CN116264751A

CN116264751A - LED constant-current driving circuit structure for realizing wide working voltage

Info

Publication number: CN116264751A
Application number: CN202111537481.6A
Authority: CN
Inventors: 邹一照; 冯雪阳
Original assignee: CRM ICBG Wuxi Co Ltd
Current assignee: CRM ICBG Wuxi Co Ltd
Priority date: 2021-12-15
Filing date: 2021-12-15
Publication date: 2023-06-16

Abstract

The invention relates to an LED constant current driving circuit structure for realizing wide working voltage, which comprises a band gap reference voltage circuit module, a voltage control module and a voltage control module, wherein the band gap reference voltage circuit module is used for generating bias voltage and reference voltage with zero temperature coefficient; a PTAT current generation circuit module generating an output current through an enable signal, a reference voltage, and a bias voltage; the LED mirror current module generates a plurality of groups of bias currents through a current mirror structure; and the 8 LED constant current source circuit modules respectively receive bias current and drive the LED lamp. By adopting the LED constant-current driving circuit structure for realizing wide working voltage, constant LED driving current can be provided, and the current can be adjusted. The invention adopts a 5V tube design, and can provide constant LED driving current in a wider working voltage range. When the invention works, an external power supply does not need to be connected with an LDO for voltage stabilization. The LED constant current source driving circuit not only can output LED driving current, but also can be used as a common cathode COM port for LED scanning to bear the filling current of more than 110 mA.

Description

LED constant-current driving circuit structure for realizing wide working voltage

Technical Field

The invention relates to the field of integrated circuits, in particular to the field of LED driving circuits, and particularly relates to an LED constant current driving circuit structure for realizing wide working voltage.

Background

The LED is used as a novel light source, has the characteristics of energy conservation, environmental protection and high efficiency, is mature in technology and is widely applied to various fields such as illumination, display and the like. The LED is used as a constant-current working load, the requirement on working voltage is severe, and the working performance of the LED can be influenced by too high and too low voltage. In different application environments, the power supply voltage may fluctuate, so that in order to ensure better performance and longer service life of the LED, the LED driving circuit is generally required to be designed to be driven by constant current.

The conventional AC/DC or DC/DC constant voltage control cannot play a role in constant current driving, and can also influence the brightness and service life of the LEDs. In the current direct current low-voltage power supply application, such as lithium battery, lead-acid battery, direct current power supply and the like, the step-down constant current technology is adopted to drive the LEDs, so that the LED driving circuit has the advantages of low power consumption, high efficiency and the like, but the LED driving current needs to be monitored in real time, and the circuit is complex and the cost is high.

In an integrated circuit, an LED driving circuit is often used to directly drive an external LED lamp through a bi-directional input/output port, but display brightness is easily affected by a power supply voltage. If the power supply voltage is reduced, the driving current is reduced, and the external LED lamp is darkened; if the power supply voltage increases, the driving current increases and the external LED lamp becomes bright.

In the prior art, the brightness of an LED lamp is easily affected by the power supply voltage, when the power supply voltage is low, the driving current is reduced, and the external LED lamp is darkened; when the power supply voltage is higher, the driving current is increased, and the external LED lamp is lightened. For the display effect of the LED, the power port of the integrated circuit is often added with LDO to provide a stable power supply voltage; in order to improve the brightness of the LED lamp, a triode is commonly used to drive the LED lamp. These all increase the overall cost and complexity of the system.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide the LED constant current driving circuit structure which has the advantages of small power consumption, high efficiency and wider application range and realizes wide working voltage.

In order to achieve the above object, the LED constant current driving circuit for achieving a wide operating voltage of the present invention has the structure as follows:

the LED constant current driving circuit structure for realizing wide working voltage is mainly characterized by comprising:

the band-gap reference voltage circuit module is used for generating bias voltage and zero temperature coefficient reference voltage;

the PTAT current generation circuit module is connected with the band gap reference voltage circuit module and is used for generating output current through an enabling signal, a reference voltage and a bias voltage;

the LED mirror current module is connected with the PTAT current generation circuit module and is used for generating a plurality of groups of bias currents through a current mirror structure;

and the 8 LED constant current source circuit modules are connected with the LED mirror current modules and respectively receive bias current to drive the LED lamps.

