CN110096089B - Driving circuit and display device - Google Patents
Driving circuit and display device Download PDFInfo
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- CN110096089B CN110096089B CN201910346418.0A CN201910346418A CN110096089B CN 110096089 B CN110096089 B CN 110096089B CN 201910346418 A CN201910346418 A CN 201910346418A CN 110096089 B CN110096089 B CN 110096089B
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/10—Regulating voltage or current
- G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
- G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
- G05F1/575—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices characterised by the feedback circuit
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Abstract
The embodiment of the application provides a driving circuit and a display device, and relates to the technical field of circuits. The driving circuit comprises a reference voltage input unit, a first current mirror unit and a constant current output unit, wherein the first current mirror unit comprises a first branch and a second branch. The reference voltage input unit is used for forming a negative feedback loop with the first branch circuit to generate a reference current, and the first current mirror unit is used for processing the reference current according to a preset mirror image ratio to obtain a mirror image current; the constant current output unit is used for generating a constant current signal to the load according to the mirror current. The application can realize convenient adjustment of the mirror ratio of the first current mirror unit.
Description
Technical Field
The application relates to the technical field of circuits, in particular to a driving circuit and a display device.
Background
At present, an LED (LIGHT EMITTING Diode) display device generally adopts a driving circuit to realize display driving, but in order to adapt to different application occasions, the output current range of the driving circuit generally needs to be adaptively adjusted according to different types or different types of display devices adopted in different application occasions, but the existing driving circuit cannot be adaptively adjusted for different display devices.
Disclosure of Invention
In view of the foregoing, embodiments of the present application provide a driving circuit and a display device, as follows.
In one aspect, an embodiment of the present application provides a driving circuit, including a reference voltage input unit, a first current mirror unit, and a constant current output unit, where the first current mirror unit includes a first branch and a second branch;
the first input end of the reference voltage input unit is used for being externally connected with a reference power supply;
the first input end of the first branch and the first input end of the second branch are respectively used for being connected with the output end of the reference voltage input unit so as to acquire branch working voltage;
The second input end of the first branch is used for being externally connected with a first control signal, the second input end of the second branch is used for being externally connected with a second control signal, and the first branch and the second branch are used for realizing the adjustment of the mirror ratio according to the first control signal and the second control signal; the output end of the first branch is used for being connected with the second input end of the reference voltage input unit;
the first input end of the constant current output unit is used for being connected with the output end of the second branch, the second input end is used for being externally connected with a first working voltage source, and the output end is used for being connected with a load;
The reference voltage input unit is used for forming a negative feedback loop with the first branch circuit to generate a reference current, the first current mirror unit is used for processing the reference current according to a preset mirror ratio to obtain a mirror current, and the constant current output unit is used for generating a constant current signal for driving the load to the load according to the mirror current.
In an option of the embodiment of the present application, the first branch includes a first sub-switch and a plurality of first switch units;
the first input end of the first sub-switch is used for being connected with the output end of the reference voltage input unit, the second input end of the first sub-switch is used for being externally connected with a second working voltage source, and the output end of the first sub-switch is used for being connected with the second input end of the reference voltage input unit;
the first input end of each first switch unit is used for being connected with the output end of the reference voltage input unit, the second input end is used for being externally connected with a second working voltage source, the third input end is used for being externally connected with a first control signal so as to adjust the turn-off state of the first switch unit under the control of the first control signal, and the output end is used for being connected with the second input end of the reference voltage input unit.
In an option of the embodiment of the present application, each of the first switch units includes a second sub-switch and a third sub-switch;
The first input end of the second sub-switch is used for being connected with the output end of the reference voltage input unit, the second input end of the second sub-switch is used for being connected with the second working voltage source, and the output end of the second sub-switch is used for being connected with the first input end of the third sub-switch;
The second input end of the third sub-switch is used for being externally connected with a first control signal to adjust the turn-off state of the third sub-switch under the control of the first control signal, and the output end of the third sub-switch is used for being connected with the second input end of the reference voltage input unit.
In an embodiment of the present application, the first sub-switch and each of the second sub-switches are PMOS (Positive CHANNEL METAL Oxide Semiconductor, P-type metal-oxide-semiconductor) transistors, and gates of the PMOS transistors are used as first input ends of the first sub-switch and the second sub-switch, drains of the PMOS transistors are used as second input ends of the first sub-switch and the second sub-switch, and sources of the PMOS transistors are used as output ends of the first sub-switch and the second sub-switch.
