit 30 to control the AC voltage of energy-saving control circuit 20 output to change the voltage of energy-saving control circuit 20 output. In addition, the energy-saving control circuit is also used for controlling the magnitude of the driving current output by the energy-saving control circuit through the input voltage, so that the driving current cannot change along with the change of the load, and further the low-power constant current control of the LED is realized. Therefore, compared with the prior art, the embodiment of the utility model provides a technical scheme has solved the unable problem to the power supply of jumbo size LED display screen of this ampere of type power, and can reduce the consumption under the condition that does not reduce the display effect through energy-conserving control circuit.

Drawings

Fig. 1 is a schematic structural diagram of a constant current power supply circuit of an intrinsically safe power supply provided by an embodiment of the present invention;

fig. 2 is a schematic structural diagram of another intrinsically safe power supply constant current supply circuit provided in an embodiment of the present invention;

fig. 3 is a schematic structural diagram of another intrinsically safe power supply constant current supply circuit provided in an embodiment of the present invention;

fig. 4 is a schematic structural diagram of another intrinsically safe power supply constant current supply circuit provided in an embodiment of the present invention;

fig. 5 is a schematic structural diagram of another intrinsically safe power supply constant current supply circuit provided in an embodiment of the present invention;

fig. 6 is a schematic structural diagram of another intrinsically safe power supply constant current supply circuit provided in an embodiment of the present invention;

fig. 7 is a schematic structural diagram of another intrinsically safe power supply constant current supply circuit provided in an embodiment of the present invention;

fig. 8 is a schematic structural diagram of another intrinsically safe power supply constant current supply circuit provided in an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

As described in the background art, the power supply standard of the constant current drive board of the large-size LED display screen is the standard of direct current 24V, but for the intrinsic safety type power supply used in the underground coal mine, the intrinsic safety type power supply in the prior art cannot reach the power supply required by the constant current drive board of the large-size display screen, and cannot meet the requirements of special products. To this end, the embodiment of the utility model provides an this ampere of type power constant current supply circuit converts this ampere of type standard DC voltage into alternating voltage through voltage conversion circuit, and this alternating voltage provides the power for jumbo size display screen after the transformer steps up to realize low-power consumption constant current control through energy-saving control circuit. The embodiment of the utility model provides a technical scheme can solve this ampere of class standard power supply and can't reduce the consumption that shows the product under the condition that does not reduce display effect to the drive control problem of the constant current drive plate of display screen.

Fig. 1 is a schematic structural diagram of a constant current power supply circuit of an intrinsically safe power supply provided by an embodiment of the present invention. Referring to fig. 1, an embodiment of the present invention provides an intrinsically safe power supply constant current power supply circuit, including: a voltage conversion circuit 10, an energy-saving control circuit 20, a first voltage control circuit 30, and a drive circuit 40; the voltage conversion circuit 10 comprises an input end A1 and an output end A2, the input end A1 of the voltage conversion circuit 10 is electrically connected with the intrinsic safety type power supply 100, and the voltage conversion circuit 10 is used for converting the direct-current voltage output by the intrinsic safety type power supply 100 into alternating-current voltage and outputting the alternating-current voltage from the output end A2 thereof; the energy-saving control circuit 20 comprises an input end B1, an output end B2 and a control end B3, the input end B1 of the energy-saving control circuit 20 is electrically connected with the output end A2 of the voltage conversion circuit 10, and the output end B2 of the energy-saving control circuit 20 is electrically connected with the LED; the driving circuit 40 comprises a power supply end E1 and an output end E2, the power supply end E1 of the driving circuit 40 is electrically connected with the intrinsic safety type power supply 100, and the driving circuit 40 is used for generating a driving control signal to drive the LED to emit light; the first voltage control circuit 30 includes an input terminal F1 and an output terminal F2, the input terminal F1 of the first voltage control circuit 30 is electrically connected to the output terminal E2 of the driving circuit 40, and the output terminal F2 of the first voltage control circuit 30 is electrically connected to the control terminal B3 of the power saving control circuit 20.

