CN219087116U - Triangular wave generating circuit and electronic device - Google Patents
Triangular wave generating circuit and electronic device Download PDFInfo
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- CN219087116U CN219087116U CN202222928861.9U CN202222928861U CN219087116U CN 219087116 U CN219087116 U CN 219087116U CN 202222928861 U CN202222928861 U CN 202222928861U CN 219087116 U CN219087116 U CN 219087116U
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Abstract
The embodiment of the application provides a triangular wave generation circuit and electronic equipment, the triangular wave generation circuit includes: a comparison unit and a triangular wave generation unit; the comparison unit comprises a comparison output end shared by at least two paths of comparators; the triangular wave generating unit comprises a switching tube and a charge-discharge capacitor; the comparison output end is connected with the control electrode of the switching tube; the charge-discharge capacitor is connected between the first pole and the second pole of the switching tube in a bridging way; the comparison unit is used for controlling the on-off of the switching tube, the switching tube is used for controlling the charge and discharge of the charge and discharge capacitor, and triangular waves are output through continuous charge and discharge of the charge and discharge capacitor. Therefore, the number of input reference clocks can be reduced, so that the number of clocks required to be provided by a board stage is reduced, the design complexity of a main board is reduced, and finally the cost is lower.
Description
Technical Field
The application relates to the technical field of zero crossing detection, in particular to a triangular wave generating circuit and electronic equipment.
Background
The zero crossing detection is an identification detection of zero crossings in the alternating current signal. By identifying zero crossings in the alternating current signal and generating controllable triangular waves at the zero crossings, a number of engineering applications can be realized. The principle of generating a controllable triangular wave at the zero crossing point is: the comparator is used for comparing the alternating current signal with the filtering signal of the alternating current signal to generate zero crossing pulse, and the triode is triggered to be turned on or off through the zero crossing pulse, so that a capacitor in a triode connection loop is charged and discharged, and controllable triangular waves are generated at the zero crossing point.
In the prior art, two independent comparators are required to output zero crossing signals to trigger a switch to generate triangular waves, namely, each comparator is required to be independently provided with auxiliary circuits such as a triode, a pull-up resistor and the like, so that the occupied space is large, and the cost is high.
Disclosure of Invention
In view of the foregoing, embodiments of the present application have been made to overcome the foregoing technical problems by providing a triangular wave generating circuit, so as to reduce the occupation space of the triangular wave generating circuit and reduce the cost.
In a first aspect, an embodiment of the present application discloses a triangle wave generating circuit, including: a comparison unit and a triangular wave generation unit; the comparison unit comprises a comparison output end shared by at least two paths of comparators; the triangular wave generating unit comprises a switching tube and a charge-discharge capacitor; the comparison output end is connected with the control electrode of the switching tube; the charge-discharge capacitor is connected between the first pole and the second pole of the switching tube in a bridging way; the comparison unit is used for controlling the on-off of the switching tube, and the switching tube is used for controlling the charge and discharge of the charge and discharge capacitor, so as to output triangular waves through continuous charge and discharge of the charge and discharge capacitor.
In some embodiments, the comparison unit further comprises at least a first input and a second input; the triangular wave generating unit further comprises a triangular wave output end;
the comparison unit is used for receiving the target alternating current signal input by the first input end and the reference signal input by the second input end, and outputting the first level to the control electrode of the switching tube under the condition that the voltage difference value between the target alternating current signal and the reference signal is smaller than or equal to a voltage threshold value; the switching tube is controlled by the first level to conduct the connection between the first pole and the second pole so as to discharge the charge-discharge capacitor; under the condition that the voltage difference is larger than the voltage threshold, outputting the second level to a control electrode of the switching tube, under the control of the second level, disconnecting the first electrode from the second electrode so as to charge the charge-discharge capacitor, and outputting triangular waves through the triangular wave output end, wherein the triangular wave output end is a connection point of the first electrode and the charge-discharge capacitor; wherein the first level is greater than the second level.
In some embodiments, the triangle wave generating unit further comprises a current limiting resistor for limiting a charging current to the charging and discharging capacitor; the current limiting resistor is connected between the first power supply and the triangular wave output end;
under the condition that the first pole is connected with the second pole, the first pole plate and the second pole plate of the charge-discharge capacitor are both connected with the grounding end, and the charge-discharge capacitor discharges; under the condition that the first pole is disconnected from the second pole, the first power supply is connected into a first polar plate of the charge-discharge capacitor through the current-limiting resistor, the charge-discharge capacitor is charged through the first power supply, and the triangular wave is output through the triangular wave output end under the condition that the charge-discharge capacitor is continuously charged and discharged.
