Control circuit and chip of electronic heating device

Abstract

The utility model discloses a control circuit and a chip of an electronic heating device, which comprise a control core (2), a rectifier bridge (1), a first power switch (PM0), a second power switch (NM0), a first control circuit (3) and a second control circuit (4). Power supply and ground in the circuit are generated, and the flexibility is high; on the other hand, considering that the power supply and the ground cannot completely turn off the power switches due to the voltage drop of components of the rectifier bridge, two control circuits corresponding to the two power switches are configured and are respectively used for generating control signals for controlling the corresponding power switches in a current pull-resistor mode; and the resistors in the two control circuits are respectively pulled up to the first input voltage so as to ensure that the corresponding power switches can be thoroughly turned off.

Description

Technical Field

[0001] This utility model relates to the field of integrated circuit design, and in particular to a control circuit and chip for an electronic heating device. Background Technology

[0002] Currently available electronic heating device control chips mostly require the power supply to be inserted in the forward direction, resulting in poor flexibility. For example... Figure 1 The diagram shows the circuit structure of a common electronic heating device control chip. MCU represents the control chip, and R1 represents the heating resistance wire. Figure 1 The circuit works as follows: an external power supply is connected in the positive terminal, which powers the MCU. The MCU's GPIO pins control the opening and closing of the external NM0 and PMO power transistors, thereby heating the heating resistance wire R1. The connection method between the MCU's positive and negative terminals and the power supply's positive and negative terminals is fixed; high voltage can only be applied from the H+ terminal, and low voltage from the H- terminal, resulting in poor flexibility.

[0003] The information disclosed in this background section is included only to enhance the understanding of the context of this disclosure, and therefore may contain information that does not constitute prior art known to those skilled in the art. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a control circuit and chip for an electronic heating device, addressing the deficiency of poor flexibility of the control chip of the above-mentioned heating device in the prior art when connected to an external power source.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] On the one hand, a control circuit for an electronic heating device is constructed, the control circuit comprising:

[0007] Control core;

[0008] The rectifier bridge has two input terminals for external power supply polarity-independent connection, and its positive and negative output terminals are respectively connected to the power supply terminal and ground terminal of the control core.

[0009] A first power switch controlled by a first control signal and a second power switch controlled by a second control signal, which are connected in parallel to each other, are connected in series with the heat-generating load between the two input terminals of the rectifier bridge to control whether the heat-generating load is working.

[0010] The first control circuit is used to generate the first control signal by a current-pull resistor based on the first enable signal of the control core. The resistor is also pulled up to the first input voltage at the positive input terminal of the rectifier bridge so that when the first enable signal cuts off the current flowing through the resistor, the first input voltage is directly used as the first control signal output to completely turn off the first power switch.

[0011] The second control circuit is used to generate the second control signal based on the second enable signal of the control core by using a current-pull resistor. The resistor is also pulled up to the first input voltage so that when the second enable signal cuts off the current flowing through the resistor, the first input voltage is directly used as the second control signal output to completely turn off the second power switch.

[0012] Furthermore, in the control circuit of the electronic heating device described in this utility model, the first control circuit includes a first current mirror, a first pull-up resistor, a first current control switch and a second current control switch for controlling whether current flows.

[0013] The reference branch and mirror branch of the first current mirror are both connected to the ground terminal. The first pull-up resistor, the first current control switch, and the second current control switch are connected in series between the positive input terminal of the rectifier bridge and the mirror branch of the first current mirror. The control terminal of the first current control switch is connected to the positive input terminal of the rectifier bridge. The control terminal of the second current control switch is connected to the first enable signal. The series node between the first pull-up resistor and the first current control switch outputs the first control signal.

[0014] Furthermore, in the control circuit of the electronic heating device described in this utility model, the second control circuit includes a second current mirror, a second pull-up resistor, a third current control switch and a fourth current control switch for controlling whether current flows.

[0015] The reference branch and mirror branch of the second current mirror are both connected to the power supply terminal. The second pull-up resistor, the third current control switch, and the fourth current control switch are connected in series between the positive input terminal of the rectifier bridge and the mirror branch of the first current mirror. The control terminal of the third current control switch is connected to the positive input terminal of the rectifier bridge. The control terminal of the fourth current control switch is connected to the second enable signal. The series connection node between the second pull-up resistor and the third current control switch outputs the second control signal.