The embodiment of the utility model provides an intrinsically safe type power supply constant current supply circuit, for example can be applicable to for the jumbo size display screen power supply more than 32 inches to it is luminous to drive LED. On the basis that the display screen can normally display, the output current is controlled by the energy-saving control circuit to be not changed along with the change of the load, so that the LED is controlled to emit light by low-power-consumption constant current. Specifically, the intrinsically safe power supply 100 outputs a standard dc voltage to the input terminal a1 of the voltage conversion circuit 10, and the voltage conversion circuit 10 performs voltage conversion on the dc voltage input at the input terminal a1 thereof to convert the dc voltage into an ac voltage. The ac voltage is boosted by a booster circuit to be raised to an ac voltage required for lighting the LED. Meanwhile, the energy-saving control circuit 20 controls the driving current output by itself by using the voltage, so that the driving current output by the energy-saving control circuit 20 does not change with the change of a Load (LED), and the constant current control of the LED is realized. The driving circuit 40 is supplied with a power voltage by the intrinsically safe power supply 100, and the driving circuit 40 is configured to generate a driving control signal to drive the LED to emit light. The control terminal B3 of the energy-saving control circuit 20 receives the driving control signal output by the output terminal E2 of the driving circuit 40, and under the action of the driving control signal, the energy-saving control circuit 20 increases the ac voltage output by the voltage conversion module 10 to the voltage required by the large-size LED display screen. The first voltage control circuit 30 is connected between the output end E2 of the driving circuit 40 and the control end B3 of the energy-saving control circuit 20 to realize the automatic regulation and control of the voltage required by the large-size LED display screen. For example, the first voltage control circuit 30 can control the voltage outputted to the control terminal B3 of the energy-saving control circuit 20, so as to control the voltage outputted by the energy-saving control circuit 30, and further change the voltage outputted to the LED.

The embodiment of the utility model provides a pair of this ampere of type power supply constant current supply circuit, through voltage conversion circuit 10 convert the standard DC voltage of this ampere of type power supply 100 output into the required AC voltage of jumbo size LED display screen, drive circuit 40 combines first voltage control circuit 30 to control the AC voltage of energy-saving control circuit 20 output to change the voltage of energy-saving control circuit 20 output. In addition, the energy-saving control circuit is also used for controlling the magnitude of the driving current output by the energy-saving control circuit through the input voltage, so that the driving current cannot change along with the change of the load, and further the low-power constant current control of the LED is realized. Therefore, compared with the prior art, the embodiment of the utility model provides a technical scheme has solved the unable problem to the power supply of jumbo size LED display screen of this ampere of type power, and can reduce the consumption under the condition that does not reduce the display effect through energy-conserving control circuit.

Optionally, fig. 2 is a schematic structural diagram of another intrinsically safe power constant current supply circuit provided in an embodiment of the present invention, and with reference to fig. 2, the voltage conversion circuit 10 includes a fuse F, a first capacitor C1 and a transformer L; a first end of the fuse F is electrically connected to the intrinsically safe power supply 100, a second end of the fuse F is electrically connected to an input end of the transformer L, an output end of the transformer L is electrically connected to the input end B1 of the energy saving control circuit 20, a first end of the first capacitor C1 is electrically connected to the input end of the transformer L, and a second end of the first capacitor C1 is grounded.

Specifically, the intrinsically safe power supply 100 outputs a standard dc voltage, which is limited by a fuse F to prevent the current output by the intrinsically safe power supply 100 from being too large; and filtering is performed through a first capacitor C1, and the filtered dc voltage is inverted into an ac voltage through a transformer L, wherein the transformer L can directly convert the dc voltage into the ac voltage. The transformer L converts the dc voltage output by the intrinsically safe power supply 100 into an ac voltage, which is convenient for a subsequent circuit to convert the ac voltage output by the voltage conversion circuit 10 into a voltage required for lighting the LED. Illustratively, the transformer L may be a voltage conversion system capable of converting a direct current voltage into an alternating current voltage. By using the principle of an oscillator, the direct current voltage output by the intrinsically safe power supply 100 is converted into a pulse alternating current voltage with the magnitude changing along with time through an oscillating circuit (not shown), the pulse alternating current voltage removes a direct current component through a DC blocking circuit, and only an alternating current component is reserved; only the pulsed ac voltage of the ac component is transformed via the transformer L to the voltage required by the LEDs.

