CN113556844B - Signal generating device and power expander - Google Patents
Signal generating device and power expander Download PDFInfo
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- CN113556844B CN113556844B CN202110892298.1A CN202110892298A CN113556844B CN 113556844 B CN113556844 B CN 113556844B CN 202110892298 A CN202110892298 A CN 202110892298A CN 113556844 B CN113556844 B CN 113556844B
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
Abstract
The invention provides a signal generating device and a power expander, wherein the signal generating device is arranged between a photoelectric coupler and a local driving switch and is used for collecting working time of an output end of the photoelectric coupler; performing compensation processing on the working time according to preset compensation time, and determining the driving time for driving the local driving switch, wherein the compensation time is preset time according to inherent parameters of the photoelectric coupler and the local driving switch; and generating a first driving signal with driving time to drive the local driving switch to work. According to the signal generating device and the power expander provided by the embodiment of the invention, the local driving switch and the front driving switch have the same on-time, so that when the power expander is used for expanding, the front and rear controlled objects have the same on-off time, and the running states of the front and rear controlled objects are consistent.
Description
Technical Field
The present invention relates to the technical field of control devices, and in particular, to a signal generating device and a power expander.
Background
In the home and business application scenarios, an LED (light emitting diode) lamp strip has been widely used as a common atmosphere baking lamp, and with the improvement of the consumption level of people, consumers have put forward new requirements of brightness adjustment, color adjustment, random extension and the like on the lamp strip.
The current LED control driver cannot achieve any length due to the limitation of power, and some general LED power expanders exist on the market to achieve the extending function, but after multi-stage extending amplification, obvious brightness and color differences exist between the extended light strip and the light strip before extending (the color differences are only for the color light strip), and the LED control driver is particularly obvious under low brightness.
Disclosure of Invention
In order to solve the above problems, an embodiment of the present invention is directed to a signal generating device and a power expander.
In a first aspect, an embodiment of the present invention provides a signal generating device, applied to a power expander, where an input end of the signal generating device is connected to an output end of a photocoupler of the power expander, and a first output end of the signal generating device is used to transmit a first driving signal to a local driving switch of the power expander;
the signal generating device is used for:
collecting the working time of the output end of the photoelectric coupler;
performing compensation processing on the working time according to preset compensation time, and determining the driving time for driving the local driving switch, wherein the compensation time is preset time according to inherent parameters of the photoelectric coupler and the local driving switch;
and generating a first driving signal with the driving time, and driving the local driving switch to work so that the on time of the local driving switch is consistent with the on time of a previous driving switch before the power expander.
In one possible implementation, the compensation time includes a first delay time determined according to an intrinsic parameter of the optocoupler and a second delay time determined according to an intrinsic parameter of the locally driven switch;
the first delay time is the difference between the working time of the output end of the photoelectric coupler and the conduction time of the front-stage driving switch; the second delay time is a difference between a turn-on time of the local drive switch and the drive time.
In one possible implementation, the intrinsic parameters of the optocoupler include: rise time Tr of the photocoupler U1 Fall time Tf U1 Delay rise time TLH U1 And delay falling time THL U1 ；
If the working time of the output end of the photocoupler is the time between the start time point of the falling edge and the end time point of the rising edge, the first delay time Td1 is:
Td1＝TLH U1 +a×Tr U1 -THL U1 +b×Tf U1 ；
if the working time of the output end of the photocoupler is the time between the ending time point of the falling edge and the starting time point of the rising edge, the first delay time Td1 is:
Td1＝TLH U1 -(1-a)×Tr U1 -THL U1 -(1-b)×Tf U1 ；
wherein a is the proportion of the non-conduction time in the falling edge of the output end of the photoelectric coupler, and b is the proportion of the non-conduction time in the rising edge of the output end of the photoelectric coupler.
In one possible implementation, the intrinsic parameters of the locally driven switch include: rise time Tr of the drive voltage of the local drive switch Q0V Fall time Tf Q0V And a rise time Tr of the drive current of the local drive switch Q0I Fall time Tf Q0I ；
The second delay time Td2 is:
Td2＝(1-c)×Tf Q0V +(1-d)×Tf Q0I -m×Tr Q0V -n×Tr Q0I ；
wherein c is the proportion of the non-conducting time in the falling edge of the driving voltage of the local driving switch, d is the proportion of the non-conducting time in the falling edge of the driving current of the local driving switch, m is the proportion of the non-conducting time in the rising edge of the driving voltage of the local driving switch, and n is the proportion of the non-conducting time in the rising edge of the driving current of the local driving switch.