Preferably, the PTAT current generating circuit module comprises a first operational amplifier, a first PMOS tube and a resistor, wherein the first operational amplifier receives bias voltage and enabling signals, the inverting input end receives reference voltage as reference voltage, the non-inverting input end is connected with the drain electrode of the first PMOS tube, the output end is connected with the grid electrode of the first PMOS tube, the drain electrode of the first PMOS tube is further connected with the resistor, the other end of the resistor is grounded, and the source electrode of the first PMOS tube is connected with external power supply voltage.

Preferably, the LED mirror current module includes a second PMOS transistor, a third PMOS transistor, a fourth PMOS transistor, and a fifth PMOS transistor, where a drain of the second PMOS transistor is connected to a source of the third PMOS transistor, the source of the second PMOS transistor is connected to an external power supply voltage, a drain of the fourth PMOS transistor is connected to a source of the fifth PMOS transistor, and the source of the fourth PMOS transistor is connected to the external power supply voltage; the gates of the first PMOS tube, the third PMOS tube and the fifth PMOS tube are all connected, and the third PMOS tube, the fifth PMOS tube and the first PMOS tube are all connected with a current mirror.

Preferably, the LED mirror current module further comprises a first NMOS tube, a third NMOS tube, a fourth NMOS tube, and 16 pairs of NMOS tube groups, wherein the first NMOS tube, the third NMOS tube, the fourth NMOS tube, and the 16 pairs of NMOS tube groups form a high swing common source common gate current mirror structure, a drain electrode of the first NMOS tube is connected with a drain electrode of the third PMOS tube, a source electrode of the first NMOS tube is grounded, a gate electrode of the first NMOS tube is connected with the drain electrode, a drain electrode of the third NMOS tube is connected with a drain electrode of the fifth PMOS tube, a source electrode of the third NMOS tube is connected with a drain electrode of the fourth NMOS tube, a source electrode of the fourth NMOS tube is grounded, and a gate electrode of the fourth NMOS tube is connected with a drain electrode of the third NMOS tube;

each NMOS tube group comprises an upper NMOS tube and a lower NMOS tube, the source electrode of the upper NMOS tube is connected with the drain electrode of the lower NMOS tube, the grid electrode of the upper NMOS tube of each NMOS tube group is connected with the grid electrode of the first NMOS tube, the grid electrode of the lower NMOS tube of each NMOS tube group is connected with the grid electrode of the fourth NMOS tube, the source electrode of the lower NMOS tube is grounded, the drain electrode of the upper NMOS tube generates bias current to form 8 groups of bias current, and the bias current is output to the LED constant current source circuit module.

Preferably, the LED constant current source circuit module comprises a second operational amplifier, a sixth PMOS tube, a seventh PMOS tube, an eighth PMOS tube, a ninth PMOS tube and a tenth NMOS tube, wherein the non-inverting input end of the second operational amplifier is connected with the drain electrode of the seventh PMOS tube, the inverting input end is connected with the drain electrode of the eighth PMOS tube, the output end is connected with the grid electrode of the ninth PMOS tube,

the drain electrode of the seventh PMOS tube IS connected with the source electrode of the sixth PMOS tube, the drain electrode of the eighth PMOS tube IS connected with the source electrode of the ninth PMOS tube, the drain electrode of the ninth PMOS tube IS connected with the drain electrode of the tenth NMOS tube, the source electrode of the tenth NMOS tube IS grounded, and the drain electrode of the sixth PMOS tube IS connected with constant current IS2<0>.

Preferably, the 8 LED constant current source circuit modules are respectively provided with a constant current source output port, and the constant current source output ports are connected to the drain electrode of the ninth PMOS tube.