[0016] Furthermore, the control circuit of the electronic heating device described in this utility model also includes a first substrate potential automatic selection circuit, whose two input terminals are used for external power supply polarity-independent access, and whose output terminal is connected to the substrate of the first power switch and the third current control switch, for selecting the input terminal with the higher voltage for output.

[0017] Furthermore, in the control circuit of the electronic heating device described in this utility model, the first substrate potential automatic selection circuit includes a first MOS transistor and a second MOS transistor, and the drain of the first MOS transistor and the drain of the second MOS transistor serve as the two input terminals of the first substrate potential automatic selection circuit.

[0018] The drain of the first MOSFET is connected to the gate of the second MOSFET, and the drain of the second MOSFET is connected to the gate of the first MOSFET. The source of the first MOSFET and the source of the second MOSFET are connected together as the output terminal of the first substrate potential automatic selection circuit.

[0019] Furthermore, the control circuit of the electronic heating device described in this utility model also includes a second substrate potential automatic selection circuit, whose two input terminals are used for external power supply polarity-independent access, and whose output terminal is connected to the substrate of the second power switch and the first current control switch, for selecting the input terminal with the lower voltage for output.

[0020] Furthermore, in the control circuit of the electronic heating device of this utility model, the second substrate potential automatic selection circuit includes a third MOS transistor and a fourth MOS transistor, and the drain of the third MOS transistor and the drain of the fourth MOS transistor serve as the two input terminals of the second substrate potential automatic selection circuit.

[0021] The drain of the third MOS transistor is connected to the gate of the fourth MOS transistor, the drain of the fourth MOS transistor is connected to the gate of the third MOS transistor, and the source of the third MOS transistor is connected to the source of the fourth MOS transistor. The two terminals are connected together as the output terminal of the second substrate potential automatic selection circuit.

[0022] Furthermore, in the control circuit of the electronic heating device described in this utility model, the rectifier bridge includes a first diode, a second diode, a third diode, and a fourth diode;

[0023] The positive terminal of the first diode and the negative terminal of the third diode are connected together as the positive input terminal of the rectifier bridge, and the positive terminal of the second diode and the negative terminal of the fourth diode are connected together as the negative input terminal of the rectifier bridge.

[0024] The cathodes of the first diode and the second diode are connected together and used as the positive output terminal to the power supply terminal. The anodes of the third diode and the fourth diode are connected together and used as the negative output terminal to the ground terminal.

[0025] Furthermore, in the control circuit of the electronic heating device described in this utility model, the rectifier bridge includes a first PMOS transistor, a second PMOS transistor, a third PMOS transistor, and a fourth PMOS transistor;

[0026] The drain of the first PMOS transistor and the source of the third PMOS transistor are connected together as the positive input terminal of the rectifier bridge, and the drain of the second PMOS transistor and the source of the fourth PMOS transistor are connected together as the negative input terminal of the rectifier bridge.

[0027] The source of the first PMOS transistor and the source of the second PMOS transistor are connected together and serve as the positive output terminal to the power supply terminal. The drain of the third PMOS transistor and the drain of the fourth PMOS transistor are connected together and serve as the negative output terminal to the ground terminal.

[0028] Secondly, a control chip for an electronic heating device is constructed, which integrates the control circuit described in the previous item.

[0029] The control circuit and chip of the electronic heating device of this utility model have the following advantages: On the one hand, this utility model can realize the polarity-independent access of the external power supply through the rectifier bridge, generating the power supply and ground inside the circuit, which is highly flexible; on the other hand, considering that the voltage drop of the components of the rectifier bridge will cause the generated power supply and ground to be unable to completely shut down the power switch, this utility model is equipped with two control circuits corresponding to the two power switches, which are used to generate control signals for the corresponding power switches by current pulling resistors, and the resistors in the two control circuits are also pulled up to the first input voltage to ensure that the corresponding power switches can be completely shut down. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the circuit structure of a control chip for an existing electronic heating device;

[0032] Figure 2 This is a schematic diagram of the control circuit of the electronic heating device of this utility model;

[0033] Figure 3 This is a schematic diagram of another type of rectifier bridge;

[0034] Figure 4 This is a schematic diagram of the first substrate potential automatic selection circuit;

[0035] Figure 5 This is a schematic diagram of the automatic selection circuit for the second substrate potential. Detailed Implementation

[0036] To address the shortcomings of existing technologies where heating device control chips lack flexibility when connected to external power supplies, this invention addresses this issue by using a rectifier bridge to allow for polarity-independent external power supply connections, creating internal power and ground connections with high flexibility. Considering that the voltage drop across the rectifier bridge components can prevent the generated power and ground connections from completely shutting down the power switches, this invention also includes two control circuits corresponding to the two power switches. These circuits generate control signals for the respective power switches via current-pull-resistance methods, and the resistors in both control circuits are pulled up to the first input voltage to ensure complete shutdown of the corresponding power switches.

