CN213818274U - Control circuit and lighting device - Google Patents

Abstract

The utility model discloses a control circuit and lighting device belongs to the lighting technology field. Compared with the prior art, in the power-on process of the control circuit, the voltage input to the driving input end of the constant current driving module slowly rises, so that the problem that the current overshoot phenomenon exists in the light source load is solved. The utility model discloses an among the control circuit, because the output current of first regulation output is positive correlation with the output voltage of voltage limiting end, and the output current of second regulation output is negative correlation with the output voltage of voltage limiting end, consequently, go up the electrical process on control circuit, the voltage of voltage limiting end is from 0 to the in-process of first threshold value exactly, the electric current of input to drive input end can be comparatively invariable, thereby make the operating current on the light source load of being connected with constant current drive module also comparatively invariable, avoid producing the phenomenon that the electric current overshot on the light source load.

Description

Control circuit and lighting device

Technical Field

The application relates to the technical field of lighting, in particular to a control circuit and a lighting device.

Background

In the lighting device, the control circuit can drive the load by using a constant power regulation technology, namely, when the input voltage of a line network is higher, the output current is reduced, and the input power of the light source load is kept basically unchanged.

However, in the current constant power regulation technology, at the moment of power-up, the current output to the light source load has an overshoot phenomenon, so that the light source load is easily damaged or broken down.

SUMMERY OF THE UTILITY MODEL

In order to solve the problem of current overshoot of a control circuit on a light source load at the moment of power-on, the application provides a control circuit and a lighting device.

The utility model provides a control circuit, include: the device comprises a signal sampling module, a constant power regulating module, a negative feedback regulating module and a constant current driving module;

the signal sampling module comprises a voltage limiting end, the voltage limiting end is used for outputting a voltage limiting voltage value, and the voltage limiting voltage value is lower than a first threshold value;

the constant power regulating module comprises a first regulating input end and a first regulating output end, the voltage limiting end is connected with the first regulating input end, and the output current of the first regulating output end is positively correlated with the input voltage of the first regulating input end;

the negative feedback adjusting module comprises a second adjusting input end and a second adjusting output end, the voltage limiting end is connected with the second adjusting input end, and the output current of the second adjusting output end is in negative correlation with the input voltage of the second adjusting input end;

the constant current driving module comprises a driving input end, and the first adjusting output end and the second adjusting output end are connected with the driving input end.

In the above control circuit, the signal sampling module includes a first resistor and a first capacitor, two ends of the first resistor are respectively connected to the signal sampling input voltage and the first capacitor, two ends of the first capacitor are respectively connected to the first resistor and the ground terminal, the voltage limiting terminal is an end point located between the first resistor and the first capacitor, and the first threshold is determined by a capacitance value of the first capacitor.

In the control circuit, the constant power adjusting module includes a second resistor and a constant power current mirror, the second resistor is connected between the voltage limiting end and the constant power current mirror, and the constant power current mirror is connected between the second resistor and the constant current driving module.

In the control circuit, the constant current driving module includes a first operational amplifier, a third resistor, a first switching tube and a current adjusting resistor; the first operational amplifier comprises a first positive input end, a first negative input end and a first amplification output end, the first switch tube comprises a first source electrode, a first drain electrode and a first grid electrode, a first reference voltage is input into the first positive input end, the first source electrode and the first grid electrode are in short circuit and are connected with the first amplification output end, the third resistor is connected between the first amplification output end and the first negative input end, the current adjusting resistor is connected between the first source electrode and the grounding end, the driving input end comprises the first negative input end, and the first drain electrode is used for being connected with a light source load.

In the control circuit, the negative feedback adjusting circuit includes a fourth resistor, a second operational amplifier, a second switching tube and a feedback current mirror; the second operational amplifier comprises a second positive input end, a second negative input end and a second amplification output end, and the second switch tube comprises a second source electrode, a second drain electrode and a second grid electrode; the feedback current mirror comprises a feedback input end and a feedback output end; the second positive input end inputs a second reference voltage, the second source electrode is in short circuit with the second grid electrode and is connected with the second amplification output end and the second negative input end, and the fourth resistor is connected between the second grid electrode and the voltage limiting end; the second drain is connected to the feedback input, and the second regulation output comprises the feedback output.

In the control circuit, the second reference voltage is equal to the first threshold.