In one possible implementation, the driving time Tout for driving the local driving switch is:
Tout＝Twork-Td1-Td2；
wherein Twirk is the collected working time of the output end of the photoelectric coupler, td1 is the first delay time, and Td2 is the second delay time.
In one possible implementation, the output of the optocoupler is the high-side output.
In a possible implementation manner, the signal generating device further comprises a second output terminal;
the second output end is used for transmitting a second driving signal irrelevant to the working time to a local driving switch of the power expander, and the first output end and the second output end do not work simultaneously.
In one possible implementation manner, the second output terminal is in a high-resistance state when the first output terminal outputs the first driving signal;
and under the condition that the second output end outputs the second driving signal, the first output end is in a high-resistance state.
In a second aspect, an embodiment of the present invention further provides a power expander, including: a photo coupler, a local drive switch and a signal generating device as described above.
In a possible implementation manner, if the signal generating device included in the power expander further includes a second output end, the second output end is configured to transmit a second driving signal unrelated to the operating time to a local driving switch of the power expander, and the first output end and the second output end do not operate simultaneously;
the first output end of the signal generating device is connected with a local driving switch of the power expander, the front stage and the rear stage of the power expander are respectively used for accessing a controlled object, and the second output end of the signal generating device does not work;
or the second output end of the signal generating device is connected with a local driving switch of the power expander, the rear stage of the power expander is used for accessing a controlled object, and the first output end of the signal generating device does not work.
In the solution provided in the first aspect of the embodiment of the present invention, the signal generating device is disposed between the photo coupler of the power expander and the local driving switch, and the signal generating device is preset with a compensation time determined based on inherent parameters of the photo coupler and the local driving switch, and compensates the collected working time of the output end of the photo coupler, so as to generate a driving time, so that when the local driving switch is driven by the first driving signal with the driving time, the local driving switch and the front driving switch have identical on time, and when the power expander expands, the front and rear controlled objects have identical on-off time, so that the running states of the front and rear controlled objects are identical.
In order to make the above objects, features and advantages of the present invention more comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 illustrates a schematic diagram of a conventional power extension;
FIG. 2 illustrates an operational timing diagram of a conventional power expander;
FIG. 3 is a schematic diagram of a power expander according to an embodiment of the present invention;
fig. 4 is a schematic flow chart of a signal generating device according to an embodiment of the present invention for outputting a driving signal;
FIG. 5 is a timing diagram illustrating operation of a power expander provided by an embodiment of the present invention;
FIG. 6 is a schematic diagram of another configuration of a power expander according to an embodiment of the present invention;
fig. 7 shows an application scenario of the power expander according to an embodiment of the present invention.
Detailed Description
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
The structure of the current power expander can be seen in fig. 1, the dashed line box in fig. 1 shows the composition of the conventional power expander, which mainly comprises a photoelectric coupler U1, an inverter U2 and a driving switch Q2, and the working principle of the power expander is as follows:
the power expander (or control driver) of the front stage outputs PWM signals (the frequency is generally 1 KHz-4 KHz), and the driving switch Q1 of the front stage is driven to be switched on and off, so that the high-frequency switching on and off of the lamp bands D1-D10 of the front stage are realized, and the aim of adjusting the macroscopic brightness of the lamp bands D1-D10 can be fulfilled by adjusting the duty ratio of the PWM signals; the multi-channel synchronous use can realize the purpose of color mixing and achieving the purpose of adjusting the colors. The photo coupler U1 is used for isolating the driving signal from the power loop, so that the front-stage power supply V 1 + and post-stage power supply V 2 + may not be identical; for example, a front-stage power supply V 1 + is 24V, the latter stage power source V 2 + is 48V, or, the front stage power source V 1 + and post-stage power supply V 2 + are 24V, except that both are powered by different voltage sources. The inverter U2 has the function of improving driving capability, and can directly drive the on-off of the driving switch Q2 of the rear stage after reversing, so as to control the high-frequency on-off of the lamp strips D11-D20 of the rear stage. Wherein, the driving switches Q1 and Q2 may be field effect transistors. DC-DC is a direct-current voltage converter for converting an external power source (e.g. power source V 2 Conversion into operating voltage V of a Power expander 3 +。
In response to the problem that the conventional power expander has brightness difference after multi-stage extension, the inventor finds that this is caused by the inherent delay characteristics of the components (such as U1, U2, Q2, etc.) in the power expander. Specifically, a timing diagram of the operation of the power expander is shown in fig. 2.
