CN111831027A - Outdoor electronic equipment and system circuit thereof - Google Patents
Outdoor electronic equipment and system circuit thereof Download PDFInfo
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- CN111831027A CN111831027A CN201910329161.8A CN201910329161A CN111831027A CN 111831027 A CN111831027 A CN 111831027A CN 201910329161 A CN201910329161 A CN 201910329161A CN 111831027 A CN111831027 A CN 111831027A
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Abstract
The application discloses a system circuit, which comprises a voltage stabilizing circuit, a main circuit and a constant power heating circuit; the constant-power heating circuit comprises a heating element and a first switch which are connected in series; the first end of the first switch is used as the input end of the constant power heating circuit, is connected with the input end of the voltage stabilizing circuit and is used for receiving a wide voltage input signal; the voltage stabilizing circuit is used for stabilizing the voltage of the wide voltage input signal so as to supply power to the main circuit; the heating control output end of the main circuit is connected with the control end of the constant power heating circuit and used for outputting a heating control signal; the first switch performs switching action based on an on-off control signal of a power switch in the voltage stabilizing circuit and is used for ensuring that the heating element performs constant-power heating under the action of the heating control signal. The output power requirement on the voltage stabilizing circuit is reduced, the circuit cost and the power loss of the voltage stabilizing circuit are further reduced, and the product benefit and the applicability are improved. The application also discloses an outdoor electronic device, which also has the beneficial effects.
Description
Technical Field
The present disclosure relates to circuit design technologies, and particularly to an outdoor electronic device and a system circuit thereof.
Background
In order to ensure normal operation in low temperature environment, outdoor electronic equipment such as outdoor monitoring equipment is often provided with a constant power heating circuit. Generally, the constant power heating circuit includes a heating element and a switch for controlling the heating element to start and stop, and the on and off of the switch is controlled by a main circuit of the outdoor electronic device according to the requirements of the actual application scene. In the prior art, a constant power heating circuit and a main circuit are both powered by a constant voltage output by a voltage stabilizing circuit after stabilizing a wide voltage input signal. Therefore, when the heating power required by the system is increased, the output power requirement of the voltage stabilizing circuit is correspondingly increased, so that related components in the voltage stabilizing circuit need to adopt higher specifications, and the circuit cost and the power consumption are further increased. In view of the above, it would be desirable to provide a solution to the above technical problems.
Disclosure of Invention
An object of the application is to provide an outdoor electronic device and a system circuit thereof, so as to effectively reduce the power requirement on a voltage stabilizing circuit under the condition of realizing constant power heating, and further reduce the circuit cost and the power loss of the voltage stabilizing circuit.
In order to solve the above technical problem, in a first aspect, the present application discloses a system circuit, which includes a voltage stabilizing circuit, a main circuit, and a constant power heating circuit; the constant power heating circuit comprises a heating element and a first switch which are connected in series;
the first end of the first switch is used as the input end of the constant power heating circuit, is connected with the input end of the voltage stabilizing circuit and is used for receiving a wide voltage input signal; the voltage stabilizing circuit is used for stabilizing the voltage of the wide voltage input signal so as to supply power to the main circuit; the heating control output end of the main circuit is connected with the control end of the constant-power heating circuit and used for outputting a heating control signal;
the first switch performs switching action based on an on-off control signal of a power switch in the voltage stabilizing circuit and is used for ensuring that the heating element performs constant-power heating under the action of the heating control signal.
Optionally, the constant power heating circuit further comprises an and gate;
the first input end of the AND gate is used as the control end of the constant power heating circuit and is used for receiving the heating control signal; the second input end of the AND gate is connected with the control end of the power switch in the voltage stabilizing circuit; the output end of the AND gate is connected with the control end of the first switch;
the first end of the heating element is connected with the second end of the first switch, and the second end of the heating element is grounded.
Optionally, the constant power heating circuit further comprises a second switch in series with both the heating element and the first switch;
the first switch is connected in parallel with the power switch in the voltage stabilizing circuit; the heating control signal is used for controlling the on-off of the second switch.
Optionally, the second switch is a triode;
the first end of the heating element is connected with the second end of the first switch, and the second end of the heating element is connected with the first end of the second switch; the second end of the second switch is grounded, and the base of the second switch is used as the control end of the constant-power heating circuit and is used for receiving the heating control signal.
Optionally, the second switch is an NPN transistor, a first end of the second switch is a collector, and a second end of the second switch is an emitter.
Optionally, the second switch is an MOS transistor; the constant-power heating circuit also comprises a pull-up resistor and a driving triode;
the first end of the heating element is connected with the second end of the first switch, and the second end of the heating element is connected with the first end of the second switch; the grid electrode of the second switch is respectively connected with the first end of the pull-up resistor and the first end of the driving triode; the second end of the pull-up resistor is connected with the output end of the voltage stabilizing circuit; the base electrode of the driving triode is used as the control end of the constant-power heating circuit and is used for receiving the heating control signal; and the second end of the driving triode and the second end of the second switch are both grounded.
