CN210694426U - Benchmark control module - Google Patents

Abstract

The embodiment of the utility model discloses a reference control module, which comprises a signal generating unit for obtaining an adjusting signal according to an input voltage; and the output unit and the signal generation unit are connected to the output node and used for obtaining the reference signal according to the adjusting signal, wherein the signal generation unit dynamically adjusts the reference signal according to the voltage difference between the input voltage and the preset threshold voltage, and the flexibility of reference adjustment is improved.

Description

Benchmark control module

Technical Field

The utility model relates to a LED lighting technology field, concretely relates to benchmark control module.

Background

Compared with the traditional Light source, the Light Emitting Diode (LED) has the advantages of small volume, energy saving, long service life, high brightness, environmental protection and the like, and is widely used for indoor and outdoor illumination.

The brightness of the LED lamp is related to the driving current, and the corresponding driving schemes are a linear driving scheme and a switching driving scheme. The two respectively adopt the modes of a linear regulating transistor and a switch control transistor to regulate the driving current.

Fig. 1 shows a schematic circuit diagram of an LED driving circuit according to the prior art. As shown in fig. 1, the LED driving circuit 100 includes an ac current source 101, a rectifier bridge 102, an input capacitor Cin, a current sampling resistor Rs, and a linear constant current module 110. An input voltage Vin is provided between two output terminals of the rectifier bridge 102. The LED lamp 103 is connected in series with the linear constant current module 110 and the current sampling resistor Rs between two output terminals of the rectifier bridge 103.

The linear constant current module 110 includes a power tube 112 and an amplifier 111. The amplifier 111 compares a current sampling signal obtained by the current sampling resistor Rs with a reference voltage Vref, and generates a driving signal according to a difference between the two signals to control a driving current flowing through the power transistor 112. After the circuit is stabilized, the driving current controlled by the linear constant current module 110 has a value of Vref/Rs.

In the above LED driving circuit, a constant reference is used to control the constant voltage or the constant current. However, in some applications, when a change needs to be made to the constant voltage or the constant current, for example, when the input voltage changes, the output voltage or the output current needs to be changed, the output voltage or the output current needs to be increased or decreased under the same input voltage, or the brightness, the color temperature, and the color of the LED lighting need to be changed, the corresponding reference needs to be changed.

The conventional reference circuit has a single adjustment mode, can only realize single increase and decrease, cannot realize dynamic reference adjustment according to input voltage, and limits the application of the reference circuit.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model is used for providing a benchmark control module can improve the flexibility that the benchmark was adjusted according to input voltage dynamic adjustment benchmark.

According to the utility model discloses an aspect provides a benchmark control module, include: a signal generating unit for generating an adjustment signal according to an input voltage; and the output unit is connected with the signal generation unit and is used for obtaining a reference signal according to the adjusting signal, wherein the signal generation unit dynamically adjusts the reference signal according to the voltage difference between the input voltage and the threshold voltage.

Preferably, the signal generating unit includes a plurality of stages of current sub-units connected in parallel, each of the current sub-units having a first terminal connected to the output node and a second terminal receiving the input voltage, wherein each of the current sub-units is configured to provide a regulating current at the output node according to the input voltage and a respective threshold voltage, and the output node is configured to provide the regulating signal according to the regulating current.

Preferably, each of the current subunits comprises: and the voltage-current conversion circuit is used for comparing the input voltage with a first threshold voltage and providing a regulating current at the output node according to the comparison result.

Preferably, each of the current subunits further comprises: and the reverse regulation circuit is used for comparing the input voltage with a second threshold voltage and providing a reverse regulation current for the voltage-current conversion circuit according to a comparison result.

Preferably, the voltage-to-current conversion circuit includes: a first transistor and a first resistor connected in series between the output node and ground; and a first voltage-dividing resistor and a second voltage-dividing resistor connected in series between the input voltage and ground, a first node between the first voltage-dividing resistor and the second voltage-dividing resistor being connected to a control terminal of the first transistor, wherein the first transistor is turned on to generate the regulating current when the input voltage is greater than the first threshold voltage.

Preferably, the reverse adjustment circuit includes: a second transistor and a second resistor connected in series between the first node and ground; and a third voltage dividing resistor and a fourth voltage dividing resistor connected in series between the input voltage and ground, a second node between the third voltage dividing resistor and the fourth voltage dividing resistor being connected to a control terminal of the second transistor, wherein the second transistor is configured to turn on to provide the reverse regulation current to the first node when the input voltage is greater than the second threshold voltage.

Preferably, the first threshold voltage is adjusted by adjusting resistance values of the first voltage-dividing resistor and the second voltage-dividing resistor, and the second threshold voltage is adjusted by adjusting resistance values of the third voltage-dividing resistor and the fourth voltage-dividing resistor.

Preferably, the first transistor and the second transistor are NPN-type bipolar transistors, respectively.

Preferably, the voltage-to-current conversion circuit includes: a third transistor, a seventh resistor, and a fourth transistor connected in series between the output node and ground; a positive input end of the third amplifier is used for receiving the input voltage, an inverted input end of the third amplifier is connected to a third node between the third transistor and the seventh resistor, and an output end of the third amplifier is connected to a control end of the third transistor; and a fourth amplifier having a non-inverting input terminal connected to a fourth node between the fourth transistor and the seventh resistor, an inverting input terminal for receiving the first threshold voltage, and an output terminal connected to a control terminal of the fourth transistor, wherein the third transistor and the fourth transistor are turned on when the input voltage is greater than the first threshold voltage to generate the regulated current at the output node.

Preferably, the current subunit further comprises: a current control unit including a fifth transistor connected between the output node and the third transistor and a fifth amplifier for driving the fifth transistor according to the second threshold voltage to control a current value of the regulated current.

Preferably, the reverse adjustment circuit includes: a sixth transistor, an eighth resistor, and a seventh transistor connected in series; a sixth amplifier, a positive input terminal of which is configured to receive the input voltage, an inverted input terminal of which is connected to a fifth node between the sixth transistor and the eighth resistor, and an output terminal of which is connected to the control terminal of the sixth transistor; and a seventh amplifier having a non-inverting input terminal connected to a sixth node between the seventh transistor and the eighth resistor, an inverting input terminal for receiving the second threshold voltage, and an output terminal connected to a control terminal of the seventh transistor, wherein the seventh transistor and the eighth transistor are turned on to generate the reverse regulation current when the input voltage is greater than the second threshold voltage.