The gate of the front-stage driving switch Q1 inputs a PWM signal, and the gate-source voltage Vgs of the front-stage driving switch Q1 is at the rising edge of the PWM signal in one period of the PWM signal Q1 Gradually increase to the miller plateau voltage Vth Q1 Time (i.e. at time t 1 ) The front driving switch Q1 starts to conduct, and the drain current Id of Q1 in the conducting process Q1 Gradually increasing. When the drain currentId Q1 Above a certain threshold (i.e. at time t 2 ) The lamp strips D1-D10 of the front stage start to conduct and emit light, and the photocoupler U1 starts to operate and after a period of time, the input voltage Vi of the inverter U2 is enabled U2 (the voltage is also the output voltage Vo of the photocoupler U1 U1 ) Start to decline (at time point t 4 ) After that, at the input voltage Vi U2 Above a certain threshold, inverter U2 begins to operate (i.e., at time t 5 ). After a delay, the output voltage Vo of the inverter U2 U2 Start to rise (i.e. at time t 7 ). The output voltage Vo of the inverter U2 U2 Gate-source voltage Vgs corresponding to rear-stage driving switch Q2 Q2 And when the voltage Vo U2 Above a certain value, the rear stage driving switch Q2 is turned on (i.e. at time t 8 ) Drain current Id of the rear stage driving switch Q2 Q2 Gradually increases when the drain current Id Q2 Above a certain threshold (i.e. at time t 10 ) The lamp strips D11-D20 of the latter stage start to conduct light emission. The process is similar to that described above at the falling edge of the PWM signal and will not be described in detail herein.
It is found by analysis that the rising time Tr exists in the front driving switch Q1 during the whole loop operation Q1 (i.e. t 1 And t 3 Time period in between), fall time Tf Q1 The method comprises the steps of carrying out a first treatment on the surface of the The photo coupler U1 has a falling delay time THL U1 (i.e. t 2 And t 5 Time period in between), fall time Tf U1 (i.e. t 4 And t 6 Time period in between), rise delay time TLH U1 Rise time Tr U1 The method comprises the steps of carrying out a first treatment on the surface of the Inverter U2 also has a rise delay time TLH U2 (i.e. t 5 And t 8 Time period between), rise time Tr U2 (i.e. t 7 And t 9 Time period in between), falling delay time THL U2 Fall time Tf U2 The method comprises the steps of carrying out a first treatment on the surface of the The post-stage driving switch Q2 has a rise time Tr Q2 Fall time Tf Q2 Etc. Since the time required for the rising process and the falling process of each device is not the same (e.g. rising time Tr of the preceding stage driving switch Q1 Q1 And falling time Tf Q1 Different) guideThe on time T1 of the front driving switch Q1 is different from the on time T2 of the rear driving switch Q2, so that the duty ratio of the front and rear PWM signals is different, and the brightness of the front and rear light bands is different. In general, in a single period, the on time T2 of the subsequent stage Q2 is longer than the on time T1 of the previous stage Q1, that is, the duty ratio becomes larger and the luminance becomes higher. When the whole loop is subjected to multistage expansion, the change amplitude is larger, and the whole brightness and color are inconsistent.
To solve this problem, an embodiment of the present invention provides a signal generating device applied to a power expander, which makes the duty ratios of the front and rear stage driving switches (i.e., the front stage driving switch Q1 and the local driving switch Q0) identical by actively controlling the duty ratio of the local driving switch Q0, so that the brightness of the lamp strip after multi-stage expansion can still be kept identical. Fig. 3 shows a schematic diagram of a configuration of the signal generating device applied to a power expander, the dashed box in fig. 3
As shown in fig. 3, an input terminal of the signal generating device U0 is connected to an output terminal of the photo coupler U1 of the power expander, and a first output terminal of the signal generating device U0 is used to transmit a first driving signal to the local driving switch Q0 of the power expander. As shown in fig. 4, the signal generating device U0 is specifically configured to perform the following steps:
step 401: the working time of the output end of the photoelectric coupler U1 is collected.