Optionally, the second switch is an NMOS transistor, a first end of the second switch is a drain, and a second end of the second switch is a source;
the driving triode is an NPN triode, a collector is arranged at the first end of the driving triode, and an emitter is arranged at the second end of the driving triode.
Optionally, the constant power heating circuit further comprises a zener diode and a first protection resistor;
the cathode of the voltage stabilizing diode and the first end of the first protection resistor are connected with the grid of the second switch, and the anode of the voltage stabilizing diode and the second end of the first protection resistor are grounded.
Optionally, the constant power heating circuit further comprises a protection capacitor and a second protection resistor;
the first end of the protection capacitor and the first end of the second protection resistor are both connected with the base electrode of the driving triode, and the second end of the protection capacitor and the second end of the second protection resistor are both grounded.
Optionally, the first switch is a MOS transistor.
Optionally, the voltage stabilizing circuit comprises a buck voltage reducing circuit or a forward circuit.
In a second aspect, the present application also provides an outdoor electronic device comprising any one of the system circuits described above.
The system circuit provided by the application comprises a voltage stabilizing circuit, a main circuit and a constant power heating circuit; the constant power heating circuit comprises a heating element and a first switch which are connected in series; the first end of the first switch is used as the input end of the constant power heating circuit, is connected with the input end of the voltage stabilizing circuit and is used for receiving a wide voltage input signal; the voltage stabilizing circuit is used for stabilizing the voltage of the wide voltage input signal so as to supply power to the main circuit; the heating control output end of the main circuit is connected with the control end of the constant-power heating circuit and used for outputting a heating control signal; the first switch performs switching action based on an on-off control signal of a power switch in the voltage stabilizing circuit and is used for ensuring that the heating element performs constant-power heating under the action of the heating control signal.
Therefore, compared with the prior art, the constant-power heating circuit directly utilizes the wide-voltage input signal to provide input power for the constant-power heating circuit, controls the power of the constant-power heating circuit to be switched into the control switch, namely the first switch, to perform switching action based on the on-off control signal of the power switch in the voltage stabilizing circuit, and can ensure that the average voltage input from the first switch to the heating element is kept stable when the main circuit starts the constant-power heating circuit to perform heating operation through the heating control signal, so that constant-power heating is realized. Because the heating power is directly provided by the wide voltage input signal instead of the voltage stabilizing circuit, the method and the device effectively reduce the output power requirement of the voltage stabilizing circuit, further reduce the circuit cost and the power loss of the voltage stabilizing circuit, and improve the applicability and the product benefit of a system circuit. The outdoor electronic equipment provided by the application comprises the system circuit and also has the beneficial effects.
Drawings
In order to more clearly illustrate the technical solutions in the prior art and the embodiments of the present application, the drawings that are needed to be used in the description of the prior art and the embodiments of the present application will be briefly described below. Of course, the following description of the drawings related to the embodiments of the present application is only a part of the embodiments of the present application, and it will be obvious to those skilled in the art that other drawings can be obtained from the provided drawings without any creative effort, and the obtained other drawings also belong to the protection scope of the present application.
FIG. 1 is a schematic diagram of a system circuit according to the present disclosure;
FIG. 2 is a schematic block diagram of an exemplary system circuit according to the present disclosure;
FIG. 3 is a logic control signal diagram of the constant power heating circuit of FIG. 2 according to the present disclosure;
FIG. 4 is a schematic block diagram of a further embodiment of a system circuit according to the present disclosure;
FIG. 5 is a specific circuit block diagram of the system circuit of FIG. 4 according to the present disclosure;
FIG. 6 is a further detailed circuit block diagram of the system circuit of FIG. 4 according to the present disclosure;
FIG. 7 is a further detailed circuit block diagram of the system circuit of FIG. 4 according to the present disclosure;
FIG. 8 is a circuit diagram of an exemplary voltage regulator circuit according to the present disclosure;
FIG. 9 is a circuit block diagram of yet another particular voltage regulator circuit disclosed herein.
Detailed Description
The core of the application lies in providing an outdoor electronic equipment and a system circuit thereof, so that the power requirement on a voltage stabilizing circuit can be effectively reduced under the condition of realizing constant power heating, and further the circuit cost and the power loss of the voltage stabilizing circuit are reduced.
In order to more clearly and completely describe the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The current outdoor electronic devices are generally provided with a constant power heating circuit in order to ensure that the outdoor electronic devices can normally work in a low-temperature environment. Constant power heating circuits, as the name implies, can continue to heat at a constant power. Unlike the main circuit for realizing the main functions of outdoor electronic equipment, the constant power heating circuit is an additional circuit dedicated to heating and generally comprises a heating element and a switch capable of controlling the on-off state of a heating loop. In the prior art, similarly to the main circuit, the input power of the constant power heating circuit is also provided by the voltage stabilizing circuit, so as to ensure the constant heating power based on the stable supply voltage output by the voltage stabilizing circuit. However, this increases the power output requirements of the voltage regulator circuit, which in turn increases the circuit cost and power consumption of the voltage regulator circuit. Therefore, the system circuit provided by the application can effectively reduce the power requirement on the voltage stabilizing circuit under the condition of realizing constant power heating, and further reduce the circuit cost and power loss of the voltage stabilizing circuit.