[0037] To facilitate understanding of this utility model, a more comprehensive description will be given below with reference to the accompanying drawings. The drawings illustrate typical embodiments of this utility model. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of this utility model more thorough and complete. It should be understood that the embodiments of this utility model and the specific features thereof are detailed descriptions of the technical solutions of this application, and not limitations thereof. Where there is no conflict, the embodiments of this utility model and the technical features thereof can be combined with each other.

[0038] refer to Figure 2 The control circuit of the electronic heating device of this utility model specifically includes the structure shown in the dashed box in the figure, which includes: rectifier bridge 1, control core 2, first control circuit 3, second control circuit 4, and first power switch PM0 and second power switch NM0 connected in parallel.

[0039] An external capacitor can be connected between the two input terminals of rectifier bridge 1. The two input terminals of rectifier bridge 1 are used for external power supply connection regardless of power polarity. The positive and negative output terminals of rectifier bridge 1 are connected to the power supply terminal VCC and the ground terminal GND of the control core 2, respectively. The first power switch PM0 and the second power switch NM0, connected in parallel, are connected in series with the heat-generating load R1 between the two input terminals of rectifier bridge 1 to control whether the heat-generating load R1 is operating.

[0040] In the diagram, the MCU core is the control core 2. The control core 2 can output a first enable signal EN1 and a second enable signal EN2 to control the first power switch PM0 and the second power switch NM0, respectively.

[0041] The first control circuit 3 is used to generate the first control signal Vgate_p by means of current pulling resistor based on the first enable signal EN1 of the control core 2. The resistor is also pulled up to the first input voltage H+ at the positive input terminal of the rectifier bridge 1 so that when the first enable signal EN1 cuts off the current flowing through the resistor, the first input voltage H+ is directly used as the first control signal Vgate_p to completely turn off the first power switch PM0.

[0042] The second control circuit 4 is used to generate the second control signal Vgate_n by means of current pulling resistor based on the second enable signal EN2 of the control core 2. The resistor is also pulled up to the first input voltage H+, so that when the second enable signal EN2 cuts off the current flowing through the resistor, the first input voltage H+ is directly used as the second control signal Vgate_n output, thereby completely turning off the second power switch NM0.

[0043] The specific components and working principles of each circuit are explained in detail below.

[0044] Specifically, the rectifier bridge 1 includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. The anode of the first diode D1 and the cathode of the third diode D3 are connected together as the positive input terminal of the rectifier bridge 1. The anode of the second diode D2 and the cathode of the fourth diode D4 are connected together as the negative input terminal of the rectifier bridge 1. The cathodes of the first diode D1 and the second diode D2 are connected together as the positive output terminal and connected to the power supply terminal VCC. The anodes of the third diode D3 and the fourth diode D4 are connected together as the negative output terminal and connected to the ground terminal GND.

[0045] The voltage at the positive input terminal of the rectifier bridge 1 is denoted as the first input voltage H+, and the voltage at the negative input terminal of the rectifier bridge 1 is denoted as the second input voltage H-. If the external power supply is connected in the positive direction, the first input voltage H+ is high voltage and the second input voltage H- is low voltage; conversely, if the external power supply is connected in the negative direction, the first input voltage H+ is low voltage and the second input voltage H- is high voltage.

[0046] The rectifier bridge 1 enables the positive and negative voltages of the control core 2 to automatically adapt to the external power supply connection method. Its working principle is as follows: when H+ is connected to high voltage and H- is connected to low voltage, the H+ terminal is input to VCC through D1, and GND is output to the H- terminal through D4; when H+ is connected to low voltage and H- is connected to high voltage, the H- terminal is input to VCC through D2, and GND is output to the H+ terminal through D3, thus realizing the function of reversible insertion.