In some embodiments, the triangle wave generation circuit further comprises: the power supply unit comprises a reference signal input end, an alternating current power supply and a filter capacitor; the reference signal input end is connected with the anode of the alternating current power supply; the filter capacitor is connected between the positive electrode and the negative electrode of the alternating current power supply in a bridging way; the connection point of the positive electrode and the filter capacitor is connected with the second input end; the connection point of the negative electrode and the filter capacitor is connected with the first input end.
In some embodiments, the comparison unit includes a first comparator, a second comparator, and a pull-up resistor;
the first input end is connected with the inverting input end of the first comparator and the non-inverting input end of the second comparator; the second input end is connected with the non-inverting input end of the first comparator and the inverting input end of the second comparator; the first output end of the first comparator is connected with the second output end of the second comparator; the pull-up resistor is connected between the first power supply and the second node; the second node represents a connection point of the first output terminal and the second output terminal.
In some embodiments, the comparison unit further comprises a first resistor and a second resistor; the first resistor is connected in series between the second input terminal and a non-inverting input terminal of the first comparator; the second resistor is connected in series between the first input and a non-inverting input of the second comparator.
In some embodiments, the first resistor and the second resistor have equal resistance values.
In some embodiments, the first resistor and the second resistor are both variable resistors; the resistance value of the first resistor or the second resistor is determined according to the starting point of the triangular wave.
In some embodiments, the switching transistor is an NMOS transistor or an NPN transistor.
In a second aspect, embodiments of the present application further provide an electronic device, including the triangle wave generating circuit according to the first aspect of the embodiments of the present application.
Embodiments of the present application include the following advantages:
in the embodiment of the application, the triangular wave generation circuit comprises a comparison unit and a triangular wave generation unit, wherein the comparison unit comprises a comparison output end shared by at least two paths of comparators; the triangular wave generating unit comprises a switching tube and a charge-discharge capacitor; the comparison output end is connected with the control electrode of the switching tube; the charge-discharge capacitor is connected between the first pole and the second pole of the switching tube in a bridging way; the comparison unit is used for controlling the on-off of the switching tube, and the switching tube is used for controlling the charge and discharge of the charge and discharge capacitor, so as to output triangular waves through continuous charge and discharge of the charge and discharge capacitor. Because the triangular wave generating circuit only comprises a switching tube and a charge-discharge capacitor, the circuit is relatively simpler, the occupied space is relatively smaller, and the cost is lower.
Drawings
Fig. 1 is a schematic diagram of a constitution of a triangular wave generating circuit in the related art;
fig. 2 is a schematic diagram of a composition structure of a triangular wave generating circuit according to an embodiment of the present application;
fig. 3a is a schematic diagram of a composition structure of a triangle wave generating circuit according to an embodiment of the present application;
fig. 3b is a schematic diagram of a composition structure of another triangular wave generating circuit according to an embodiment of the present application;
fig. 4 is a schematic waveform diagram of a target ac signal and a triangular wave signal according to an embodiment of the present application;
FIG. 5 is a schematic diagram of waveforms of another target AC signal and triangular wave signal according to an embodiment of the present disclosure;
fig. 6 is a schematic implementation flow chart of a triangular wave generating method according to an embodiment of the present application.
Detailed Description
In order that the above-recited objects, features and advantages of the present application will become more readily apparent, a more particular description of the utility model briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings.
In the related art, a zero crossing signal is output by two independent comparators to trigger a switch to generate a triangular wave, and in a circuit for generating the triangular wave at the zero crossing point of an alternating current signal, in order to realize the controllability of a starting point, an additional monostable trigger is added between the output ends of the two independent comparators and a corresponding triode. As shown in fig. 1, the triangular wave generating circuit includes: AC power supply AC, reference dc signal Base, 3.3V power supply VCC, ground GND, comparator U13, comparator U14, resistor R18, resistor R19, resistor R20, resistor R21, resistor R22, resistor R23, resistor R24, resistor R25, resistor R26, resistor R27, resistor R28, resistor R29, capacitor C6, capacitor C7, capacitor C8, capacitor C9, transistor Q5, and transistor Q6.
Wherein the positive electrode of the AC is connected with the Base; r18 is connected in parallel between the positive and negative poles of the AC; the first end of R19 is connected with Base (the first end of R18), and the first end of R20 is connected with the second end of R18; c7 is connected between the second end of R19 and the second end of R20 in a bridging manner; the first end of C7 is connected with the non-inverting input end of U14 through R23; the second end of C7 is connected with the negative phase input end of U14; the positive end of the power supply of U14 is connected with VCC; the negative end of a power supply of U14 is connected with GND; the monostable trigger formed by connecting C8 and R25 in series is connected between the output end of U14 and the control electrode of Q5 in series; the output end of U14 is connected with VCC through a pull-up resistor R21; the base electrode of Q5 is connected with GND through R26; the emitter of Q5 is connected with GND; the collector of Q5 is connected with the first end of C6; the second end of C6 is connected with GND; the first end of C6 is connected to VCC through R22.