Preferably, the current subunit further includes an eighth transistor and a ninth transistor, where the eighth transistor and the ninth transistor constitute a first current mirror, an input end of the first current mirror is connected to the first end of the sixth transistor, an output end of the first current mirror is connected to an inverting input end of the third amplifier, a power supply end of the third current mirror is connected to a power supply voltage, and the first current mirror is configured to provide the inverse adjustment current to the voltage-to-current conversion circuit.

Preferably, the third to seventh transistors are N-type metal oxide semiconductor field effect transistors, respectively, and the eighth transistor and the ninth transistor are P-type metal oxide semiconductor field effect transistors, respectively.

Preferably, the output unit includes: a first output resistor connected between a reference voltage and the output node, the first output resistor being configured to obtain the reference signal in the form of a voltage from the reference voltage and the adjustment signal.

Preferably, the output unit includes a tenth transistor and an eleventh transistor, wherein the tenth transistor and the eleventh transistor constitute a second current mirror, a power supply terminal of the second current mirror is connected to a power supply voltage, an input terminal of the second current mirror is connected to the output node, and the second current mirror is configured to obtain the reference signal in the form of a current according to the power supply voltage and the adjustment signal.

Preferably, the output unit includes twelfth to fifteenth transistors and a second output resistor, wherein the twelfth to fifteenth transistors constitute a third current mirror, a power supply terminal of the third current mirror is connected to a power supply voltage, an input terminal of the third current mirror is connected to the output node, the second output resistor is connected between a reference voltage and an output terminal of the third current mirror, and the second output resistor is configured to obtain the reference signal in a voltage form according to the reference voltage and the adjustment current.

Preferably, the twelfth transistor and the thirteenth transistor are P-type metal oxide semiconductor field effect transistors, respectively, and the fourteenth transistor and the fifteenth transistor are N-type metal oxide semiconductor field effect transistors, respectively.

Preferably, the output unit includes a sixteenth transistor and a seventeenth transistor, wherein the sixteenth transistor and the seventeenth transistor constitute a fourth current mirror, a power supply terminal of the fourth current mirror is connected to a power supply voltage, an input terminal of the fourth current mirror is connected to the output node, and the fourth current mirror is configured to obtain the reference signal in the form of a current according to the adjustment current and the power supply voltage.

To sum up, the utility model discloses reference control module generates the regulation signal according to input voltage and the pressure differential of predetermineeing threshold voltage, then obtains reference signal according to the regulation signal, then can be according to input voltage and the pressure differential dynamic adjustment of predetermineeing threshold voltage reference signal has improved the flexibility that the benchmark was adjusted.

In a preferred embodiment, the reference control module is realized by a semiconductor field effect transistor, the threshold voltage can be adjusted without changing the circuit structure, the circuit stability is higher, and compared with a bipolar transistor, the threshold voltage of the semiconductor field effect transistor is less affected by the process and has higher precision.

Adopt the utility model discloses benchmark control module's LED drive circuit is applicable to the input voltage of various voltage ranges for the wider or more complicated electric wire netting of being applicable to of LED linear drive scheme practices thrift manufacturing manufacturer's manufacturing cost.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent by describing embodiments of the present invention with reference to the following drawings, in which:

fig. 1 shows a schematic circuit diagram of an LED driving circuit according to the prior art;

fig. 2 shows a schematic block diagram of an LED drive circuit according to an embodiment of the present invention;

fig. 3 and 4 are circuit configuration diagrams of two application examples based on the inventive concept;

FIG. 5 shows a schematic block diagram of a reference control module according to an embodiment of the present invention;

fig. 6 shows a schematic circuit diagram of a reference control module according to a first embodiment of the invention;

fig. 7 shows another schematic circuit diagram of a reference control module according to a first embodiment of the invention;

fig. 8 shows a schematic circuit diagram of a reference control module according to a second embodiment of the invention;

fig. 9 shows another schematic circuit diagram of a reference control module according to a second embodiment of the invention;

FIG. 10 is a schematic diagram showing waveforms between the voltage sampling signal and the reference signal in FIG. 3;

FIG. 11 shows another waveform schematic between the voltage sample signal and the reference signal of FIG. 3;

FIG. 12 is a schematic diagram showing waveforms between the voltage sampling signal and the reference signal in FIG. 4;

fig. 13 shows another waveform diagram between the voltage sampling signal and the reference signal in fig. 4.

Detailed Description

The present invention will be described below based on examples, but the present invention is not limited to only these examples. In the following detailed description of the present invention, certain specific details are set forth in detail. It will be apparent to those skilled in the art that the present invention may be practiced without these specific details. Well-known methods, procedures, and procedures have not been described in detail so as not to obscure the present invention. The figures are not necessarily drawn to scale.

In this application, the term "LED lamp" is, for example, an LED lamp string formed by connecting a plurality of LEDs in series. If multiple LEDs are formed into a string of LEDs, the cathode of the previous LED in the string is connected to the anode of the next LED. The anode of the LED lamp refers to the anode of the first LED lamp in the LED lamp string, and the cathode of the LED lamp refers to the cathode of the last LED lamp in the LED lamp string.

The present invention may be presented in a variety of forms, some of which are described below.

Fig. 2 shows a schematic block diagram of an LED driving circuit according to an embodiment of the present invention. As shown in fig. 2, the LED driving circuit 200 includes an ac current source 201, a rectifier bridge 202, an input capacitor Cin, a constant current circuit 230, and a control circuit 240. The rectifier bridge 202 is used for rectifying the ac power into dc power, and an input voltage Vin is provided between two output terminals of the rectifier bridge 202, and the input voltage Vin supplies power to the LED lamp 203. The input capacitor Cin smoothly filters the input voltage Vin.

As shown in fig. 2, the control circuit 240 is configured to provide a reference signal to the constant current circuit 230 according to the input voltage Vin, and the constant current circuit 230 is connected in series with the LED lamp 203 and configured to adjust a driving current flowing through the LED lamp 203 according to the reference signal.

The control circuit 240 includes a voltage detection module 210 and a reference control module 220, the voltage detection module 210 is connected to the first output terminal of the rectifier bridge 202 to receive the input voltage Vin, and the voltage detection module 210 is configured to detect the input voltage Vin to obtain a voltage sampling signal. The reference control module 220 is connected to the voltage detection module 210, and is configured to obtain a reference signal according to the voltage sampling signal.