[0047] Of course, the diodes in rectifier bridge 1 can also be replaced by MOSFETs, see reference. Figure 3 Another embodiment of the rectifier bridge 1 includes a first PMOS transistor PM1, a second PMOS transistor PM2, a third PMOS transistor PM3, and a fourth PMOS transistor PM4. The drain of the first PMOS transistor PM1 and the source of the third PMOS transistor PM3 are connected together as the positive input terminal of the rectifier bridge 1, and the drain of the second PMOS transistor PM2 and the source of the fourth PMOS transistor PM4 are connected together as the negative input terminal of the rectifier bridge 1. The source of the first PMOS transistor PM1 and the source of the second PMOS transistor PM2 are connected together as the positive output terminal and connected to the power supply terminal VCC, and the drain of the third PMOS transistor PM3 and the drain of the fourth PMOS transistor PM4 are connected together as the negative output terminal and connected to the ground terminal GND.

[0048] In this embodiment, the first power switch PM0 is a PMOS transistor, and the second power switch NM0 is an NMOS transistor. If the output of the control core 2 is used directly to control NM0 and PM0, NM0 and PM0 cannot be completely turned off. This is because the output voltage range of the control core 2 is VD to 5-VD. NM0 can only be turned off when Vgate_n = 0. Therefore, when Vgate_n = VD, NM0 will still conduct, causing leakage. Similarly, PM0 can only be turned off when Vgate_p = 5V. Therefore, when Vgate_p = 5-VD, PM0 will still conduct, causing leakage.

[0049] In this embodiment, the first control circuit 3 includes a first current mirror 31, a first pull-up resistor R1, a first current control switch N1 and a second current control switch N2 for controlling whether current flows. The first current control switch N1 and the second current control switch N2 are NMOS transistors. The first current mirror 31 includes a reference branch (also called the input branch) and a mirror branch (also called the output branch) respectively composed of MOS transistors. The first terminal of the reference branch is connected to a current source, which can be generated based on VCC. The specific method for generating the current source can be a mature technology, which will not be elaborated here. The second terminal of the reference branch and the second terminal of the mirror branch are both connected to the ground terminal GND. The first pull-up resistor R1, the first current control switch N1, and the second current control switch N2 are connected in series between the positive input terminal of the rectifier bridge 1 and the first terminal of the mirror branch. The control terminal of the first current control switch N1 is connected to the first input voltage H+, the control terminal of the second current control switch N2 is connected to the first enable signal EN1, and the series node between the first pull-up resistor R1 and the first current control switch N1 outputs the first control signal Vgate_p.

[0050] In this embodiment, the second control circuit 4 includes a second current mirror, a second pull-up resistor R2, and a third current control switch P1 and a fourth current control switch P2 for controlling whether current flows. The third current control switch P1 and the fourth current control switch P2 are PMOS transistors. The second current mirror includes a reference branch and a mirror branch, each composed of a MOS transistor. The first end of the reference branch and the first end of the mirror branch are both connected to VCC, and the second end of the reference branch is connected to a current source. The second pull-up resistor R2, the third current control switch P1, and the fourth current control switch P2 are connected in series between the positive input terminal of the rectifier bridge 1 and the second end of the mirror branch of the first current mirror 31. The control terminal of the third current control switch P1 is connected to the first input voltage H+, and the control terminal of the fourth current control switch P2 is connected to the second enable signal EN2. The series connection node between the second pull-up resistor R2 and the third current control switch P1 outputs the second control signal Vgate_n.

[0051] The working principle of control circuits 3 and 4 is described below:

[0052] 1) The conduction condition for PMOS and NMOS is that the gate-source voltage difference is greater than the threshold voltage, i.e., |Vgate-Vsource|>|Vth|. In this embodiment, R1 and R2 are large resistors, the gate voltages of NM0 and PMO are Vgate_n and Vgate_p, respectively, and the source voltages of both are VH+.

[0053] 2) When the external power supply is connected in positive voltage, i.e., H+ = 5V:

[0054] For PM0, H+ turns on transistor N1, and EN1 controls transistor N2. When PM0 needs to be turned on, EN1 turns on transistor N2, and the current flows through the current mirror and then through resistor R1, creating a voltage drop such that Vgate_p = VH+ - I*R1, and |Vgate_p - VH+| = I*R1 > |Vth|, thus turning on PM0. When PM0 needs to be turned off, EN1 turns off transistor N2, and no current flows through resistor R1, so Vgate_p = VH+, and |Vgate_p - VH+| = 0 < |Vth|, thus turning off PM0.