The second end of C7 is connected with the non-inverting input end of U13 through R24; the first end of C7 is connected with the negative phase input end of U13; the positive end of the power supply of U13 is connected with VCC; the negative end of the power supply of U13 is connected with GND; the monostable trigger formed by connecting C9 and R28 in series is connected between the output end of U13 and the control electrode of Q6 in series; the output end of U13 is connected with VCC through a pull-up resistor R27; the base electrode of Q6 is connected with GND through R29; the emitter of Q6 is connected with GND; the collector of Q6 is connected to the first end of C6.
It can be seen that the zero-crossing triangular wave generating circuit of the alternating current signal in the related art has the defects of more devices, more complex circuits, larger occupied space and higher cost.
Based on the above technical problems, the present embodiment provides a triangular wave generating circuit, as shown in fig. 2, the triangular wave generating circuit 20 includes a comparing unit 201 and a triangular wave generating unit 202; the comparing unit 201 includes a comparing output 2011 shared by at least two comparators; the triangular wave generation unit 202 includes a switching tube 2021 and a charge-discharge capacitor 2022; the comparison output terminal 2011 is connected with the control electrode of the switch tube 2021; the charge-discharge capacitor 2022 is connected between the first pole and the second pole of the switch tube 2021 in a bridging manner; the comparing unit 201 is configured to control on/off of the switching tube 2021, and the switching tube 2021 is configured to control charge/discharge of the charge/discharge capacitor 2022, so as to output a triangular wave by continuously charging/discharging the charge/discharge capacitor 2022.
In some possible implementations, the switching tube 2021 may be a triode or a field effect tube that operates in a switching state; for example, the switching transistor 2021 may be a P-type metal oxide semiconductor (Positive Channel Metal Oxide Semiconductor, PMOS) transistor, an N-type metal oxide semiconductor (Negative Channel Metal Oxide Semiconductor, NMOS) transistor, or an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT) or other type of transistor operating in a switching state.
In one embodiment, where the switching tube 2021 is an NMOS tube, the first pole of the switching tube 2021 may be the drain of the switching tube; the second pole of the switching tube 2021 may be a source of the switching tube 2021; the control electrode of the switching tube 2021 may be a gate electrode of the switching tube 2021; in the case where the switching tube 2021 is an NPN transistor, the first pole of the switching tube 2021 may be the collector of the switching tube 2021; the second pole of the switching tube 2021 may be an emitter of the switching tube 2021; the control pole of the switching tube 2021 may be the base of the switching tube 2021.
It can be appreciated that under the control of the first level, the switching tube 2021 is turned on, and the switching tube 2021 may turn on the connection between the first pole and the second pole, i.e., the switching tube 2021 is connected in series in the discharging loop of the charging and discharging capacitor 2022; under the control of the second level, the switching tube 2021 is turned off, the switching tube 2021 may disconnect the connection between the first pole and the second pole, and the switching tube 2021 turns off the discharging circuit of the charging and discharging capacitor 2022, so that the charging and discharging capacitor 2022 may be charged.
In the embodiment of the application, the comparison unit comprises a comparison output end shared by at least two paths of comparators; the triangular wave generating unit comprises a switching tube and a charge-discharge capacitor; the comparison output end is connected with the control electrode of the switching tube; the charge-discharge capacitor is connected between the first pole and the second pole of the switching tube in a bridging way; the comparison unit is used for controlling the on-off of the switching tube, and the switching tube is used for controlling the charge and discharge of the charge and discharge capacitor, so as to output triangular waves through continuous charge and discharge of the charge and discharge capacitor. Because the triangular wave generating circuit only comprises a switching tube and a charge-discharge capacitor, the circuit is relatively simpler, the occupied space is relatively smaller, and the cost is lower.
