Driving circuit with chopping and current limiting functions and stage lamp

Abstract

The utility model provides a drive circuit with chopping and current limiting functions and a stage lamp, comprising an ILIMIT pin, an external pull-down resistor arranged on the ILIMIT pin; the output end of the H bridge is connected with a load; the first input end of the control logic circuit is connected with the ILIMIT pin, and the driving output end of the control logic circuit is connected with the H bridge; the control logic circuit comprises a calculation circuit, a current detection circuit, a comparison circuit and a chopper circuit, the ILIMIT pin serves as the input end of the calculation circuit, the input end of the comparison circuit is connected with the output end of the calculation circuit and the output end of the current detection circuit, and the input end of the chopper circuit is connected with the output end of the comparison circuit and the output end of the current detection circuit. The driving circuit provided by the utility model has a current chopping and current limiting function so as to prevent the output current of the H bridge from infinitely increasing, and surge current can be effectively limited without damaging a chip and a load during the starting or transient period of the load.

Description

TECHNICAL FIELD

[0001] The utility model relates to drive circuit technical field especially, it relates to a drive circuit with the function of chopping current limiting and stage lamp. BACKGROUND

[0002] At present in the field of stage lamp, the mainstream scheme of each movement component is all using drive circuit to drive, drives each component to run. Different components need different driving current because of the factors such as movement speed or weight. Stage lamp has the application of current of focusing, amplifying, vertical scanning, horizontal scanning etc. and also has the application of current of color disc, pattern disc, cutting, aperture etc.

[0003] When the current provided by prior art in drive circuit is greater than the current required by component, there is no protection measure, and the component is damaged. SUMMARY

[0004] The utility model provides a drive circuit with the function of chopping current limiting and stage lamp to solve the defect that driving current is too large in prior art, and the component is damaged, realizes the drive circuit with the function of chopping current limiting and protects the component.

[0005] The utility model provides a drive circuit with the function of chopping current limiting, it includes:

[0006] ILIMIT pin, be equipped with external pull-down resistance on the ILIMIT pin;

[0007] H bridge, the output of H bridge is connected with load;

[0008] Control logic circuit, the first input of control logic circuit is connected ILIMIT pin, and drive output is connected H bridge;

[0009] Including calculation circuit, current detection circuit, comparison circuit and chopping circuit in the control logic circuit, the input of calculation circuit is ILIMIT pin, the input of comparison circuit is connected calculation circuit, the output of current detection circuit, the input of chopping circuit is connected comparison circuit, the output of current detection circuit;

[0010] The calculation circuit is used to calculate chopping current limiting threshold according to the resistance on the ILIMIT pin;

[0011] The current detection circuit is used to detect the output current of H bridge;

[0012] The comparison circuit is used to compare the output current of H bridge with chopping current limiting threshold and carries out output;

[0013] The chopper circuit is used for chopping the output current of the H-bridge according to the output of the comparison circuit.

[0014] According to the driving circuit with the chopper current limiting function, the comparison circuit outputs a high level when the output current of the H-bridge is greater than or equal to the chopper current limiting threshold, and outputs a low level when the output current of the H-bridge is less than the chopper current limiting threshold.

[0015] The chopper circuit sends a drive duty ratio or a high or low level of the H-bridge drive when the comparison circuit outputs a high level.

[0016] According to the driving circuit with the chopper current limiting function, the calculation circuit calculates the chopper current limiting threshold according to the resistance on the ILIMIT pin, and the formula is as follows:

[0017]

[0018] Among them, is the chopper current limiting threshold, is the output voltage of the ILIMIT pin, is the resistance on the ILIMIT pin, is a preset coefficient.

[0019] According to the driving circuit with the chopper current limiting function, the preset coefficient is determined according to the type of the H-bridge.

[0020] In the case that the type of the H-bridge is a double H-bridge, the preset coefficient is a first value.

[0021] In the case that the type of the H-bridge is a single H-bridge, and the two outputs of the single H-bridge are in parallel, the preset coefficient is a second value.

[0022] The first value is greater than the second value.