In the control circuit, the number of the constant current driving modules is one;

or the number of the constant current driving modules is at least two, at least two constant current driving modules are arranged in parallel, and at least two second drain electrodes are used for being connected with a light source load in parallel.

In the control circuit, the control circuit further comprises a power supply module, and the power supply module provides power for the signal sampling module, the constant power regulating module, the negative feedback regulating module and the constant current driving module.

In the control circuit, the signal sampling module, the constant power adjusting module, the negative feedback adjusting module and the constant current driving module are arranged in an integrated circuit in a centralized manner; or the constant power regulation module and the negative feedback regulation module are arranged in an integrated circuit in a centralized way.

In the control circuit, when the output voltage of the voltage limiting end is from zero to the first threshold value, the sum of the output current of the first regulating output end and the output current of the second regulating output end is a constant value.

The utility model provides a lighting device, including light source load and as above arbitrary the control circuit, the light source load is the LED light source.

The utility model discloses an above-mentioned at least one technical scheme can reach following beneficial effect:

compared with the prior art, in the power-on process of the control circuit, the voltage input to the driving input end of the constant current driving module slowly rises, so that the problem that the current overshoot phenomenon exists in the light source load is solved. The utility model discloses among the control circuit, because the output current of first regulation output is positive correlation with the output voltage of voltage limiting end, and the output current of second regulation output is negative correlation with the output voltage of voltage limiting end, consequently, go up the electrical process on control circuit, the voltage that also is the voltage limiting end is from 0 to the in-process of first threshold value, the electric current of input to drive input end can be comparatively invariable, thereby make the operating current on the light source load of being connected with constant current drive module also comparatively invariable, avoid producing the phenomenon that the electric current overshot on the light source load.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

FIG. 1 shows a block schematic diagram of a control circuit in the prior art;

FIG. 2 shows a schematic diagram of the devices included in each module of FIG. 1;

FIG. 3a shows a waveform diagram of the operating process Vt';

FIG. 3b is a waveform diagram of the operation process Iout';

FIG. 3c shows a waveform diagram of Vt' at the moment of power-up;

FIG. 3d shows a waveform diagram of IA 1' at power-on instant;

FIG. 3e shows a waveform diagram of Iout' at the moment of power-on;

fig. 4 is a schematic block diagram of a control circuit provided in embodiment 1 of the present invention;

FIG. 5 shows a schematic diagram of the devices included in each module of FIG. 4;

FIG. 6a shows a waveform diagram of Vt at the power-up instant in FIG. 5;

FIG. 6b shows a waveform schematic of IA1 at power-on instant in FIG. 5;

FIG. 6c shows a waveform schematic of IA2 at power-on instant in FIG. 5;

FIG. 6d shows a waveform schematic of IA3 at power-on instant in FIG. 5;

FIG. 6e is a waveform diagram of Iout at the power-on instant in FIG. 5;

fig. 7 shows a schematic diagram of an application circuit after the modules in fig. 5 except for the light source load are integrated.

Fig. 8 shows a device schematic diagram of a control circuit of embodiment 2 of the present invention including two parallel constant current driving modules;

description of reference numerals:

100' -prior art control circuitry; 10' -a signal sampling module; 20' -a constant power regulation module; 30' -constant current driving module; 40' -a power supply module; 50' -light source load;

vin' -signal sampling input voltage; r1' -first resistance; r2' -second resistor; r3' -third resistor; c1' -first capacitance; m1' -the first switch tube; rext' -current regulating resistance; VT' -voltage limiting end; vt' -voltage limiting value; vth' -drain voltage; INV 1' -first operational amplifier; a W' -current mirror module; IA 1' -first regulated output current; vref 1' -a first reference voltage; iout' -load working current;