Preferably, the LED constant current source circuit module further includes a control terminal connected to the second operational amplifier, and receives a control signal ENH <0>, where the control signal ENH <0> IS obtained by selecting a signal phase from an enable signal and the LED segment, and the constant current source output port outputs the LED constant current source under the condition of high level ENH <0>, and the bias current IS1<0> of the LED mirror current module provides the bias current for the second operational amplifier.

Preferably, the LED constant current source circuit module further includes a function selecting end connected to the gate of the tenth NMOS transistor, and receiving a signal ENL <0>, where the constant current source output port is an analog channel as the LED constant current driving port in the case that AIEN <0> is low level; when AIEN <0> is high, the constant current source output port is a digital channel and is used as a COM port for LED scanning.

Preferably, the constant current source output ports of the 8 constant current source circuit modules are sequentially set as common cathode COM ports of the LEDs, and the rest 7 constant current source output ports are used as driving ports of the LEDs.

Preferably, the width-to-length ratio of the first PMOS transistor, the third PMOS transistor and the fifth PMOS transistor is 3:2:2.

By adopting the LED constant-current driving circuit structure for realizing wide working voltage, constant LED driving current can be provided, and the current can be adjusted. The invention adopts a 5V tube design, and can provide constant LED driving current in a wider working voltage range. When the invention works, an external power supply does not need to be connected with an LDO for voltage stabilization. The LED constant current source driving circuit not only can output LED driving current, but also can be used as a common cathode COM port for LED scanning to bear the filling current of more than 110 mA.

Drawings

Fig. 1 is a schematic diagram of an LED constant current driving circuit for realizing a wide operating voltage according to the present invention.

Fig. 2 is a schematic diagram of a PTAT current generation circuit module and an LED mirror current module of the LED constant current driving circuit structure for realizing a wide operating voltage according to the present invention.

Fig. 3 is a schematic diagram of an LED constant current source circuit module of the LED constant current driving circuit structure for realizing a wide operating voltage according to the present invention.

Detailed Description

In order to more clearly describe the technical contents of the present invention, a further description will be made below in connection with specific embodiments.

The invention discloses an LED driving circuit, which does not need an external triode to drive an LED lamp, directly drives the LED lamp through a bidirectional input/output port, reduces the overall cost, has the characteristic of wide working voltage, and improves the display performance because the LED driving current is not influenced by external power supply voltage VDD. The invention has the advantages of wide working voltage, constant driving current and low cost, and has better display effect.

As shown in fig. 1, the LED constant current driving circuit structure for realizing a wide operating voltage of the present invention includes:

a band gap reference voltage circuit module for generatingBias voltage and zero temperature coefficient reference voltage；

the LED mirror current module LED_IBIAS is connected with the PTAT current generation circuit module and is used for generating a plurality of groups of bias currents through a current mirror structure;

and the 8 LED constant current source circuit modules IO_LEDs are connected with the LED mirror current modules and respectively receive bias current to drive the LED lamps.

At least 2 LED constant current source circuit modules IO_LEDs can drive 2 LED lamps; in the embodiment of the invention, the number of the LED constant current source circuit modules IO_LEDs is 8, and the maximum number of the LED lamps can be 8×7.

The bandgap reference voltage circuit generates a bias voltage VA and a zero temperature coefficient 1.2V reference voltage, and both VBG and VA are input to the PTAT module to generate a PTAT current independent of the supply voltage. Before LEDEN is enabled, ENVB needs to be enabled.

As shown in fig. 2, the PTAT current generation circuit module includes a first operational amplifier, a first PMOS tube and a resistor, the first operational amplifier receives a bias voltage and an enable signal, the inverting input terminal receives a reference voltage as a reference voltage, the non-inverting input terminal is connected with the drain of the first PMOS tube, the output terminal is connected with the gate of the first PMOS tube, the drain of the first PMOS tube is further connected with the resistor, the other end of the resistor is grounded, and the source of the first PMOS tube is connected with an external power supply voltage.