The embodiment of the present application also provides another triangular wave generating circuit, see fig. 2, the triangular wave generating circuit 20 includes a comparing unit 201 and a triangular wave generating unit 202; the comparing unit 201 includes a comparison output 2011, a first input 2012 and a second input 2013, which are common to at least two comparators; the triangular wave generating unit 202 includes a switching tube 2021, a charge-discharge capacitor 2022, and a triangular wave output terminal 2023; the comparison output terminal 2011 is connected with the control electrode of the switch tube 2021; the charge-discharge capacitor 2022 is connected between the first pole and the second pole of the switch tube 2021 in a bridging manner;
the comparing unit 201 is configured to receive a target ac signal input by the first input terminal 2012 and a reference signal input by the second input terminal 2013, and output the first level to a control electrode of the switching tube 2021 when a voltage difference between the target ac signal and the reference signal is less than or equal to a voltage threshold, where the switching tube 2021 conducts a connection between the first electrode and the second electrode under control of the first level to discharge the charge-discharge capacitor 2022; outputting the second level to a control electrode of the switching tube 2021 when the voltage difference is greater than the voltage threshold, under the control of the second level, disconnecting the connection between the first electrode and the second electrode to charge the charge-discharge capacitor 2022, and outputting a triangular wave through the triangular wave output end 2023, wherein the triangular wave output end 2023 is a connection point of the first electrode and the charge-discharge capacitor;
wherein the first level is greater than the second level.
Here, the first level may be a high level, for example, the first level may be 3.3V or 5V. The second level may be a low level, for example, the second level may be 0V. It will be appreciated that the reference signal may be a dc signal of a particular amplitude; the target ac signal may be an ac signal obtained by superimposing the initial ac signal with the reference signal.
In a possible embodiment, the comparison unit 201 may comprise two identical first and second comparators; correspondingly, the voltage threshold is determined from each turn-on current of the first comparator or the second comparator.
In this embodiment of the present application, the comparing unit receives the target ac signal input by the first input end and the reference signal input by the second input end, and outputs the first level to the control electrode of the switching tube when the voltage difference between the target ac signal and the reference signal is less than or equal to the voltage threshold; and under the condition that the voltage difference is larger than the voltage threshold, outputting the second level to the control electrode of the switching tube, and outputting different levels to the control electrode of the switching tube according to the change of the target alternating current signal so as to facilitate the switching tube to be turned on or turned off according to the change of the target alternating current signal.
The present embodiment provides a further triangular wave generating circuit, as shown in fig. 3a, the triangular wave generating circuit 30 (corresponding to the triangular wave generating circuit 20 of fig. 2) includes a comparing unit 301 (corresponding to the comparing unit 201 of fig. 2) and a triangular wave generating unit 302 (corresponding to the triangular wave generating unit 202 of fig. 2); the comparing unit 301 includes a comparing output 3011 (corresponding to the comparing output 2011 in fig. 2) shared by at least two comparators, a first input 3012 (corresponding to the first input 2012 in fig. 2), and a second input 3013 (corresponding to the second input 2013 in fig. 2); the triangular wave generating unit 302 includes a switching tube 3021 (corresponding to 2021 in fig. 2), a charge-discharge capacitor 3022 (corresponding to the charge-discharge capacitor 2022 in fig. 2), a current limiting resistor 3023, and a triangular wave output end 3024 (corresponding to the triangular wave output end 2024 in fig. 2); the comparison output end 3011 is connected with a control electrode of the switch tube 3021; the charge-discharge capacitor 3022 is connected between the first pole and the second pole of the switching tube 3021 in a bridging manner; the current limiting resistor 3023 is connected to the first power source VCC and the triangular wave output end 3024;
the comparing unit 301 is configured to receive a target ac signal input by the first input terminal 3012 and a reference signal input by the second input terminal 3013, output the first level to a control electrode of the switching tube 3021 through a comparison output terminal 3011 when a voltage difference between the target ac signal and the reference signal is less than or equal to a voltage threshold, and the switching tube 3021 conducts connection between the first electrode and the second electrode under control of the first level, where both a first electrode plate and a second electrode plate of the charge-discharge capacitor 3022 are connected to the ground terminal GND when the first electrode and the second electrode are connected, and the charge-discharge capacitor 3022 discharges; outputting the second level to a control electrode of the switching tube 3021 when the voltage difference is greater than the voltage threshold, and disconnecting the first electrode from the second electrode under control of the second level; when the first pole is disconnected from the second pole, the first power supply VCC is connected to the first pole plate of the charge-discharge capacitor 3022 through the current limiting resistor 3033, the charge-discharge capacitor 3022 is charged by the first power supply VCC, and the triangular wave is output through the triangular wave output terminal under the condition of continuously charging and discharging the charge-discharge capacitor;
the current limiting resistor 3033 is configured to limit a charging current to the charge and discharge capacitor 3022.
It can be appreciated that the triangular wave output end 3024 represents a first connection point between the first electrode and the upper electrode plate of the charge-discharge capacitor 3022; the second connection point of the second pole and the lower pole plate of the charge-discharge capacitor 3022 is connected to the ground GND.
In this embodiment of the application, through setting up current-limiting resistor between first power and triangular wave output, can make under the circumstances that the first pole of triode and second pole break off, the first power is in a preset current range to the charge current of the first base plate of charge-discharge capacitor, avoids the harm to charge-discharge capacitor.