In the embodiment of the present invention, the working time of the output end of the photo-coupler U1 refers to the duration that the output end of the photo-coupler U1 can output an effective voltage, where the effective voltage is the voltage output by the photo-coupler U1 when responding to the high level output by one side of the controlled object (such as the front-stage lamp bands D1-D10) of the front stage. Specifically, when the output terminal of the photo coupler U1 outputs an effective voltage, the effective voltage can be collected by the input terminal of the signal generating device U0, so that the signal generating device U0 can determine the operating time of the output terminal of the photo coupler U1.
Step 402: the working time is compensated according to preset compensation time, and the driving time for driving the local driving switch Q0 is determined, wherein the compensation time is preset according to intrinsic parameters of the photoelectric coupler U1 and the local driving switch Q0.
Step 403: the first driving signal having the driving time is generated to drive the local driving switch Q0 to operate such that the on time of the local driving switch Q0 coincides with the on time of the previous driving switch Q1 before the power expander.
As described above in connection with fig. 1 and 2, in the conventional power expander, intrinsic parameters (such as rise time, fall time, etc.) of the photo coupler U1, the inverter U2, the post-stage driving switch Q2, etc. may cause the on-time of the pre-stage and the post-stage to be different; in the embodiment of the present invention, the intrinsic parameters of the photo coupler U1 and the post-stage driving switch Q2 still affect the on-time of the pre-stage and the post-stage driving switch Q2, but the intrinsic parameters are fixed, so in the embodiment, the compensation time is preset, and the working time is compensated based on the compensation time, so that the on-time of the post-compensation driving time can be consistent with the on-time of the previous pre-stage driving switch Q1 when the local driving switch Q0 is driven. Specifically, the signal generating device U0 generates a driving signal having the driving time, that is, a first driving signal, and drives the local driving switch Q0 to operate with the first driving signal, so that the local driving switch Q0 and the previous driving switch Q1 have the same on time, that is, are driven by PWM signals having the same duty ratio. For example, the local driving switch Q0 may be a field effect transistor, and the first driving signal is connected to the gate of the field effect transistor to control the on-off condition of the field effect transistor.
It should be noted that, in the embodiment of the present invention, the driving switches Q0, Q1, etc. all adopt PWM control, that is, the first driving signal is a PWM signal, and the "working time", "driving time", and "on time of the preceding driving switch Q1" are all time within one period. The local driving switch Q0 is substantially the same as the rear driving switch Q2, and is a driving switch in the current power expander, and the driving switch is named differently, which is only for convenience in distinguishing the power expander provided in this embodiment from the conventional power expander.
The signal generating device provided by the embodiment of the invention is arranged between the photoelectric coupler U1 of the power expander and the local driving switch Q0, the signal generating device is preset with compensation time determined based on inherent parameters of the photoelectric coupler U1 and the local driving switch Q0, and compensates the acquired working time of the output end of the photoelectric coupler U1 to generate driving time, so that when a first driving signal with the driving time drives the local driving switch Q0, the local driving switch Q0 and the front driving switch Q1 have consistent on time, and when the power expander expands, the front and rear controlled objects have the same on-off time, and the running states of the front and rear controlled objects are consistent. For example, the lamp strips of the front and rear stages have the same brightness, and the like.
On the basis of the above embodiment, the compensation time includes a first delay time determined from the intrinsic parameter of the photo coupler U1 and a second delay time determined from the intrinsic parameter of the local drive switch Q0; the first delay time is a difference value between the working time of the output end of the photoelectric coupler U1 and the on time of the front-stage driving switch Q1; the second delay time is the difference between the on time and the driving time of the local driving switch Q0.
In the embodiment of the invention, when compensating the collected working time, the delay time caused by the photoelectric coupler U1, namely the first delay time, needs to be compensated; when the local driving switch Q0 is driven by the first driving signal generated by the signal generating device U0, the actual on time of the local driving switch Q0 is also different from the driving time of the first driving signal, and the second delay time is used to characterize the difference in this embodiment. The present embodiment determines the compensation time by combining the first delay time and the second delay time, so that the local driving switch Q0 driven by the first driving signal and the previous driving switch Q1 have the same on time.