In the PTAT current generation circuit, LEDEN is an enabling signal, VA provides bias voltage for the operational amplifier, VBG is input to an inverting input end of the operational amplifier to serve as reference voltage, output voltage VBH of the operational amplifier is connected to a gate end of a first PMOS tube P0, a drain end VX of the first PMOS tube P0 is connected to a resistor R0 to the ground, and VX is fed back to an in-phase input end of the operational amplifier. According to the principle of "virtual short" and "virtual break" of the operational amplifier, vx=vbg, so that the current flowing through the first PMOS transistor P0 and the resistor R0 is a constant value, and is not affected by the supply voltage, iptat=vbg/R0, about 12uA.

As shown in fig. 2, the LED mirror current module includes a second PMOS transistor, a third PMOS transistor, a fourth PMOS transistor, and a fifth PMOS transistor, where a drain of the second PMOS transistor is connected to a source of the third PMOS transistor, the source of the second PMOS transistor is connected to an external power supply voltage, a drain of the fourth PMOS transistor is connected to a source of the fifth PMOS transistor, and the source of the fourth PMOS transistor is connected to the external power supply voltage; the gates of the first PMOS tube, the third PMOS tube and the fifth PMOS tube are all connected, and the third PMOS tube, the fifth PMOS tube and the first PMOS tube are all connected with a current mirror.

As a preferred embodiment of the invention, the LED mirror current module further comprises a first NMOS tube, a third NMOS tube, a fourth NMOS tube and 16 pairs of NMOS tube groups, wherein the first NMOS tube, the third NMOS tube, the fourth NMOS tube and the 16 pairs of NMOS tube groups form a high-swing common-source common-gate current mirror structure, the drain electrode of the first NMOS tube is connected with the drain electrode of the third PMOS tube, the source electrode of the first NMOS tube is grounded, the grid electrode of the first NMOS tube is connected with the drain electrode, the drain electrode of the third NMOS tube is connected with the drain electrode of the fifth PMOS tube, the source electrode of the third NMOS tube is connected with the drain electrode of the fourth NMOS tube, the source electrode of the fourth NMOS tube is grounded, and the grid electrode of the fourth NMOS tube is connected with the drain electrode of the third NMOS tube;

In the LED mirror current module LED_IBIAS, the third PMOS tube P2, the fifth PMOS tube P4 and the first PMOS tube P0 in the PTAT form a current mirror, and the width-to-length ratio of the first PMOS tube P0, the third PMOS tube P2 and the fifth PMOS tube P4 is 3:2:2, so that the currents IT1 and IT2 are about 8uA. Meanwhile, a first NMOS tube N0, a third NMOS tube N2 and a fourth NMOS tube N3, N17 and N27, …, N10 and N20, N37 and N47, …, N30 and N40 in the LED mirror current module form a high-swing-amplitude cascode current mirror structure, the structure IS high in output impedance, large in output swing amplitude and small in influence of power supply voltage, the current proportion of 1:1 can be relatively accurately achieved, and 8 groups of bias currents IS1< i > = IT1, IS2< i > = 5×IT1 are generated by utilizing two paths of currents IT1 and IT2, and

i IS

0, 1, …, 6 and 7 respectively. Thus, IS1< i > IS about 8uA and IS2< i > IS about 40uA. These 8 sets of bias currents are supplied to the 8 LED constant current source output ports PT1<0>, PT1<1>, … PT1<7>, respectively.

The 8 sets of image currents IS1<0> and IS2<0>, IS1<1> and IS2<1>, IS1<2> and IS2<2>, IS1<3> and IS2<3>, IS1<4> and IS2<4>, IS1<5> and IS2<5>, IS1<6> and IS2<6>, IS1<7> and IS2<7> generated by the LED mirror current module are connected to 8 LED constant current source circuits IO_LED, respectively, which 8 LED constant current source circuits IO_LED are connected to external bi-directional input ports PT1<0>, PT1<1>, … PT1<7>, respectively.