[0023] According to the driving circuit with the chopper current limiting function, further comprising an nSLEEP pin, the nSLEEP pin is a second input end of the control logic circuit, under the triggering of the nSLEEP pin, the control logic circuit turns off the internal circuit, so that the H-bridge outputs a static current.

[0024] According to the driving circuit with the chopper current limiting function, under the triggering of the nSLEEP pin, the control logic circuit turns off the drive of the H-bridge, and realizes overcurrent protection, short circuit protection, undervoltage lock protection and over-temperature protection.

[0025] According to the driving circuit with the chopper current limiting function, when the output current of the H bridge is greater than or equal to the chopper current limiting threshold, the control logic circuit closes the pin output to the H bridge, and controls the H bridge to work in a fast decay state.

[0026] In the fast decay state, the H bridge reverses the state to allow the winding current to flow reversely.

[0027] When the winding current approaches zero, the H bridge does not work.

[0028] According to the driving circuit with the chopper current limiting function, the nFAULT pin is further included, the nFAULT pin is used as an error output end of the control logic circuit, and the control logic circuit controls an output fault signal under the triggering of the nFAULT pin.

[0029] According to the driving circuit with the chopper current limiting function, the H bridge has multiple paths, and the number of the H bridges connected to the control logic circuit is controlled by an external control signal input into the control logic circuit.

[0030] The stage lamp provided by the utility model, comprising a plurality of movement components, drives each movement component to move based on the driving circuit with the chopper current limiting function of any one of the above.

[0031] The driving circuit with the chopper current limiting function and the stage lamp provided by the utility model have the current chopper current limiting function by comparing the output of the circuit when the output current of the H bridge is greater than or equal to the chopper current limiting threshold, triggering the driving circuit to enter the chopper current limiting mode, and chopper processing the output current of the H bridge, so that the output current of the H bridge can be prevented from increasing unlimitedly, and the chip and the load can be effectively limited from being damaged by surge current during load starting or transient period. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical scheme in the utility model or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or the prior art description, and obviously, the drawings in the following description are some embodiments of the utility model, and for those skilled in the art, other drawings can also be obtained without creative labor according to these drawings.

[0033] Figure 1 It is the driving circuit frame schematic diagram provided by the utility model with the chopper current limiting function;

[0034] Figure 2 It is the driving circuit structure schematic diagram provided by the utility model with the chopper current limiting function;

[0035] Figure 3 is the state diagram of the driving circuit with the chopper current limiting function in the fast decay mode provided by the utility model, wherein (a) is the current change in the 10us fast decay time, (b) is the current flow direction path;

[0036] Figure 4 is the connection principle schematic diagram of the driving circuit with the chopper current limiting function and external circuit provided by the utility model;

[0037] Figure 5 is the structure schematic diagram of the stage lamp provided by the utility model;

[0038] Figure 6 is the structure schematic diagram of the focusing amplification module in the stage lamp provided by the utility model. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the utility model more clear, the technical scheme in the utility model will be described clearly and completely below in combination with the drawings in the utility model, obviously, the described embodiment is a part of the embodiment of the utility model, rather than all the embodiment. Based on the embodiment in the utility model, all other embodiments obtained by the person skilled in the art without making the creative labor are within the protection scope of the utility model.

[0040] The utility model discloses a kind of driving circuits with chopper current limiting function, including: Figure 1 And Figure 2 Described below is a kind of driving circuit with chopper current limiting function of the utility model, comprising:

[0041] ILIMIT pin, the ILIMIT pin is equipped with external pull-down resistance (such as Figure 4 R1_1 in it);

[0042] H bridge, the output of the H bridge is connected with load;

[0043] Control logic circuit, the first input of the control logic circuit is connected with the ILIMIT pin, and drive output end is connected with the H bridge;

[0044] Including calculation circuit, current detection circuit, comparison circuit and chopper circuit in the control logic circuit, the ILIMIT pin is as the input of the calculation circuit, the input of the comparison circuit is connected with the output of the calculation circuit, the current detection circuit, the input of the chopper circuit is connected with the output of the comparison circuit, current detection circuit;

[0045] The calculation circuit is used to calculate chopper current limiting threshold according to the resistance on the ILIMIT pin;

[0046] The current detection circuit is configured to detect the output current of the H-bridge.