100-a control circuit; 10-a signal sampling module; 20-a constant power regulation module; 21-a first regulation input; 22-a first regulation output; 30-a negative feedback regulation module; 31-a second regulation input; 32-a second regulated output; 40-a constant current driving module; 41-drive input; 50-a power supply module; 60-light source load;

vin-signal sampling input voltage; r1 — first resistance; r2 — second resistance; r3 — third resistance; r4-fourth resistor; c1 — first capacitance; m1-first switch tube; m2-second switch tube; m3-a third switching tube, M1-1-a fourth switching tube; rext-current regulation resistance; VT-voltage limiting end; vt-voltage limited voltage value; vth-drain voltage; INV 1-first fortune ware; INV 2-second operation device; INV 1-1-third fortune ware; w1-constant Power Current mirror; w2 — feedback current mirror; IA1 — first regulated output current; IA2 — second regulated output current; IA3 — drive input current; vref1 — first reference voltage; vref2 — second reference voltage; iout is load operating current; iout 1-first load current; iout 2-second load current; u1-chip.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described in detail and completely with reference to the following specific embodiments of the present application and the accompanying drawings. It should be apparent that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Before the embodiments of the present invention are introduced, referring to fig. 1, fig. 2 and fig. 3a to fig. 3e, the phenomenon of current overshoot generated in the light source load 50 'in the present control circuit 100' will be specifically described.

As shown in fig. 1, which is a block schematic diagram of a conventional control circuit 100 'based on a constant power technology, the control circuit 100' includes a signal sampling module 10 ', a constant power adjusting module 20', a constant current driving module 30 ', and a power supply module 40', and the control circuit 100 'provides an operating current for a light source load 50'. Fig. 2 is a detailed schematic diagram of the control circuit 100 'in fig. 1, and the signal sampling input voltage Vin' input to the signal sampling module 10 'in fig. 2 can be obtained from an input terminal of the power supply module 40' or the constant current input module. In addition, the power supply module 40 ' can also simultaneously supply power to the signal sampling module 10 ', the constant power adjusting module 20 ', the constant current driving module 30 ' and the light source load 50 '. In fig. 2, a first resistor R1 ', a second resistor R2', and a first switch transistor M1 'form a working loop, and a working current of the working loop passes through a current mirror module W' in the constant power regulator module 20 'to generate a first regulated output current IA 1', wherein after the first switch transistor M1 'is turned on, a drain voltage Vth' at a drain of the first switch transistor M1 ', the current mirror module W' includes a first current mirror and a second current mirror, a current ratio of the first current mirror is K1, and a current ratio of the second current mirror is K2, so that the following formula can be obtained.

Further, in fig. 2, the first reference voltage Vref1 ' input to the first positive input terminal of the first operational amplifier INV1 ', and the current adjusting resistor Rext ' can adjust the current flowing through the light source load 50 ', and the load operating current Iout ' including the LED string is obtained by the following formula.

In the formula (1), only the signal sampling input voltage Vin ' is a variable, and as the input voltage of the power supply module 40 ' increases as shown in fig. 1, the signal sampling input voltage Vin ' becomes larger, the first regulated output current IA1 ' becomes larger, and the load working current Iout ' on the string of lights in the formula (2) becomes smaller; when the input voltage of the power supply module 40 'decreases, the signal sampling input voltage Vin' decreases, the first regulated output current IA1 'decreases, and the load operating current Iout' on the string increases. Specifically, as shown in the waveform diagrams of fig. 3a and 3b, when the signal sampling input voltage Vin ' is a fixed value, the voltage-limiting voltage value Vt ' is also a fixed value, and the corresponding load operating current Iout ' is a fixed value. Specifically, as can be seen from fig. 3a and 3b, the voltage-limiting voltage value Vt 'and the load operating current Iout' have opposite or negative correlation in the operating process. The first capacitor C1 'converts the voltage signal of the voltage-limiting terminal VT' into a dc voltage as shown in fig. 2. At the moment of powering up the control circuit 100, the signal sampling input voltage Vin 'charges the first capacitor C1' through the first resistor R1 ', and during the charging process of the first capacitor C1', the voltage value of the voltage limiting terminal VT ', i.e. the voltage limiting voltage value VT', rises from 0V to a fixed value after the time t, as shown in fig. 3C. During this time t, the current through the voltage limiting terminal VT ' changes from 0 to a fixed value, and is equal to the ratio of (Vin ' -Vth ') to (R1 ' + R2 '). The first regulated output current IA1 'generated after passing through the first current mirror and the second current mirror in the current mirror module W' has a waveform rising from 0 to a fixed value at the power-on instant of the control circuit 100, as shown in the waveform diagram of fig. 3 d. When IA1 is at the minimum value of 0V, the load operating current Iout' is at the maximum value as shown in fig. 3e according to equation (2). After the control circuit 100 is powered on and fully charges the first capacitor C1 ', the voltage-limiting end VT' maintains a fixed voltage, and at this time, when the first regulated output current IA1 'is at the maximum value, the load working current Iout' is reduced to the minimum value and the fixed current value is output. The load operating current Iout 'of the light source load 50' at the moment of power-on of the control circuit 100 is as shown in fig. 3e, and a current overshoot waveform is generated at the moment of power-on.