Referring to fig. 1, an embodiment of the present application discloses a system circuit, which includes a voltage stabilizing circuit, a main circuit, and a constant power heating circuit; the constant power heating circuit comprises a heating element R and a first switch K1 which are connected in series;
a first end of the first switch K1 is used as an input end of the constant power heating circuit, is connected with an input end of the voltage stabilizing circuit, and is used for receiving a wide voltage input signal Vin; the voltage stabilizing circuit is used for stabilizing the voltage of the wide voltage input signal Vin so as to supply power to the main circuit; the heating control output end of the main circuit is connected with the control end of the constant-power heating circuit and used for outputting a heating control signal CTRL; the first switch K1 performs a switching operation based on an on-off control signal of a power switch G in the voltage regulator circuit, so as to ensure that the heating element R performs constant power heating under the action of the heating control signal CTRL.
It should be noted that the constant power heating circuit in this embodiment is not directly connected to the output terminal of the voltage regulator circuit, i.e. the voltage regulator circuit provides input power, but the first switch K1 in the constant power heating circuit is directly connected to the input terminal of the voltage regulator circuit to receive the wide voltage input signal Vin, and the input power is directly provided by the input signal of the whole system circuit, i.e. the wide voltage input signal Vin.
It is easy to understand that the input signal of the system circuit, i.e. the wide voltage input signal Vin, is a signal with fluctuating amplitude and unstable, so that the input signal is regulated by the voltage regulator circuit in the system circuit to obtain the constant supply voltage Vo. The specific type of the voltage stabilizing circuit is not limited in the present application, for example, the voltage stabilizing circuit may be a buck voltage reducing circuit or a forward circuit.
In this embodiment, the first terminal of the first switch K1 in the constant power heating circuit is used as the input terminal of the constant power heating circuit for receiving the input wide voltage input signal Vin, so the first switch K1 is the power access control switch of the constant power heating circuit. When the first switch K1 is closed, the wide voltage input signal Vin is connected to the constant power heating circuit to provide a heating energy source for the constant power heating circuit; when the first switch K1 is open, the wide voltage input signal Vin is disconnected from the constant power heating circuit. When the on frequency of the first switch K1 is faster, the duty ratio of the on/off control signal of the first switch K1 will determine the magnitude of the average voltage U input into the constant power heating circuit.
The above process is similar to the operation principle of the voltage stabilizing circuit. In fact, the voltage regulator circuit generally includes a power switch G for controlling the magnitude of the output voltage, and the on-off control signal of the power switch G, i.e., the duty ratio of the PWM wave, is adjusted based on a PWM (Pulse width modulation) technique according to the magnitude of the feedback voltage, so as to adjust the magnitude of the supply voltage Vo output by the voltage regulator circuit, thereby achieving the function of voltage regulation.
It follows that the key to maintaining the supply voltage Vo output by the voltage regulator circuit stable is the on/off control signal of the power switch G. Similarly, in the present embodiment, the constant power heating circuit inputs the wide voltage input signal Vin with fluctuating voltage amplitude via the first switch K1, and the on-off control signal of the first switch K1 determines the magnitude of the average voltage U input to the constant power heating circuit.
Therefore, in order to realize constant power heating, i.e., to ensure that the average voltage U input to the heating element R is kept stable, the first switch K1 performs a switching operation based on the on/off control signal of the power switch G in the voltage regulator circuit. Specifically, the on/off of the first switch K1 may be controlled directly by the on/off control signal of the power switch G, or the on/off of the first switch K1 may be controlled by a processing signal obtained based on the on/off control signal of the power switch G and the heating control signal CTRL. Therefore, when the heating control signal CTRL output by the main circuit is in an effective state for starting the heating element to heat, the average voltage U input by the first switch K1 can be effectively ensured to be the same as the power supply voltage Vo output by the voltage stabilizing circuit, namely, the average voltage U is also constant and stable voltage, and further the realization of constant power heating can be ensured.
Among them, the first switch K1 is a controllable switch that performs a switching operation based on an on/off control signal of the power switch G, and in consideration of a high on frequency requirement of the power switch G, the first switch K1 is a MOS transistor as a preferred embodiment.
Because the power input to the constant power heating circuit is directly provided by the wide voltage input signal Vin instead of from the voltage stabilizing circuit, the change of the heating power requirement is irrelevant to the voltage stabilizing circuit, and even when the system circuit needs to output larger heating power, the voltage stabilizing circuit does not need to be changed and improved, so the power output requirement on the voltage stabilizing circuit is effectively reduced, and the flexible applicability of the system circuit is improved.
In addition, the heating control signal CTRL is a start/stop control signal outputted from the main circuit to control the heating element R to perform a heating operation. In practical application, the control module in the main circuit can judge whether constant power heating is needed according to the current temperature detected by the temperature sensor, and if so, the control module can output a corresponding heating control signal CTRL such as a high level signal to start the constant power heating circuit to operate; if not, the corresponding heating control signal CTRL, such as a low level signal, can be output to stop the operation of the constant power heating circuit.