[0047] The comparison circuit is configured to compare the output current of the H-bridge with the chopping current limit threshold and output.

[0048] The chopping circuit is configured to chop the output current of the H-bridge according to the output of the comparison circuit.

[0049] The driving circuit in the embodiment can drive one or more H-bridges. Each H-bridge can provide a large peak current and drive the load connected thereto to move.

[0050] The load driven by the H-bridge can be a brush DC motor, a two-phase stepper motor, a three-phase stepper motor, a solenoid or other inductive load.

[0051] When the driving current provided by the H-bridge is overcurrent, the chopping current limit technology can be applied to limit the current. The current detection circuit is integrated in the control logic circuit to detect the output current of the H-bridge. The chopping current limit threshold (I I CHOP ) can be set by an external pull-down resistor of the ILIMIT pin. The ILIMIT pin can output a 1.2V voltage source, for example.

[0052] Chopping current limit threshold I CHOP is inversely proportional to the resistance on the ILIMIT pin. For example, when the resistance on the ILIMIT pin is 15kΩ, the chopping current limit threshold I CHOP reaches the maximum, reaching the OCP (Overcurrent Protection) value. When the resistance continues to decrease, the chopping current threshold I CHOP will not increase again.

[0053] The comparison circuit compares the output current of the H-bridge with the chopping current limit threshold. When the output current of the H-bridge is greater than or equal to the chopping current limit threshold, the driving circuit is triggered to enter the chopping current limit mode.

[0054] In the chopping current limit mode, the output current of the H-bridge is chopped to prevent the output current of the H-bridge from increasing indefinitely. The chopping current limit function is performed on the driving circuit instead of prematurely shutting down the chip output of the driving circuit. This function can effectively limit the inrush current during load startup or transient without damaging the chip.

[0055] This embodiment triggers the drive circuit to enter the chopping current limiting mode when the output current of the H-bridge is greater than or equal to the chopping current limiting threshold. This mode chops the output current of the H-bridge, thus preventing the output current of the H-bridge from increasing indefinitely. It can effectively limit surge current during load startup or transient periods without damaging the chip or load.

[0056] Based on the above embodiments, the comparison circuit in this embodiment outputs a high level when the output current of the H-bridge is greater than or equal to the chopper current limiting threshold, and outputs a low level when the output current of the H-bridge is less than the chopper current limiting threshold.

[0057] When the comparator circuit outputs a high level, the chopper circuit sends the drive duty cycle or level high / low to the H-bridge driver.

[0058] The comparator circuit outputs a high level (1) when the output current of the H-bridge is greater than or equal to the chopper current limiting threshold, and a low level (0) when the output current of the H-bridge is less than the chopper current limiting threshold.

[0059] The output current of the H-bridge detected by the current detection circuit can be a sine wave. When the comparator circuit outputs a high level (1), it triggers the chopper circuit to chop the sine wave of the H-bridge output current.

[0060] Based on the above embodiments, the calculation circuit in this embodiment calculates the chopper current limiting threshold according to the resistance on the ILIMIT pin using the following formula:

[0061]

[0062] in, The chopper current limiting threshold, The output voltage of the ILIMIT pin. The resistor on the ILIMIT pin, These are preset coefficients.

[0063] Figure 1 The output voltage of the ILIMIT pin is 1.2V, but it is not limited to this. These are preset coefficients, calculated based on hardware parameters.

[0064] Based on the above embodiments, the preset coefficient in this embodiment is determined according to the type of the H-bridge;

[0065] When the H-bridge type is a double H-bridge, the preset coefficient is a first value;

[0066] When the H-bridge is a single H-bridge and the two outputs of the single H-bridge are connected in parallel, the preset coefficient is the second value;

[0067] The first value is greater than the second value.

[0068] In the case where the type of the H-bridge is a double H-bridge, the preset coefficient can be 20. In the case where the type of the H-bridge is a single H-bridge, the preset coefficient can be 10. For example, The threshold value calculation is shown in Table 1.

[0069] Table 1

[0070]

[0071] On the basis of the above-mentioned embodiments, the present embodiment further includes an nSLEEP pin, which serves as a second input end of the control logic circuit. Upon triggering of the nSLEEP pin, the control logic circuit turns off the internal circuit, so that the H-bridge outputs static current.