As shown in fig. 3, the LED constant current source circuit module includes a second operational amplifier, a sixth PMOS transistor, a seventh PMOS transistor, an eighth PMOS transistor, a ninth PMOS transistor, and a tenth NMOS transistor, where the in-phase input terminal of the second operational amplifier is connected to the drain of the seventh PMOS transistor, the inverting input terminal is connected to the drain of the eighth PMOS transistor, and the output terminal is connected to the gate of the ninth PMOS transistor.

The port of connection of the LED constant current source circuit IO_LED is PT1<0>. IS1<0> provides a stable bias current to the second operational amplifier I1, IS2<0> IS an input constant current source for mirroring to produce a larger output constant current source.

The LED constant current driving circuit consists of a second operational amplifier I1 and PMOS tubes P5-P8. LEDEN is the enable signal of the LED module, LEDSEG <0> is the LED segment select signal of PT1<0>, LEDEN, LEDSEG <0> and, when ENH <0> is obtained, ENH <0> is high, LED constant current source output of PT1<0> is allowed, thereby lighting the external LED lamp. According to the principle of 'virtual short' and 'virtual break' of the operational amplifier, the voltages of the two input ends of the second operational amplifier I1 are equal, namely VN=VP, so that the voltages of the three ends of the seventh PMOS tube P6 and the eighth PMOS tube P7 are equal, and the current can be accurately calculated according to 1: m is mirrored to achieve the purpose of constant current output. LEDCUR0<1:0> is the current selection signal of the PT1<0> constant current driving circuit, mmin is 200, mmax is 400, namely PT1<0> output constant current source is 8mA at minimum and 16mA at maximum.

AIEN <0> is the function select signal for the PT1<0> port and IO_BGDRV is the high current drive enable for the COM port during LED scanning. When AIEN <0> is at a low level, PT1<0> is configured as an analog channel, and the functions of input, output and pull-up of the bidirectional input/output port are forbidden, and the bidirectional input/output port is only used as an LED constant current driving port; when AIEN <0> is high, PT1<0> is configured as a digital channel, at this time, if PT1<0> is set to output low level, CN <0> will be high level, when IO_BGDRV is high level, ENL <0> is high level, PT1<0> will output low level with strong driving capability, can bear 110mA or more of filling current, and is used as COM port during LED scanning.

The 8 LED driving ports PT1<0>, PT1<1>, … and PT1<7> can be sequentially provided with a common cathode COM port with one port being an LED, and the other 7 ports are used as LED end driving ports, so that external 7 LED lamps can be driven simultaneously at the moment; throughout the scanning period, up to 56 LED lamps can be driven.

ENVB, LEDEN, AIEN <7:0>, IO_BGDRV, LEDCUR0<1:0>, LEDCUR1<1:0>, … LEDCUR7<1:0>, LEDCEG <7:0> are from a digital control circuit. ENVB enables a band gap reference voltage circuit; LEDEN enables the whole LED constant current driving circuit; AIEN <7:0> sets whether each LED constant current driving port is used as a constant current output port or a COM port used as a current input port; when the LED constant current driving port is used as a COM port for current input, the IO_BGDRV can enable large current driving; LEDCUR0<1:0>, LEDCUR1<1:0>, … LEDCUR7<1:0> are used for controlling the output current of each LED constant current driving port; LEDSEG <7:0> determines whether each LED constant current module outputs a constant current source.

As a preferred embodiment of the invention, the 8 LED constant current source circuit modules are respectively provided with constant current source output ports, and the constant current source output ports are connected to the drain electrode of the ninth PMOS tube.

As a preferred embodiment of the invention, the LED constant current source circuit module further comprises a control end connected with the second operational amplifier and receiving a control signal ENH <0>, wherein the control signal ENH <0> IS obtained by selecting a signal phase with an LED segment by an enabling signal, the output port of the constant current source outputs an LED constant current source under the condition of high level of ENH <0>, and the bias current IS1<0> of the LED mirror current module provides bias current for the second operational amplifier.