Example 1

For solving power-on in-process, the problem that current overshoots on the light source load including LED lamp cluster, the embodiment of the utility model provides a control circuit 100, the operating current that this control circuit 100 provided for light source loads 60 such as LED lamp cluster can not have the problem that current overshoots in power-on.

As shown in fig. 4, the control circuit 100 according to the embodiment of the present invention includes: the constant power source comprises a signal sampling module 10, a constant power regulating module 20, a negative feedback regulating module 30 and a constant current driving module 40.

Referring to fig. 5, the signal sampling module 10 includes a voltage limiting terminal VT, and the voltage limiting terminal VT is configured to output a voltage limiting voltage value VT lower than a first threshold. The constant power regulation module 20 includes a first regulation input terminal 21 and a first regulation output terminal 22, the voltage limiting terminal VT is connected to the first regulation input terminal 21, and the output current of the first regulation output terminal 22 is in positive correlation with the input voltage of the first regulation input terminal 21. The negative feedback regulation module 30 includes a second regulation input terminal 31 and a second regulation output terminal 32, the voltage limiting terminal VT is connected to the second regulation input terminal 31, and the output current of the second regulation output terminal 32 is in negative correlation with the input voltage of the second regulation input terminal 31. The constant current driving module 40 includes a driving input terminal 41, the first adjusting output terminal 22 and the second adjusting output terminal 32 are connected to the driving input terminal 41, and since the output current of the first adjusting output terminal 22 is positively correlated to the voltage limiting value VT of the voltage limiting terminal VT, and the output current of the second adjusting output terminal 32 is negatively correlated to the voltage limiting value VT of the voltage limiting terminal VT, the current input to the driving input terminal 41 can be relatively constant in the power-on process of the control circuit 100, that is, in the process of the voltage limiting terminal VT from 0 to the first threshold value, so that the load working current Iout on the light source load 60 connected to the constant current driving module 40 is relatively constant, and the phenomenon of current overshoot generated on the light source load 60 is avoided.

The embodiment of the present invention provides a signal sampling module 10, which comprises a first capacitor C1 and a first resistor R1, wherein the first resistor R1 and the first capacitor C1 are sequentially connected in series between the signal sampling input voltage Vin and the ground terminal, in other words, the signal sampling input voltage Vin and the first capacitor C1 are respectively connected to the two ends of the first resistor R1, the first resistor R1 and the ground terminal are respectively connected to the two ends of the first capacitor C1, and the voltage limiting terminal VT is located at the end point between the first capacitor C1 and the first resistor R1. Since the two ends of the first capacitor C1 are the voltage-limiting end VT and the ground end, respectively, at the initial time when the power supply supplies power to the signal sampling module 10, the voltage value at the two ends of the first capacitor C1 is 0V, and the voltage-limiting value VT at the voltage-limiting end VT is also 0V, until the first capacitor C1 is fully charged, the voltage-limiting value VT at the voltage-limiting end VT is also fixed to, in other words, the maximum value of the voltage that can be output at the voltage-limiting end VT can be determined by the capacitance value of the first capacitor C1, that is, the capacitance value of the first capacitor C1 determines the first threshold value. Of course, as a variation, other components may also be used to determine the first threshold on the voltage limiting end, so that the voltage of the voltage limiting end VT is increased from 0V to the first threshold during the power-on process, which is not described herein again.

In the embodiment of the present invention, the constant power adjusting module 20 may include a second resistor R2 and a constant power current mirror W1. The second resistor R2 is connected between the voltage-limiting terminal VT and the constant power current mirror W1, and the constant power current mirror W1 is connected between the second resistor R2 and the constant current driving module 40. The constant power current mirror W1 includes at least one current mirror module, and specifically, may include a first current mirror and a second current mirror connected in series, and of course, more current mirrors may be connected in series. The current ratio of the first current mirror is K1, and the current ratio of the second current mirror is K2.