[0072] For example, when the nSLEEP pin is at a low level, the control logic circuit is triggered to turn off the internal circuit, and the H-bridge outputs static current.

[0073] The present embodiment provides a low-power sleep mode to turn off the internal circuit, so as to achieve very low static current. This sleep mode is realized by setting the nSLEEP pin. Turning off the internal circuit is controlled by the internal logic of the control logic circuit.

[0074] On the basis of the above-mentioned embodiments, in the present embodiment, upon triggering of the nSLEEP pin, the control logic circuit turns off the drive of the H-bridge, so as to realize overcurrent protection, short-circuit protection, undervoltage lockout protection, and over-temperature protection.

[0075] On the basis of the above-mentioned embodiments, in the present embodiment, in the case where the output current of the H-bridge is greater than or equal to the chopping current limit threshold value, the control logic circuit closes the pins output to the H-bridge, so as to control the H-bridge to work in a fast decay state;

[0076] In the fast decay state, the H-bridge reverses the state to allow the winding current to flow in the opposite direction;

[0077] When the winding current approaches zero, the H-bridge does not work.

[0078] In the chopping current limit mode, the chip output of the drive circuit is monitored by two protection systems, which are controlled by the internal logic of the control logic circuit. The first protection system uses a formula to calculate the chopping current limit threshold value according to the resistance on the ILIMIT pin and the 1.2V voltage source output, and uses the chopping current limit threshold value for chopping current limit.

[0079] In the case of short circuit to power supply and short circuit to ground, the chopper current limiting circuit can not control the current to the appropriate level, the second protection system triggers the drive circuit chip to close all output pins for overcurrent protection, that is, all outputs will be set to high impedance (Hi-Z) state, which is controlled by the internal logic of the control logic circuit.

[0080] The chopper current limiting function and overcurrent protection are independent. Once the chopper current limiting threshold is reached, the H-bridge enters the fast decay state and works as shown in Figure 3 (a). In the fast decay mode, once the PWM (Pulse Width Modulation) chopper current level is reached, the H-bridge will reverse the state to allow the winding current to flow in the opposite direction, as shown in Figure 3 (b). When the winding current approaches zero, the H-bridge stops working to prevent any reverse current from flowing in. Figure 3 (a) is the current change in the 10us fast decay time, Figure 3 (b) is the current flow path, where ① is the reverse drive current flow direction, and ② is the fast decay current flow direction.

[0081] Figure 4 The principle diagram of the drive circuit is shown. Among them, R8_1, R10_1, R12_1, R4_1, U9 and U9 peripheral circuit are not welded, R6_1, R7_1, R9_1, R11_1, R17_1 are welded, R3_1 is welded 0R (MODE is 0), and R1_1 is the resistance value control chopper current limiting threshold.

[0082] On the basis of the above embodiments, the nFAULT pin is further included in the embodiment, which is connected as an error output end of the control logic circuit. Under the triggering of the nFAULT pin, the control logic circuit controls the output of the fault signal.

[0083] For example, the output current of the H-bridge is too large, exceeding the overall limit range of the drive circuit, or the drive circuit is overheated, the nFAULT pin triggers the control logic circuit to output the fault signal.

[0084] On the basis of the above embodiments, the H-bridge has multiple paths in the embodiment, and the number of H-bridges connected to the control logic circuit is controlled by an external control signal input to the control logic circuit.

[0085] The H-bridge has multiple paths, and the number of H-bridges connected is controlled according to the current required by the load driven by the drive circuit. Each H-bridge can provide a large peak current and can drive the load connected thereto to move.

[0086] The application further provides a stage lamp, comprising a plurality of moving components, and each moving component is driven to move by the driving circuit with the chopping current limiting function according to any one of the above embodiments.

[0087] The structure of the stage lamp is shown in Figure 5 The stage lamp comprises a base 1, support arms 2 and a lamp head 3. The support arms 2 are pivoted on the base 1, and the lamp head 3 is pivoted between the support arms 2. The driving circuit is used to drive the lamp head 3 and / or the support arms 2 to rotate.