Optionally, fig. 3 is a schematic structural diagram of another intrinsically safe power supply constant current power supply circuit provided in an embodiment of the present invention, and with reference to fig. 3, the energy saving control circuit 20 includes a first transistor Q1, a second transistor Q2, a first resistor R1, a first voltage regulator D1, a second voltage regulator D2, and a second capacitor C2; a first pole of the first transistor Q1 and a first pole of the second transistor Q2 are electrically connected to the output terminal F2 of the first voltage control circuit 30 through a first resistor R1, a second pole of the first transistor Q1 is electrically connected to the output terminal a2 of the voltage conversion circuit 10, a third pole of the first transistor Q1 is grounded, a second pole of the second transistor Q2 is electrically connected to the second pole of the first transistor Q1, and a third pole of the second transistor Q2 is grounded; the first end of a first voltage regulator tube D1 is electrically connected with the second end of a second transistor Q2, the second end of a first voltage regulator tube D1 is electrically connected with the LED, a second voltage regulator tube D2 is connected with the first voltage regulator tube D1 in parallel, the first end of a second capacitor C2 is electrically connected with the second end of the first voltage regulator tube D1, and the second end of the second capacitor C2 is grounded.

Specifically, the first transistor Q1 and the second transistor Q2 are used for equalizing alternating current output by the voltage conversion circuit 10, and the first transistor Q1 and the second transistor Q2 are both field effect transistors, which can convert the voltage output by the voltage conversion circuit 10 into current to realize constant current driving control of the LED. Illustratively, when the first transistor Q1 and the second transistor Q2 are operated in a saturation region, the current (drain current) of the second pole of the first transistor Q1 or the second transistor Q2 may be approximate to a current controlled by the voltage (gate-source voltage) between the first pole and the second pole, that is, when the voltage of the second pole of the first transistor Q1 or the second transistor Q2 is constant, the current of the second pole and the voltage between the first pole and the second pole satisfy a certain functional relationship, and as long as the voltage between the first pole and the second pole is constant, the current of the second pole is constant, so as to realize a constant current output. The first voltage regulator tube D1 and the second voltage regulator tube D2 are used for stabilizing the voltage output by the first transistor Q1 and the second transistor Q2, and filtering the voltage through the second capacitor C2, so that the voltage output by the energy-saving control circuit 20 is ensured to be stable, and the power supply stability of the LED is improved. The first resistor R1 is a sampling resistor, and is used for collecting the voltage output by the first voltage control circuit 30 and controlling the first transistor Q1 and the second transistor Q2 to be turned on. The first resistor R1 can be wound by constantan wire to reduce the influence of temperature on the resistance of the first resistor R1.

Optionally, fig. 4 is a schematic structural diagram of another intrinsically safe power supply constant current supply circuit according to an embodiment of the present invention, and referring to fig. 4, the first voltage control circuit 30 includes a first transistor Q3, a second transistor Q4, and a second resistor R2; a first pole of the first transistor Q3 is electrically connected to the output terminal E2 of the driving circuit 40, a second pole of the first transistor Q3 is electrically connected to a first end of the second resistor R2, a second end of the second resistor R2 is electrically connected to the power supply terminal E1 and the output terminal E2 of the driving circuit 20, respectively, and a third pole of the first transistor Q3 is electrically connected to the control terminal B3 of the power-saving control circuit 20; a first pole of the second transistor Q4 is grounded, a second pole of the second transistor Q4 is electrically connected to a first terminal of a second resistor R2, and a third pole of the second transistor Q4 is electrically connected to a control terminal B3 of the power-saving control circuit 20.