Referring to equation (1) above, the current output by the first regulated output terminal 22 of the constant power regulation module 20 is the first regulated output current IA1, and it can be determined that:

as shown in the formula (3), the magnitude of the first regulated output current IA1 is positively correlated with the signal sampling input voltage Vin, i.e., with the voltage-limiting value VT of the voltage-limiting terminal VT.

In the embodiment of the present invention, as shown in fig. 5, the constant current driving module 40 may include a first operational amplifier INV1, a third resistor R3, a first switch tube M1, and a current regulation resistor Rext. The first operational amplifier INV1 includes a first positive input terminal, a first negative input terminal, and a first amplified output terminal, the first switch M1 includes a first source, a first drain, and a first gate, the first positive input terminal inputs the first reference voltage Vref1, the first source and the first gate are shorted and connected to the first amplified output terminal, the third resistor R3 is connected between the first amplified output terminal and the first negative input terminal, the current regulating resistor Rext is connected between the first source and the ground terminal, the driving input terminal 41 includes a first negative input terminal, and the first drain is used for connecting to the light source load 60. It can be seen that the first operational amplifier INV1, the third resistor R3 and the current adjusting resistor Rext are used as a non-inverting closed-loop amplifier in the constant current driving module 40, and the first switch transistor M1 may be a MOS transistor. In practical applications, if the load operating current Iout flowing through the light source load 60 needs to be adjusted, the resistance of the current adjusting resistor Rext may be adjusted, the first reference voltage Vref1 input at the first positive input end may be adjusted, or the fourth resistor R4 may be adjusted. In order to adjust the load operating current Iout flowing through the light source load 60 proportionally and finely, the current adjusting resistor Rext is usually set as an adjustable resistor, and the load operating current Iout is adjusted by changing the resistance value of the current adjusting resistor Rext. Of course, other electronic components may be connected to form the constant current driving module 40, and details are not described here.

The drain voltage Vth in the formula (3) is the drain voltage of the third switching tube M3 in fig. 5.

In the embodiment of the present invention, the negative feedback regulating circuit 30 includes a fourth resistor R4, a second operational amplifier INV2, a second switch tube M2 and a feedback current mirror W2. The second operational amplifier INV2 includes a second positive input terminal, a second negative input terminal, and a second amplified output terminal, the second switch M2 includes a second source, a second drain, and a second gate, the feedback current mirror W2 includes a feedback input terminal and a feedback output terminal, the second positive input terminal inputs the second reference voltage Vref2, the second source and the second gate are shorted and connected to the second amplified output terminal and the second negative input terminal, the fourth resistor R4 is connected between the second gate and the voltage limiting terminal VT, the second drain is connected to the feedback input terminal, and the second regulation output terminal 32 includes a feedback output terminal. The second operational amplifier INV2 is used as a non-inverting closed-loop amplifier in the negative feedback adjustment module 30, and the second switch transistor M2 may be a MOS transistor. By using the non-inverse closed loop amplification effect of the second operational amplifier INV2, the current value entering the feedback input terminal of the feedback current mirror W2 in the negative feedback regulation module 30 is in negative correlation with the voltage-limiting VT voltage value of the voltage-limiting terminal VT, thereby achieving the purpose of negative feedback. The current ratio of the feedback current mirror W2 may be K3, and the feedback current mirror W2 may include at least one current mirror.

Referring to fig. 5, the current output by the second regulation output terminal 32 of the negative feedback regulation module 30 is a second regulation output current IA2, wherein the second regulation output current IA2 is specifically obtained by the following formula:

at the moment when the control circuit 100 is powered on, the signal sampling input voltage Vin charges the first capacitor C1 through the first resistor R1, and the voltage-limiting voltage value VT at the voltage-limiting terminal VT rises from 0 to a fixed value (as shown in fig. 6 a), i.e., to the first threshold. At the power-on moment of the control circuit 100, as mentioned above, the waveform of the first regulated output current IA1 is in a rising trend, i.e. the value of the first regulated output current IA1 is in a positive correlation with the voltage-limiting voltage value Vt (as shown in fig. 6 b), and as can be known from the formula (4), the waveform of the second regulated output current IA2 is in a falling trend, i.e. the value of the second regulated output current IA2 is in a negative correlation with the voltage-limiting voltage value Vt (as shown in fig. 6 c).

