Galvanometer drive circuit, control method and projector

Abstract

This application discloses a galvanometer driving circuit, control method, and projector. The galvanometer driving circuit includes: a control module with an AND gate circuit, configured to output a power control signal through the AND gate circuit; a drive module, configured to output a control voltage to the galvanometer according to the power control signal; and a feedback module, configured to send a feedback signal according to the control voltage. The AND gate circuit of the control module is configured to receive the feedback signal and adjust the power control signal according to the feedback signal. The galvanometer control circuit of this application can adjust the control voltage to 0 through the feedback signal when the control voltage is abnormal, preventing damage to the galvanometer or motherboard when encountering abnormal voltage / current. It also effectively avoids damage to the galvanometer from startup spike pulses, saving galvanometer wear costs and improving product reliability.

Description

Technical Field

[0001] This application relates to the field of circuit design technology, and more specifically, to a galvanometer driving circuit, a control method for controlling the galvanometer driving circuit, and a projector including the galvanometer driving circuit. Background Technology

[0002] DLP is an abbreviation for "Digital Light Processing," meaning that this technology first digitally processes the image signal before projecting the light. It is a technology that uses a digital micromirror device (DMD) to display visual digital information.

[0003] In DLP projection technology, XPR technology utilizes the persistence of vision phenomenon and the rapid jitter of the display chip to help improve resolution. XPR technology is achieved through a galvanometer, which works by using a current-carrying coil to generate torque in a magnetic field. The deflection angle is proportional to the current; by adjusting the deflection angle, light is shifted, thus achieving the target resolution.

[0004] However, in the operation of existing galvanometers, abnormally high voltage / current may be encountered, leading to abnormal situations such as damage to the galvanometer or motherboard. In addition, during the power-on process, spike pulses may be generated that may damage the galvanometer. Summary of the Invention

[0005] One objective of this application is to provide a galvanometer driving circuit that can at least solve the problem of galvanometers being damaged by abnormally high voltage / current in the prior art.

[0006] Another objective of this application is to provide a control method for controlling the aforementioned galvanometer drive circuit.

[0007] Another object of this application is to provide a projector that includes the above-described galvanometer driving circuit.

[0008] According to a first aspect of this application, a galvanometer driving circuit is provided, comprising: a control module having an AND gate circuit, the control module being configured to output a power control signal through the AND gate circuit; a driving module being configured to output a control voltage to the galvanometer according to the power control signal; and a feedback module being configured to send a feedback signal according to the control voltage; wherein the AND gate circuit of the control module is configured to receive the feedback signal and adjust the power control signal according to the feedback signal.

[0009] Optionally, the control module is further configured to output a drive control signal to the drive module, and the drive module is further configured to output a control voltage to the galvanometer according to the drive control signal.

[0010] Optionally, the feedback module is configured such that: if the control voltage is lower than a preset threshold, the feedback signal output by the feedback module is a normal feedback signal; if the control voltage is not lower than the preset threshold, the feedback signal output by the feedback module is an abnormal feedback signal; and the AND gate circuit prevents the power control signal from being output when it receives an abnormal feedback signal.

[0011] Optionally, the feedback module includes a transistor, a fourth resistor, a fifth resistor, and a sixth resistor. The base of the transistor is connected to the output terminal of the driving module through the fifth resistor and receives the control voltage. The base of the transistor is grounded through the fourth resistor. The collector of the transistor is connected to the feedback power supply through the sixth resistor. The collector of the transistor is connected to the AND gate circuit. The emitter of the transistor is grounded. If the control voltage is lower than a preset threshold, the transistor is turned off, and under the action of the feedback power supply, the feedback module outputs a high-level normal feedback signal. If the control voltage is not lower than the preset threshold, the transistor is turned on, and the feedback module outputs a low-level abnormal feedback signal.

[0012] Optionally, the control module further includes a first input terminal connected to the AND gate circuit. The first input terminal is configured to receive a power control signal. If the feedback signal is an abnormal feedback signal, the AND gate circuit blocks the output of the power control signal. If the feedback signal is a normal feedback signal, the AND gate circuit allows the output of the power control signal. The power control signal is an enable signal.

[0013] Optionally, the AND gate circuit includes a first diode and a second diode, the anodes of the first diode and the second diode are connected as the output terminal of the AND gate circuit, the cathode of the first diode is used to receive the feedback signal, and the cathode of the second diode is connected to the first input terminal.

[0014] Optionally, the control module further includes a first resistor, one end of which is connected to the first input terminal, and the other end of which is grounded.

[0015] According to a second aspect of this application, a control method for the above-mentioned galvanometer driving circuit is provided, comprising the following steps: outputting a power control signal; outputting a control voltage to the galvanometer according to the power control signal; sending a feedback signal according to the control voltage; and adjusting the power control signal according to the feedback signal.

[0016] Optionally, the control method for the galvanometer driving circuit further includes the following steps: outputting a driving control signal; and outputting the control voltage to the galvanometer according to the driving control signal.

[0017] Optionally, the control method for the galvanometer drive circuit further includes the following steps: determining whether the control voltage is lower than a preset threshold; when the control voltage is lower than the preset threshold, sending a normal feedback signal; when the control voltage is not lower than the preset threshold, sending an abnormal feedback signal; and once the abnormal feedback signal is received, preventing the power control signal from being output.

[0018] According to a third aspect of this application, a projector is provided that includes the above-described galvanometer driving circuit.