[0055] For NM0, H+ turns off P1, so Vgate_n = VH+, |Vgate_n - VH+| = 0 < |Vth|, therefore NM0 remains off.

[0056] 3) When the external power supply is connected in the positive terminal, i.e., H+ = 0V:

[0057] For NM0, H+ turns on P1, and EN2 controls P2. When NM0 needs to be turned on, EN2 turns on P2, and the current flows through the current mirror and then through resistor R2, generating a voltage drop such that Vgate_n = VH+ + I*R2, and |Vgate_n - VH+| = I*R2 > |Vth|, thus turning on NM0. When NM0 needs to be turned off, EN2 turns off P2, and no current flows through resistor R2, so Vgate_n = VH+, and |Vgate_n - VH+| = 0 < |Vth|, thus turning off NM0.

[0058] For PM0, H+ turns off N1, so Vgate_p = VH+, |Vgate_p - VH+| = 0 < |Vth|, therefore PM0 remains off.

[0059] Furthermore, due to the uncertainty of the external power supply insertion direction, the H+ and H- voltages are not fixed, resulting in uncertainty of the substrate voltages of the two switching transistors PM0 and NM0. To solve this problem, this embodiment also includes a first substrate potential automatic selection circuit 5 and a second substrate potential automatic selection circuit 6.

[0060] like Figure 4As shown, the two input terminals of the first substrate potential automatic selection circuit 5 are used for external power supply polarity-independent connection. The output terminal of the first substrate potential automatic selection circuit 5 is connected to the substrates of the first power switch PM0 and the third current control switch P1. The first substrate potential automatic selection circuit 5 is used to select the higher voltage among the input terminals for output. Specifically, the first substrate potential automatic selection circuit 5 includes a first MOSFET PM5 and a second MOSFET PM6, both of which are PMOS transistors. The drains of the first MOSFET PM5 and the second MOSFET PM6 are used for external power supply polarity-independent connection; the drain of the first MOSFET PM5 is connected to the gate of the second MOSFET PM6, the drain of the second MOSFET PM6 is connected to the gate of the first MOSFET PM5, and the source of the first MOSFET PM5 is connected to the source of the second MOSFET PM6, forming a common connection as the output terminal of the first substrate potential automatic selection circuit 5.

[0061] like Figure 5 As shown, the two input terminals of the second substrate potential automatic selection circuit 6 are used for external power supply polarity-independent connection. The output terminal of the second substrate potential automatic selection circuit 6 is connected to the substrates of the second power switch NM0 and the first current control switch N1. The second substrate potential automatic selection circuit 6 is used to select the input terminal with the lower voltage for output. Specifically, the second substrate potential automatic selection circuit 6 includes a third MOSFET NM1 and a fourth MOSFET NM2. The drains of the third MOSFET NM1 and the fourth MOSFET NM2 are used for external power supply polarity-independent connection. The drain of the third MOSFET NM1 is connected to the gate of the fourth MOSFET NM2, the drain of the fourth MOSFET NM2 is connected to the gate of the third MOSFET NM1, and the source of the third MOSFET NM1 is connected to the source of the fourth MOSFET NM2, which together form the output terminal of the second substrate potential automatic selection circuit 6.

[0062] The working principle of the substrate potential automatic selection circuits 5 and 6 is described below: When H+ is connected to high voltage and H- is connected to low voltage, PM5 is turned on and PM6 is turned off, so that pmos_sub is connected to H+ (high), NM1 is turned off and NM2 is turned on, so that nmos_sub is connected to H- (low); when H+ is connected to low voltage and H- is connected to high voltage, PM5 is turned off and PM6 is turned on, so that pmos_sub is connected to H- (low), NM1 is turned on and NM2 is turned off, so that nmos_sub is connected to H+ (high).