In order to make the second regulated output current IA2 output from the second regulated output terminal 32 of the negative feedback regulation module 30 be 0 when the charge capacity of the first capacitor C1 is fully charged to reach the first threshold, that is, after the control circuit 100 finishes powering up, and further make the first regulated output current IA1 output from the first regulated output terminal 22 of the constant power regulation module 20 be equal to the current value input to the constant current driving module 40, the second reference voltage Vreft2 may be set to be equal to the first threshold.

As shown in fig. 5, the first regulated output current IA1 output by the first regulated output terminal 22 of the constant power regulation module 20, the second regulated output current IA2 output by the second regulated output terminal 32 of the negative feedback regulation module 30, and the two current waveforms are combined to form a driving input current IA3 (as shown in fig. 6 d), which is input to the constant current driving module 40 from the driving input terminal 41. At the instant t when the control circuit 100 is powered on, since the first regulated output current IA1 is in an upward trend and the second regulated output current IA2 is in a downward trend, the driving input current IA3 can be a fixed value by adjusting the relevant parameters of the formula (1) and the formula (3).

Specifically, at the moment of starting to power up, the first regulated output current IA1 is 0, and at this time, the voltage-limiting voltage value is 0, and the second regulated output current IA2 is

After the power-up is completed, the value of the first regulated output current IA1 should be equal to the value of the power-up starting instant current IA2, that is:

also, the drive input current IA3, which is the sum of the first regulated output current IA1 and the second regulated output current IA2, should be a fixed value.

Referring to FIG. 5 and FIGS. 6 a-6 e, the load operating current Iout is

When the driving input current IA3 is a fixed value, the waveform of the corresponding load operating current Iout is as shown in fig. 6e, and it can be seen that the load operating current Iout has no current overshoot phenomenon during the power-on process. In the embodiment of the present invention, the control circuit 100 further includes a power supply module 50, and the power supply module 50 provides power for the signal sampling module 10, the constant power adjusting module 20, the negative feedback adjusting module 30 and the constant current driving module 40. Of course, the power sources of the signal sampling module 10, the constant power adjusting module 20, the negative feedback adjusting module 30 and the constant current driving module 40 may not be provided by the same power supply module 50.

In the embodiment of the present invention, in order to improve the integration level, the signal sampling module 10, the constant power adjusting module 20, the negative feedback adjusting module 30, and the constant current driving module 40 can be centrally disposed in the integrated circuit. Alternatively, at least two of the signal sampling module 10, the constant power adjusting module 20, the negative feedback adjusting module 30, and the constant current driving module 40 are collectively disposed in an integrated circuit. As shown in fig. 7, after the signal sampling module 10, the constant power adjusting module 20, the negative feedback adjusting module 30 and the constant current driving module 40 are integrated on the chip U1, a circuit is disposed on the periphery of the chip U1, and supplies operating current to the LED light string.

In the embodiment of the present invention, the number of the constant current driving modules 40 may be one.

In addition, each switching tube in fig. 5 may be a MOS tube, wherein M5, M6, M7 and M8 may be P-type MOS tubes, that is, the MOS tube connected to VDD is a P-type MOS tube.

Example 2

The utility model discloses control circuit 100 of embodiment 2, the difference with embodiment 1 lies in: the number of the constant current driving modules 40 is at least two, at least two of the constant current driving modules 40 are arranged in parallel, and at least two of the second drains are used for connecting the light source load 60 in parallel. As shown in fig. 8, a constant current driving module in which the first operational amplifier INV1 and the first switching transistor M1 are located generates a first load current Iout1, and a constant current driving module in which the third operational amplifier INV1-1 and the fourth switching transistor M1-1 are located generates a second load current Iout2, so that the load working current passing through the LED string is the sum of the first load current Iout1 and the second load current Iout 2.

The utility model discloses control circuit 100 sets up a plurality of parallelly connected constant current drive module 40, can increase control circuit 100's output, makes control circuit 100 have more extended function moreover, has bigger application scope.

Example 3

In addition, the embodiment of the utility model also provides a lighting device,

an embodiment of the present invention provides a lighting device, which includes the light source load 60 as mentioned above, and the control circuit 100 of embodiment 1 or embodiment 2. The light source load 60 is an LED light source, and since the control circuit 100 does not have a current overshoot phenomenon during the power-on process, the light source load 60 in the lighting device can have a longer service life, so that the lighting device has higher reliability.