Specifically, a first pole of the first transistor Q3 receives the driving control signal output by the driving circuit 40, and a second pole of the first transistor is electrically connected to the power supply terminal E1 of the driving circuit 40 through a second resistor, that is, the intrinsically safe power supply 100 provides a power supply voltage for the first transistor Q3 after dividing and limiting the voltage through the second resistor R2; the driving control signal controls the first transistor Q3 to be turned on, and the third transistor of the first transistor Q3 outputs a control voltage to the control terminal B3 of the power saving control circuit 20 to provide a driving voltage for the first electrodes of the first transistor Q1 and the second transistor Q2. The first triode Q3 and the second triode Q4 are of a common collector structure and form a voltage follower, so that the input of the first voltage control circuit 30 presents high impedance, the output presents low impedance, and the impedance matching function can be achieved. In the normal operation process of the first voltage control circuit 30, the first voltage control circuit 30 may be equivalent to a constant voltage source for the energy-saving control circuit 20, that is, the voltage sampled by the first resistor R1 is not changed by the change of the load, so that the output current of the energy-saving control circuit 20 is controlled by the input voltage of the first voltage control circuit 30, the output current of the energy-saving control circuit 20 is not changed by the change of the load, and the constant current driving control is realized.

Optionally, fig. 5 is a schematic structural diagram of another intrinsic safety type constant current power supply circuit according to an embodiment of the present invention, and referring to fig. 5, the driving circuit 40 includes a driving chip U1 and a third resistor R3, and the driving chip U1 includes a power supply terminal 1, a signal output terminal 2, a first voltage calibration terminal 3, and a second voltage calibration terminal 4; the power source terminal 1 of the driving chip U1 is electrically connected to the intrinsically safe power source 100, the signal output terminal 2 of the driving chip U1 is electrically connected to the input terminal F1 of the first voltage control circuit 30, and the first voltage calibration terminal 3 of the driving chip U1 is electrically connected to the second voltage calibration terminal 4 through the third resistor R3.

Specifically, the driving chip U1 is used for generating a driving control signal to drive the LED to emit light, for example, the driving control signal may be a PWM signal. The intrinsically safe power supply 100 provides a power voltage for the driver chip U1, and after the driver chip U1 normally operates, the PWM driving control signal is output from the signal output terminal 2 to the input terminal F1 of the first voltage control circuit 30, so as to drive the first voltage control circuit 30 to normally operate. The third resistor R3 is a voltage calibration resistor, and is used for calibrating the voltage of the PWM driving control signal output by the driving chip U1, so as to ensure the accuracy of the driving control signal output by the driving chip U1.

Optionally, with continued reference to fig. 5, the constant current power supply circuit of the intrinsically safe power supply further includes an enable control circuit 50, and the driving circuit 40 further includes an enable terminal; the enable control circuit 50 includes a fourth resistor R4, a first end of the fourth resistor R4 is connected to the enable control signal EN, and a second end of the fourth resistor R4 is electrically connected to the enable end of the driving circuit 40. Specifically, the enable terminal of the driving circuit 40 is directly connected to the enable terminal 5 of the driving chip U1, and the enable control circuit 50 receives the enable control signal EN and controls the activation of the driving chip U1 through the enable control signal EN. Illustratively, the enable control signal EN is output to the enable control terminal 5 of the driver chip U1 through a fourth resistor R4 (which may also include a capacitor), and controls the output PWM driving control signal of the driver chip U1. When the enable control signal EN is at a high level (3-5V), the driving chip U1 works normally; when the enable control signal EN is at a low level (less than 0.7V), the driver chip U1 is completely turned off and does not output the PWM driving control signal. The enabling control circuit 50 has a simple structure and a fast dynamic response speed, and can perform on-off control on the driving circuit 40 without a compensation circuit, thereby controlling the LED.