In order to improve the reliability and safety of the LED driving circuit, it is necessary to ensure that the input power of the circuit during operation is always within the rated power range, and therefore, when the input voltage Vin is located in the first rated voltage interval and the second rated voltage interval, the driving current flowing through the LED lamp 203 needs to be controlled to be constant; when the input voltage Vin is in a first voltage interval, controlling the driving current flowing through the LED lamp 203 to decrease with the increase of the input voltage Vin; when the input voltage Vin is in a second voltage interval, the driving current flowing through the LED lamp 203 is controlled to increase with the increase of the input voltage Vin, the first voltage interval and the second voltage interval are in a transition interval of the first rated voltage interval and the second rated voltage interval, and the minimum value of the second voltage interval is equal to the maximum value of the first voltage interval.

In order to achieve the above technical effect, the reference control module is required to provide a corresponding reference signal while the input voltage is changed. The conventional reference control module has a single adjustment mode, can only realize single increase and decrease, cannot realize dynamic reference adjustment according to input voltage, and limits the application of a reference circuit. Therefore in order to solve the prior art problem, the utility model provides a new benchmark control module can be according to input voltage dynamic adjustment reference signal.

Fig. 3 and 4 show circuit structure diagrams of two application examples based on the inventive concept, respectively, and the main difference between the two is the form of the reference signal. If the reference signal is a voltage signal, the reference voltage of the constant current circuit 230 is adjusted according to the reference signal, and then the driving current is adjusted; if the reference signal is a current signal, the current sampling signal of the constant current circuit 230 is adjusted according to the reference signal, and then the driving current is adjusted. It should be noted that these two embodiments are only two specific circuit implementations based on the concept of the present invention, and do not limit the basic implementation scheme of the present invention.

As shown in fig. 3, the LED driving circuit 300 includes an ac current source 301, a rectifier bridge 302, an LED lamp 303, an input capacitor Cin, a voltage detection module 310, a reference control module 320, and a constant current circuit 330. The ac current source 301, the rectifier bridge 302, the LED lamp 303, and the input capacitor Cin are the same as the ac current source 201, the rectifier bridge 202, the LED lamp 203, and the input capacitor Cin shown in fig. 2 in structure and function, and are not described herein again.

The voltage detection module 310 includes voltage dividing resistors R1 and R2, and an amplifier U1. The non-inverting input of the amplifier U1 is connected to the middle node of the resistor R1 and the resistor R2, the inverting input of the amplifier U1 is connected to the output, and the output of the amplifier U1 is connected to the reference control block 320 to provide the voltage sampling signal V1.

The reference control module 320 is used for obtaining a reference signal Vref1 in the form of voltage according to the voltage sampling signal V1. The constant current circuit 330 includes an amplifier U2, a power tube M1, and a current sampling resistor Rs 1. The power tube M1 and the current sampling resistor Rs1 are connected in series between the LED lamp 303 and ground, and an intermediate node between the power tube M1 and the current sampling resistor Rs1 is used to provide a first current sampling signal. The amplifier U2 has a non-inverting input terminal for receiving the reference signal Vref1, an inverting input terminal for receiving the first current sampling signal, and the amplifier U2 is configured to drive the power transistor M1 according to the reference signal Vref1 and the first current sampling signal to adjust the driving current, for example, the constant current value Iout of the driving current is Vref1/Rs 1.

As can be seen from the above equation, the constant current value of the driving current Iout can be adjusted by adjusting the magnitude of the reference signal Vref 1. As shown in FIG. 10, when V1 ≦ Va, the reference signal Vref1 is unchanged and the drive current is kept constant; when Va < V1 ≦ Vb, the reference signal Vref1 decreases with an increase in the voltage sampling signal V1; when Vb < V1 ≦ Vc, the reference signal Vref1 increases with an increase in the voltage sampling signal V1, and when the reference signal Vref1 increases to the preset voltage value Vref, the reference signal Vref1 is held constant; when V1> Vc, the reference signal Vref1 decreases with an increase in the voltage sampling signal V1.

Fig. 11 shows another waveform diagram between the voltage sampling signal and the reference signal in fig. 3. As shown in fig. 11, in another embodiment, the voltage sampling signal V1 has increased to the threshold voltage Vc before the reference signal Vref1 has not increased to the preset voltage value Vref, at which time the reference signal Vref1 decreases with the increase of the voltage sampling signal V1.

Wherein the threshold voltage Va is used to characterize the minimum value of the first voltage interval; the threshold voltage Vb is used for representing the minimum value of the second voltage interval; the threshold voltage Vc is used to characterize the minimum value of the third voltage interval. Wherein the minimum value of the second voltage interval is equal to the maximum value of the first voltage interval, and the minimum value of the third voltage interval is greater than/equal to the maximum value of the second voltage interval.

The threshold voltage may be preset, for example, a rated voltage range of an existing LED driving circuit generally includes a first rated voltage section (e.g., 110Vac to 130Vac) and a second rated voltage section (e.g., 220Vac to 240Vac), the threshold voltage Va and the threshold voltage Vb are located in a transition section between the first rated voltage section and the second rated voltage section, and the threshold voltage Vb is greater than the threshold voltage Va. Of course, in a preferred embodiment, a third rated voltage interval is also included, and the threshold voltage Vc is located in a transition interval between the second rated voltage interval and the third rated voltage interval.

When the input voltage Vin is greater than the threshold voltage Va (i.e., the input voltage Vin is greater than the maximum voltage of the first rated voltage interval), the reference signal Vref1 is decreased as the input voltage Vin increases, so as to reduce the driving current flowing through the LED lamp, reduce the input power, ensure that the input power is always within the range of the rated power in this interval, and further improve the reliability and safety of the system. In order to ensure that the system can stably operate when the input voltage Vin increases to the second rated voltage section when the input voltage Vin is greater than the threshold voltage Vb, the reference signal Vref1 increases as the input voltage Vin increases during a period when the input voltage Vin is greater than the threshold voltage Vb and less than the threshold voltage Vc, and the reference signal Vref1 is kept constant when the reference signal Vref1 increases to the preset voltage value Vref to ensure that the system can stably operate when the input voltage Vin is in the second rated voltage section. When the input voltage Vin is greater than the threshold voltage Vc, the reference signal Vref1 decreases with the increase of the input voltage Vin to reduce the driving current flowing through the LED lamp, reduce the input power, and ensure that the input power is always within the range of the rated power when the input voltage Vin is greater than the maximum voltage of the second rated voltage interval, thereby improving the reliability and safety of the system.