[0019] According to the galvanometer driving circuit of this application, through the cooperation of the feedback module and the AND gate circuit in the control module, the feedback module sends a feedback signal to the AND gate circuit based on the control voltage output by the driving module. The AND gate circuit performs an AND logic judgment on the power control signal and the feedback signal, and adjusts the power control signal according to the judgment result, thereby changing the control voltage of the driving module to adjust the state of the galvanometer. The galvanometer protection driving circuit of this application can, when the control voltage is abnormal, control the driving module to adjust the control voltage to 0 through the power control signal adjusted by the feedback signal, causing the galvanometer to stop deflecting. This provides protection for the galvanometer driving circuit, preventing damage to the galvanometer or motherboard when encountering abnormal voltage / current. It also effectively avoids damage to the galvanometer from startup spike pulses, saving galvanometer wear costs and improving product reliability.

[0020] Other features and advantages of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the present application and, together with their description, serve to explain the principles of the present application.

[0022] Figure 1 This is a block diagram of a galvanometer driving circuit according to an embodiment of this application;

[0023] Figure 2 This is a circuit schematic diagram of a galvanometer driving circuit according to an embodiment provided in this application;

[0024] Figure 3 This is a flowchart of a control method for a galvanometer driving circuit according to an embodiment of this application;

[0025] Figure 4This is a flowchart of a control method for a galvanometer driving circuit according to another embodiment of this application;

[0026] Figure 5 This is a flowchart of a control method for a galvanometer driving circuit according to another embodiment of the present application.

[0027] Figure Labels

[0028] Control module 10; First diode D1; Second diode D2; First input terminal ctrl1; Second input terminal ctrl2; First resistor R1;

[0029] Driver module 20; power switch 21; second resistor R2; operational amplifier U1; third resistor R3;

[0030] Feedback module 30; transistor Q1; feedback power supply Vcc3; fourth resistor R4; fifth resistor R5; sixth resistor R6. Detailed Implementation

[0031] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0032] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0033] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0034] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0035] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0036] The mirror driving circuit according to an embodiment of this application will now be described in detail with reference to the accompanying drawings.

[0037] like Figures 1 to 5 As shown, the galvanometer driving circuit according to an embodiment of this application includes: a control module 10, a driving module 20, and a feedback module 30.

[0038] Specifically, the control module 10 has an AND gate circuit, and the control module 10 is configured to output a power control signal through the AND gate circuit. The drive module 20 is configured to output a control voltage Vo to the galvanometer according to the power control signal. The feedback module 30 is configured to send a feedback signal according to the control voltage Vo. The AND gate circuit of the control module 10 is configured to receive the feedback signal and adjust the power control signal according to the feedback signal.

[0039] In other words, the galvanometer driving circuit according to the embodiments of this application mainly consists of a control module 10 that outputs a power control signal through an AND gate circuit, a driving module 20 that can output a control voltage Vo to the galvanometer, and a feedback module 30 that sends a feedback signal according to the control voltage Vo.

[0040] The AND gate can have multiple input terminals and one output terminal. Specifically, the AND gate can perform AND logic processing on the signals input from multiple input terminals and then output them. For example, the output terminal of the AND gate will only output a high level when all multiple output terminals of the AND gate are at a high level. Once any one of the multiple output terminals of the AND gate is at a low level, the output terminal of the AND gate will output a low level.

[0041] The power control signal is output through an AND gate circuit. That is, the power control signal can be input to the AND gate circuit from one of its input terminals, and output after AND logic processing. Optionally, the power control signal can be a square wave signal including both high and low level signals. After AND logic judgment by the AND gate circuit, the power control signal is output to the driver module 20. According to the AND logic judgment rules of the AND gate circuit, the AND gate circuit can change the level state of the power control signal.

[0042] The drive module 20 can output a control voltage Vo to the galvanometer based on the power control signal. Specifically, the drive module 20 may have an output terminal, and the voltage output from this terminal is the control voltage Vo. It should be noted that the galvanometer can be driven by a galvanometer coil. The control voltage Vo output by the drive module 20 causes the galvanometer coil to generate torque in the magnetic field, thereby driving the galvanometer to deflect. In other words, the state of the galvanometer can be changed depending on whether the control voltage Vo is 0. When the control voltage Vo is 0, the galvanometer stops deflecting; when the control voltage Vo is not 0, the galvanometer deflects.

[0043] Taking a square wave power control signal as an example, the method of controlling the galvanometer by the drive module 20 will be explained in detail. When the power control signal is high, the control voltage Vo output by the drive module 20 can be greater than 0, and the galvanometer coil will drive the galvanometer to deflect. When the power control signal is low, the control voltage Vo output by the drive module 20 can be equal to 0, and the voltage across the galvanometer coil will be 0, so the galvanometer will not deflect.

[0044] Feedback module 30 can send a feedback signal to the AND gate circuit based on the control voltage Vo. The AND gate circuit then adjusts the power control signal based on the feedback signal. In other words, the feedback signal can be input to the AND gate circuit from one input terminal, and the power control signal can be input to the AND gate circuit from the other input terminal. After performing an AND logic judgment on the feedback signal and the power control signal, the AND gate circuit adjusts the power control signal and sends the adjusted power control signal to the drive module 20.

[0045] Specifically, the feedback signal can be changed according to the control voltage Vo. For example, when the galvanometer is working normally and does not encounter an abnormal voltage, the feedback module 30 sends a first type of feedback signal, and when the galvanometer encounters an abnormal voltage, the feedback module 30 sends a second type of feedback signal.

[0046] When the AND gate receives the first type of feedback signal, it can directly send the power control signal to the drive module 20 without adjusting its level. When the AND gate receives the second type of feedback signal, it can adjust the level of the power control signal and send the adjusted power control signal to the drive module 20. After receiving the adjusted power control signal, the drive module 20 can adjust the control voltage Vo to 0, thereby stopping the galvanometer from deflecting.