Optionally, fig. 6 is the structural schematic diagram of another kind of this ampere of type power supply constant current supply circuit that the embodiment of the utility model provides, on the basis of above-mentioned each embodiment, refer to fig. 6, the utility model provides an this ampere of type power supply constant current supply circuit still includes second voltage control circuit 60, and second voltage control circuit 60 includes input G1 and output G2, and input G1 of second voltage control circuit 60 is connected with this ampere of type power supply 100 electricity, and output G2 of second voltage control circuit 60 is connected with drive circuit 40's power end E1 electricity.

Specifically, the second voltage control circuit 60 is configured to regulate the voltage of the power supply end 1 of the driving chip U1 input by the intrinsically safe power supply 100, so as to ensure that the voltage received by the driving chip U1 does not fluctuate, which is beneficial to implementing the constant current control of the constant current power supply circuit of the intrinsically safe power supply. The second voltage control circuit 60 comprises a fifth resistor R5, a sixth resistor R6, a third triode Q5 and a third regulator D3; a first end of the fifth resistor R5 is electrically connected to the intrinsically safe power supply 100, a second end of the fifth resistor R5 is electrically connected to a first terminal of the third transistor Q5, a second terminal of the third transistor Q5 is electrically connected to the intrinsically safe power supply 100 through the sixth resistor R6, and a third terminal of the third transistor Q5 is electrically connected to the power supply terminal E1 of the driving circuit 40; a first terminal of a third regulator D3 is electrically connected to the second pole of the third transistor Q5, and a second terminal of the third regulator D3 is grounded. The fifth resistor R5 is a current limiting resistor for limiting the output current of the intrinsically safe power supply 100 to prevent damage to the third transistor Q5. The third voltage regulator D3 is used to stabilize the output voltage of the intrinsically safe power supply 100, so that the voltage input by the power supply terminal 1 of the driver chip U1 will not fluctuate. The third pole of the third transistor Q5 is also electrically connected to the first pole of the first transistor Q3, which can amplify the output current of the intrinsically safe power supply 100 to increase the drive capability of the first transistor Q3.

Optionally, fig. 7 is a schematic structural diagram of another intrinsically safe power supply constant current power supply circuit provided by an embodiment of the present invention, referring to fig. 7 on the basis of the above embodiments, an intrinsically safe power supply constant current power supply circuit provided by an embodiment of the present invention further includes a dimming circuit 70, the dimming circuit 70 includes an input end H1 and an output end H2, the input end H1 of the dimming circuit 70 is connected to a dimming control signal DIM, and the output end H2 of the dimming circuit 70 is electrically connected to the output end B2 of the energy saving control circuit 20; the dimming circuit 70 includes a first diode D4, a seventh resistor R7, a second diode D5, a third capacitor C3, and an eighth resistor R8; the first end of the first diode D4 is connected to the dimming control signal DIM, the second end of the first diode D4 is electrically connected to the first end of the second diode D5 through the seventh resistor R7, the second end of the second diode D5 is electrically connected to the output terminal B2 of the power saving control circuit 20, the first end of the third capacitor C3 is electrically connected to the second end of the second diode D5, the second end of the third capacitor C3 is grounded, and the eighth resistor R8 is connected in parallel to the third capacitor C3.

The dimming control signal DIM may be a decoded output voltage of a decoding driving display panel (not shown), and the output voltage of the energy-saving control circuit 70 is divided by the dimming circuit 70 composed of the first diode D4, the seventh resistor R7, the second diode D5, the third capacitor C3 and the eighth resistor R8. That is, the dimming circuit 70 can pull down the voltage output by the power saving control circuit 20 to different degrees according to the magnitude of the dimming control signal DIM to reduce the output voltage of the power saving control circuit 20, thereby changing the brightness of the LED. Illustratively, the voltage output by the energy-saving control circuit 20 is 80V, the light-emitting brightness of the LED reaches the maximum under the action of the 80V voltage, at this time, the dimming control signal DIM is controlled to be 5V, the 80V voltage output by the energy-saving control circuit 20 is pulled down to 60V by the dimming circuit 70, and then the output current of the energy-saving control circuit 20 is reduced, so that the light-emitting brightness of the LED is reduced.