[0088] The structure of the focusing and amplifying module in the stage lamp is shown in Figure 6 The focusing and amplifying module comprises a focusing component 301, a prism component 302, an amplifying component 303, a motor board 304 and a motor 305. The focusing component 301, the prism component 302 and the amplifying component 303 respectively realize the functions of focusing, prism and amplifying. The driving circuit needs to drive the motor 305 to move at different speeds according to different application functions of the focusing and amplifying module.

[0089] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A drive circuit with chopper current limiting function, characterized by, The application relates to a current-limiting control circuit for an H-bridge, comprising: an ILIMIT pin provided with an external pull-down resistor; an H-bridge, the output end of which is connected with a load; a control logic circuit, the first input end of which is connected with the ILIMIT pin, and the drive output end of which is connected with the H-bridge; the control logic circuit comprises a calculation circuit, a current detection circuit, a comparison circuit and a chopping circuit, the ILIMIT pin is used as the input end of the calculation circuit, the input ends of the comparison circuit are connected with the calculation circuit and the output end of the current detection circuit, and the input end of the chopping circuit is connected with the output ends of the comparison circuit and the current detection circuit; the calculation circuit is used for calculating a chopping current-limiting threshold according to the resistance on the ILIMIT pin; the current detection circuit is used for detecting the output current of the H-bridge; the comparison circuit is used for comparing the output current of the H-bridge with the chopping current-limiting threshold and outputting; the chopping circuit is used for chopping the output current of the H-bridge according to the output of the comparison circuit.

2. The drive circuit with current limit function of chopper according to claim 1, characterized in that, the comparison circuit outputs a high level when the output current of the H-bridge is greater than or equal to the chopping current-limiting threshold, and outputs a low level when the output current of the H-bridge is less than the chopping current-limiting threshold; the chopping circuit sends a drive duty ratio or a high-low level to the H-bridge drive when the comparison circuit outputs a high level.

3. The drive circuit with current limit function of chopper according to claim 1, characterized in that, the formula for calculating the chopping current-limiting threshold by the calculation circuit according to the resistance on the ILIMIT pin is as follows: Wherein, I CHOP is a chopping current limiting threshold, V is an output voltage of the ILIMIT pin, R ILIM is a resistance on the ILIMIT pin, and a is a preset coefficient.

4. The drive circuit with current limit function of chopper according to claim 3, characterized in that, the preset coefficient is determined according to the type of the H-bridge; in the case that the type of the H-bridge is a double H-bridge, the preset coefficient is a first value; in the case that the type of the H-bridge is a single H-bridge and the two outputs of the single H-bridge are connected in parallel, the preset coefficient is a second value; the first value is greater than the second value.

5. The drive circuit with current limit function of chopper according to claim 1, wherein the application further comprises an nSLEEP pin, which is used as the second input end of the control logic circuit, and under the triggering of the nSLEEP pin, the control logic circuit turns off the internal circuit, so that the H-bridge outputs a static current.

6. The drive circuit with current limit function of chopper according to claim 5, wherein under the triggering of the nSLEEP pin, the control logic circuit turns off the drive of the H-bridge, and overcurrent protection, short-circuit protection, under-voltage lock protection and over-temperature protection are realized.

7. The drive circuit with current limit function of chopper according to claim 5, wherein in the case that the output current of the H-bridge is greater than or equal to the chopping current-limiting threshold, the control logic circuit turns off the pins outputting to the H-bridge, and controls the H-bridge to work in a fast decay state; in the fast decay state, the H-bridge reverses the state to allow the winding current to flow reversely; when the winding current approaches zero, the H-bridge does not work.

8. The drive circuit with current limit function of chopper according to any one of claims 1 to 7, characterized in that, the application further comprises an nFAULT pin, which is used as the error output end of the control logic circuit, and under the triggering of the nFAULT pin, the control logic circuit outputs a fault signal.

9. The drive circuit with current limit function of chopper according to any one of claims 1 to 7, characterized in that, the H-bridge has multiple paths, and the number of the H-bridges connected with the control logic circuit is controlled through an external control signal inputted to the control logic circuit.

10. A stage light, characterized by The drive circuit with current chopping function drives each motion component to move based on any one of claims 1-9.

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