[0047] It should be noted that the resistance of the galvanometer coil can be fixed. Therefore, when the galvanometer encounters an abnormal voltage, that is, when the galvanometer encounters an abnormal current.

[0048] Therefore, according to the galvanometer driving circuit of this application, through the cooperation of the feedback module 30 and the AND gate circuit in the control module 10, the feedback module 30 sends a feedback signal to the AND gate circuit based on the control voltage Vo output by the driving module 20. The AND gate circuit performs AND logic judgment on the power control signal and the feedback signal, and adjusts the power control signal according to the judgment result, thereby changing the control voltage Vo of the driving module 20 to adjust the state of the galvanometer. In other words, the galvanometer protection driving circuit of this application can control the driving module 20 to adjust the control voltage Vo to 0 through the power control signal adjusted by the feedback signal when the control voltage Vo is abnormal, so that the galvanometer stops deflecting. This provides protection for the galvanometer driving circuit, avoiding damage to the galvanometer or motherboard when the galvanometer encounters abnormal voltage / current. At the same time, it can also effectively avoid damage to the galvanometer by spike pulses during startup, saving galvanometer wear costs and improving product reliability.

[0049] According to one embodiment of this application, the control module 10 is configured to also output a drive control signal Ui to the drive module 20, and the drive module 20 is also configured to output a control voltage Vo to the galvanometer according to the drive control signal Ui.

[0050] It should be noted that the deflection angle of the galvanometer is directly proportional to the current. When the resistance of the galvanometer coil remains constant, the deflection angle of the galvanometer is directly proportional to the control voltage Vo applied to the galvanometer coil. Therefore, the deflection angle of the galvanometer can be changed by changing the control voltage Vo.

[0051] In other words, the drive module 20 can adjust the magnitude of the control voltage Vo output to the galvanometer according to the drive control signal Ui. Optionally, the drive control signal Ui can be a variable signal including a series of voltage values. The magnitude of the control voltage Vo can be proportional to the voltage value of the drive control signal Ui. By changing the voltage value of the drive control signal Ui, the voltage value of the control voltage Vo can be changed, thereby changing the deflection angle of the galvanometer.

[0052] Specifically, taking the drive module 20, which includes the operational amplifier U1, as an example, we will explain in detail how the drive control signal Ui controls the deflection of the galvanometer.

[0053] The control module 10 may include a second input terminal Ctrl2, which may be the output terminal of the front-end control circuit for sending drive control signal Ui.

[0054] Operational amplifier U1 can be a non-inverting amplifier, having a non-inverting input, an inverting input, a power supply terminal, and an output terminal. The second input terminal Ctrl2 is connected to the non-inverting input terminal of operational amplifier U1, the output terminal of the AND gate is connected to the power supply terminal of operational amplifier U1, one end of the galvanometer coil is connected to the output terminal of operational amplifier U1, and the other end is connected to the inverting input terminal of operational amplifier U1. Furthermore, the other end of the galvanometer coil can be grounded through the third resistor R3.

[0055] In other words, the drive control signal Ui is input to the operational amplifier U1 through the non-inverting input terminal of the operational amplifier U1, the power control signal is input to the operational amplifier U1 through the power supply terminal of the operational amplifier U1, and the output terminal of the operational amplifier U1 outputs the control voltage Vo.

[0056] Operational amplifier U1 has voltage amplification function. According to the virtual short principle of operational amplifier U1, it can be known that... therefore, Among them, V + V is the voltage at the non-inverting input terminal of op-amp U1. - R is the voltage at the inverting input terminal of op-amp U1, R3 is the resistance value of the third resistor R3, R coil This is the resistance value of the galvanometer coil. The voltage V of the drive control signal Ui at the input of operational amplifier U1 is adjusted. + The magnitude of the value can be adjusted to control the magnitude of the control voltage Vo at the output terminal of op-amp U1, thereby controlling the deflection angle of the galvanometer.

[0057] It should be noted that op-amp U1 will only operate normally and perform voltage amplification when its power supply terminal has a high-level input. If the power supply terminal of op-amp U1 has a low-level input, op-amp U1 will not operate, and the control voltage Vo output by op-amp U1 will be 0. The power control signal output by the AND gate circuit after adjustment based on the feedback signal can include a square wave signal with both high-level and low-level signals. By controlling the different states of the levels, the control voltage Vo output by op-amp U1 is controlled to determine whether it is 0, thereby controlling whether the galvanometer deflects.

[0058] Based on the working principle that the galvanometer is deflected by the galvanometer coil, it can be known that Vo = I·(R coil +R3), F=BIL, F=kx, therefore Among them, R coil denoted as Ω, where Ω is the resistance of the galvanometer coil, B is the magnetic flux density of the galvanometer, I is the current flowing through the galvanometer coil, L is the length of the galvanometer coil, F is the deflection torque, k is the elastic coefficient of the galvanometer, and x is the deflection displacement of the galvanometer.

[0059] according to and It can be known that, Therefore, the parameters of the drive control signal Ui and the third resistor R3 can be designed according to the design requirements.

[0060] According to one embodiment of this application, the feedback module 30 is configured such that: if the control voltage Vo is lower than a preset threshold, the feedback signal output by the feedback module 30 is a normal feedback signal; if the control voltage Vo is not lower than the preset threshold, the feedback signal output by the feedback module 30 is an abnormal feedback signal; and the AND gate circuit prevents the power control signal from being output when it receives an abnormal feedback signal.