The embodiment of the present application provides a triangle wave generation circuit, and referring to fig. 2, the triangle wave generation circuit 20 includes a power supply unit 200, a comparison unit 201, and a triangle wave generation unit 202; the power supply unit 200 includes a reference signal input terminal 2001, an ac power supply 2002, and a filter capacitor 2003; the comparing unit 201 includes a comparison output 2011, a first input 2012 and a second input 2013, which are common to at least two comparators; the triangular wave generating unit 202 includes a switching tube 2021, a charge-discharge capacitor 2022, and a triangular wave output terminal 2023; the reference signal input terminal 2001 is connected to the positive electrode of the ac power supply 2002; the filter capacitor 2003 is connected between the positive electrode and the negative electrode of the alternating current power supply 2002 in a bridging way; the connection point of the positive electrode and the filter capacitor 2003 is connected with the second input terminal 2013; the connection point of the negative electrode and the filter capacitor 2003 is connected with the first input terminal 2013; the comparison output terminal 2011 is connected with the control electrode of the switch tube 2021; the charge-discharge capacitor 2022 is connected between the first pole and the second pole of the switch tube 2021 in a bridging manner;
the comparing unit 201 is configured to receive a target ac signal input by the first input terminal 2012 and a reference signal input by the second input terminal 2013, and output the first level to a control electrode of the switching tube 2021 when a voltage difference between the target ac signal and the reference signal is less than or equal to a voltage threshold, where the switching tube 2021 conducts a connection between the first electrode and the second electrode under control of the first level to discharge the charge-discharge capacitor 2022; outputting the second level to a control electrode of the switching tube 2021 when the voltage difference is greater than the voltage threshold, under the control of the second level, disconnecting the connection between the first electrode and the second electrode to charge the charge-discharge capacitor 2022, and outputting a triangular wave through the triangular wave output end 2023, wherein the triangular wave output end 2023 is a connection point of the first electrode and the charge-discharge capacitor;
wherein the first level is greater than the second level.
It will be appreciated that the filter capacitor may be used to filter differential mode noise; the pull-up resistor can accurately output high level or low level under the control of the control electrode of the triode.
In the embodiment of the application, the triangular wave generating circuit further comprises a power supply unit, wherein the power supply unit comprises a reference signal input end, an alternating current power supply and a filter capacitor; the reference signal input end is connected with the anode of the alternating current power supply; the filter capacitor is connected between the positive electrode of the alternating current power supply and the negative electrode of the alternating current power supply in a bridging way; the connection point of the anode of the alternating current power supply and the filter capacitor is connected with the second input end; the connection point of the negative electrode of the alternating current power supply and the filter capacitor is connected with the first input end, so that the input of the target alternating current signal and the reference signal of the comparison unit can be realized.
The present embodiment provides another triangular wave generating circuit, and as shown in fig. 2, the triangular wave generating circuit 20 includes a power supply unit 200, a comparing unit 201, and a triangular wave generating unit 202; the power supply unit 200 includes a reference signal input terminal 2001, an ac power supply 2002, and a filter capacitor 2003; the comparing unit 201 includes a comparison output 2011 shared by at least two comparators, a first input 2012, a second input 2013, a first comparator 2014, a second comparator 2015, a pull-up resistor 2016, a first resistor 2017, and a second resistor 2018; the triangular wave generating unit 202 includes a switching tube 2021, a charge-discharge capacitor 2022, and a triangular wave output terminal 2023; the reference signal input terminal 2001 is connected to the positive electrode of the ac power supply 2002; the filter capacitor 2003 is connected between the positive electrode and the negative electrode of the alternating current power supply 2002 in a bridging way; the connection point of the positive electrode and the filter capacitor 2003 is connected with the second input terminal 2013; the connection point of the negative electrode and the filter capacitor 2003 is connected with the first input terminal 2013;
the first input 2012 is connected to an inverting input of the first comparator 2014 and a non-inverting input of the second comparator 2015; the second input terminal 2013 is connected to the non-inverting input terminal of the first comparator 2014 and the inverting input terminal of the second comparator 2015; the first resistor 2017 is connected in series between the second input terminal 2013 and a non-inverting input terminal of the first comparator 2014; the second resistor 2018 is connected in series between the first input 2013 and a non-inverting input of the second comparator 2015; a first output end of the first comparator 2014 is connected to a second output end of the second comparator 2015; the pull-up resistor 2016 is connected between the first power source VCC and the comparison output 2011; the comparison output end represents a connection point of the first output end and the second output end;
the comparison output terminal 2011 is connected with the control electrode of the switch tube 2021; the charge-discharge capacitor 2022 is connected between the first pole and the second pole of the switch tube 2021 in a bridging manner;
the comparing unit 201 is configured to receive a target ac signal input by the first input terminal 2012 and a reference signal input by the second input terminal 2013, and output the first level to a control electrode of the switching tube 2021 when a voltage difference between the target ac signal and the reference signal is less than or equal to a voltage threshold, where the switching tube 2021 conducts a connection between the first electrode and the second electrode under control of the first level to discharge the charge-discharge capacitor 2022; outputting the second level to a control electrode of the switching tube 2021 when the voltage difference is greater than the voltage threshold, under the control of the second level, disconnecting the connection between the first electrode and the second electrode to charge the charge-discharge capacitor 2022, and outputting a triangular wave through the triangular wave output end 2023, wherein the triangular wave output end 2023 is a connection point of the first electrode and the charge-discharge capacitor 2022;
wherein the first level is greater than the second level.