Specifically, the first delay time is a difference between the working time of the output end of the photo coupler U1 and the on time (i.e., the front-stage on time) of the front-stage driving switch Q1, and the second delay time is a difference between the on time (i.e., the rear-stage on time) of the local driving switch Q0 and the driving time; i.e. a first delay time td1=the operation time Twork-the pre-stage on-time T1, and a second delay time td2=the post-stage on-time T2-the driving time Tout. As can be seen from the addition of the two formulas, td1+td2=twork-t1+t2-Tout; if the front stage on-time T1 is the same as the rear stage on-time T2, td1+td2=twork-Tout, so the driving time tout=collected working time Twork-Td1-Td2; the compensation time is Td1+Td2.
In the embodiment of the invention, the signal generating device U0 is disposed between the photo coupler U1 and the local driving switch Q0 of the power expander, so that the compensation time can be determined based on the intrinsic parameters of the photo coupler U1 and the local driving switch Q0, and is irrelevant to the previous driving switch Q1, that is, the power expander can also better compensate the voltage output by the previous driving switch Q1 (that is, the voltage collected by the input end of the photo coupler U1) without knowing the intrinsic parameters of the previous driving switch Q1, and make the two driving switches Q0 and Q1 have the same on time.
The signal generating device U0 provided by the embodiment of the invention can determine the driving time after collecting the working time, so the signal generating device U0 can normally output the first driving signal after a period of time; however, since the first driving signal is a PWM signal, the time delay of about one cycle does not affect the operation state of the front and rear controlled objects, for example, the brightness of the front stage light bands D1 to D10 and the rear stage light bands D11 to D20. In addition, the time of one cycle is generally relatively small, in the order of milliseconds, and the user cannot feel the difference between the front stage and the rear stage. For example, the frequency of the driving signal is 1kHz, and the period thereof is 1ms.
The operation of the power expander shown in fig. 3 is described in detail below in conjunction with the timing diagram shown in fig. 5.
In the embodiment of the present invention, the working principle of the photo-coupler U1 of the power expander is the same as that of the photo-coupler of the conventional power expander, and specifically, the description related to fig. 1 and fig. 2 can be referred to, which is not repeated here. In an embodiment of the present invention, lightIntrinsic parameters of the electrical coupler U1 include: rise time Tr of photocoupler U1 U1 Fall time Tf U1 Delay rise time TLH U1 And delay falling time THL U1 . Wherein, as shown in FIG. 5, the delay falling time THL U1 To start the switch Q1 to be turned on (i.e., at the time t 2 ) The voltage to the output of the optocoupler U1 drops to a certain threshold (i.e. point t 5 ) The fall time Tf of (a) U1 The time elapsed for the falling edge of the output of the photo-coupler U1 (i.e. time point t 4 To t 6 Time between), delay rise time TLH U1 To drive the switch Q1 to stop conducting (i.e. at time t 7 ) The voltage to the output of the optocoupler U1 rises to a certain threshold (i.e. point t 9 ) Rise time Tr of (2) U1 The time elapsed for the rising edge of the output of the photo-coupler U1 (i.e., time point t 8 To t 10 Time between) of the first and second clock signals.
In the embodiment of the invention, the input end of the signal acquisition device U0 acquires the voltage of the output end of the photoelectric coupler U1, and the input end voltage Vi of the signal acquisition device U0 U0 Output voltage Vo of photo coupler U1 U1 The same; since the working time of the output end of the photocoupler U1 is the time acquired by the signal generating device U0, the working time may be acquired in different manners. For example, the operation time Twork of the output terminal of the photo-coupler U1 may be a start time point of the falling edge of the output terminal of the photo-coupler U1 (i.e., the time point t 4 ) With the ending time point of the rising edge (i.e., time point t 10 ) The time in between, or the operation time Twork may be the end time point of the falling edge of the output terminal of the photo coupler U1 (i.e., the time point t 6 ) With the starting time point of the rising edge (i.e. time point t 8 ) Time between them. FIG. 5 shows the working time Twirk as a time point t 4 To time point t 10 The time between them is shown as an example. After the working time Twork is acquired, the first delay time described above may be determined.