The heating control signal CTRL may act on the first switch K1 to implement a heating start-stop control effect, or may act on other switches in the constant-power heating circuit to implement a heating start-stop control effect, which is not limited in this application, and can be selected and set by a person skilled in the art according to actual application requirements.
In addition, the heating element R in the constant power heating circuit may be specifically an electric heating wire, a heating resistor, an electric heating film, etc., and those skilled in the art can select and set a suitable heating element R according to the requirements of the actual application scenario. For example, lenses, cover glasses, etc. of outdoor electronic devices may be heated by using an electrothermal film formed in a thin film form.
The system circuit provided by the embodiment of the application comprises a voltage stabilizing circuit, a main circuit and a constant power heating circuit; the constant power heating circuit comprises a heating element R and a first switch K1 which are connected in series; a first end of the first switch K1 is used as an input end of the constant power heating circuit, is connected with an input end of the voltage stabilizing circuit, and is used for receiving a wide voltage input signal Vin; the voltage stabilizing circuit is used for stabilizing the voltage of the wide voltage input signal Vin so as to supply power to the main circuit; the heating control output end of the main circuit is connected with the control end of the constant-power heating circuit and used for outputting a heating control signal CTRL; the first switch K1 performs a switching operation based on an on-off control signal of a power switch G in the voltage regulator circuit, so as to ensure that the heating element R performs constant power heating under the action of the heating control signal CTRL. Therefore, the constant-power heating circuit directly utilizes the wide-voltage input signal Vin to provide input power for the constant-power heating circuit, controls the power of the constant-power heating circuit to be switched into the control switch, namely the first switch K1 to perform switching action based on the on-off control signal of the power switch G in the voltage stabilizing circuit, and can ensure that the average voltage U input from the first switch K1 to the heating element R is kept stable when the main circuit starts the constant-power heating circuit to perform heating operation through the heating control signal CTRL, so that constant-power heating is realized. Because the heating power is directly provided by the wide voltage input signal Vin instead of the voltage stabilizing circuit, the output power requirement on the voltage stabilizing circuit is effectively reduced, the circuit cost and the power loss of the voltage stabilizing circuit are further reduced, and the applicability and the product benefit of a system circuit are improved.
Referring to fig. 2, an embodiment of the present application discloses a specific system circuit, which includes a voltage stabilizing circuit, a main circuit, and a constant power heating circuit; the constant power heating circuit comprises a heating element R and a first switch K1 which are connected in series; the constant-power heating circuit further comprises an AND gate;
a first end of the first switch K1 is used as an input end of the constant power heating circuit, is connected with an input end of the voltage stabilizing circuit, and is used for receiving a wide voltage input signal Vin; the voltage stabilizing circuit is used for stabilizing the voltage of the wide voltage input signal Vin so as to supply power to the main circuit; a first input end of the AND gate is used as a control end of the constant-power heating circuit, is connected with a heating control output end of the main circuit and is used for receiving a heating control signal CTRL; the second input end of the AND gate is connected with the control end of a power switch G in the voltage stabilizing circuit; the output end of the AND gate is connected with the control end of the first switch K1; a first terminal of the heating element R is connected to a second terminal of the first switch K1, and a second terminal of the heating element R is grounded.
It should be noted that, in this embodiment, the heating control signal CTRL output by the main circuit and the on-off control signal of the power switch G in the voltage stabilizing circuit act on the first switch K1 together, that is, the first switch K1 not only serves as a power access control switch of the constant power heating circuit, but also serves as a heating start-stop control switch of the constant power heating circuit. Therefore, the number of the switches required by the constant-power heating circuit in the embodiment can be at least one, so that the circuit structure and the cost are further effectively simplified, and the realization is convenient.
Specifically, the heating control signal CTRL and the on-off control signal of the power switch G are logically processed by an and gate, and an output terminal of the and gate is directly connected to the control terminal of the first switch K1, so as to control on/off of the first switch K1. Taking high level driving as an example, only when the heating control signal CTRL and the on-off control signal of the power switch G are both at high level, the output signal DRIVER of the and gate is at high level, and the first switch K1 is turned on, so that the heating element R starts heating; when any one of the heating control signal CTRL and the on-off control signal of the power switch G is at a low level, the output signal DRIVER of the and gate is at a low level, and the first switch K1 is turned off, so that the heating element R stops heating.
Referring to fig. 3, the present embodiment discloses a logic control signal of the constant power heating circuit in fig. 2.
The on-off control signal of the power switch G is a periodic signal with higher frequency and can reach the level of hundreds of Hz and kHz; the duration of the heating control signal CTRL depends on the heating requirements of the electronic device in the actual application. The output signal DRIVER of the and gate is used to make the first switch K1 perform a switching action based on the on-off control signal of the power switch G and the heating control signal CTRL, so as to ensure that the heating element R performs constant power heating under the action of the heating control signal CTRL.