In some possible embodiments, the first resistor 2017 and the second resistor 2018 have the same resistance.
In the embodiment of the present application, since the output terminals of the first comparator 2014 and the second comparator 2015 are connected, and the pull-up resistor 2016 is connected between the first power source VCC and the comparison output terminal 2011; the comparison output 2011 represents a connection point of the first output and the second output; two pull-up resistors are not needed, and the structure is simpler;
meanwhile, the second input terminal 2013 and the non-inverting input terminal of the first comparator 2014 are connected in series through a first resistor 2017; the second resistor 2018 is connected in series between the first input 2012 and the non-inverting input of the second comparator 2015, and the current on the non-inverting inputs of the first comparator 2014 and the second comparator 2015 can be adjusted by adjusting the resistances of the first resistor 2017 and the second resistor 2018.
In some embodiments of the present application, the first resistor 2017 and the second resistor 2018 are both variable resistors; the resistance of the first resistor 2017 or the second resistor 2018 is determined according to the starting point of the triangular wave.
In some possible embodiments, the switching transistor is an NMOS transistor or an NPN transistor.
It can be understood that, in the case that the switching transistor is an NMOS transistor, a connection point between the drain electrode of the NMOS transistor and the charge-discharge capacitor is the triangular wave output end; and under the condition that the switching tube is an NPN triode, the connection point of the collector electrode of the NPN triode and the charge-discharge capacitor is the triangular wave output end.
In this embodiment of the present application, when the first resistor and the second resistor are both variable resistors, and the current required for opening the first comparator and the second comparator is unchanged, the resistance values of the first resistor and the second resistor are adjusted, so that the voltage difference between the target ac signal and the reference signal can be adjusted, that is, the voltage threshold is adjusted, so that the offset control of the triangle wave starting point can be implemented.
Fig. 3b is a schematic diagram of a composition structure of another triangular wave generating circuit according to an embodiment of the present application, as shown in fig. 3b, the triangular wave generating circuit includes an initial ac signal source V1, a reference signal input terminal Base1, a dc power source VCC, a ground terminal GND, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a capacitor C1, a capacitor C2, a comparator U1, a comparator U2, and a triode Q3;
wherein the positive electrode of V1 is connected with Base; the negative electrode of V1 is connected with the first end of C1; the second end of the C1 is connected with the connection point of the positive electrode of the V1 and the Base; in this way, the ac signal V1 is superimposed on the dc voltage Base. The second end of the C1 is connected with the non-inverting input end of the U1 through the series connection R1; the first end of C1 is connected with the inverting input end of U1; the positive electrode of the power supply of U1 is connected with VCC, and the negative electrode of the power supply of U1 is connected with GND; the output end of the U12 is connected with the base electrode of the Q3; the first end of C1 is connected with the non-inverting input end of U2 through series connection R2; the second end of the C1 is connected with the negative phase input end of the U2; the positive electrode of the power supply of U2 is connected with VCC, and the negative electrode of the power supply of U2 is connected with GND; the output end of the U2 is connected with the output end of the U1; the connection point of the output end of the U1 and the output end of the U2 is connected with VCC through a series connection R3, so that the output ends of the U1 and the U2 are pulled up; the emitter of Q3 is connected with the lower polar plate of C2; the collector electrode of Q3 is connected with the upper polar plate of C2; the lower polar plate of C2 is connected with GND; the upper plate of C2 is connected to VCC through series R4.