In an embodiment of the present application, the number of the first switch units is 2 M-1, M >0, and the first control signal is implemented by using a thermometer code.
In an option of the embodiment of the present application, the second branch includes a fourth sub-switch and a plurality of second switch units;
the first input end of the fourth sub-switch is used for being connected with the output end of the reference voltage input unit, the second input end of the fourth sub-switch is used for being externally connected with a second working voltage source, and the output end of the fourth sub-switch is used for being connected with the first input end of the constant current output unit;
the first input end of each second switch unit is respectively used for being connected with the output end of the reference voltage input unit, the second input end is respectively used for being connected with the second working voltage source, the third input end is respectively used for being externally connected with a second control signal so as to adjust the turn-off state of the second switch unit under the control of the second control signal, and the output end is respectively used for being connected with the first input end of the constant current output unit.
In the selection of the embodiment of the present application, the number of the second switch units is 2 N -1, n >0, and the second control signal is implemented by using a binary code value.
In an option of an embodiment of the present application, the mirror ratio of the first current mirror unit isWherein M is the number of first switch units in the first branch, N is the number of second switch units in the second branch, DR [ j ] is the first control signal, DI [ i ] is the second control signal, i, j are integers greater than or equal to 0.
In an option of the embodiment of the present application, the reference voltage input unit includes a first error amplifier and a built-in resistor;
The first input end of the first error amplifier is used for being connected with the reference power supply, the second input end of the first error amplifier is used for being connected with the output end of the first branch, and the output end of the first error amplifier is used for being respectively connected with the first input end of the first branch and the first input end of the second branch;
one end of the built-in resistor is connected with the output end of the first branch circuit, and the other end of the built-in resistor is grounded.
In an option of the embodiment of the present application, the constant current output unit includes a second error amplifier and a second current mirror unit;
The first input end of the second error amplifier is used for being connected with the output end of the second branch, the second input end of the second error amplifier is used for being connected with the first working voltage source, and the output end of the second error amplifier is used for being connected with the first input end of the second current mirror unit;
The second input end of the second current mirror unit is used for being connected with the output end of the second branch circuit, and the output end of the second current mirror unit is used for being connected with the load.
In an option of the embodiment of the present application, the second current mirror unit includes a first MOS device and a second MOS device;
The grid electrode of the first MOS device is used for being connected with the output end of the second error amplifier, the drain electrode of the first MOS device is used for being connected with the output end of the second branch circuit, and the source electrode of the first MOS device is grounded;
and the grid electrode of the second MOS device is used for being connected with the output end of the second error amplifier, the drain electrode of the second MOS device is used for being connected with the load, and the source electrode of the second MOS device is grounded.
On the other hand, the embodiment of the application also provides a display device which comprises the driving circuit.
In the driving circuit and the display device provided by the embodiment of the application, through ingenious design of the circuit structure, the mirror ratio of the first current mirror unit can be conveniently adjusted through the first control signal and the second control signal, so that the driving circuit can be used for display driving of different types of display devices. In addition, the first current mirror unit in the implementation of the application is formed by a plurality of unit current sources, so that the current mismatch of the driving circuit is constant in different application occasions and is irrelevant to the output current.
In order to make the above objects, features and advantages of the present application more comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a block diagram of a driving circuit according to an embodiment of the present application.
Fig. 2 is a schematic circuit diagram of a negative feedback loop formed by the reference voltage input unit and the first current mirror unit shown in fig. 1.
Fig. 3 is a schematic circuit diagram of the first current mirror unit shown in fig. 1.
Fig. 4 is a circuit configuration diagram of the constant current output unit shown in fig. 1.
Fig. 5 is a schematic circuit diagram of a driving circuit according to an embodiment of the present application.
Fig. 6 is a schematic device structure diagram of a MOS device constituting the first current mirror unit.
Icon: 10-a driving circuit; 11-a reference voltage input unit; 110-a first error amplifier; 111-built-in resistor; 12-a first current mirror unit; 120-a first branch; 1200-a first sub-switch; 1201-a first switching unit; 1202-a second sub-switch; 1203-third sub-switch; 121-a second leg; 1210-a fourth sub-switch; 1211-a second switching unit; 13-a constant current output unit; 130-a second error amplifier; 131-a second current mirror unit; 1310-a first MOS device; 1311-second MOS devices.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, but not all embodiments of the present application. The components of the embodiments of the present application generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the application, as presented in the figures, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures. In the description of the present application, the terms "first, second, third, fourth, etc. are used merely to distinguish between the descriptions and are not to be construed as merely or implying relative importance.