As shown in fig. 4, the LED driving circuit 400 includes an ac current source 401, a rectifier bridge 402, an LED lamp 403, an input capacitor Cin, a voltage detection module 410, a reference control module 420, and a constant current circuit 430. The ac current source 401, the rectifier bridge 402, the LED lamp 403, the voltage detection module 410, and the input capacitor Cin are the same as the ac current source 301, the rectifier bridge 302, the LED lamp 303, the voltage detection module 310, and the input capacitor Cin shown in fig. 3 in structure and function, and are not described herein again.

The reference control module 420 is configured to obtain a reference signal Io according to the voltage sampling signal V1. The constant current circuit 430 includes a power tube M2, a current sampling resistor Rs2, an amplifier U3, and a feedback resistor R3. The power tube M2 and the current sampling resistor Rs2 are connected in series between the LED lamp 403 and ground, and the intermediate node of the power tube M2 and the current sampling resistor Rs2 is used to provide a second current sampling signal. The amplifier U3 has a non-inverting input for receiving a reference voltage Vref2 and an inverting input for receiving a voltage feedback signal. A feedback resistor R3 is connected between the inverting input and the output of amplifier U3. In the present embodiment, the amplifier U3 superimposes the reference signal Io on the second current sampling signal to obtain a voltage feedback signal, and drives the power transistor M2 according to the reference voltage Vref2 and the voltage feedback signal to adjust the driving current, for example, the constant current value of the driving current Iout is (Vref2-Io × R3)/Rs 2.

As can be seen from the above equation, the constant current value of the driving current Iout can be adjusted by adjusting the magnitude of the reference signal Io. As shown in FIG. 12, when V1 ≦ Va, the reference signal Io is 0, and the drive current is kept constant; when Va < V1 ≦ Vb, the reference signal Io increases with the increase of the voltage sampling signal V1, and the driving current Iout decreases with the increase of the voltage sampling signal V1; when Vb < V1 ≦ Vc, the reference signal Io decreases with an increase in the voltage sampling signal V1, and when the reference signal Io decreases to 0, the reference signal Io is held unchanged; when V1> Vc, the reference signal Io increases with an increase in the voltage sampling signal V1. Similarly, the threshold voltage Va is used to characterize the minimum value of the first voltage interval; the threshold voltage Vb is used for representing the minimum value of the second voltage interval; the threshold voltage Vc is used to characterize the minimum value of the third voltage interval. Wherein the minimum value of the second voltage interval is equal to the maximum value of the first voltage interval, and the minimum value of the third voltage interval is greater than/equal to the maximum value of the second voltage interval.

When the input voltage Vin is greater than the threshold voltage Va (that is, the input voltage Vin is greater than the maximum voltage of the first rated voltage interval), the reference signal Io increases with the increase of the input voltage Vin, then the driving current Iout gradually decreases, the input power is reduced, the input power is ensured to be always within the range of the rated power in the voltage interval, and then the reliability and the safety of the system are improved. When the input voltage Vin is greater than the threshold voltage Vb, in order to ensure that the system can stably operate when the input voltage Vin is increased to a second rated voltage interval, the reference signal Io is reduced along with the increase of the input voltage Vin during the period that the input voltage Vin is greater than the threshold voltage Vb and is less than the threshold voltage Vc, and when the reference signal Io is reduced to 0, the reference signal Io is kept constant, so that the system can stably operate when the input voltage Vin is in the second rated voltage interval. When the input voltage Vin is greater than the threshold voltage Vc, the reference signal Io increases with the increase of the input voltage Vin to reduce the driving current flowing through the LED lamp, reduce the input power, and ensure that the input power is always within the range of the rated power when the input voltage Vin is greater than the maximum voltage of the second rated voltage interval, thereby improving the reliability and safety of the system.

Fig. 13 shows another waveform diagram between the voltage sampling signal and the reference signal in fig. 4. As shown in fig. 13, in another embodiment, the voltage sample signal V1 has increased to the threshold voltage Vc before the reference signal Io has not decreased to 0, at which time the reference signal Io increases with the increase of the voltage sample signal V1.

To sum up, the LED driving circuit using the reference control module of the above embodiment controls the driving current to decrease along with the increase of the input voltage in the first voltage interval where the input voltage is greater than the rated voltage interval, so as to ensure that the input power is always within the rated power range, improve the reliability and the service life of the circuit, improve the utilization rate of the lamp bead, reduce the overall cost, and improve the efficiency.

In addition, the LED driving circuit controls the driving current to increase along with the increase of the input voltage in a second voltage interval after the input voltage increases to the first voltage interval so as to ensure that the system can work stably when the input voltage increases to the next rated voltage interval, so that the LED driving circuit is suitable for the input voltage in various voltage ranges, and the production cost of manufacturers is saved.

It should be noted that the voltage detection module is not essential to the present invention. For example, when the input voltage Vin is small, the reference control module may obtain the reference signal directly according to the input voltage Vin without the need of the voltage detection module to perform voltage sampling. The present invention will be described below by taking an example in which the reference control module obtains the reference signal according to the input signal Vin.

Fig. 5 shows a schematic block diagram of a reference control module according to an embodiment of the invention. As shown in fig. 5, the reference control module 520 includes a signal generation unit 501 and an output unit 502. The signal generating unit 501 is configured to obtain an adjusting signal Ig according to the input voltage Vin, and the output unit 502 and the signal generating unit 501 are connected to an output node, and are configured to obtain a reference signal Vref1 or a reference signal Io according to the adjusting signal Ig. The signal generating unit 501 dynamically adjusts the reference signal according to a difference between the input voltage and a threshold voltage.

In one embodiment, the signal generation unit 501 compares the input voltage Vin with a threshold voltage and dynamically adjusts the reference signal Vref1 or the reference signal Io according to a voltage difference between the input voltage Vin and the threshold voltage.