It is understood that C1 is used to filter differential mode noise; r3 and R4 are pull-up resistors; the working principle of the embodiment of the application is as follows:
when V1 is near the zero crossing point (the superposition of V1 and Base is near the Base), as the voltage difference between the input voltages of the positive input end and the negative input end of U1 and U2 is smaller, and the input voltages of U1 and U2 still need weak current, in a very small range, U1 and U2 output high level, so that Q3 is closed, the upper polar plate and the lower polar plate of C2 are connected with GND, a discharge loop of C2 is formed, and C2 is discharged;
when V1 is not near the zero crossing point (the superposition of V1 and Base is not near Base), one of U1 and U2 outputs a low level because the voltage difference between the inputs of the positive input terminal and the negative input terminal of U1 and U2 is large, so that the control electrode of Q3 is low, Q3 is disconnected, the upper electrode plate of C2 is connected with VCC through R4, a charging loop of C2 is formed, and C2 is charged through VCC.
In some embodiments of the present application, when the voltage difference between the input voltages of the positive input terminal and the negative input terminal of U1 and U2 is small, and the current required for opening the inside of U1 and U2 is not satisfied, U1 and U2 will present a high resistance state (output high level), resulting in that Q3 is opened (turned on), and C2 is discharged.
When V1 is not near the zero crossing point (the superposition of V1 and Base is not near Base), after the voltage difference between the input voltages of the positive input end and the negative input end of U1 and U2 differ by a certain voltage, one of U1 or U2 outputs a low level, so that Q3 is disconnected, C2 starts to be charged, and a triangular wave is formed on the upper polar plate of C2.
In the embodiment of the application, when the amplitude of the target alternating current signal is greater than that of the reference signal, the output of U2 presents high resistance, and the output of U1 presents low level. Q3 is non-conductive and charges C2 through VCC.
In the embodiment of the application, when the amplitude of the target alternating current signal is smaller than that of the reference signal, the output of the U1 presents high resistance, and the output of the U2 presents low level. Q3 is non-conductive and charges C2 through VCC.
In the embodiment of the application, the two paths of comparators U1 and U2 can realize the generation of the alternating current signal zero crossing point detection triangular wave by only configuring one auxiliary circuit, compared with the prior art, the device required by one auxiliary circuit is reduced, and meanwhile, the resistor R3 is shared, so that the circuit constitution is simplified, the occupied space of a PCB is reduced, and the cost is reduced.
Meanwhile, it can be understood that if the resistance values of R1 and R2 are increased, the voltage difference between the input target ac signal and the reference signal needs to be greater to satisfy the current required for the internal opening of the comparators U1, U2. Thus, only when the voltage amplitude of the target alternating current signal is larger than that of the reference signal, the Q3 is not conducted, and the C2 is charged. This achieves the initial point shift of the triangular wave.
Fig. 4 is a schematic waveform diagram of a target ac signal and a triangular wave signal according to an embodiment of the present application, as shown in fig. 4, a waveform 401 is a voltage waveform of the target ac signal in the triangular wave generating circuit when the resistance values of R1 and R2 are smaller; the waveform 402 is a voltage waveform of a triangular wave generated in the triangular wave generation circuit when the resistance values of R1 and R2 are both small.
As can be seen from fig. 4, when the resistance values of R1 and R2 are both small, the start point of the triangular wave is substantially coincident with the zero-crossing point of the target ac signal.
Fig. 5 is a schematic diagram of waveforms of another target ac signal and a triangular wave signal according to an embodiment of the present application, as shown in fig. 5, a waveform 501 is a voltage waveform of the target ac signal in the triangular wave generating circuit when the resistance values of R1 and R2 are both larger; the waveform 502 is a voltage waveform of a triangular wave generated in the triangular wave generation circuit when the resistance values of R1 and R2 are both large.
As can be seen from fig. 5, when the resistance values of R1 and R2 are both large, the start point of the triangular wave and the zero-crossing point of the target ac signal do not coincide, but are delayed backward for a certain time (a certain offset is generated).
On the basis of the above embodiment, the embodiment of the present application provides a triangular wave generating method, which is applied to the triangular wave generating circuit, as shown in fig. 6, and includes the following steps:
step S601: the comparison unit receives a target alternating current signal input by a first input end and a reference signal input by a second input end, and outputs a first level to a control electrode of the switching tube under the condition that the voltage difference value between the target alternating current signal and the reference signal is smaller than or equal to a voltage threshold value; outputting a second level to a control electrode of the switching tube under the condition that the voltage difference value is larger than the voltage threshold value; the first level is greater than the second level;
step S602: the switching tube is controlled by the first level to conduct the connection between the first pole and the second pole so as to discharge the charge-discharge capacitor; and under the control of the second level, disconnecting the first pole from the second pole so as to charge the charge-discharge capacitor, and outputting triangular waves through the output end of the triangular wave generating unit.
The embodiment of the application also provides electronic equipment, which comprises the triangular wave generation circuit.
In this specification, each embodiment is described in a progressive manner, and each embodiment is mainly described by differences from other embodiments, and identical and similar parts between the embodiments are all enough to be referred to each other.