In the description of the present application, unless explicitly stated and limited otherwise, the terms "disposed," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present application will be understood in specific cases by those of ordinary skill in the art.
As shown in fig. 1, a driving circuit 10 provided by an embodiment of the present application may include a reference voltage input unit 11, a first current mirror unit 12, and a constant current output unit 13, where the first current mirror unit 12 includes a first branch 120 and a second branch 121. The reference voltage input unit 11 and the first branch 120 form a negative feedback loop to generate a reference current, the first current mirror unit 12 formed by the first branch 120 and the second branch 121 processes the reference current according to a preset mirror ratio to obtain a mirror current, and the constant current output unit 13 generates a constant current signal for driving the load according to the mirror current.
Specifically, referring to fig. 1 again, a first input end of the reference voltage input unit 11 is used for externally connecting a reference power supply to obtain a reference voltage Vref; the first input end of the first branch 120 and the first input end of the second branch 121 are respectively connected to the output end of the reference voltage input unit 11 to obtain a branch working voltage; a second input end of the first branch 120 is used for being externally connected with a first control signal, a second input end of the second branch 121 is used for being externally connected with a second control signal, and the first branch 120 and the second branch 121 are used for realizing adjustment of the mirror ratio according to the first control signal and the second control signal; the output end of the first branch 120 is used for being connected with the second input end of the reference voltage input unit 11; the first input end of the constant current output unit 13 is used for being connected with the output end of the second branch 121, the second input end is used for being externally connected with a first working voltage source, and the output end is used for being connected with a load.
In the foregoing driving circuit 10 according to the embodiment of the present application, the mirror ratio of the first current mirror unit 12 may be quickly and conveniently adjusted in the form of control words (e.g., the first control signal and the second control signal) so as to increase the range of the output current of the driving circuit 10, and be used for display driving of different types of display devices.
In detail, the reference voltage input unit 11 is used for acquiring a reference voltage during the operation of the driving circuit 10. As shown in fig. 2, in one embodiment, the reference voltage input unit 11 may include a first error amplifier 110 and a built-in resistor 111. Wherein, a first input end of the first error amplifier 110 is used for being connected with the reference power supply, a second input end is used for being connected with an output end of the first branch 120, and an output end is used for being respectively connected with a first input end of the first branch 120 and a first input end of the second branch 121; one end of the built-in resistor 111 is connected to the output end of the first branch 120, and the other end is grounded. Alternatively, the reference power source may be, but not limited to, a bandgap reference source inside the chip, and the sizes, types, etc. of the first error amplifier 110 and the built-in resistor 111 may be selected according to actual requirements, which is not limited herein.
In addition, as shown in fig. 2, the first branch circuit 120 may include a first sub-switch 1200 and a plurality of first switching units 1201; a first input end of the first sub-switch 1200 is used for being connected with an output end of the reference voltage input unit 11, a second input end is used for being externally connected with a second working voltage source, and an output end is used for being connected with a second input end of the reference voltage input unit 11; the first input end of each first switch unit 1201 is respectively connected to the output end of the reference voltage input unit 11, the second input end is respectively connected to the external second working voltage source, the third input end is respectively connected to the external first control signal, the turn-off state of each switch in the first switch unit is adjusted under the control of the first control signal, so that the mirror ratio of the first current mirror unit 12 is adjusted, and the output end is respectively connected to the second input end of the reference voltage input unit 11.
In practical implementation, since the reference voltage input unit 11 and the first branch 120 in the present application can form a negative feedback loop for generating a reference current, the reference voltage Vref provided by the reference power supply can be processed through the negative feedback loop formed by the first error amplifier 110, the first branch 120 and the built-in resistor 111 shown in fig. 2 to generate a reference current I0, where i0=vref/Rext, where Vref represents the reference voltage, rext is the resistance value of the built-in resistor 111, and it should be noted that, in the driving circuit in the embodiment of the present application, the resistance value of the built-in resistor 111 determines the magnitude of the reference current I0.