[0061] Specifically, the feedback module 30 can send a feedback signal based on the control voltage Vo. When the control voltage Vo is lower than the preset threshold, the feedback module 30 sends a normal feedback signal to the AND gate circuit. After the AND gate circuit performs an AND logic judgment on the normal feedback signal and the power control signal, it can allow the power control signal to be output. That is to say, without changing the level of the power control signal, the power control signal directly controls the drive module 20 to output the control voltage Vo.

[0062] When the control voltage Vo is not lower than the preset threshold, the feedback module 30 sends an abnormal feedback signal to the AND gate circuit. After the AND gate circuit performs an AND logic judgment on the abnormal feedback signal and the power control signal, it can change the level of the power control signal to reduce the output of the power control signal. For example, if the original power control signal is high, it can output a low level to the power supply terminal of the operational amplifier U1, so that the control voltage Vo output by the operational amplifier U1 is 0, thus avoiding damage to the galvanometer caused by a voltage not lower than the preset threshold.

[0063] It should be noted that the galvanometer can operate normally under a specific voltage. Exceeding this specific voltage will easily damage the galvanometer. In other words, the galvanometer will operate normally when the control voltage Vo output by the drive module 20 is lower than the aforementioned specific voltage, but it is prone to damage when the control voltage Vo output by the drive module 20 is not lower than the aforementioned specific voltage. The preset threshold can be designed based on the aforementioned specific voltage.

[0064] According to one embodiment of this application, the feedback module 30 includes a transistor Q1, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. The base of transistor Q1 is connected to the output terminal of the drive module 20 through the fifth resistor R5 and receives the control voltage Vo. The base of transistor Q1 is grounded through the fourth resistor R4. The collector of transistor Q1 is connected to the feedback power supply Vcc3 through the sixth resistor R6. The collector of transistor Q1 is connected to an AND gate circuit, and the emitter of transistor Q1 is grounded. If the control voltage Vo is lower than a preset threshold, transistor Q1 is turned off, and under the action of the feedback power supply Vcc3, the feedback module 30 outputs a high-level normal feedback signal. If the control voltage Vo is not lower than the preset threshold, transistor Q1 is turned on, and the feedback module 30 outputs a low-level abnormal feedback signal.

[0065] In other words, one end of the fifth resistor R5 is connected to the output terminal of the drive module 20, and the other end of the fifth resistor R5 is connected to the base of the transistor Q1. One end of the fourth resistor R4 is connected to the base of the transistor Q1, and the other end of the fourth resistor R4 is grounded. One end of the sixth resistor R6 is connected to the feedback power supply Vcc3, and the other end of the sixth resistor R6 is connected to the collector of the transistor Q1 and one input terminal of the AND gate circuit. The emitter of the transistor Q1 is grounded.

[0066] The feedback power supply Vcc3 can provide a high-level signal. At this time, when transistor Q1 is off, the collector level of transistor Q1 is high, and when transistor Q1 is on, the collector level of transistor Q1 is low.

[0067] The following detailed explanation uses a square wave signal, which includes both high and low levels, as an example of a power drive signal.

[0068] When the control voltage Vo is lower than the preset threshold, transistor Q1 is turned off. Under the influence of the high level of the feedback power supply Vcc3, the collector of transistor Q1 sends a high-level normal feedback signal to the AND gate circuit. The AND gate circuit performs AND logic processing on this high-level normal feedback signal and the power drive signal, allowing the power drive signal to be output to the drive module. At this time, if the power drive signal is high, the signal sent to the drive module 20 after passing through the AND gate circuit is also high; if the power drive signal is low, the signal sent to the drive module 20 after passing through the AND gate circuit is also low. Therefore, the galvanometer operates normally according to the original power drive signal when the control voltage Vo is lower than the preset threshold.

[0069] When the control voltage Vo is not lower than the preset threshold, transistor Q1 is turned on. The collector of transistor Q1 sends a low-level abnormal feedback signal to the AND gate circuit. The AND gate circuit performs AND logic processing on this low-level normal feedback signal and the power drive signal. If the power drive signal is high, the AND gate circuit outputs a low-level signal to the drive module 20; if the power drive signal is low, the AND gate circuit still outputs a low-level signal to the drive module 20. In other words, once the abnormal feedback signal sent by transistor Q1 is low, regardless of the level of the power drive signal, the AND gate circuit outputs a low-level signal to the drive module 20, controlling the drive module 20 to adjust the control voltage Vo to 0, thereby preventing damage to the galvanometer when the voltage is too high.

[0070] Optionally, transistor Q1 can be an NPN transistor. The turn-on voltage of transistor Q1 can be set to 0.7V. When the base voltage Vb of transistor Q1 is less than 0.7V, transistor Q1 is cut off, and the collector voltage of transistor Q1 is zero. When the base voltage Vb of transistor Q1 is greater than or equal to 0.7V, Where Ib is the base current, Ic is the collector current, and β is the DC amplification factor of the transistor. At this time, transistor Q1 is turned on, and there is a voltage output at the collector of transistor Q1, and this voltage is a low voltage.

[0071] Based on the circuit connections of driver module 20, transistor Q1, fourth resistor R4, and fifth resistor R5, it can be deduced that when the transistor just turns on, Where R4 is the resistance of the fourth resistor R4, R5 is the resistance of the fifth resistor R5, Vo is the output voltage of the drive module 20, and Ib is the base current. Based on the above formula, the parameters of the fourth resistor R4, the fifth resistor R5, and the transistor Q1 can be calculated, and these parameters can be used to select the appropriate resistors.