[0063] It is understandable that the substrate voltage of an NMOS transistor must be less than or equal to the source and drain voltages, while the substrate voltage of a PMOS transistor must be greater than or equal to the source and drain voltages; otherwise, leakage will occur. Therefore, the N1 substrate must be connected to nmos_sub to ensure that N1 will not leak when H+ equals 0 (nmos_sub = 0). Since N1 is not conducting when H+ equals 0, N2 will not see 0V, so there is no need to connect the strong substrate to nmos_sub. The N2 substrate can be connected to nmos_sub or GND. Similarly, the P1 substrate must be connected to pmos_sub to ensure that P1 will not leak when H+ equals 5V (pmos_sub = 5). Since P1 is not conducting when H+ equals 5, P2 will not see 5V, so there is no need to connect the strong substrate to pmos_sub. The N2 substrate can be connected to pmos_sub or VCC.

[0064] In practical products, the circuit of this invention can also be implemented as follows: Figure 2 The control circuit shown in the dashed box is integrated into a single control chip, meaning the power transistors are also integrated into the chip. This results in fewer GPIOs and lower costs for the chip product.

[0065] In summary, the control circuit and chip of the electronic heating device of this utility model have the following beneficial effects: On the one hand, this utility model can realize the polarity-independent access of the external power supply through the rectifier bridge, generating the power supply and ground inside the circuit, which is highly flexible; on the other hand, considering that the voltage drop of the components of the rectifier bridge will cause the generated power supply and ground to be unable to completely shut down the power switch, this utility model is equipped with two control circuits corresponding to the two power switches, which are used to generate control signals for the corresponding power switches by current pulling resistors, and the resistors in the two control circuits are also pulled up to the first input voltage to ensure that the corresponding power switches can be completely shut down.

[0066] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0067] The terms "first," "second," and other ordinal numbers used in this specification are used to describe various constituent elements, but these constituent elements are not limited by these terms. The purpose of using these terms is solely to distinguish one constituent element from others. For example, without departing from the scope of this utility model, a first constituent element may be named a second constituent element, and similarly, a second constituent element may be named a first constituent element.

[0068] It should be noted that the term "connection" or "linkage" in this article includes not only directly connecting two entities, but also indirectly connecting them through other entities that have beneficial improvement effects.

[0069] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0070] Similarly, it should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, this disclosure should not be construed as reflecting an intention that the claimed invention requires more features than expressly recited in each claim. Rather, as reflected in the claims, the inventive aspect lies in fewer than all features of the single embodiment disclosed above. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0071] It should be noted that the above embodiments are illustrative of the present invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims.

[0072] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A control circuit for an electronic heating device, characterized in that The control circuit includes: Control core (2); The rectifier bridge (1) has two input terminals for external power supply polarity-independent connection, and its positive and negative output terminals are respectively connected to the power supply terminal VCC and ground terminal GND of the control core (2). The first power switch PM0, controlled by the first control signal Vgate_p, and the second power switch NM0, controlled by the second control signal Vgate_n, which are connected in parallel, are connected in series with the heat load between the two input terminals of the rectifier bridge (1) to control whether the heat load is working. The first control circuit (3) is used to generate the first control signal Vgate_p by current pulling resistor based on the first enable signal EN1 of the control core (2). The resistor is also pulled up to the first input voltage H+ at the positive input terminal of the rectifier bridge (1) so that when the first enable signal EN1 cuts off the current flowing through the resistor, the first input voltage H+ is directly used as the first control signal Vgate_p to completely turn off the first power switch PM0. The second control circuit (4) is used to generate the second control signal Vgate_n by means of current pulling resistor based on the second enable signal EN2 of the control core (2). The resistor is also pulled up to the first input voltage H+ so that when the second enable signal EN2 cuts off the current flowing through the resistor, the first input voltage H+ is directly used as the second control signal Vgate_n output to completely turn off the second power switch NM0.

2. The control circuit for an electronic heating device of claim 1, wherein, The first control circuit (3) includes a first current mirror (31), a first pull-up resistor R1, a first current control switch N1 and a second current control switch N2 for controlling whether current flows; The reference branch and mirror branch of the first current mirror (31) are connected to the ground terminal GND. The first pull-up resistor R1, the first current control switch N1, and the second current control switch N2 are connected in series between the positive input terminal of the rectifier bridge (1) and the mirror branch of the first current mirror (31). The control terminal of the first current control switch N1 is connected to the positive input terminal of the rectifier bridge (1). The control terminal of the second current control switch N2 is connected to the first enable signal EN1. The series node between the first pull-up resistor R1 and the first current control switch N1 outputs the first control signal Vgate_p.