The signal generating unit 501 includes a plurality of current sub-units 511-51n connected in parallel, where n is a natural number greater than zero, a first terminal of each current sub-unit is connected to an output node, a second terminal of each current sub-unit receives an input voltage Vin, and the plurality of current sub-units 511-51n are configured to provide a regulating current Ig1-Ign at the output node according to the input voltage Vin and a respective threshold voltage. The current subunits are independent of each other, and the output node is used for obtaining the adjusting signal Ig according to the adjusting current Ig 1-Ign.

The reference control module of the present invention will be described in detail below with reference to some specific examples.

Fig. 6 shows a circuit structure diagram of a reference control module according to a first embodiment of the present invention, and as shown in fig. 6, the reference control module 620 includes two stages of current subunits, namely a current subunit 611 and a current subunit 612. The current subunit 611 and the current subunit 612 are connected in parallel, first ends of the current subunit 611 and the current subunit 612 are respectively connected to an output node, second ends of the current subunit 611 and the current subunit 612 respectively receive an input voltage Vin, the current subunit 611 is configured to obtain a regulating current Ig1 according to the input voltage Vin, the current subunit 612 is configured to obtain a regulating current Ig2 according to the input voltage Vin, and the output node obtains a regulating signal Ig according to the regulating current Ig1 and/or the regulating current Ig 2. The reference control module 620 further comprises an output unit 602, the output unit 602 being configured to provide a reference signal Vref1 in the form of a voltage in dependence on the adjustment signal Ig.

The current sub-unit 611 and the current sub-unit 612 include a voltage-to-current conversion circuit 6111 and a voltage-to-current conversion circuit 6121, respectively. The voltage-current conversion circuit 6111 is configured to obtain the regulated current Ig1 according to a voltage difference between the input voltage Vin and the threshold voltage Va. The voltage-current conversion circuit 6121 is configured to obtain the regulated current Ig2 according to a voltage difference between the input voltage Vin and the threshold voltage Vc.

The voltage-current conversion circuit 6111 includes a transistor Q1 and a resistor R21 connected in series between the output node and the ground, and a voltage division circuit composed of a voltage division resistor R13 and a voltage division resistor R14 connected between the input voltage Vin and the ground, and an intermediate node between the voltage division resistor R13 and the voltage division resistor R14 is used to provide a turn-on signal to the transistor Q1. The voltage divider circuit is configured to turn on the transistor Q1 when the input voltage Vin is greater than the threshold voltage Va, and a current I1 flowing through the transistor Q1 is (Vbq1-Vbeq1)/R21, where Vbq1 is a base voltage of the transistor Q1, and Vbeq1 is a junction voltage of the transistor Q1, so that an adjustment current Ig1 is (Vbq1-Vbeq 1)/R21.

The output unit 602 includes an output resistor R31 connected between a reference voltage Vref and an output node, and the output resistor R31 provides a reference signal Vref1 at the output node according to the adjustment signal Ig. For example, when the transistor Q1 is turned on, the adjustment signal Ig is Ig1, and Vref1 is Vref-Ig R31 is Vref- (Vbq1-Vbeq1) (R31/R21). From the above equation, the larger the voltage difference between the input voltage Vin and the threshold voltage Va, the larger the base voltage of the transistor Q1, and thus the smaller the reference signal Vref 1.

The current sub-unit 611 further includes a reverse regulation circuit 6112, where the reverse regulation circuit 6112 is configured to provide a reverse regulation current I2 to the voltage-to-current conversion circuit 6111 according to a voltage difference between the input voltage Vin and the threshold voltage Vb, so as to reduce the base voltage of Q1, and further reduce Ig1, and when the base voltage of Q1 is smaller than its turn-on threshold, turn off the voltage-to-current conversion circuit 6111.

The reverse regulation circuit 6112 includes a transistor Q2 and a resistor R22 connected in series between the control terminal of the transistor Q1 and ground, the transistor Q2 is used to provide a reverse regulation current to the transistor Q1 when turned on.

The reverse adjustment circuit 6112 further includes a voltage division circuit composed of a voltage division resistor R11 and a voltage division resistor R12 connected in series between the input voltage Vin and ground, and an intermediate node between the voltage division resistor R11 and the voltage division resistor R12 is used to provide a turn-on signal to the transistor Q2. The voltage divider circuit is configured to turn on the transistor Q2 when the input voltage Vin is greater than the threshold voltage Vb, and a current I2 flowing through the transistor Q2 is (Vbq2-Vbeq2)/R22, where Vbq2 is a base voltage of the transistor Q2, and Vbeq2 is a be junction voltage of the transistor Q2. The larger the voltage difference between the input voltage Vin and the threshold voltage Vb, the larger the base voltage of the transistor Q2, and in turn the larger the current I2.

The current I2 compensates the base voltage of the transistor Q1, so that the reference signal Vref1 ═ Vref- [ V1-I2 × R13-V1 × R13/(R13+ R14) -Vbeq1] × R31/R21 when the input voltage Vin is greater than the threshold voltage Vb can be obtained, and it can be seen from the above formula that the larger the current I2, the larger the reference signal Vref1, and therefore the reference signal Vref1 increases with the increase of the input voltage Vin.

As shown in fig. 10, due to the compensation effect of the current I2 on the base voltage of the transistor Q1, when the base voltage of the transistor Q1 gradually decreases with the increase of the voltage difference between the input voltage Vin and the threshold voltage Vb, the transistor Q1 is turned off when the base voltage of the transistor Q1 is smaller than the turn-on threshold of the transistor Q1, and the reference signal Vref1 is equal to the reference voltage Vref, keeping the reference signal Vref1 constant.

The voltage-current conversion circuit 6121 includes a transistor Q3 and a resistor R23 connected in series between the output node and the ground, and a voltage division circuit composed of a voltage division resistor R15 and a voltage division resistor R16 connected in series between the input voltage Vin and the ground, and an intermediate node between the voltage division resistor R15 and the voltage division resistor R16 is used to provide a turn-on signal to the transistor Q3. The voltage divider circuit is configured to turn on the transistor Q3 when the input voltage Vin is greater than the threshold voltage Vc, and a current I3 flowing through the transistor Q3 is (Vbq3-Vbeq3)/R23, where Vbq3 is a base voltage of the transistor Q3, and Vbeq3 is a base emitter junction voltage of the transistor Q3, so that an adjustment current Ig2 is (Vbq3-Vbeq 3)/R23.