In the embodiments of the present application, the difference between the embodiments is described in detail, and different optimization features between the embodiments can be combined to form a better embodiment as long as the differences are not contradictory, and further description is omitted here in view of brevity of the text.

The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to 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 scope of the claims of the present application.

Claims (11)

1. A control circuit, comprising: the device comprises a signal sampling module, a constant power regulating module, a negative feedback regulating module and a constant current driving module;

the signal sampling module comprises a voltage limiting end, the voltage limiting end is used for outputting a voltage limiting voltage value, and the voltage limiting voltage value is lower than a first threshold value;

the constant power regulating module comprises a first regulating input end and a first regulating output end, the voltage limiting end is connected with the first regulating input end, and the output current of the first regulating output end is positively correlated with the input voltage of the first regulating input end;

the negative feedback adjusting module comprises a second adjusting input end and a second adjusting output end, the voltage limiting end is connected with the second adjusting input end, and the output current of the second adjusting output end is in negative correlation with the input voltage of the second adjusting input end;

the constant current driving module comprises a driving input end, and the first adjusting output end and the second adjusting output end are connected with the driving input end.

2. The control circuit according to claim 1, wherein the signal sampling module includes a first resistor and a first capacitor, two ends of the first resistor are respectively connected to the signal sampling input voltage and the first capacitor, two ends of the first capacitor are respectively connected to the first resistor and a ground terminal, the voltage limiting terminal is an end point between the first resistor and the first capacitor, and the first threshold is determined by a capacitance value of the first capacitor.

3. The control circuit according to claim 1, wherein the constant power regulating module comprises a second resistor and a constant power current mirror, the second resistor is connected between the voltage limiting end and the constant power current mirror, and the constant power current mirror is connected between the second resistor and the constant current driving module.

4. The control circuit according to claim 1, wherein the constant current driving module comprises a first operational amplifier, a third resistor, a first switching tube and a current regulating resistor; the first operational amplifier comprises a first positive input end, a first negative input end and a first amplification output end, the first switch tube comprises a first source electrode, a first drain electrode and a first grid electrode, a first reference voltage is input into the first positive input end, the first source electrode and the first grid electrode are in short circuit and are connected with the first amplification output end, the third resistor is connected between the first amplification output end and the first negative input end, the current adjusting resistor is connected between the first source electrode and the grounding end, the driving input end comprises the first negative input end, and the first drain electrode is used for being connected with a light source load.

5. The control circuit of claim 1, wherein the negative feedback regulating circuit comprises a fourth resistor, a second operational amplifier, a second switching tube and a feedback current mirror; the second operational amplifier comprises a second positive input end, a second negative input end and a second amplification output end, and the second switch tube comprises a second source electrode, a second drain electrode and a second grid electrode; the feedback current mirror comprises a feedback input end and a feedback output end; the second positive input end inputs a second reference voltage, the second source electrode is in short circuit with the second grid electrode and is connected with the second amplification output end and the second negative input end, and the fourth resistor is connected between the second grid electrode and the voltage limiting end; the second drain is connected to the feedback input, and the second regulation output comprises the feedback output.

6. The control circuit of claim 5, wherein the second reference voltage is equal to the first threshold.

7. The control circuit of claim 5,

the number of the constant current driving modules is one;

or the number of the constant current driving modules is at least two, at least two constant current driving modules are arranged in parallel, and at least two second drain electrodes are used for being connected with a light source load in parallel.

8. The control circuit of claim 1, further comprising a power supply module that provides power to the signal sampling module, the constant power regulation module, the negative feedback regulation module, and the constant current driving module.

9. The control circuit of claim 1, wherein the signal sampling module, the constant power regulating module, the negative feedback regulating module and the constant current driving module are collectively disposed in an integrated circuit; or the constant power regulation module and the negative feedback regulation module are arranged in an integrated circuit in a centralized way.

10. The control circuit of claim 1 wherein the sum of the output current of the first regulated output and the output current of the second regulated output is a constant value between the output voltage of the voltage limit terminal from zero to the first threshold.

11. A lighting device comprising a light source load and a control circuit as claimed in any one of claims 1 to 10, the light source load being an LED light source.

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