Referring to fig. 4, an embodiment of the present application discloses another specific system circuit, which includes a voltage stabilizing circuit, a main circuit, and a constant power heating circuit; the constant power heating circuit comprises a heating element R and a first switch K1 which are connected in series; the constant power heating circuit further comprises a second switch K2 in series with both the heating element R and the first switch K1;
a first end of the first switch K1 is used as an input end of the constant power heating circuit, is connected with an input end of the voltage stabilizing circuit, and is used for receiving a wide voltage input signal Vin; the voltage stabilizing circuit is used for stabilizing the voltage of the wide voltage input signal Vin so as to supply power to the main circuit; the heating control output end of the main circuit is connected with the control end of the constant-power heating circuit and is used for outputting a heating control signal CTRL, and the heating control signal CTRL is used for controlling the on-off of the second switch K2; the first switch K1 is connected in parallel with a power switch G in the regulator circuit, and is used for ensuring that the heating element R performs constant power heating under the action of the heating control signal CTRL.
It should be noted that, in this embodiment, the first switch K1 is connected in parallel with the power switch G of the voltage regulator circuit, specifically, each end of the first switch K1 is connected to a corresponding end of the power switch G, and includes control ends of the two, so that the first switch K1 is turned on and off synchronously with the power switch G of the voltage regulator circuit, and the average voltage U input from the first switch K1 to the constant power heating circuit is equal to the supply voltage Vo output by the voltage regulator circuit.
In this embodiment, the on-off control signal of the power switch G directly acts on the first switch K1 to control the on-off of the first switch K1; the heating control signal CTRL acts directly on the second switch K2 for controlling the on/off of the second switch K2. Therefore, in the present embodiment, the first switch K1 is used as a power access control switch of the constant power heating circuit for maintaining the average voltage U stable; the second switch K2 is used as a heating start-stop control switch of the constant power heating circuit and is used for controlling the work start-stop of the heating element R. Since the first switch K1, the second switch K2 and the heating element R are all connected in series in the same heating circuit, the heating element R will start heating only when the first switch K1 and the second switch K2 are closed simultaneously, so as to ensure that the heating element R performs constant power heating under the action of the heating control signal CTRL.
Referring to fig. 5, an embodiment of the present application discloses a specific circuit structure of the system circuit in fig. 4, which includes a voltage stabilizing circuit, a main circuit, and a constant power heating circuit; the constant power heating circuit comprises a heating element R and a first switch K1 which are connected in series; the constant-power heating circuit further comprises a second switch K2 connected in series with both the heating element R and the first switch K1, wherein the second switch K2 is a triode;
a first end of the first switch K1 is used as an input end of the constant power heating circuit, is connected with an input end of the voltage stabilizing circuit, and is used for receiving a wide voltage input signal Vin; the voltage stabilizing circuit is used for stabilizing the voltage of the wide voltage input signal Vin so as to supply power to the main circuit; a first terminal of the heating element R is connected with a second terminal of the first switch K1, and a second terminal of the heating element R is connected with a first terminal of the second switch K2; a second end of the second switch K2 is grounded, and a base of the second switch K2 is used as a control end of the constant power heating circuit, is connected with a heating control output end of the main circuit, and is used for receiving a heating control signal CTRL; the first switch K1 is connected in parallel with a power switch G in the regulator circuit, and is used for ensuring that the heating element R performs constant power heating under the action of the heating control signal CTRL.
It should be noted that the second switch K2 in this embodiment is embodied as a transistor. In a specific embodiment, a high-level active driving scheme is adopted, the second switch K2 is an NPN transistor, a first end of the second switch K2 is a collector, and a second end of the second switch K2 is an emitter. Specifically, when the heating control signal CTRL is at a high level, the second switch K2 is turned on, thereby activating the heating element R to heat.
Of course, a person skilled in the art may also select a PNP transistor as the second switch K2, and change the driving scheme accordingly, which is not limited in this application.
Referring to fig. 6, an embodiment of the present application discloses yet another specific circuit structure of the system circuit in fig. 4, which includes a voltage stabilizing circuit, a main circuit, and a constant power heating circuit; the constant power heating circuit comprises a heating element R and a first switch K1 which are connected in series; the constant power heating circuit further comprises a second switch K2 in series with both the heating element R and the first switch K1; the second switch K2 is an MOS tube; the constant-power heating circuit further comprises a pull-up resistor Rt and a driving triode Q;
a first end of the first switch K1 is used as an input end of the constant power heating circuit, is connected with an input end of the voltage stabilizing circuit, and is used for receiving a wide voltage input signal Vin; the voltage stabilizing circuit is used for stabilizing the voltage of the wide voltage input signal Vin so as to supply power to the main circuit; a first terminal of the heating element R is connected with a second terminal of the first switch K1, and a second terminal of the heating element R is connected with a first terminal of the second switch K2; the grid electrode of the second switch K2 is respectively connected with the first end of the pull-up resistor Rt and the first end of the driving triode Q; the second end of the pull-up resistor Rt is connected with the output end of the voltage stabilizing circuit; the base electrode of the driving triode Q is used as the control end of the constant-power heating circuit, is connected with the heating control output end of the main circuit and is used for receiving a heating control signal CTRL; the second end of the driving triode Q and the second end of the second switch K2 are both grounded; the first switch K1 is connected in parallel with a power switch G in the regulator circuit, and is used for ensuring that the heating element R performs constant power heating under the action of the heating control signal CTRL.