In addition, as can be seen from the negative feedback loop shown in fig. 2, when the driving circuit 10 provided in the embodiment of the present application generates the reference current, no additional external resistor is required to be set for adjusting the reference current, and the first control signal controls the on-off number of the first switch unit 1201 to realize the adjustment of the reference current, so that the number of PINs in the driving circuit 10 is effectively reduced, and meanwhile, the circuit design cost and the circuit power consumption of the driving circuit 10 can be reduced.
As an embodiment, referring to fig. 2 again, each of the first switch units 1201 may include a second sub-switch 1202 and a third sub-switch 1203 for controlling the on-off state of the second sub-switch 1202. Wherein, a first input end of the second sub-switch 1202 is used for being connected with an output end of the reference voltage input unit 11, a second input end is used for being connected with the second working voltage source, and an output end is used for being connected with a first input end of the third sub-switch 1203; a second input end of the third sub-switch 1203 is configured to be externally connected with a first control signal to adjust an off state of the third sub-switch under control of the first control signal, and an output end of the third sub-switch is configured to be connected with a second input end of the reference voltage input unit 11.
Alternatively, the first sub-switch 1200 and each of the second sub-switches 1202 may be, but not limited to, PMOS transistors, where gates of the PMOS transistors are used as first input terminals of the first sub-switch 1200 and the second sub-switch 1202, drains of the PMOS transistors are used as second input terminals of the first sub-switch 1200 and the second sub-switch 1202, and sources of the PMOS transistors are used as output terminals of the first sub-switch 1200 and the second sub-switch 1202. In addition, the number of the first switch units 1201 may be 2 M-1, M >0, and the first control signal DR [ j ] may be implemented by using a thermometer code, where j is greater than or equal to 0. In addition, the third sub-switch 1203 may also use, but is not limited to, a MOS transistor or other type of transistor.
Further, in the embodiment of the present application, the first branch 120 is configured to form a negative feedback loop with the reference voltage input unit 11 as shown in fig. 2, and also form a first current mirror unit 12 with the second branch 121 as shown in fig. 3, and the first current mirror unit 12 may obtain a precisely matched mirror current based on the reference current.
Referring to fig. 3 again, the second branch 121 may include a fourth sub-switch 1210 and a plurality of second switch units 1211; a first input end of the fourth sub-switch 1210 is used for being connected with an output end of the reference voltage input unit 11, a second input end is used for being externally connected with a second working voltage source, and an output end is used for being connected with a first input end of the constant current output unit 13; the first input end of each second switch unit 1211 is respectively connected to the output end of the reference voltage input unit 11, the second input end is respectively connected to the second working voltage source, the third input end is respectively connected to a second control signal externally, so as to adjust the turn-off state of the second switch unit under the control of the second control signal, and the output end is respectively connected to the first input end of the constant current output unit 13.
It should be noted that, similar to the first branch 120, each of the second switch units 1211 in the second branch 121 provided in the embodiment of the present application is similar to the circuit structure of the first switch unit 1201, for example, each of the second switch units 1211 may also include a second sub-switch 1202 and a third sub-switch 1203. In actual implementation, the first input end of the second sub-switch 1202 in the second branch 121 is used for being connected to the output end of the reference voltage input unit 11, the second input end is used for being connected to the second working voltage source, and the output end is used for being connected to the first input end of the third sub-switch 1203; the second input end of the third sub-switch 1203 is used for externally connecting a second control signal to adjust the turn-off state of the third sub-switch under the control of the first control signal, and the output end is used for being connected with the first input end of the constant current output unit 13.
Optionally, the third sub-switch 1203 and the fourth sub-switch 1210 in the second switch unit 1211 may be, but are not limited to, PMOS transistors. In addition, the number of the second switch units 1211 is 2 N -1, n >0, and the second control signal may be implemented with, but not limited to, binary code values.
Based on the first current mirror unit 12 described above, assuming that the first sub-switch 1200 and the second sub-switch 1202 are all PMOS devices, when the plurality of PMOS devices have the same bias voltage, the output current of each PMOS device is proportional to the device size, so that the plurality of PMOS devices with the same size may be used to form the first current mirror unit 12 as described above in the embodiment of the present application, and the mirror ratio of the first current mirror unit 12 is determined by the number of PMOS devices in the on state, and then the number of PMOS devices in the first current mirror unit 12 may be adjusted by the first control signal and the second control signal to obtain the desired preset mirror ratio.