Specifically, if the working time Twirk is the time point t 4 To time point t 10 The time between them, as shown in FIG. 5, the previous stage on time T1 minus THL U1 Plus the time of non-conduction in the falling edge of U1 (i.e. time point t 4 To t 5 The time of (2) can be obtained as the start point of the working time (i.e. the time point t) 4 ) By time point t 7 The time between; and, in addition to TLH U1 And the time of non-conduction in the rising edge of U1 (i.e., time point t 9 To t 10 Time of (2) to obtain the working time Twork. Namely, T1-THL U1 +b×Tf U1 +TLH U1 +a×Tr U1 =twork, and thus, the first delay time td1=twork-t1=tlh U1 +a×Tr U1 -THL U1 +b×Tf U1 。
Where a is the proportion of the non-conducting time in the rising edge of the output end of the photo-coupler U1, and b is the proportion of the non-conducting time in the falling edge of the output end of the photo-coupler U1. Thus b×tf U1 Namely the time point t 4 To t 5 a×Tr U1 Namely the time point t 9 To t 10 Is a time of (a) to be used.
Correspondingly, if the working time of the output terminal of the photocoupler U1 is the time between the ending time point of the falling edge and the starting time point of the rising edge, namely the working time Twirk is the time point t 6 To time point t 8 The time between them, the same thing can be said: T1-THL U1 -(1-b)×Tf U1 +TLH U1 -(1-a)×Tr U1 Twink, td1=TLH U1 -(1-a)×Tr U1 -THL U1 -(1-b)×Tf U1 . Wherein, (1-b) ×Tf U1 Namely the time point t 5 To t 6 Time of (1-a) x Tr U1 Namely the time point t 8 To t 9 Is a time of (a) to be used.
In the embodiment of the present invention, the first driving signal output by the signal generating device U0 is used to drive the on-off state of the local driving switch Q0, and the voltage Vo output by the signal generating device U0 U0 Namely the gate-source voltage Vgs of the local driving switch Q0 Q0 . At time point t 11 The first driving signal starts to drive the local driving switch Q0; when the first driving signal is connected toAt beam driving, i.e. at time t 16 Stopping driving Q0, corresponding gate-source voltage Vgs Q0 Gradually decrease. In the present embodiment, the driving time Tout of the first driving signal is the time point (i.e. time point t 11 ) By the time point when the driving is ended (i.e., the time point t 16 )。
The working principle of the local driving switch Q0 is similar to that of the previous driving switch Q1, and the working process of the local driving switch Q0 is not described here. In the embodiment of the present invention, the intrinsic parameters of the local driving switch Q0 include: rise time Tr of driving voltage (e.g., gate-source voltage) of local driving switch Q0 Q0V (i.e., instant point t) 11 To t 13 Time of (f), fall time Tf Q0V (i.e., instant point t) 16 To t 18 Time of (a) and rise time Tr of a driving current (e.g., source current) of the local driving switch Q0 Q0I (i.e., instant point t) 12 To t 15 Time of (f), fall time Tf Q0I (i.e., instant point t) 17 To t 20 Time of (d) a).
In the embodiment of the present invention, let c be the proportion of the non-conducting time in the falling edge of the driving voltage of the local driving switch Q0, d be the proportion of the non-conducting time in the falling edge of the driving current of the local driving switch Q0, m be the proportion of the non-conducting time in the rising edge of the driving voltage of the local driving switch Q0, and n be the proportion of the non-conducting time in the rising edge of the driving current of the local driving switch Q0. Then the drive time Tout minus the rise time Tr is shown in fig. 5 Q0V The non-conduction time of (1) minus the rise time Tr Q0I The non-conduction time of the local driving switch Q0 is the time point t (i.e. the time point t 14 ) To the end of driving (i.e. instant t 16 ) Time of (2); then add the falling time Tf Q0V In turn-on time and in fall time Tf Q0I The on-time of the local drive switch Q0, i.e., the latter-stage on-time T2, is remembered.
Thus, tout-m.times.Tr Q0V -n×Tr Q0I +(1-c)×Tf Q0V +(1-d)×Tf Q0I The second delay time Td2=T2-Tout＝(1-c)×Tf Q0V +(1-d)×Tf Q0I -m×Tr Q0V -n×Tr Q0I 。
Wherein the coefficients a, b, c, d, m, n are each a number between 0 and 1, the data of which is based specifically on the actual performance of the device. Typically, the above coefficient is approximately equal to 0.5.