It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or terminal device comprising the element.
The foregoing has described in detail a triangle wave generating circuit, method and electronic device provided by the present application, and specific examples have been used herein to illustrate the principles and embodiments of the present application, the above examples being provided only to assist in understanding the method and core idea of the present utility model; meanwhile, as those skilled in the art will have modifications in the specific embodiments and application scope in accordance with the ideas of the present application, the present description should not be construed as limiting the present application in view of the above.
Claims (10)
1. A triangular wave generation circuit, comprising: a comparison unit and a triangular wave generation unit; the comparison unit comprises a comparison output end shared by at least two paths of comparators; the triangular wave generating unit comprises a switching tube and a charge-discharge capacitor; the comparison output end is connected with the control electrode of the switching tube; the charge-discharge capacitor is connected between the first pole and the second pole of the switching tube in a bridging way; the comparison unit is used for controlling the on-off of the switching tube, and the switching tube is used for controlling the charge and discharge of the charge and discharge capacitor, so as to output triangular waves through continuous charge and discharge of the charge and discharge capacitor.
2. The triangular wave generation circuit of claim 1, wherein the comparison unit further comprises at least a first input terminal and a second input terminal; the triangular wave generating unit further comprises a triangular wave output end;
the comparison unit is used for receiving a target alternating current signal input by the first input end and a reference signal input by the second input end, outputting a first level to a control electrode of the switching tube under the condition that the voltage difference value between the target alternating current signal and the reference signal is smaller than or equal to a voltage threshold value, and enabling the switching tube to conduct connection between the first electrode and the second electrode under the control of the first level so as to discharge the charge-discharge capacitor; under the control of the second level, the connection between the first pole and the second pole is disconnected to charge the charge-discharge capacitor, and triangular waves are output through the triangular wave output end, wherein the triangular wave output end is a connection point of the first pole and the charge-discharge capacitor;
wherein the first level is greater than the second level.
3. The triangular wave generation circuit according to claim 2, wherein the triangular wave generation unit further includes a current limiting resistor for limiting a charging current to the charge-discharge capacitor; the current limiting resistor is connected between the first power supply and the triangular wave output end;
under the condition that the first pole is connected with the second pole, the first pole plate and the second pole plate of the charge-discharge capacitor are both connected with a grounding end, and the charge-discharge capacitor discharges; under the condition that the first pole is disconnected from the second pole, the first power supply is connected into a first polar plate of the charge-discharge capacitor through the current-limiting resistor, the charge-discharge capacitor is charged through the first power supply, and the triangular wave is output through the triangular wave output end under the condition that the charge-discharge capacitor is continuously charged and discharged.
4. The triangular wave generation circuit according to claim 2, further comprising: the power supply unit comprises a reference signal input end, an alternating current power supply and a filter capacitor; the reference signal input end is connected with the anode of the alternating current power supply; the filter capacitor is connected between the positive electrode and the negative electrode of the alternating current power supply in a bridging way; the connection point of the positive electrode and the filter capacitor is connected with the second input end; the connection point of the negative electrode and the filter capacitor is connected with the first input end.
5. The triangular wave generation circuit of claim 3, wherein the comparison unit includes a first comparator, a second comparator, and a pull-up resistor;
the first input end is connected with the inverting input end of the first comparator and the non-inverting input end of the second comparator; the second input end is connected with the non-inverting input end of the first comparator and the inverting input end of the second comparator; the first output end of the first comparator is connected with the second output end of the second comparator; the pull-up resistor is connected between the first power supply and the comparison output end; the comparison output represents a connection point of the first output and the second output.
6. The triangular wave generation circuit of claim 5, wherein the comparison unit further comprises a first resistor and a second resistor; the first resistor is connected in series between the second input terminal and a non-inverting input terminal of the first comparator; the second resistor is connected in series between the first input and a non-inverting input of the second comparator.
7. The triangular wave generation circuit of claim 6, wherein the first resistor and the second resistor have equal resistance values.
8. The triangle wave generation circuit of claim 6, wherein the first resistor and the second resistor are each a variable resistor; the resistance value of the first resistor or the second resistor is determined according to the starting point of the triangular wave.
9. The triangle wave generation circuit according to any one of claims 1 to 8, wherein the switching transistor is an NMOS transistor or an NPN transistor.
10. An electronic device comprising the triangular wave generating circuit according to any one of claims 1 to 8.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202222928861.9U CN219087116U (en) | 2022-10-31 | 2022-10-31 | Triangular wave generating circuit and electronic device |
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| CN202222928861.9U CN219087116U (en) | 2022-10-31 | 2022-10-31 | Triangular wave generating circuit and electronic device |
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