Optionally, fig. 8 is a schematic structural diagram of another intrinsically safe power constant current supply circuit provided by an embodiment of the present invention, on the basis of each of the above embodiments, the circuit shown in fig. 8 is taken as an example to specifically describe the working principle of the intrinsically safe power constant current supply circuit provided by the embodiment of the present invention.

The intrinsically safe power supply 100 outputs a dc voltage of 12V, and the transformer L may be a voltage conversion system capable of converting the dc voltage into an ac voltage. By using the principle of an oscillator, the direct-current voltage output by the intrinsically safe power supply 100 is converted into a pulse alternating-current voltage with the magnitude changing along with time through a fuse F and an oscillation circuit (not shown), the pulse alternating-current voltage removes a direct-current component through a DC blocking circuit, and only an alternating-current component is reserved; only the pulsed ac voltage of the ac component is transformed via the transformer L to the voltage required by the LEDs. The first transistor Q1 and the second transistor Q2 are used for equalizing alternating current output by the voltage conversion circuit 10, and the first transistor Q1 and the second transistor Q2 are both field effect transistors, and can convert the voltage output by the voltage conversion circuit 10 into current to realize constant current driving control of the LED. When the first transistor Q1 and the second transistor Q2 operate in the saturation region, the current (drain current) of the second pole of the first transistor Q1 or the second transistor Q2 may be approximate to a current controlled by the voltage between the first pole and the second pole (gate-source voltage), that is, when the voltage of the second pole of the first transistor Q1 or the second transistor Q2 is constant, the current of the second pole and the voltage between the first pole and the second pole satisfy a certain functional relationship, and as long as the voltage between the first pole and the second pole is constant, the current of the second pole is constant, so that the constant current output is realized. The first voltage regulator tube D1 and the second voltage regulator tube D2 are used for stabilizing the voltage output by the first transistor Q1 and the second transistor Q2, and filtering the voltage through the second capacitor C2, so that the voltage output by the energy-saving control circuit 20 is ensured to be stable, and the power supply stability of the LED is improved. The first resistor R1 is a sampling resistor, and is used for collecting the voltage output by the first voltage control circuit 30 and controlling the first transistor Q1 and the second transistor Q2 to be turned on. The first resistor R1 can be wound by constantan wire to reduce the influence of temperature on the resistance of the first resistor R1.

The driving chip U1 is used for generating a driving control signal to drive the LED to emit light. The voltage output by the intrinsically safe power supply 100 is stabilized by the second voltage control circuit 60 and then provides power supply voltage for the driving chip U1, under the action of the enable control signal EN, the driving chip U1 works normally and outputs a driving signal to the input end F1 of the first voltage control circuit 30, the first pole of the first triode Q3 receives the driving control signal output by the driving circuit 40, and the second pole of the first triode Q3 is electrically connected with the power supply end E1 of the driving circuit 40 through a second resistor, namely, the intrinsically safe power supply 100 provides power supply voltage for the first triode Q3 after being divided and limited by the second resistor R2; the driving control signal controls the first transistor Q3 to be turned on, and the third transistor of the first transistor Q3 outputs a control voltage to the control terminal B3 of the power saving control circuit 20 to provide a driving voltage for the first electrodes of the first transistor Q1 and the second transistor Q2. The first triode Q3 and the second triode Q4 are of a common collector structure and form a voltage follower, so that the input of the first voltage control circuit 30 presents high impedance, the output presents low impedance, and the impedance matching function can be achieved. In the normal operation process of the first voltage control circuit 30, the first voltage control circuit 30 may be equivalent to a constant voltage source for the energy-saving control circuit 20, that is, the voltage sampled by the first resistor R1 is not changed by the change of the load, so that the output current of the energy-saving control circuit 20 is controlled by the input voltage of the first voltage control circuit 30, the output current of the energy-saving control circuit 20 is not changed by the change of the load, and the constant current driving control is realized. The dimming circuit 70 can pull down the voltage output by the energy saving control circuit 20 to different degrees according to the magnitude of the dimming control signal DIM, so as to reduce the output voltage of the energy saving control circuit 20, that is, reduce the output current of the energy saving control circuit 20, thereby changing the brightness of the LED. It is right the embodiment of the utility model provides an this ampere of type power supply constant current supply circuit adopts HSPICE to carry out emulation verification, and the result shows in 8 ~ 14V input voltage within ranges, and circuit output current can reach 1A the most, and the output current precision is steerable within 5.5%, and power efficiency can reach 97%.