In the embodiment of the invention, the compensation time (i.e., the first delay time and the second delay time) is preset, after the working time Twork is acquired, the corresponding driving time Tout can be determined to be Twork-Td1-Td2, and when the signal generating device U0 drives the local driving switch Q0 with the driving time Tout, the local driving switch Q0 and the previous driving switch Q1 can be ensured to have the same conduction time.
Further alternatively, as shown in fig. 3, the output terminal of the photocoupler U1 is the output terminal on the high level side. That is, the input end of the signal generating device U0 is connected to the high side of the photo coupler U1, and by the digital high-low level characteristic (for example, 0.6Vcc or higher and 0.2Vcc or lower) of the microprocessor MCU in the signal generating device U0, the acquisition rate is accelerated, the influence of delay (inconsistent delays under different brightness) caused by the rising edge and the falling edge of the photo coupler U1 is reduced, meanwhile, under the condition that CTR (current transfer ratio, current transmission ratio) is fixed, a smaller photo coupler input current can be used, the performance attenuation of the photo coupler U1 is slowed down, the service life of the power expander is prolonged, and the anti-interference capability of the power expander is improved.
Further optionally, referring to fig. 6, the signal generating device U0 further comprises a second output 2; the second output 2 is used for transmitting a second drive signal, independent of the operating time, to the local drive switch Q0 of the power expander.
In the embodiment of the present invention, the first output terminal 1 of the signal generating device U0 is configured to output a first driving signal based on a working time, so that the local driving switch Q0 and the previous driving switch Q1 can have the same on time; the signal generating device U0 is further provided with a second output terminal 2 capable of autonomously generating a second drive signal, i.e. the second drive signal is independent of the operating time, or the second drive signal can be output even if the operating time of U1 is not acquired. In order to avoid that the two output terminals send driving signals to the local driving switch Q0 at the same time, the first output terminal 1 and the second output terminal 2 in this embodiment do not operate at the same time.
Optionally, in the case that the first output terminal 1 outputs the first driving signal, the second output terminal 2 is in a high-impedance state; in the case where the second output terminal 2 outputs the second driving signal, the first output terminal 1 is in a high resistance state. In the embodiment of the invention, when one output end of the signal generating device U0 works, the other end is set to be in a high-resistance state, so that the influence on the other output end when the one output end outputs the driving signal can be avoided, and the source of the driving signal of the power expander can be conveniently switched.
Based on the same inventive concept, the embodiment of the present invention further provides a power expander, as shown in fig. 3 or 6, including: a photo coupler U1, a local drive switch Q0 and a signal generating device U0 as provided in any of the embodiments above.
Further alternatively, if the signal generating device U0 includes the second output terminal 2, the power expander may be used in a scenario required by a conventional power expander, or the power expander may be regarded as a control driver, that is, the power expander does not have a controlled object in a previous stage. Specifically, as shown in fig. 7, the front stage power expander 100 drives the front stage lamp strips D1 to D10 as a control driver, and then the rear stage power expander 200 is connected to drive the rear stage lamp strips D11 to D20.
Specifically, if the power expander is used as a control driver, that is, for the power expander 100 in the previous stage, the second output terminal 2 of the signal generating device U0 is connected to the driving switch Q1 of the power expander 100, and outputs a second driving signal (also a PWM signal) to the driving switch Q1; the rear stage of the power expander 100 is used for accessing the controlled objects D1-D10; at this time, the first output terminal 1 of the signal generating device U0 is not operated, i.e., the first driving signal is not generated.
If the power expander is used as a conventional power expander, i.e. for the power expander 200 of the rear stage, the first output terminal 1 of the signal generating device U0 is connected to the driving switch Q0 of the power expander 200, and the front stage and the rear stage of the power expander 200 are respectively used for accessing the controlled object, i.e. the lamp strips D1-D10 and the lamp strips D11-D20 respectively; the second output terminal 2 of the signal generating device U0 is not operated, that is, does not output the second driving signal.