[0072] According to one embodiment of this application, the control module 10 further includes a first input terminal Ctrl1, which is connected to an AND gate circuit. The first input terminal Ctrl1 is configured to receive a power control signal. If the feedback signal is an abnormal feedback signal, the AND gate circuit blocks the output of the power control signal. If the feedback signal is a normal feedback signal, the AND gate circuit enables the output of the power control signal. The power control signal is an enable signal.

[0073] Specifically, the first input terminal Ctrl1 can be the output terminal of the front-end control circuit, used to receive the power control signal sent by the front-end control circuit and transmit the power control signal to the AND gate circuit. There can be multiple first input terminals Ctrl1, and the AND gate circuit can have multiple input terminals. One of the input terminals is connected to the output terminal of the feedback module 30 to receive the feedback signal, and the remaining input terminals can be connected to the multiple first input terminals Ctrl1 respectively.

[0074] The power control signal received by the first input terminal Ctrl1 is an enable signal. This enable signal can be a square wave signal including high and low levels. The high and low levels control whether the drive module 20 outputs control voltage Vo.

[0075] The following detailed explanation uses the example of control module 10 having a first input terminal Ctrl1 and an AND gate circuit having two input terminals. The output terminal of feedback module 30 is connected to one input terminal of the AND gate circuit, and the first input terminal Ctrl1 is connected to the other input terminal of the AND gate circuit.

[0076] When the feedback module 30 detects an abnormality in the control voltage Vo, it can send an abnormality feedback signal; when the feedback module 30 detects that the control voltage Vo is normal, it can send a normality feedback signal.

[0077] When the feedback signal is an abnormal feedback signal, the AND gate circuit can output the power control signal. In other words, the drive module 20 will not receive the power control signal. At this time, the drive module 20 will not output the control voltage Vo, and the voltage across the galvanometer coil controlling the galvanometer deflection will be 0, thereby avoiding damage to the galvanometer by abnormal voltage / current.

[0078] When the feedback signal is a normal feedback signal, the AND gate circuit can allow the power control signal to be output to the drive module 20. After receiving the power control signal, the drive module 20 can output the control voltage Vo, thereby controlling the deflection of the galvanometer and enabling the galvanometer to work normally.

[0079] According to one embodiment of this application, the AND gate circuit includes a first diode D1 and a second diode D2. The positive terminals of the first diode D1 and the second diode D2 are connected as the output terminals of the AND gate circuit. The negative terminal of the first diode D1 is used to receive feedback signals, and the negative terminal of the second diode D2 is connected to the first input terminal Ctrl1.

[0080] Specifically, an AND gate circuit may include multiple diodes. Taking an AND gate circuit including two diodes as an example, the two diodes may be a first diode D1 and a second diode D2. The cathode of the first diode D1 is one input terminal of the AND gate circuit, and the cathode of the second diode D2 is the other input terminal of the AND gate circuit. The anodes of the first diode D1 and the anodes of the second diode D2 are connected to form the output terminal of the AND gate circuit.

[0081] A diode has unidirectional conduction performance. When the signal received by either the cathode of the first diode D1 or the second diode D2 is low, the anode of the first diode D1 and the second diode D2 outputs a low-level signal. When the signals received by the cathodes of the first diode D1 and the second diode D2 are both high, the anodes of the first diode D1 and the second diode D2 output a high-level signal.

[0082] Taking square wave signals, both the feedback signal and the power control signal, which include high and low levels, as an example, the specific process of adjusting the power signal using an AND gate circuit includes the following situations:

[0083] Case 1: When both the power control signal and the feedback signal are low, the positive terminals of the first diode D1 and the second diode D2 output a low-level signal to the drive module 20, the drive module 20 does not output the control voltage Vo, and the galvanometer does not deflect.

[0084] Case 2: When the power control signal is low and the feedback signal is high, the positive terminals of the first diode D1 and the second diode D2 output a low-level signal to the drive module 20. The drive module 20 does not output the control voltage Vo, and the galvanometer does not deflect.

[0085] Case 3: When the power control signal is high and the feedback signal is low, the positive terminals of the first diode D1 and the second diode D2 output a low-level signal to the drive module 20, the drive module 20 does not output the control voltage Vo, and the galvanometer does not deflect.

[0086] Case 4: When both the power control signal and the feedback signal are high, the positive terminals of the first diode D1 and the second diode D2 output a high-level signal to the drive module 20, and the drive module 20 outputs a control voltage Vo, allowing the galvanometer to deflect.

[0087] In the above situation, when the feedback signal is low, the feedback signal is an abnormal feedback signal; when the feedback signal is high, the feedback signal is a normal feedback signal.

[0088] By using multiple diodes connected to form an AND gate circuit, the logic AND function can be implemented at a lower cost compared to an AND gate chip, which helps to reduce production costs.

[0089] It should be noted that AND gate circuits can also use AND gate chips to implement the logic AND function. Using AND gate chips is beneficial for miniaturizing the circuit and reducing its size.

[0090] According to one embodiment of this application, the control module 10 further includes a first resistor R1, one end of which is connected to the first input terminal Ctrl1, and the other end of which is grounded.

[0091] In other words, the first input terminal Ctrl1 is grounded after passing through the first resistor R1, which is a pull-down resistor. This ensures that the enable signal received by the first input terminal Ctrl1 has an initial level, guaranteeing that the output of the AND gate circuit has no output when powered on. That is, the output of the AND gate circuit is at a low level. Based on this low-level signal, the galvanometer does not output the control voltage Vo, which can avoid the generation of spike pulses at the galvanometer coil when the drive control signal Ui output by the front-end control circuit defaults to a high level, thus protecting the galvanometer from damage.