Since the transistor Q3 is also connected to the output node, when the transistor Q1 is turned off and the transistor Q3 is turned on, the adjustment signal Ig2 is obtained, and at this time, the reference signal Vref1 is Vref-Ig R31-Vref- (Vbq3-Vbeq3) (R31/R23). From the above equation, the larger the voltage difference between the input voltage Vin and the threshold voltage Vc, the larger the base voltage of the transistor Q3, and thus the smaller the reference signal Vref 1.

As shown in fig. 10, in another embodiment, the transistor Q1 and the transistor Q3 are both in the on state, so the adjusting signal Ig is obtained by the combination of the adjusting current Ig1 and the adjusting current Ig2, and the reference signal Vref1 is decreased before the reference voltage Vref is increased due to the adjusting current Ig2, i.e., the reference signal Vref is increased with the increase of the input voltage Vin.

In addition, the threshold voltage Va is Vbeq1 (R13+ R14)/R14, the threshold voltage Vb is Vbeq2 (R11+ R12)/R12, and the threshold voltage Vc is Vbeq3 (R15+ R16)/R16, so that the value of the threshold voltage Va-the threshold voltage Vc can be changed by changing the resistance values of the voltage dividing resistors R11-R16, the magnitude of the threshold voltage is actually changed, and the magnitude of the threshold voltage can be changed by preset conditions.

Further, in the above-described embodiment, the transistor Q1, the transistor Q2, and the transistor Q3 are NPN-type bipolar transistors, respectively.

Fig. 7 shows another circuit configuration diagram of the reference control module according to the first embodiment of the present invention. As shown in fig. 7, the reference control block 720 includes two stages of current sub-units, a current sub-unit 711 and a current sub-unit 712. The current subunit 711 and the current subunit 712 are connected in parallel, first ends of the current subunit 711 and the current subunit 712 are respectively connected to an output node, second ends of the current subunit 711 and the current subunit 712 respectively receive an input voltage Vin, the current subunit 711 is configured to generate a regulating current Ig3 according to the input voltage Vin, the current subunit 712 is configured to generate a regulating current Ig4 according to the input voltage Vin, and the output node obtains a regulating signal Ig according to the regulating current Ig3 and/or the regulating current Ig 4. The reference control block 720 further comprises an output unit 702, the output unit 702 being connected to the output nodes with a current subunit 711 and a current subunit 712 for deriving a reference signal Vref1 in the form of a voltage from the adjustment signal Ig.

The current subunit 711 and the current subunit 712 include a voltage-to-current conversion circuit 7111 and a voltage-to-current conversion circuit 7121, respectively. The voltage-current conversion circuit 7111 is configured to obtain a regulated current Ig3 according to a voltage difference between the input voltage Vin and the threshold voltage Va. The voltage-current conversion circuit 7121 is configured to obtain a regulated current Ig4 according to a voltage difference between the input voltage Vin and the threshold voltage Vc.

The voltage-current conversion circuit 7111 includes a transistor N4, a resistor R52, and a transistor N5, and amplifiers U14 and U15, which are connected in series.

The amplifier U14 has a non-inverting input terminal for receiving the input voltage Vin, an inverting input terminal connected to the intermediate node of the transistor N4 and the resistor R52, and an amplifier U14 for driving the transistor N4 according to a voltage difference between the input voltage Vin and the intermediate node of the transistor N4 and the resistor R52. The amplifier U15 has a non-inverting input coupled to the intermediate node of the transistor N5 and the resistor R52, an inverting input for receiving the threshold voltage Va, and an amplifier U15 for driving the transistor N5 according to a voltage difference between the threshold voltage Va and the intermediate node of the transistor N5 and the resistor R52.

When the input voltage Vin is less than the threshold voltage Va, the transistor N4 and the transistor N5 are turned off; when the input voltage Vin is greater than the threshold voltage Va and less than the threshold voltage Vb, the transistors N4 and N5 are turned on, the voltage of the intermediate node between the transistor N4 and the resistor R52 is equal to V1, and the voltage of the intermediate node between the transistor N5 and the resistor R52 is equal to the threshold voltage Va, so that the current I4 flowing through the transistor N4 and the transistor N5 is (V1-Va)/R52, and as can be seen from the above formula, the larger the difference between the input voltage Vin and the threshold voltage Va, the larger the current I4 is, and the larger the adjustment current Ig3 is I4.

The output unit 702 includes transistors P3 and P4, transistors N8 and N9, and an output resistor R41. The transistors P3 and P4 and the transistors N8 and N9 constitute a current mirror structure. The input terminal of the current mirror is connected to the output node, the power supply terminal is connected to the power supply voltage Vdd, and the output terminal is connected to the output resistor R41, for mirroring the regulation signal Ig to the output resistor R41 to obtain the reference signal Vref 1. For example, when the transistor N4 and the transistor N5 are turned on, the adjustment signal Ig is Ig3, and Vref1 is Vref-Ig3 × R41. From the above equation, it can be obtained that the reference signal Vref1 decreases as the current I4 increases.

In a preferred embodiment, the current subunit 711 further comprises a current control circuit 7113, the current control circuit 7113 comprising a transistor N3 and an amplifier U13. The transistor N3 has a first terminal connected to the output node, a second terminal connected to the first terminal of the transistor N4, a non-inverting input terminal of the amplifier U13 for receiving the threshold voltage Vb, an inverting input terminal connected to the second terminal of the transistor N3, and an output terminal connected to the control terminal of the transistor N3. The amplifier U13 is used to control the maximum current value of the current I4, e.g., the current I4max ═ (Vb-Va)/R52, according to the threshold voltage Vb.

The current subunit 711 also includes an inversion regulating circuit 7112, and the inversion regulating circuit 7112 includes a transistor N1, a transistor N2, and a resistor R51, and an amplifier U11 and an amplifier U12, which are connected in series. The amplifier U11 has a non-inverting input terminal for receiving the input voltage Vin, an inverting input terminal connected to the intermediate node of the transistor N1 and the resistor R51, and an amplifier U11 for driving the transistor N1 according to a voltage difference between the input voltage Vin and the intermediate node of the transistor N1 and the resistor R51. The amplifier U12 has a non-inverting input connected to the intermediate node of the transistor N2 and the resistor R51, an inverting input for receiving the threshold voltage Vb, and an amplifier U12 for driving the transistor N2 according to a voltage difference between the threshold voltage Vb and the intermediate node of the transistor N2 and the resistor R51.