Further, according to practical requirements, in the first current mirror unit 12 shown in fig. 3, the first branch 120 and the second branch 121 are each formed by a unit current source (such as PMOS devices), and each PMOS device in the first branch 120 and the second branch 121 has the same gate-source and drain-source bias voltages, that is, the ratio of the mirrored current output by the first current mirror unit 12 to the reference current output by the negative feedback loop is equal to the ratio of the number of PMOS devices in the first branch 120 in the connected state to the number of PMOS devices in the second branch 121 in the conducting state, that is, the ratio of the mirrored current output by the first current mirror unit 12 to the reference current output by the negative feedback loop is determined by the code values corresponding to the two sets of control signals (control words) of the first control signal DR and the second control signal DI.
For example, when the number of the first switch units 1201 is 2 M-1, M >0, the number of the second switch units 1211 is 2 N -1, N >0, the code value corresponding to the first control signal is DR [ j ], and the code value corresponding to the second control signal is DI [ i ], the mirror ratio of the first current mirror unit 12 isThat is, the ratio of the mirror current output by the first current mirror unit 12 to the reference current output by the negative feedback loop is
It should be noted that, the code value corresponding to the first control signal is DR [ j ] and the code value corresponding to the second control signal is DI [ i ] may be implemented by writing the register, which is not described herein.
Further, in order to precisely control the gate-source voltage and the drain-source voltage in the first current mirror unit 12 in the driving circuit 10 and comprehensively consider the balance between the driving capability of the current mirror and the circuit power consumption when designing the driving circuit 10, the driving circuit 10 according to the embodiment of the present application may adopt a current mirror structure twice, once the first current mirror unit 12 described above, and another time may add a current mirror structure in the constant current output unit 13.
Specifically, as an embodiment, as shown in fig. 4, the constant current output unit 13 may include a second error amplifier 130 and a second current mirror unit 131; a first input end of the second error amplifier 130 is used for being connected with an output end of the second branch 121, a second input end is used for being connected with the first working voltage source (VCRES), and an output end is used for being connected with a first input end of the second current mirror unit 131; a second input terminal of the second current mirror unit 131 is configured to be connected to an output terminal of the second branch 121, and an output terminal is configured to be connected to the load.
According to actual requirements, the second current mirror unit 131 may include a first MOS device 1310 and a second MOS device 1311; the gate of the first MOS device 1310 is connected to the output end of the second error amplifier 130, the drain is connected to the output end of the second branch 121, and the source is grounded; the gate of the second MOS device 1311 is used to connect to the output terminal of the second error amplifier 130, the drain is used to connect to the load, and the source is grounded.
In practical implementation, assuming that the first MOS device 1310 and the second MOS device 1311 may be respectively formed by a plurality of NMOS transistors with the same size but different numbers, and each NMOS transistor forms a current mirror structure under the same bias voltage, the output current Iout (constant current signal) of the driving circuit 10 may beWhere K is the mirror ratio of the second current mirror unit 131.
Based on the above description of the driving circuit 10, as shown in fig. 5, assuming that the first sub-switch 1200 and the second sub-switch 1202 in the first current mirror unit 12 are PMOS devices, the first MOS device 1310 and the second MOS device 1311 in the second current mirror unit 131 may be respectively formed by a plurality of NMOS transistors with the same size but different numbers, and the mirror ratio of the second current mirror unit 131 is K, then the principle of constant current mismatch during the operation of the driving circuit 10 given in the present application will be described below.
First, the current mismatch in the first current mirror unit 12 according to the present application is mainly determined by the unit current sources constituting the circuit, such as PMOS devices, and then, when the PMOS devices constituting the first current mirror unit 12 are in the deep saturation region, the current mismatch in the first current mirror unit 12 is mainly derived from the mismatch of the threshold voltages δ Vth of the PMOS devices.
Next, referring to fig. 6 in combination, the ratio of the equivalent mismatch current δ I of the mos device to the drain current I ds is:
where W is the width of the conduction channel in the PMOS device, L is the length of the conduction channel in the PMOS device, delta Vth is the variation of threshold voltage introduced by mismatch, Kappa is a scale factor, and is dependent on the process of the PMOS device, the kappa can be obtained according to the PMOS device modelTherefore, on the premise that the output signal is constant and the L value of the PMOS device is unchanged, the ratio of the equivalent mismatch current delta I of the PMOS device to the source drain current I ds is irrelevant to the W value of the device.