3. The control circuit for an electronic heating device of claim 2, wherein, The second control circuit (4) includes a second current mirror, a second pull-up resistor R2, a third current control switch P1 and a fourth current control switch P2 for controlling whether current flows; The reference branch and mirror branch of the second current mirror are connected to the power supply terminal VCC. The second pull-up resistor R2, the third current control switch P1, and the fourth current control switch P2 are connected in series between the positive input terminal of the rectifier bridge (1) and the mirror branch of the first current mirror (31). The control terminal of the third current control switch P1 is connected to the positive input terminal of the rectifier bridge (1). The control terminal of the fourth current control switch P2 is connected to the second enable signal EN2. The series node between the second pull-up resistor R2 and the third current control switch P1 outputs the second control signal Vgate_n.

4. The control circuit for an electronic heating device of claim 3, wherein, It also includes a first substrate potential automatic selection circuit (5), whose two input terminals are used for external power supply polarity-independent access, and whose output terminal is connected to the substrate of the first power switch PM0 and the third current control switch P1, for selecting the output of the one with the higher voltage among the input terminals.

5. The control circuit for an electronic heating device of claim 4, wherein, The first substrate potential automatic selection circuit (5) includes a first MOS transistor PM5 and a second MOS transistor PM6. The drain of the first MOS transistor PM5 and the drain of the second MOS transistor PM6 serve as the two input terminals of the first substrate potential automatic selection circuit (5). The drain of the first MOS transistor PM5 is connected to the gate of the second MOS transistor PM6, the drain of the second MOS transistor PM6 is connected to the gate of the first MOS transistor PM5, and the source of the first MOS transistor PM5 and the source of the second MOS transistor PM6 are connected together as the output terminal of the first substrate potential automatic selection circuit (5).

6. The control circuit for an electronic heating device of claim 2, wherein, It also includes a second substrate potential automatic selection circuit (6), whose two input terminals are used for external power supply polarity-independent access, and whose output terminal is connected to the substrate of the second power switch NM0 and the first current control switch N1, for selecting the output of the one with the lower voltage among the input terminals.

7. The control circuit for an electronic heating device of claim 6, wherein, The second substrate potential automatic selection circuit (6) includes a third MOS transistor NM1 and a fourth MOS transistor NM2. The drain of the third MOS transistor NM1 and the drain of the fourth MOS transistor NM2 serve as the two input terminals of the second substrate potential automatic selection circuit (6). The drain of the third MOS transistor NM1 is connected to the gate of the fourth MOS transistor NM2, the drain of the fourth MOS transistor NM2 is connected to the gate of the third MOS transistor NM1, and the source of the third MOS transistor NM1 is connected to the source of the fourth MOS transistor NM2. They are all connected as the output terminal of the second substrate potential automatic selection circuit (6).

8. The control circuit for an electronic heating device of claim 1, wherein, The rectifier bridge (1) includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4; The positive terminal of the first diode D1 and the negative terminal of the third diode D3 are connected together as the positive input terminal of the rectifier bridge (1), and the positive terminal of the second diode D2 and the negative terminal of the fourth diode D4 are connected together as the negative input terminal of the rectifier bridge (1). The cathodes of the first diode D1 and the second diode D2 are connected together and serve as the positive output terminal to the power supply terminal VCC. The anodes of the third diode D3 and the fourth diode D4 are connected together and serve as the negative output terminal to the ground terminal GND.

9. The control circuit for an electronic heating device of claim 1, wherein, The rectifier bridge (1) includes a first PMOS transistor PM1, a second PMOS transistor PM2, a third PMOS transistor PM3, and a fourth PMOS transistor PM4; The drain of the first PMOS transistor PM1 and the source of the third PMOS transistor PM3 are connected together as the positive input terminal of the rectifier bridge (1), and the drain of the second PMOS transistor PM2 and the source of the fourth PMOS transistor PM4 are connected together as the negative input terminal of the rectifier bridge (1). The source of the first PMOS transistor PM1 and the source of the second PMOS transistor PM2 are connected together and serve as the positive output terminal to the power supply terminal VCC. The drain of the third PMOS transistor PM3 and the drain of the fourth PMOS transistor PM4 are connected together and serve as the negative output terminal to the ground terminal GND.

10. A control chip of an electronic heating device, characterized in that, It integrates the control circuit as described in any one of claims 1-9.

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