[0092] Optionally, the drive module 20 further includes a power switch 21 and a second resistor R2. The power switch 21 is connected to the output terminal of the AND gate circuit and the power supply terminal of the operational amplifier U1, respectively. The two ends of the second resistor R2 are connected to the output terminal of the AND gate circuit and the power switch 21, respectively.

[0093] The power switch 21 can be any switch to control the on / off state of the circuit. For example, the power switch 21 can be a switching transistor. The base of the switching transistor can be connected to the output terminal of the AND gate circuit, the collector of the switching transistor can be connected to one end of the second resistor R2, the emitter of the switching transistor can be connected to the power supply terminal of the operational amplifier U1, and the other end of the second resistor R2 can be connected to the output terminal of the AND gate circuit.

[0094] The second resistor R2 is a pull-up resistor, used in conjunction with the first diode D1 and the second diode D2 that form the AND gate circuit to control the power switch 21 between the output terminal of the AND gate circuit and the power supply terminal of the operational amplifier U1.

[0095] The following detailed explanation uses a switching power supply with a switching transistor as an example. The voltage between the emitter of the switching transistor and the power supply terminal of the operational amplifier is Vcc2, and the voltage between one end of the second resistor R2 and the collector of the switching transistor is Vcc1.

[0096] When the AND gate outputs a low level, the switching transistor is cut off, and there is no output from the emitter of the switching transistor. In other words, Vcc2 is 0, the power supply voltage of op-amp U1 is 0, so op-amp U1 does not work, the voltage at the output of op-amp U1 is also 0, and the galvanometer does not deflect.

[0097] When the AND gate outputs a high level, the switching transistor is turned on, and both Vcc2 and Vcc1 have voltage. That is, the emitter of the switching transistor provides the voltage required for the operational amplifier U1 to operate. The output of operational amplifier U1 outputs a control voltage Vo based on the voltage at its non-inverting input, driving the mirror to deflect. The connection of the second resistor R2 allows the base of the switching transistor to be fixed at a high level at this time.

[0098] The control method for the galvanometer driving circuit according to this application includes the following steps:

[0099] Output power control signal;

[0100] The control voltage Vo is output to the galvanometer according to the power control signal;

[0101] A feedback signal is sent based on the control voltage Vo;

[0102] Adjust the power control signal based on the feedback signal.

[0103] Specifically, firstly, the control module 10 can output a power control signal to the drive module 20 through an AND gate circuit. Secondly, the drive module 20 can output a control voltage Vo to the galvanometer based on the received power control signal. Then, the feedback module 30 can detect the control voltage Vo and send a feedback signal to the AND gate circuit based on the control voltage Vo. Next, the AND gate circuit in the control module 10 can adjust the power control signal based on the feedback signal.

[0104] Since the galvanometer driving circuit according to this application has the above-mentioned technical effects, the control method of the galvanometer driving circuit according to this application also has the corresponding technical effects, that is, the output of the control voltage Vo is controlled according to the magnitude of the control voltage Vo, so that when the control voltage Vo is abnormal, the galvanometer stops deflecting, avoiding damage to the galvanometer or the main board, and effectively avoiding damage to the galvanometer by spike pulses during startup, saving galvanometer wear costs and improving product reliability.

[0105] According to one embodiment of this application, the control method for the galvanometer driving circuit further includes the following steps:

[0106] Output drive control signal Ui;

[0107] The control voltage Vo is output to the galvanometer according to the drive control signal Ui.

[0108] In other words, the control module 10 can also output a drive control signal Ui to the drive module 20 to control the control voltage Vo output by the drive module 20 to the galvanometer. Since the deflection angle of the galvanometer is proportional to the magnitude of the voltage, the deflection angle of the galvanometer can be controlled by adjusting the magnitude of the drive control signal Ui to meet the actual deflection requirements.

[0109] According to one embodiment of this application, the control method for the galvanometer driving circuit further includes the following steps:

[0110] Determine whether the control voltage Vo is lower than the preset threshold. When the control voltage Vo is lower than the preset threshold, send a normal feedback signal. When the control voltage Vo is not lower than the preset threshold, send an abnormal feedback signal.

[0111] Once an abnormal feedback signal is received, the resistance power control signal is output.

[0112] Specifically, the feedback module 30 can determine whether the control voltage Vo output by the drive module 20 is lower than a preset threshold. When the feedback module 30 determines that the control voltage Vo is lower than the preset threshold, the feedback module 30 sends a normal feedback signal to the AND gate circuit. Based on this normal feedback signal, the AND gate circuit can send a normal power control signal to the drive module 20, controlling the drive module 20 to drive the galvanometer according to the power control signal. When the feedback module 30 determines that the control voltage Vo is not lower than the preset threshold, the feedback module 30 sends an abnormal feedback signal to the AND gate circuit. Based on this abnormal feedback signal, the AND gate circuit blocks the output of the power control signal. When the drive module 20 does not receive the power control signal, it will not output the control voltage Vo, thereby protecting the galvanometer under abnormal voltage conditions.

[0113] The control method of the galvanometer drive circuit will be described in detail below with reference to a specific embodiment.

[0114] When the galvanometer is working normally, the control method of the galvanometer drive circuit can include the following steps:

[0115] First, power on the mirror drive circuit, then set the mirror enable signal to low level. Specifically, the front-end control circuit can provide a low-level signal as the mirror enable signal, which is equivalent to the power control signal. At this time, the AND gate output is low, and the operational amplifier U1 does not work.

[0116] Next, the DAC outputs a default level, which is a high level. Specifically, the DAC can be an analog-to-digital converter in the front-end control circuit to drive the control signal Ui. The default level of the DAC output is equivalent to driving the control signal Ui to the default level. At this time, the AND gate output is still at a low level, so the op-amp U1 does not work.