In practical applications, therefore, although the driving circuit 10 needs to be adapted to a plurality of applications, so that the current range of the output constant current signal Iout needs to be generally changed between 0.5mA and 20mA, since the matching current of the first current mirror unit 12 in the foregoing application is determined by the minimum current unit, as the current range increases, the number of PMOS devices in the first branch 120 is halved, the current of the current unit is doubled,Halving, while the mismatch of the threshold voltage Vth is doubled, the final equivalent mismatch current is unchanged, i.e. the current mismatch contributed by the first current mirror cell 12 is unchanged for different current ranges.
Further, the embodiment of the present application further provides a display device, which includes the driving circuit 10, wherein, since the display device has the same or similar technical features as the driving circuit 10, the detailed description of the display device can refer to the description of the driving circuit 10, and the embodiments of the present application are not repeated here. In addition, it is understood that the display device may be, but is not limited to, an LED display device.
In summary, in the above-mentioned driving circuit 10 and display device according to the embodiments of the present application, through smart design of the circuit structure, the mirror ratio of the first current mirror unit 12 can be conveniently adjusted by the first control signal and the second control signal, so that the driving circuit 10 can be used for display driving of different types of display devices. Furthermore, the first current mirror unit 12 in the implementation of the present application is configured by using a plurality of unit current sources, so that the current mismatch of the driving circuit 10 is constant in different applications.
The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (8)
1. The driving circuit is characterized by comprising a reference voltage input unit, a first current mirror unit and a constant current output unit, wherein the first current mirror unit comprises a first branch and a second branch;
the first input end of the reference voltage input unit is used for being externally connected with a reference power supply;
the first input end of the first branch and the first input end of the second branch are respectively used for being connected with the output end of the reference voltage input unit so as to acquire branch working voltage;
The second input end of the first branch is used for being externally connected with a first control signal, the second input end of the second branch is used for being externally connected with a second control signal, and the first branch and the second branch are used for realizing the adjustment of the mirror ratio according to the first control signal and the second control signal; the output end of the first branch is used for being connected with the second input end of the reference voltage input unit;
the first input end of the constant current output unit is used for being connected with the output end of the second branch, the second input end is used for being externally connected with a first working voltage source, and the output end is used for being connected with a load;
The reference voltage input unit is used for forming a negative feedback loop with the first branch circuit to generate a reference current, the first current mirror unit is used for processing the reference current according to a preset mirror ratio to obtain a mirror current, and the constant current output unit is used for generating a constant current signal for driving the load according to the mirror current;
the first branch circuit comprises a first sub-switch and a plurality of first switch units;
the first input end of the first sub-switch is used for being connected with the output end of the reference voltage input unit, the second input end of the first sub-switch is used for being externally connected with a second working voltage source, and the output end of the first sub-switch is used for being connected with the second input end of the reference voltage input unit;
the first input end of each first switch unit is used for being connected with the output end of the reference voltage input unit, the second input end is used for being externally connected with a second working voltage source, the third input end is used for being externally connected with a first control signal so as to adjust the turn-off state of the first switch unit under the control of the first control signal, and the output end is used for being connected with the second input end of the reference voltage input unit;
each first switch unit comprises a second sub switch and a third sub switch;
The first input end of the second sub-switch is used for being connected with the output end of the reference voltage input unit, the second input end of the second sub-switch is used for being connected with the second working voltage source, and the output end of the second sub-switch is used for being connected with the first input end of the third sub-switch;
The second input end of the third sub-switch is used for being externally connected with a first control signal so as to adjust the turn-off state of the third sub-switch under the control of the first control signal, and the output end of the third sub-switch is used for being connected with the second input end of the reference voltage input unit;
the second branch circuit comprises a fourth sub-switch and a plurality of second switch units;
the first input end of the fourth sub-switch is used for being connected with the output end of the reference voltage input unit, the second input end of the fourth sub-switch is used for being externally connected with a second working voltage source, and the output end of the fourth sub-switch is used for being connected with the first input end of the constant current output unit;
The first input end of each second switch unit is respectively used for being connected with the output end of the reference voltage input unit, the second input end is respectively used for being connected with the second working voltage source, the third input end is respectively used for being externally connected with a second control signal so as to adjust the turn-off state of the second switch unit under the control of the second control signal, and the output end is respectively used for being connected with the first input end of the constant current output unit;
The constant current output unit comprises a second error amplifier and a second current mirror unit;
The first input end of the second error amplifier is used for being connected with the output end of the second branch, the second input end of the second error amplifier is used for being connected with the first working voltage source, and the output end of the second error amplifier is used for being connected with the first input end of the second current mirror unit;
The second input end of the second current mirror unit is used for being connected with the output end of the second branch circuit, and the output end of the second current mirror unit is used for being connected with the load.