It should be noted that the second switch K2 in this embodiment is specifically a MOS transistor. Since the driving current of the main circuit is limited for the MOS transistor, the pull-up resistor Rt and the driving transistor Q are provided in this embodiment. The second end of the pull-up resistor Rt is connected with the output end of the voltage stabilizing circuit, and the power supply voltage Vo output by the voltage stabilizing circuit is used as a pull-up power supply. The base electrode of the driving triode Q is connected with the heating control output end of the main circuit, and the base electrode voltage depends on the heating control signal CTRL output by the main circuit. When the transistor Q is driven to conduct, the gate of the second switch K2 is equivalent to ground; when the driving transistor Q is turned off, the gate of the second switch K2 is limited to a high level by the pull-up power supply. Therefore, the on-off control of the heating control signal CTRL on the second switch K2 can be realized by utilizing the circuit structure of the driving triode Q and the pull-up resistor Rt.
In addition, as a specific embodiment, a low level active driving scheme is adopted, the second switch K2 is an NMOS transistor, a first end of the second switch K2 is a drain, and a second end of the second switch K2 is a source; the driving triode Q is an NPN triode, a collector is arranged at the first end of the driving triode Q, and an emitter is arranged at the second end of the driving triode Q.
Therefore, when the system circuit is powered on, the gate of the second switch K2 is at a high level, and the second switch K2 is turned on. When the heating control signal CTRL output by the main circuit is at a high level, the driving triode Q is switched on, the grid electrode of the second switch K2 is grounded and becomes a low level, and the second switch K2 is switched off; when the heating control signal CTRL changes to a low level, the driving transistor Q is turned off, the gate of the second switch K2 is limited to a high level by the pull-up power source again, and the second switch K2 is turned on. This enables the heating control signal CTRL to open and close the second switch K2.
Of course, a person skilled in the art may also select a PMOS transistor as the second switch K2, and replace relevant components and connections for driving the second switch K2 accordingly, which is not limited in this application.
Referring to fig. 7, an embodiment of the present application discloses yet another specific circuit structure of the system circuit in fig. 4, which includes a voltage stabilizing circuit, a main circuit, and a constant power heating circuit; the constant power heating circuit comprises a heating element R and a first switch K1 which are connected in series; the constant power heating circuit further comprises a second switch K2 in series with both the heating element R and the first switch K1; the second switch K2 is an NMOS tube; the constant-power heating circuit further comprises a pull-up resistor Rt, a driving triode Q, a voltage stabilizing diode Z, a first protection resistor Rs1, a protection capacitor Cs and a second protection resistor Rs2, wherein the driving triode Q is an NPN triode;
a first end of the first switch K1 is used as an input end of the constant power heating circuit, is connected with an input end of the voltage stabilizing circuit, and is used for receiving a wide voltage input signal Vin; the voltage stabilizing circuit is used for stabilizing the voltage of the wide voltage input signal Vin so as to supply power to the main circuit; a first terminal of the heating element R is connected to a second terminal of the first switch K1, and a second terminal of the heating element R is connected to a drain of the second switch K2; the grid electrode of the second switch K2 is respectively connected with the first end of the pull-up resistor Rt and the collector end of the driving triode Q; the second end of the pull-up resistor Rt is connected with the output end of the voltage stabilizing circuit; the base electrode of the driving triode Q is used as the control end of the constant-power heating circuit, is connected with the heating control output end of the main circuit and is used for receiving a heating control signal CTRL; the emitting electrode of the driving triode Q and the source electrode of the second switch K2 are both grounded; the first switch K1 is connected in parallel with a power switch G in the voltage stabilizing circuit and is used for ensuring that the heating element R performs constant power heating under the action of the heating control signal CTRL;
the cathode of the zener diode Z and the first end of the first protection resistor Rs1 are both connected with the gate of the second switch K2, and the anode of the zener diode Z and the second end of the first protection resistor Rs1 are both grounded; the first end of the protection capacitor Cs and the first end of the second protection resistor Rs2 are both connected to the base of the driving transistor Q, and the second end of the protection capacitor Cs and the second end of the second protection resistor Rs2 are both grounded.
Note that, in the present embodiment, the zener diode Z and the first protection resistor Rs1 are provided for protecting the second switch K2. The zener diode Z and the first protection resistor Rs1 are connected in parallel between the gate and the source of the second switch K2, and are used for preventing the gate voltage from being too high to cause the second switch K2 to be damaged.
Similarly, in the present embodiment, a protection capacitor Cs and a second protection resistor Rs2 are provided for protecting the driving transistor Q. The protection capacitor Cs and the second protection resistor Rs2 are both connected in parallel between the base and the emitter of the driving transistor Q, and are used for preventing the base current from being too large and have a certain filtering function.