[0117] Then adjust the valid level of the DAC output. This valid level can be one of several values ​​lower than the default level. The op-amp U1 can adjust the output control voltage Vo according to the voltage value of the valid level of the DAC output. At this time, the AND gate output is still at a low level, so the op-amp U1 does not work.

[0118] Next, the galvanometer enable signal is high, which means that one input of the AND gate is high. At this time, since the output voltage is 0, the feedback signal is high by default due to the influence of the feedback power supply.

[0119] Based on the AND logic of the AND gate circuit, the power supply EN is at a high level. It should be noted that... Figure 2 The output of the AND gate is equivalent to the power supply EN, used to provide voltage.

[0120] Next, after the power switch receives a high level, Vcc2 outputs the mirror power supply, which means that when the power switch is turned on, the power supply terminal of the op-amp U1 has an output.

[0121] Then, operational amplifier U1 operates. Since operational amplifier U1 has a power output at its power supply terminal, and the active level at the non-inverting input terminal of operational amplifier U1 serves as the drive control signal Ui, operational amplifier U1 operates normally.

[0122] Finally, operational amplifier U1 outputs a control voltage Vo to the galvanometer based on the magnitude of the effective voltage level, thereby controlling the deflection of the galvanometer.

[0123] Operational amplifier U1 operates and outputs a control voltage Vo based on the effective voltage level of the DAC output, driving the mirror to deflect.

[0124] The control method of the galvanometer drive circuit will be described in detail below with reference to another specific embodiment.

[0125] When the control voltage Vo is abnormal, that is, when the control voltage Vo is not less than the preset threshold, the control method of the galvanometer drive circuit may include the following steps:

[0126] First, overcurrent / overvoltage of the galvanometer is detected. That is, the feedback module detects that the control voltage Vo output by the drive module is not less than a preset threshold. Specifically, the base voltage Vb of transistor Q1 is detected to be not less than 0.7V. Then, transistor Q1 turns on, causing the feedback signal to go low. This low-level feedback signal is sent to the AND gate circuit, which outputs a low level, causing the power supply EN to go low. It should be noted that... Figure 2 The output of the AND gate is equivalent to the power supply EN, used to provide voltage.

[0127] Next, since the power supply EN is at a low level, the power switch is effectively off, and Vcc2 has no output. In other words, there is no voltage input to the power supply terminal of op-amp U1. Therefore, op-amp U1 does not work, which causes the galvanometer to turn off. Turning the galvanometer off is equivalent to the galvanometer not deflecting.

[0128] The control method of the galvanometer drive circuit will be described in detail below with reference to another specific embodiment.

[0129] Adopting such Figure 2 When the galvanometer driving circuit shown drives the galvanometer, the control method of the galvanometer driving circuit may specifically include the following steps:

[0130] S1. The galvanometer drive circuit is powered on, and the feedback power supply Vcc3 outputs a high level. At this time, the feedback signal sent by the collector of transistor Q1 is a high level signal, and then the process proceeds to step S2.

[0131] S2. The front-end control circuit sends a low-level enable signal to the first input terminal Ctrl1. According to the AND logic processing principle of the AND gate circuit, the output terminal of the AND gate circuit outputs a low-level signal. After the power supply terminal of the operational amplifier U1 receives the low-level signal, the control voltage Vo output by the output terminal is 0, the galvanometer does not deflect, and then proceeds to step S3.

[0132] S3. The front-end control circuit sends a default level drive control signal Ui to the second input terminal Ctrl2. For example, it sends a 3.3V default level signal to the second input terminal Ctrl2. The non-inverting input terminal of the operational amplifier U1 receives the default level signal. At this time, since the power supply terminal of the operational amplifier U1 is at a low level, the output terminal of the operational amplifier U1 still does not output the control voltage Vo, and the galvanometer does not deflect. Then, proceed to step S4.

[0133] S4. The front-end control circuit sends a valid level drive control signal Ui to the second input terminal Ctrl2. The valid level voltage can be a voltage value lower than 3.3V, such as 1.1V or 1.2V, so as to output a suitable control voltage Vo for the galvanometer when the op-amp U1 is working. Then proceed to step S5.

[0134] S5. The front-end control circuit sends a high-level enable signal to the first input terminal Ctrl1. According to the AND logic processing principle of the AND gate circuit, the output terminal of the AND gate circuit sends the enable signal to the power supply terminal of the operational amplifier U1. That is to say, the AND gate circuit outputs a high-level signal, and then proceeds to step S6.

[0135] S6. Taking the power switch 21 switching transistor as an example, after the base of the switching transistor receives a high-level signal, it turns on, so that the emitter of the switching transistor supplies power to the power supply terminal of the operational amplifier U1. The operational amplifier U1 works normally. The output terminal of the operational amplifier U1 outputs the control voltage Vo according to the voltage value of the drive control signal Ui received by the non-inverting input terminal of the operational amplifier U1, so that the galvanometer deflects, and then proceeds to step S7.

[0136] S7. Feedback module 30 detects control voltage Vo and determines whether control voltage Vo is lower than a preset threshold. Specifically, the base of transistor Q1 determines whether control voltage Vo is lower than a preset threshold by detecting whether the voltage at one end of the fifth resistor R5 is less than 0.7V. When the determination is yes, proceed to step S8; when the determination is no, proceed to step S10.

[0137] S8. Transistor Q1 is cut off. The collector of transistor Q1 sends a high-level feedback signal to the gate circuit, and then proceeds to step S9.

[0138] S9. The AND gate circuit performs AND logic processing on the high-level feedback signal and the high-level enable signal, allowing the high-level enable signal to be output, and then proceeds to step S6.