The embodiment of the utility model provides a pair of this ampere of type power supply constant current supply circuit, through voltage conversion circuit 10 convert the standard DC voltage of this ampere of type power supply 100 output into the required AC voltage of jumbo size LED display screen, drive circuit 40 combines first voltage control circuit 30 to control the AC voltage of energy-saving control circuit 20 output to change the voltage of energy-saving control circuit 20 output. In addition, the energy-saving control circuit is also used for controlling the magnitude of the driving current output by the energy-saving control circuit through the input voltage, so that the driving current cannot change along with the change of the load, and further the low-power constant current control of the LED is realized. Therefore, compared with the prior art, the embodiment of the utility model provides a technical scheme has solved the unable problem to the power supply of jumbo size LED display screen of this ampere of type power, and can reduce the consumption under the condition that does not reduce the display effect through energy-conserving control circuit. The brightness control of the intrinsic safety type power supply on the large-size LED display screen is met to a certain extent, and the situation that the large-size LED display screen cannot be used in a coal mine is changed.

Optionally, the embodiment of the utility model provides a display device is still provided, and this display device can be the large-size LED display screen. The embodiment of the utility model provides a display device includes the intrinsic safe type power constant current supply circuit that above-mentioned arbitrary embodiment provided, consequently the embodiment of the utility model provides a display device also possesses the beneficial effect that above-mentioned arbitrary embodiment described.

It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.

Claims (10)

1. The constant current supply circuit of the intrinsic safety type power supply is characterized by comprising: the energy-saving control circuit comprises a voltage conversion circuit, an energy-saving control circuit, a first voltage control circuit and a driving circuit;

the voltage conversion circuit comprises an input end and an output end, the input end of the voltage conversion circuit is electrically connected with the intrinsic safety type power supply, and the voltage conversion circuit is used for converting direct-current voltage output by the intrinsic safety type power supply into alternating-current voltage and outputting the alternating-current voltage from the output end of the intrinsic safety type power supply;

the energy-saving control circuit comprises an input end, an output end and a control end, wherein the input end of the energy-saving control circuit is electrically connected with the output end of the voltage conversion circuit, and the output end of the energy-saving control circuit is electrically connected with the LED;

the driving circuit comprises a power end and an output end, the power end of the driving circuit is electrically connected with the intrinsic safety type power supply, and the driving circuit is used for generating a driving control signal to drive the LED to emit light;

the first voltage control circuit comprises an input end and an output end, the input end of the first voltage control circuit is electrically connected with the output end of the driving circuit, and the output end of the first voltage control circuit is electrically connected with the control end of the energy-saving control circuit.

2. The intrinsically safe constant current power supply circuit of claim 1, wherein the voltage conversion circuit comprises a fuse, a first capacitor and a transformer;

the first end of the protective tube is electrically connected with the intrinsic safety type power supply, the second end of the protective tube is electrically connected with the input end of the transformer, the output end of the transformer is electrically connected with the input end of the energy-saving control circuit, the first end of the first capacitor is electrically connected with the input end of the transformer, and the second end of the first capacitor is grounded.