For other specific related contents in this embodiment, reference may be made to the foregoing embodiments, which are not described herein again.
Referring to fig. 8, the embodiment of the present application further discloses a specific circuit structure of a voltage stabilizing circuit, where the voltage stabilizing circuit is a buck voltage reducing circuit, and includes a power switch G, a ground switch S, a first inductor L1, and a first capacitor C1;
a first end of the power switch G is used as an input end of the voltage stabilizing circuit, a second end of the power switch G, a first end of the grounding switch S, and a first end of the first inductor L1 are all connected, and a second end of the first inductor L1 is connected with a first end of the first capacitor C1 and is used as an output end of the voltage stabilizing circuit; the second terminal of the grounding switch S and the second terminal of the first capacitor C1 are both grounded.
As mentioned above, most of the power switches G are MOS transistors due to the requirement of high on-frequency; of course, the transistor can be used in low-demand applications. The grounding switch S is used to form a freewheeling loop with the first inductor L1 and the first capacitor C1 when the power switch G is turned off. In one embodiment, the ground switch S may be a freewheeling diode, and the first terminal of the ground switch S is a cathode and the second terminal of the ground switch S is an anode. In another embodiment, the grounding switch S and the first switch K1 may be MOS transistors, and in this case, the power switch G may be referred to as a high-side driving MOS transistor, and the grounding switch S may be referred to as a low-side driving MOS transistor.
It should be noted that, on the basis of any of the foregoing embodiments, a person skilled in the art may use the voltage stabilizing circuit provided in this embodiment in a matching manner, and the related contents may refer to the foregoing embodiments, which are not described herein again.
In fact, when the heating control signal CTRL is in an active state, i.e. a state controlling the heating element R to start heating, the constant power heating circuit in any of the above embodiments can be simplified to a first switch K1 which is turned on and off synchronously with the power switch G and the heating element R connected in series therewith. If power is onIf the duty ratio of the on-off control signal of the switch G is D, in an ideal state in which circuit parasitic parameters are ignored, when the heating control signal CTRL is in an active state, the duty ratio of the first switch K1 is also D, and the average voltage U input to the constant power heating circuit through the first switch K1 is U-Vin · D; according to the formula P ═ U of the heating power2and/R, the heating power of the heating element R can be obtained as follows:
P＝D2·Vin2/R。
in the buck voltage reducing circuit, when Vo represents the output power supply voltage, and Vin represents the input wide-voltage input signal, the duty ratio of the on-off control signal of the power switch G is specifically D Vo/Vin in an ideal state in which the parasitic parameters of the circuit are ignored. The calculation formula of the heating power is substituted to obtain, and the heating power corresponding to the embodiment is as follows:
P＝(Vo/Vin)2·Vin2/R＝Vo2/R。
in the prior art, the power supply voltage Vo output by the voltage stabilizing circuit is used for supplying power to the constant power heating circuit, so that the heating power in the prior art is specifically P ═ Vo2and/R. It can be seen that the heating power of the system circuit provided by the present embodiment is equal to that of the prior art.
Referring to fig. 9, the embodiment of the present application further discloses a circuit structure of another specific voltage stabilizing circuit, where the voltage stabilizing circuit is a forward circuit, and includes a transformer, a power switch G, a first diode D1, a second diode D2, a second inductor L2, and a second capacitor C2;
the first end of the primary winding of the transformer is used as the input end of a voltage stabilizing circuit, and the primary winding is coupled with the power switch G; the first end of the secondary winding of the transformer is grounded, the second end of the secondary winding is connected with the anode of the first diode D1, the cathode of the first diode D1, the cathode of the second diode D2 and the first end of the second inductor L2 are connected with each other, the second end of the second inductor L2 is connected with the first end of the second capacitor C2 and serves as the output end of the voltage stabilizing circuit, and the anode of the second diode D2 and the second end of the second capacitor C2 are grounded.
It should be noted that, on the basis of any of the foregoing embodiments, a person skilled in the art may use the voltage stabilizing circuit provided in this embodiment in a matching manner, and the related contents may refer to the foregoing embodiments, which are not described herein again.
Similarly, when the heating control signal CTRL is in an active state, i.e., controls the heating element R to start heating, the constant power heating circuit in any of the above embodiments can be simplified to a first switch K1 that is turned on and off synchronously with the power switch G and the heating element R connected in series therewith. If the duty ratio of the on-off control signal of the power switch G is D, in an ideal state in which circuit parasitic parameters are ignored, when the heating control signal CTRL is in an active state, the duty ratio of the first switch K1 is also D, and the average voltage U input to the constant power heating circuit through the first switch K1 is U, which is Vin · D; according to the formula P ═ U of the heating power2and/R, the heating power of the heating element R can be obtained as follows:
P＝D2·Vin2/R。
in the forward circuit, when Vo represents the output power supply voltage, Vin represents the input wide voltage input signal, Np represents the number of turns of the primary winding, and Ns represents the number of turns of the secondary winding, Vo is Vin · D · Ns/Np in an ideal state in which circuit parasitic parameters are ignored, and thus, a duty ratio is obtained as D ═ Vo/Vin · (Np/Ns). When n is Np/Ns, the following are recorded:
D＝n·Vo/Vin。
the calculation formula of the heating power is substituted to obtain, and the heating power corresponding to the embodiment is as follows:
P＝(n·Vo/Vin)2·Vin2/R＝n2·Vo2/R。
as described above, in the prior art, since the constant power heating circuit is supplied with the supply voltage Vo output by the voltage regulator circuit, the heating power in the prior art is specifically P ═ Vo2and/R. It can be seen that the heating power of the system circuit provided by the present embodiment is n of the heating power in the prior art2And (4) doubling.