When the input voltage Vin is less than the threshold voltage Vb, the transistor N1 and the transistor N2 are turned off; when the input voltage Vin is greater than the threshold voltage Vb, the transistors N1 and N2 are turned on, the voltage of the intermediate node between the transistor N1 and the resistor R51 is equal to V1, the potential of the intermediate node between the transistor N2 and the resistor R51 is equal to Vb, and the current I5 flowing through the transistor N1 and the transistor N2 is equal to (V1-Vb)/R51. As can be seen from the above equation, the larger the difference between the input voltage Vin and the threshold voltage Vb, the larger the current I5.

The current subunit 711 also includes a current mirror 7114, the current mirror 7114 including transistor P1 and transistor P2. The input of the current mirror 7114 is connected to the first terminal of the transistor N1, the output is connected to the inverting input of the comparator U14, the supply terminal is connected to the supply voltage Vdd, for mirroring the current I5 to the inverting input of the inverter U14 to compensate the current I4, then the current I4 is I4 max-I5. From the above equation, it can be seen that the larger the current I5, the smaller the current I4 will be, and in turn the larger the reference signal Vref 1.

The voltage-current conversion circuit 7121 includes a transistor N6, a transistor N7, and a resistor R53, and an amplifier U16 and an amplifier U17, which are connected in series between an output node and ground. The amplifier U16 has a non-inverting input terminal for receiving the input voltage Vin, an inverting input terminal connected to the intermediate node of the transistor N6 and the resistor R53, and an amplifier U16 for driving the transistor N6 according to a voltage difference between the input voltage Vin and the intermediate node of the transistor N6 and the resistor R53. The amplifier U17 has a non-inverting input terminal connected to the intermediate node of the transistor N7 and the resistor R53, an inverting input terminal for receiving the threshold voltage Vc, and an amplifier U17 for driving the transistor N7 according to a voltage difference between the threshold voltage Vb and the intermediate node of the transistor N7 and the resistor R53.

When the input voltage Vin is less than the threshold voltage Vc, the transistor N6 and the transistor N7 are turned off; when the input voltage Vin is greater than the threshold voltage Vc, the transistors N6 and N7 are turned on, the voltage at the intermediate node between the transistor N6 and the resistor R53 is equal to V1, the voltage at the intermediate node between the transistor N7 and the resistor R53 is equal to Vc, and the current I6 flowing through the transistor N6 and the transistor N7 is (V1-Vc)/R53. As can be seen from the above equation, the larger the difference between the input voltage Vin and the threshold voltage Vc, the larger the current I6. At this time, since the adjustment current Ig4 is I6, the larger the current I6 is, the larger the adjustment current Ig4 is, and the smaller the reference signal Vref1 is.

In the above embodiments, the transistors N1-N9 are N-type MOSFETs, respectively, and the transistors P1-P4 are P-type MOSFETs, respectively.

In a preferred embodiment, the reference control module is implemented by a semiconductor field effect transistor, the threshold voltage can be adjusted without changing the circuit structure, the circuit stability is higher, and compared with a bipolar transistor, the threshold voltage of the semiconductor field effect transistor is less affected by the process and has higher precision.

Fig. 8 shows a circuit configuration diagram of a reference control module according to a second embodiment of the present invention, and as shown in fig. 8, a reference control module 820 includes a signal generating unit 801 and an output unit 802. The signal generating unit 801 is configured to generate a regulation signal Ig according to an input voltage Vin, the output unit 802 is connected to the signal generating unit 801, and the output unit 802 is configured to provide a reference signal Io according to the regulation signal Ig. The signal generating unit 801 has the same structure and principle as those of the signal generating unit shown in fig. 6, and is not described herein again.

The output unit 802 comprises a transistor P5 and a transistor P6, the transistor P5 and the transistor P6 form a current mirror structure, a power supply terminal of the current mirror is connected to a power supply voltage Vdd, and an input terminal of the current mirror is connected to an output node for obtaining a reference signal Io in the form of a current according to a regulation signal and the power supply voltage Vdd.

Fig. 9 shows another circuit structure diagram of a reference control module according to a fourth embodiment of the present invention, and as shown in fig. 9, a reference control module 920 includes a signal generating unit 901 and an output unit 902. The signal generating unit 901 is configured to generate a regulating signal Ig according to an input voltage Vin, the output unit 902 is connected to the output node with the signal generating unit 901, and the output unit 902 is configured to provide a reference signal Io according to the regulating signal Ig. The signal generating unit 901 has the same structure and principle as those of the signal generating unit shown in fig. 7, and is not described herein again.

The output unit 902 includes a transistor P7 and a transistor P8, the transistor P7 and the transistor P8 constitute a current mirror structure, a power supply terminal of the current mirror is connected to a power supply voltage Vdd, and an input terminal of the current mirror is connected to the output node, for obtaining a reference signal Io in the form of a current according to the adjustment signal and the power supply voltage Vdd.

In the above embodiments, the transistors P5-P8 are P-type oxide semiconductor field effect transistors, respectively.

To sum up, the utility model discloses reference control module generates the regulation signal according to input voltage and the pressure differential of predetermineeing threshold voltage, then obtains reference signal according to the regulation signal, then can be according to input voltage and the pressure differential dynamic adjustment of predetermineeing threshold voltage reference signal has improved the flexibility that the benchmark was adjusted.

In a preferred embodiment, the reference control module is realized by a semiconductor field effect transistor, the threshold voltage can be adjusted without changing the circuit structure, the circuit stability is higher, and compared with a bipolar transistor, the threshold voltage of the semiconductor field effect transistor is less affected by the process and has higher precision.

Adopt the utility model discloses a benchmark control module's LED drive circuit is applicable to the input voltage of various voltage range for the wider or more complicated electric wire netting of being applicable to of LED linear drive scheme practices thrift manufacturing manufacturer's manufacturing cost.

In accordance with the present invention, as set forth above, these embodiments do not set forth all of the details nor limit the invention to the specific embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and its various embodiments with various modifications as are suited to the particular use contemplated. The protection scope of the present invention should be subject to the scope defined by the claims of the present invention.