As a preferred embodiment of the invention, the LED constant current source circuit module further comprises a function selection end connected with the grid electrode of the tenth NMOS tube, and receiving a signal ENL <0>, wherein the output port of the constant current source is an analog channel as an LED constant current driving port under the condition that AIEN <0> is low level; when AIEN <0> is high, the constant current source output port is a digital channel and is used as a COM port for LED scanning.

As a preferred embodiment of the invention, the constant current source output ports of the 8 LED constant current source circuit modules are sequentially arranged as common cathode COM ports of LEDs, and the rest 7 constant current source output ports are used as driving ports of the LEDs.

As a preferred embodiment of the invention, the aspect ratio of the first PMOS tube, the third PMOS tube and the fifth PMOS tube is 3:2:2.

The circuit has a simple structure, 2 bidirectional input/output ports can only drive one LED lamp at the same time, if the LED lamp is scanned in a time-sharing way, n constant current driving ports can drive n x (n-1) LED lamps at most, and the circuit is suitable for small LED display screens formed by the LED lamps, such as display screens of body scales and kitchen scales. The constant current sources of the circuit structure are all mirrored from the same mirror current module LED_IBIAS, and the current error among the constant current sources is small.

The circuit structure has wide working voltage range and is suitable for the working occasions of double batteries and three batteries. The output current of the circuit structure is constant, the brightness of a single LED lamp or a plurality of LED lamps is the same at the same time, and the display effect is good. The output current of the circuit structure can be adjusted. The external power supply does not need to be connected with LDO voltage stabilization, nor a triode is needed to provide large driving current, and the cost is low.

In this specification, the invention has been described with reference to specific embodiments thereof. It will be apparent, however, that various modifications and changes may be made without departing from the spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

Claims

1. The LED constant current driving circuit structure for realizing wide working voltage is characterized by comprising:

the PTAT current generation circuit module is connected with the band gap reference voltage circuit module and is used for generating output current through an external enabling signal LEDEN, the reference voltage and the bias voltage;

the LED mirror current module is connected with the PTAT current generation circuit module and is used for generating a plurality of groups of bias currents;

and the LED constant current source circuit modules are connected with the LED mirror current modules and respectively receive the bias current, so that the LED lamp is driven.

2. The LED constant current driving circuit structure for realizing wide working voltage according to claim 1, wherein the PTAT current generating circuit module comprises a first operational amplifier, a first PMOS tube and a resistor, wherein the first operational amplifier receives the bias voltage and the enabling signal, an inverting input end receives the reference voltage as a reference voltage, an in-phase input end is connected with a drain electrode of the first PMOS tube, an output end is connected with a grid electrode of the first PMOS tube, the drain electrode of the first PMOS tube is also connected with the resistor, the other end of the resistor is grounded, and a source electrode of the first PMOS tube is connected with an external power supply voltage.

3. The LED constant current driving circuit structure for realizing wide working voltage according to claim 2, wherein the LED mirror current module comprises a second PMOS tube, a third PMOS tube, a fourth PMOS tube and a fifth PMOS tube, wherein the drain electrode of the second PMOS tube is connected with the source electrode of the third PMOS tube, the source electrode of the second PMOS tube is connected with the external power supply voltage, the drain electrode of the fourth PMOS tube is connected with the source electrode of the fifth PMOS tube, and the source electrode of the fourth PMOS tube is connected with the external power supply voltage; the grid electrodes of the first PMOS tube, the third PMOS tube and the fifth PMOS tube are sequentially connected, and the third PMOS tube, the fifth PMOS tube and the first PMOS tube form the current mirror structure.