The power expander provided by the embodiment of the invention can be applied to different scenes by controlling different output ends to output the driving signals, namely, the power expander not only can have an expanding function, but also can be used as a driving controller with the driving function.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any person skilled in the art can easily think about variations or alternatives within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (9)
1. A signal generating device applied to a power expander, wherein an input end of the signal generating device is used for being connected with an output end of a photoelectric coupler of the power expander, and a first output end of the signal generating device is used for transmitting a first driving signal to a local driving switch of the power expander;
the signal generating device is used for:
collecting the working time of the output end of the photoelectric coupler;
performing compensation processing on the working time according to preset compensation time, and determining the driving time for driving the local driving switch, wherein the compensation time is preset time according to inherent parameters of the photoelectric coupler and the local driving switch; the compensation time comprises a first delay time determined according to an intrinsic parameter of the photocoupler and a second delay time determined according to an intrinsic parameter of the local drive switch; the first delay time is a difference value between the working time of the output end of the photoelectric coupler and the on time of the front-stage driving switch; the second delay time is the difference between the on time of the local drive switch and the drive time;
and generating a first driving signal with the driving time, and driving the local driving switch to work so that the on time of the local driving switch is consistent with the on time of a previous driving switch before the power expander.
2. The signal generating apparatus of claim 1, wherein the intrinsic parameters of the optocoupler comprise: rise time Tr of the photocoupler U1 Fall time Tf U1 Delay rise time TLH U1 And delay falling time THL U1 ；
If the working time of the output end of the photocoupler is the time between the start time point of the falling edge and the end time point of the rising edge, the first delay time Td1 is:
Td1＝TLH U1 +a×Tr U1 -THL U1 +b×Tf U1 ；
if the working time of the output end of the photocoupler is the time between the ending time point of the falling edge and the starting time point of the rising edge, the first delay time Td1 is:
Td1＝TLH U1 -(1-a)×Tr U1 -THL U1 -(1-b)×Tf U1 ；
wherein a is the proportion of the non-conduction time in the falling edge of the output end of the photoelectric coupler, and b is the proportion of the non-conduction time in the rising edge of the output end of the photoelectric coupler.
3. The signal generating apparatus according to claim 1, wherein,
intrinsic parameters of the locally driven switch include: rise time Tr of the drive voltage of the local drive switch Q0V Fall time Tf Q0V And a rise time Tr of the drive current of the local drive switch Q0I Fall time Tf Q0I ；
The second delay time Td2 is:
Td2＝(1-c)×Tf Q0V +(1-d)×Tf Q0I -m×Tr Q0V -n×Tr Q0I ；
wherein c is the proportion of the non-conducting time in the falling edge of the driving voltage of the local driving switch, d is the proportion of the non-conducting time in the falling edge of the driving current of the local driving switch, m is the proportion of the non-conducting time in the rising edge of the driving voltage of the local driving switch, and n is the proportion of the non-conducting time in the rising edge of the driving current of the local driving switch.
4. The signal generating apparatus according to claim 1, wherein a driving time Tout for driving the local driving switch is:
Tout＝Twork-Td1-Td2；
wherein Twirk is the collected working time of the output end of the photoelectric coupler, td1 is the first delay time, and Td2 is the second delay time.
5. The signal generating apparatus according to claim 1, wherein the output terminal of the photocoupler is a high-side output terminal.
6. The signal generating device of any one of claims 1-5, further comprising a second output;
the second output end is used for transmitting a second driving signal irrelevant to the working time to a local driving switch of the power expander, and the first output end and the second output end do not work simultaneously.
7. The signal generating apparatus according to claim 6, wherein,
under the condition that the first output end outputs the first driving signal, the second output end is in a high-resistance state;
and under the condition that the second output end outputs the second driving signal, the first output end is in a high-resistance state.
8. A power expander, comprising: a photo coupler, a local drive switch and a signal generating device as claimed in any one of claims 1 to 7.
9. The power expander of claim 8, wherein, in the case where the power expander comprises the signal generating device of claim 6,
the first output end of the signal generating device is connected with a local driving switch of the power expander, the front stage and the rear stage of the power expander are respectively used for accessing a controlled object, and the second output end of the signal generating device does not work;
or the second output end of the signal generating device is connected with a local driving switch of the power expander, the rear stage of the power expander is used for accessing a controlled object, and the first output end of the signal generating device does not work.
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