2. The driving circuit of claim 1, wherein the first sub-switch and each of the second sub-switches are PMOS transistors, a gate of the PMOS transistors being a first input terminal of the first sub-switch and the second sub-switch, a drain being a second input terminal of the first sub-switch and the second sub-switch, and a source being an output terminal of the first sub-switch and the second sub-switch.
3. The drive circuit of claim 1, wherein the number of first switch cells is 2 M-1, M >0, and the first control signal is implemented using a thermometer code.
4. The driving circuit of claim 1, wherein the number of the second switch units is 2 N -1, n >0, and the second control signal is implemented using a binary code value.
5. The drive circuit of claim 1, wherein the mirror ratio of the first current mirror unit isWherein M is the number of first switch units in the first branch, N is the number of second switch units in the second branch, DR [ j ] is the first control signal, DI [ i ] is the second control signal, i, j are integers greater than or equal to 0.
6. The drive circuit according to claim 1, wherein the reference voltage input unit includes a first error amplifier and a built-in resistor;
The first input end of the first error amplifier is used for being connected with the reference power supply, the second input end of the first error amplifier is used for being connected with the output end of the first branch, and the output end of the first error amplifier is used for being respectively connected with the first input end of the first branch and the first input end of the second branch;
one end of the built-in resistor is connected with the output end of the first branch circuit, and the other end of the built-in resistor is grounded.
7. The drive circuit according to claim 1, wherein the second current mirror unit includes a first MOS device and a second MOS device;
The grid electrode of the first MOS device is used for being connected with the output end of the second error amplifier, the drain electrode of the first MOS device is used for being connected with the output end of the second branch circuit, and the source electrode of the first MOS device is grounded;
and the grid electrode of the second MOS device is used for being connected with the output end of the second error amplifier, the drain electrode of the second MOS device is used for being connected with the load, and the source electrode of the second MOS device is grounded.
8. A display device comprising a drive circuit as claimed in any one of claims 1 to 7.
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| CN112423436A (en) * | 2020-12-17 | 2021-02-26 | 北京集创北方科技股份有限公司 | Power supply circuit and display device |
| CN113571011B (en) * | 2021-08-11 | 2023-01-24 | 中科芯集成电路有限公司 | Current mirror circuit with built-in resistance type LED display driving chip |
| CN114142578B (en) * | 2022-01-30 | 2022-04-26 | 深圳英集芯科技股份有限公司 | EOC current setting circuit, chip and electronic equipment |
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| JP4805643B2 (en) * | 2005-09-21 | 2011-11-02 | 株式会社リコー | Constant voltage circuit |
| JP5168910B2 (en) * | 2007-01-18 | 2013-03-27 | 株式会社リコー | Light-emitting diode driving device using constant current circuit and constant current circuit |
| CN202210399U (en) * | 2011-09-28 | 2012-05-02 | 合肥工业大学 | LED display screen constant current drive circuit with optional mirror image ratio |
| CN102881251B (en) * | 2012-08-20 | 2015-08-26 | 深圳市易事达电子有限公司 | Current driving circuit |
| JP6168864B2 (en) * | 2012-09-07 | 2017-07-26 | エスアイアイ・セミコンダクタ株式会社 | Voltage regulator |
| US9715245B2 (en) * | 2015-01-20 | 2017-07-25 | Taiwan Semiconductor Manufacturing Company Limited | Circuit for generating an output voltage and method for setting an output voltage of a low dropout regulator |
| JP6426030B2 (en) * | 2015-03-13 | 2018-11-21 | 新日本無線株式会社 | Drive circuit |
| CN105163431B (en) * | 2015-08-21 | 2017-10-31 | 上海艾为电子技术股份有限公司 | Drive circuit, illuminating circuit and mobile terminal |
| CN204883456U (en) * | 2015-09-06 | 2015-12-16 | 湘潭大学 | To temperature adaptive LED constant -current drive circuit |
| CN107678486B (en) * | 2017-10-19 | 2020-02-07 | 珠海格力电器股份有限公司 | Reference circuit and chip |
| CN208239921U (en) * | 2018-06-01 | 2018-12-14 | 上海汉容微电子有限公司 | A kind of reference voltage source circuit |
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