Claims (18)

1. A reference control module, comprising:

a signal generating unit for generating an adjustment signal according to an input voltage; and

an output unit connected to the output node with the signal generation unit for obtaining a reference signal according to the adjustment signal,

wherein the signal generation unit dynamically adjusts the reference signal according to a voltage difference between the input voltage and a threshold voltage.

2. The reference control module of claim 1, wherein the signal generation unit comprises a plurality of stages of current sub-units connected in parallel, each of the current sub-units having a first terminal connected to the output node and a second terminal receiving the input voltage,

wherein each of the current subunits is configured to provide a regulated current at the output node according to the input voltage and a respective threshold voltage, and the output node is configured to provide the regulated signal according to the regulated current.

3. The reference control module of claim 2, wherein each of the current subunits comprises:

and the voltage-current conversion circuit is used for comparing the input voltage with a first threshold voltage and providing a regulating current at the output node according to the comparison result.

4. The reference control module of claim 3, wherein each of the current subunits further comprises:

and the reverse regulation circuit is used for comparing the input voltage with a second threshold voltage and providing a reverse regulation current for the voltage-current conversion circuit according to a comparison result.

5. The reference control module of claim 4, wherein the voltage-to-current conversion circuit comprises:

a first transistor and a first resistor connected in series between the output node and ground; and

a first voltage-dividing resistor and a second voltage-dividing resistor connected in series between the input voltage and ground, a first node between the first voltage-dividing resistor and the second voltage-dividing resistor being connected to a control terminal of the first transistor,

wherein the first transistor is turned on to generate the regulation current when the input voltage is greater than the first threshold voltage.

6. The reference control module of claim 5, wherein the back regulation circuit comprises:

a second transistor and a second resistor connected in series between the first node and ground; and

a third voltage dividing resistor and a fourth voltage dividing resistor connected in series between the input voltage and ground, a second node between the third voltage dividing resistor and the fourth voltage dividing resistor being connected to the control terminal of the second transistor,

wherein the second transistor is to turn on to provide the reverse regulation current to the first node when the input voltage is greater than the second threshold voltage.

7. The reference control module of claim 6, wherein the first threshold voltage is adjusted by adjusting resistance values of the first and second divider resistors,

the second threshold voltage is adjusted by adjusting the resistance values of the third voltage dividing resistor and the fourth voltage dividing resistor.

8. The reference control module of claim 6, wherein the first transistor and the second transistor are each an NPN-type bipolar transistor.

9. The reference control module of claim 4, wherein the voltage-to-current conversion circuit comprises:

a third transistor, a seventh resistor, and a fourth transistor connected in series between the output node and ground;

a positive input end of the third amplifier is used for receiving the input voltage, an inverted input end of the third amplifier is connected to a third node between the third transistor and the seventh resistor, and an output end of the third amplifier is connected to a control end of the third transistor; and

a fourth amplifier having a non-inverting input terminal connected to a fourth node between the fourth transistor and the seventh resistor, an inverting input terminal for receiving the first threshold voltage, and an output terminal connected to a control terminal of the fourth transistor,

wherein the third transistor and the fourth transistor are turned on when the input voltage is greater than the first threshold voltage to generate the regulated current at the output node.

10. The reference control module of claim 9, wherein the current subunit further comprises:

a current control unit including a fifth transistor and a fifth amplifier connected between the output node and the third transistor,

the fifth amplifier is used for driving the fifth transistor according to the second threshold voltage so as to control the current value of the regulating current.

11. The reference control module of claim 10, wherein the back regulation circuit comprises:

a sixth transistor, an eighth resistor, and a seventh transistor connected in series;

a sixth amplifier, a positive input terminal of which is configured to receive the input voltage, an inverted input terminal of which is connected to a fifth node between the sixth transistor and the eighth resistor, and an output terminal of which is connected to the control terminal of the sixth transistor; and

a seventh amplifier having a non-inverting input terminal connected to a sixth node between the seventh transistor and the eighth resistor, an inverting input terminal for receiving the second threshold voltage, and an output terminal connected to the control terminal of the seventh transistor,

wherein the seventh transistor and the sixth transistor are turned on to generate the reverse regulation current when the input voltage is greater than the second threshold voltage.

12. The reference control module of claim 11, wherein the current subunit further comprises an eighth transistor and a ninth transistor,

wherein the eighth transistor and the ninth transistor constitute a first current mirror, an input terminal of the first current mirror is connected to the first terminal of the sixth transistor, an output terminal of the first current mirror is connected to the inverting input terminal of the third amplifier, and a power supply terminal of the first current mirror is connected to a power supply voltage,

the first current mirror is used for providing the reverse regulation current to the voltage-current conversion circuit.

13. The reference control module of claim 12, wherein the third through seventh transistors are NMOS transistors,

the eighth transistor and the ninth transistor are P-type metal oxide semiconductor field effect transistors respectively.

14. The reference control module of claim 5, wherein the output unit comprises:

a first output resistor connected between a reference voltage and the output node, the first output resistor being configured to obtain the reference signal in the form of a voltage from the reference voltage and the adjustment signal.

15. The reference control module of claim 5, wherein the output unit includes tenth and eleventh transistors,

wherein the tenth transistor and the eleventh transistor constitute a second current mirror having a supply terminal connected to a supply voltage and an input terminal connected to the output node,

the second current mirror is used for obtaining the reference signal in a current form according to the power supply voltage and the adjusting signal.

16. The reference control module of claim 9, wherein the output unit includes twelfth to fifteenth transistors and a second output resistor,

wherein the twelfth to fifteenth transistors constitute a third current mirror having a power supply terminal connected to a power supply voltage and an input terminal connected to the output node,

the second output resistor is connected between a reference voltage and an output end of the third current mirror, and the second output resistor is used for obtaining the reference signal in a voltage form according to the reference voltage and the regulating current.

17. The reference control module of claim 16, wherein the twelfth transistor and the thirteenth transistor are P-type metal oxide semiconductor field effect transistors,

the fourteenth transistor and the fifteenth transistor are N-type metal oxide semiconductor field effect transistors, respectively.

18. The reference control module of claim 9, wherein the output unit includes a sixteenth transistor and a seventeenth transistor,

wherein the sixteenth transistor and the seventeenth transistor constitute a fourth current mirror, a power supply terminal of the fourth current mirror is connected to a power supply voltage, an input terminal is connected to the output node,

and the fourth current mirror is used for obtaining the reference signal in a current form according to the regulating current and the power supply voltage.

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