4. The LED constant current driving circuit structure for realizing wide working voltage according to claim 3, wherein the LED mirror current module further comprises a first NMOS tube, a third NMOS tube, a fourth NMOS tube and a plurality of NMOS tube groups, wherein the first NMOS tube, the third NMOS tube, the fourth NMOS tube and the 16 pair NMOS tube groups form a high swing common source common gate current mirror structure, the drain electrode of the first NMOS tube is connected with the drain electrode of the third PMOS tube, the source electrode of the first NMOS tube is grounded, the grid electrode of the first NMOS tube is connected with the drain electrode of the first NMOS tube, the drain electrode of the third NMOS tube is connected with the drain electrode of the fifth NMOS tube, the source electrode of the third NMOS tube is connected with the drain electrode of the fourth NMOS tube, the source electrode of the fourth NMOS tube is grounded, and the grid electrode of the fourth NMOS tube is connected with the drain electrode of the third NMOS tube;

each NMOS tube group comprises an upper NMOS tube and a lower NMOS tube, the source electrode of the upper NMOS tube is connected with the drain electrode of the lower NMOS tube, the grid electrode of the upper NMOS tube of each NMOS tube group is connected with the grid electrode of the first NMOS tube, the grid electrode of the lower NMOS tube of each NMOS tube group is connected with the grid electrode of the fourth NMOS tube, the source electrode of the lower NMOS tube of each NMOS tube group is grounded, the drain electrodes of the upper NMOS tubes of each NMOS tube group respectively generate bias currents, and the bias currents generated by each NMOS tube group are output to the corresponding LED constant current source circuit modules.

5. The LED constant current driving circuit structure for realizing wide operating voltage according to claim 1, wherein said LED constant current source circuit module comprises a second operational amplifier, a sixth PMOS transistor, a seventh PMOS transistor, an eighth PMOS transistor, a ninth PMOS transistor, a tenth NMOS transistor, said second operational amplifier having an in-phase input connected to the drain of said seventh PMOS transistor, an inverting input connected to the drain of said eighth PMOS transistor, an output connected to the gate of said ninth PMOS transistor,

the grid electrodes of the sixth PMOS tube, the seventh PMOS tube and the eighth PMOS tube are all connected to one point and are connected with the drain electrode of the sixth PMOS tube, the source electrode of the seventh PMOS tube and the source electrode of the eighth PMOS tube are both connected with the external power supply voltage, the drain electrode of the seventh PMOS tube IS connected with the source electrode of the sixth PMOS tube, the drain electrode of the eighth PMOS tube IS connected with the source electrode of the ninth PMOS tube, the drain electrode of the ninth PMOS tube IS connected with the drain electrode of the tenth NMOS tube, the source electrode of the tenth NMOS tube IS grounded, and the drain electrode of the sixth PMOS tube IS connected with constant current IS2<0>.

6. The LED constant current driving circuit structure for realizing a wide operating voltage according to claim 5, wherein said plurality of LED constant current source circuit modules each have a constant current source output port connected to the drain of said ninth PMOS transistor.

7. The LED constant current driving circuit structure according to claim 6, wherein said LED constant current source circuit module further comprises a control terminal connected to said second operational amplifier for receiving an LED current output enable signal ENH <0>, said LED current output enable signal ENH <0> being obtained by performing an and operation on said external enable signal LEDEN and an LED segment select signal LEDSEG <0>, said constant current source output port outputting an LED constant current source in case said LED current output enable signal ENH <0> IS at a high level, said LED mirror current module for providing said second operational amplifier with said bias current IS1<0>.

8. The LED constant current driving circuit structure for realizing a wide operating voltage according to claim 6, wherein said LED constant current source circuit module further comprises a function selecting terminal connected to the gate of said tenth NMOS transistor, for receiving an LED current input enable signal ENL <0>, and in case that the function selecting signal AIEN <0> is low level, said constant current source output port is an analog channel as an LED constant current driving port; when the function selection signal AIEN <0> is at a high level, the constant current source output port is a digital channel, and is used as a COM port for LED scanning.

9. The LED constant current driving circuit structure for realizing wide operating voltage according to claim 6, wherein the constant current source output ports of the plurality of LED constant current source circuit modules are sequentially provided with common cathode COM ports, one of which is LED, and the other ports are LED constant current source output ports.

10. The LED constant current driving circuit structure for realizing wide operating voltage according to claim 3, wherein the width-to-length ratio of the first PMOS transistor, the third PMOS transistor and the fifth PMOS transistor is 3:2:2.