Further, the application also discloses an outdoor electronic device, which comprises the system circuit disclosed by any embodiment.
For specific contents of the system circuit, reference may be made to corresponding contents disclosed in the foregoing embodiments, and details are not repeated here.
The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
It is further noted that, throughout this document, relational terms such as "first" and "second" 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. Furthermore, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus 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 apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The technical solutions provided by the present application are described in detail above. The principles and embodiments of the present application are explained herein using specific examples, which are provided only to help understand the method and the core idea of the present application. It should be noted that, for those skilled in the art, without departing from the principle of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall into the protection scope of the present application.
Claims (10)
1. A system circuit is characterized by comprising a voltage stabilizing circuit, a main circuit and a constant power heating circuit; the constant power heating circuit comprises a heating element and a first switch which are connected in series;
the first end of the first switch is used as the input end of the constant power heating circuit, is connected with the input end of the voltage stabilizing circuit and is used for receiving a wide voltage input signal; the voltage stabilizing circuit is used for stabilizing the voltage of the wide voltage input signal so as to supply power to the main circuit; the heating control output end of the main circuit is connected with the control end of the constant-power heating circuit and used for outputting a heating control signal;
the first switch performs switching action based on an on-off control signal of a power switch in the voltage stabilizing circuit and is used for ensuring that the heating element performs constant-power heating under the action of the heating control signal.
2. The system circuit of claim 1, wherein the constant power heating circuit further comprises an and gate;
the first input end of the AND gate is used as the control end of the constant power heating circuit and is used for receiving the heating control signal; the second input end of the AND gate is connected with the control end of the power switch in the voltage stabilizing circuit; the output end of the AND gate is connected with the control end of the first switch;
the first end of the heating element is connected with the second end of the first switch, and the second end of the heating element is grounded.
3. The system circuit of claim 1, wherein the constant power heating circuit further comprises a second switch in series with both the heating element and the first switch;
the first switch is connected in parallel with the power switch in the voltage stabilizing circuit; the heating control signal is used for controlling the on-off of the second switch.
4. The system circuit of claim 3, wherein the second switch is a triode;
the first end of the heating element is connected with the second end of the first switch, and the second end of the heating element is connected with the first end of the second switch; the second end of the second switch is grounded, and the base of the second switch is used as the control end of the constant-power heating circuit and is used for receiving the heating control signal.
5. The system circuit of claim 4, wherein the second switch is an NPN transistor, a first terminal of the second switch is a collector, and a second terminal of the second switch is an emitter.
6. The system circuit of claim 3, wherein the second switch is a MOS transistor; the constant-power heating circuit also comprises a pull-up resistor and a driving triode;
the first end of the heating element is connected with the second end of the first switch, and the second end of the heating element is connected with the first end of the second switch; the grid electrode of the second switch is respectively connected with the first end of the pull-up resistor and the first end of the driving triode; the second end of the pull-up resistor is connected with the output end of the voltage stabilizing circuit; the base electrode of the driving triode is used as the control end of the constant-power heating circuit and is used for receiving the heating control signal; and the second end of the driving triode and the second end of the second switch are both grounded.
7. The system circuit of claim 6, wherein the second switch is an NMOS transistor, a first terminal of the second switch is a drain, and a second terminal of the second switch is a source;
the driving triode is an NPN triode, a collector is arranged at the first end of the driving triode, and an emitter is arranged at the second end of the driving triode.
8. The system circuit of claim 7, wherein the constant power heating circuit further comprises a zener diode and a first protection resistor;
the cathode of the voltage stabilizing diode and the first end of the first protection resistor are connected with the grid of the second switch, and the anode of the voltage stabilizing diode and the second end of the first protection resistor are grounded.
9. The system circuit according to any one of claims 6 to 8, wherein the constant power heating circuit further comprises a protection capacitor and a second protection resistor;
the first end of the protection capacitor and the first end of the second protection resistor are both connected with the base electrode of the driving triode, and the second end of the protection capacitor and the second end of the second protection resistor are both grounded.
10. An outdoor electronic device, characterized in that it comprises a system circuit according to any one of claims 1 to 9.
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| CN112347718A (en) * | 2020-10-28 | 2021-02-09 | 山东超越数控电子股份有限公司 | Board level heating circuit, PCB board and computer of adjustable power |
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