[0139] S10, transistor Q1 is turned on, and the collector of transistor Q1 sends a low-level feedback signal to the gate circuit, and then proceeds to step S11;

[0140] S11. The AND gate circuit performs AND logic processing on the low-level feedback signal and the high-level enable signal to prevent the high-level enable signal from being output. That is, the AND gate circuit outputs a low-level signal, and then proceeds to step S12.

[0141] S12. After the base of the switching transistor receives a low-level signal, it is cut off, making the voltage of the emitter of the switching transistor 0. That is to say, the voltage of the power supply terminal of the operational amplifier U1 is 0, the operational amplifier U1 does not work, the output terminal of the operational amplifier U1 does not output the control voltage Vo, the galvanometer does not deflect, and then proceed to step S7.

[0142] By controlling the galvanometer drive using the above method, when the galvanometer encounters an abnormal voltage, the control voltage Vo output to the galvanometer can be adjusted to 0, thereby cutting off the power supply to the galvanometer and protecting the galvanometer and the entire galvanometer drive circuit. Simultaneously, after cutting off the power supply to the galvanometer, since the control voltage Vo is 0, it will inevitably be less than a preset threshold. Therefore, the power supply to the galvanometer can be automatically restored through the feedback signal sent by the feedback module 30, causing the galvanometer to deflect. In other words, this galvanometer drive circuit can both protect the galvanometer in case of abnormal voltage and enable the galvanometer to automatically resume operation, avoiding the inconvenience of manual restart.

[0143] The projector according to this application includes the aforementioned galvanometer driving circuit.

[0144] Since the galvanometer driving circuit according to this application has the above-mentioned technical effects, the projector according to this application also has the corresponding technical effects, namely, controlling the output of the control voltage Vo according to the magnitude of the control voltage Vo, thereby stopping the galvanometer from deflecting when the control voltage Vo is abnormal, avoiding damage to the galvanometer or the main board, and effectively avoiding damage to the galvanometer by spike pulses during startup, saving galvanometer wear costs and improving product reliability.

[0145] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A galvanometer driving circuit, characterized in that, include: A control module having an AND gate circuit, the control module being configured to output a power control signal via the AND gate circuit; The drive module is configured to output a control voltage to the galvanometer according to the power control signal; A feedback module is configured to send a feedback signal based on the control voltage; The AND gate circuit of the control module is configured to receive the feedback signal and adjust the power control signal according to the feedback signal; The control module is also configured to output a drive control signal to the drive module, and the drive module is also configured to output a control voltage to the galvanometer according to the drive control signal; The control module includes a second input terminal for sending drive control signals; the drive module includes a non-inverting amplifier, which has a non-inverting input terminal, an inverting input terminal, a power supply terminal, and an output terminal. The second input terminal is connected to the non-inverting input terminal, the output terminal of the AND gate circuit is connected to the power supply terminal, one end of the galvanometer coil is connected to the output terminal, the other end of the galvanometer coil is connected to the inverting input terminal, and the other end of the galvanometer coil is grounded after passing through a third resistor. The feedback module includes a transistor, a fourth resistor, a fifth resistor, and a sixth resistor. The base of the transistor is connected to the output terminal of the drive module through the fifth resistor and receives the control voltage. The base of the transistor is grounded through the fourth resistor. The collector of the transistor is connected to the feedback power supply through the sixth resistor. The collector of the transistor is connected to the AND gate circuit. The emitter of the transistor is grounded. If the control voltage is lower than the preset threshold, the transistor is turned off, and under the action of the feedback power supply, the feedback module outputs a high-level normal feedback signal; If the control voltage is not lower than the preset threshold, the transistor is turned on, and the feedback module outputs a low-level abnormal feedback signal. The AND gate circuit prevents the power control signal from being output when it receives an abnormal feedback signal.

2. The galvanometer driving circuit according to claim 1, characterized in that, The control module further includes a first input terminal, which is connected to the AND gate circuit, and the first input terminal is configured to receive a power control signal. If the feedback signal is an abnormal feedback signal, the AND gate circuit will prevent the power control signal from being output. If the feedback signal is a normal feedback signal, then the AND gate circuit allows the power control signal to be output; The power control signal is an enable signal.

3. The galvanometer driving circuit according to claim 2, characterized in that, The AND gate circuit includes a first diode and a second diode. The positive terminals of the first diode and the second diode are connected as the output terminal of the AND gate circuit. The negative terminal of the first diode is used to receive the feedback signal, and the negative terminal of the second diode is connected to the first input terminal.

4. The galvanometer driving circuit according to claim 3, characterized in that, The control module further includes a first resistor, one end of which is connected to the first input terminal, and the other end of which is grounded.

5. The control method for the galvanometer driving circuit according to any one of claims 1 to 4, characterized in that, Includes the following steps: Output power control signal; A control voltage is output to the galvanometer according to the power control signal; A feedback signal is sent according to the control voltage; The power control signal is adjusted based on the feedback signal.

6. The control method for the galvanometer driving circuit according to claim 5, characterized in that, It also includes the following steps: Output drive control signal; The control voltage is output to the galvanometer according to the drive control signal.

7. The control method for the galvanometer driving circuit according to claim 6, characterized in that, It also includes the following steps: Determine whether the control voltage is lower than a preset threshold. If the control voltage is lower than the preset threshold, send a normal feedback signal. If the control voltage is not lower than the preset threshold, send an abnormal feedback signal. Once the abnormal feedback signal is received, the power control signal output is prevented.

8. A projector, characterized in that, Includes the galvanometer driving circuit according to any one of claims 1 to 4.

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