3. The intrinsic safety type power supply constant-current power supply circuit of claim 1, wherein the energy-saving control circuit comprises a first transistor, a second transistor, a first resistor, a first voltage regulator tube, a second voltage regulator tube and a second capacitor;

a first pole of the first transistor and a first pole of the second transistor are both electrically connected with the output end of the first voltage control circuit through the first resistor, a second pole of the first transistor is electrically connected with the output end of the voltage conversion circuit, a third pole of the first transistor is grounded, a second pole of the second transistor is electrically connected with the second pole of the first transistor, and a third pole of the second transistor is grounded;

the first end of the first voltage-regulator tube is electrically connected with the second end of the second transistor, the second end of the first voltage-regulator tube is electrically connected with the LED, the second voltage-regulator tube is connected with the first voltage-regulator tube in parallel, the first end of the second capacitor is electrically connected with the second end of the first voltage-regulator tube, and the second end of the second capacitor is grounded.

4. The intrinsically safe power supply constant-current power supply circuit of claim 1, wherein the first voltage control circuit comprises a first triode, a second triode and a second resistor;

a first pole of the first triode is electrically connected with the output end of the driving circuit, a second pole of the first triode is electrically connected with a first end of the second resistor, a second end of the second resistor is respectively electrically connected with a power supply end and the output end of the driving circuit, and a third pole of the first triode is electrically connected with a control end of the energy-saving control circuit;

the first pole of the second triode is grounded, the second pole of the second triode is electrically connected with the first end of the second resistor, and the third pole of the second triode is electrically connected with the control end of the energy-saving control circuit.

5. The intrinsic safety type power supply constant-current power supply circuit as claimed in claim 1, wherein the driving circuit comprises a driving chip and a third resistor, the driving chip comprises a power supply end, a signal output end, a first voltage calibration end and a second voltage calibration end;

the power end of the driving chip is electrically connected with the intrinsic safety type power supply, the signal output end of the driving chip is electrically connected with the input end of the first voltage control circuit, and the first voltage calibration end of the driving chip is electrically connected with the second voltage calibration end through the third resistor.

6. The intrinsic safety type power supply constant-current power supply circuit as claimed in claim 1, further comprising an enable control circuit, wherein the driving circuit further comprises an enable terminal;

the enabling control circuit comprises a fourth resistor, a first end of the fourth resistor is connected to an enabling control signal, and a second end of the fourth resistor is electrically connected with an enabling end of the driving circuit.

7. The intrinsically safe power supply constant-current power supply circuit of claim 1, further comprising a second voltage control circuit, wherein the second voltage control circuit comprises an input end and an output end, the input end of the second voltage control circuit is electrically connected with the intrinsically safe power supply, and the output end of the second voltage control circuit is electrically connected with a power supply end of the driving circuit.

8. The intrinsic safety type power supply constant-current power supply circuit as claimed in claim 7, wherein the second voltage control circuit comprises a fifth resistor, a sixth resistor, a third triode and a third voltage regulator tube;

a first end of the fifth resistor is electrically connected with the intrinsic safety type power supply, a second end of the fifth resistor is electrically connected with a first electrode of the third triode, a second electrode of the third triode is electrically connected with the intrinsic safety type power supply through the sixth resistor, and a third electrode of the third triode is electrically connected with a power supply end of the driving circuit;

and the first end of the third voltage-stabilizing tube is electrically connected with the second pole of the third triode, and the second end of the third voltage-stabilizing tube is grounded.

9. The intrinsic safety type power supply constant-current power supply circuit of claim 1, further comprising a dimming circuit, wherein the dimming circuit comprises an input end and an output end, the input end of the dimming circuit is connected with a dimming control signal, and the output end of the dimming circuit is electrically connected with the output end of the energy-saving control circuit; the dimming circuit comprises a first diode, a seventh resistor, a second diode, a third capacitor and an eighth resistor;

the first end of the first diode is connected to the dimming control signal, the second end of the first diode is electrically connected with the first end of the second diode through the seventh resistor, the second end of the second diode is electrically connected with the output end of the energy-saving control circuit, the first end of the third capacitor is electrically connected with the second end of the second diode, the second end of the third capacitor is grounded, and the eighth resistor is connected with the third capacitor in parallel.

10. A display device comprising the intrinsically safe power supply constant current supply circuit as claimed in any one of claims 1 to 9.

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