A bidirectional constant current source circuit and household appliance

Abstract

The present invention discloses a bidirectional constant current source circuit and household appliances, including a chopper circuit module, a duty cycle adjustment module, a positive and negative voltage generation module, an output module, an output control module, and a compensation module; the duty cycle adjustment module can output a control wave with an adjustable duty cycle, and is connected to the chopper circuit module; the positive and negative voltage generation module is connected to the chopper circuit module, and is used to generate positive and negative voltage sources; the output module is respectively connected to the positive and negative voltage generation module and the load circuit, and is used to select a positive voltage source or a negative voltage source to be connected to the load circuit; the output control module is connected to the output module, and is used to control the output module to select a positive voltage source or a negative voltage source to output; the compensation module is respectively connected to the duty cycle adjustment module and the load circuit, and collects an electrical signal of the load circuit for adjusting the duty cycle of the control wave, so that the load circuit has a constant current. The present invention realizes the generation of a bidirectional constant current source by a DC power supply through feedback of the positive and negative voltage generation module and the compensation module, and is adapted to the positive and negative operation of the inductive load.

Description

Technical Field

[0001] The invention belongs to the technical field of power supply, and in particular relates to a bidirectional constant current source circuit and a household appliance. Background Art

[0002] In recent years, the electronics industry has developed rapidly. Whether in industry or in civil applications, the demand for bidirectional current actuators is increasing. For example, motors, fans and other loads are bidirectional current control devices. Such loads are used in white goods such as refrigerators, ice makers, air conditioners, ovens and other products.

[0003] In the prior art, in order to ensure that the forward and reverse currents of such loads can be switched freely, a driver chip is generally used to control such loads. Specifically, the positive and negative pins of the load are connected to the output drive pins in the chip, and the direction of the load current is switched by controlling the positive and negative poles of the two drive pins of the driver chip. This control method can generally only control the positive and negative output pins of the driver chip in a fixed voltage manner, and cannot achieve constant current setting. Most existing constant current source designs use unidirectional current control and cannot achieve the function of current reversal. Summary of the invention

[0004] The present invention provides a bidirectional constant current source circuit and household appliances, which output controllable direction power through a positive and negative voltage generation module, an output module, and an output control module, and realize positive and negative voltage source constant current through feedback from a compensation module, adapt to the positive and reverse rotation requirements of an inductive load, and improve control efficiency and efficiency.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0006] A bidirectional constant current source circuit is used to provide a bidirectional constant current power supply for a load circuit, comprising a chopper circuit module, a duty cycle adjustment module, a positive and negative voltage generation module, an output module, an output control module, and a compensation module;

[0007] The chopper circuit module comprises a first voltage output terminal;

[0008] The duty cycle adjustment module can output a control wave with an adjustable duty cycle, and is connected to the chopper circuit module to control the output voltage of the first voltage output terminal;

[0009] The positive and negative voltage generating module is connected to the first voltage output terminal and is used to generate positive and negative voltage sources;

[0010] The output module is connected to the positive and negative voltage generation modules and the load circuit respectively, and is used to select a positive voltage source or a negative voltage source to be connected to the load circuit;

[0011] The output control module is connected to the output module and is used to control the output module to select the positive voltage source or the negative voltage source for output;

[0012] The compensation module is connected to the duty cycle adjustment module and the load circuit respectively, and collects the electrical signal of the load circuit for adjusting the duty cycle of the control wave.

[0013] In one embodiment, the chopper circuit module is a BUCK chopper circuit, a Boost chopper circuit or a BUCK-Boost chopper circuit, which includes a first controllable switch element;

[0014] The first controllable switch element includes a control terminal connected to the duty cycle adjustment module.

[0015] In some embodiments, the positive and negative voltage generating module includes a forward transformer, which includes a primary winding and a secondary winding; the middle tap of the secondary winding is grounded; the two ends of the secondary winding respectively generate the positive voltage source and the negative voltage source.

[0016] In some embodiments, the positive and negative voltage generation module further includes a first freewheeling diode, a second freewheeling diode, a third freewheeling diode, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first resistor, and a second resistor;

[0017] The first capacitor is connected in series with the primary winding and then connected in parallel with the first freewheeling diode; the positive electrode of the first freewheeling diode is grounded;

[0018] The two ends of the secondary winding are respectively connected to the positive electrode of the second freewheeling diode and the negative electrode of the third freewheeling diode; the second capacitor is connected in parallel with the first resistor to generate a first parallel circuit; the third capacitor is connected in parallel with the second resistor to generate a second parallel circuit; the negative electrode of the second freewheeling diode is connected to one end of the first parallel circuit and one end of the fourth capacitor; the middle tap of the secondary winding is connected to the other end of the first parallel circuit and one end of the second parallel circuit; the positive electrode of the third freewheeling diode is connected to the other end of the second parallel circuit and the other end of the fourth capacitor.

[0019] In one embodiment, the output module is a transistor push-pull circuit, which includes a first transistor and a second transistor;

[0020] The first transistor is an NPN transistor; the second transistor is a PNP transistor; the base of the first transistor is connected to the base of the second transistor; the emitter of the first transistor is connected to the emitter of the second transistor and then connected to the load circuit; the collector of the first transistor is connected to the positive voltage source; and the collector of the second transistor is connected to the negative voltage source.

[0021] In one embodiment, the output control module includes a first amplifier, a second amplifier, a second controllable switch, a third controllable switch, a third resistor, and a fourth resistor;

[0022] The positive input terminal of the first amplifier is input with a set voltage, the negative input terminal is input with a first reference voltage, and the output terminal is connected to the negative input terminal of the second amplifier; the positive input terminal of the second amplifier is grounded, and the output terminal is connected to the control terminal of the second controllable switch element; the second controllable switch element is respectively connected to the control terminal and the ground of the third controllable switch element; the two ends of the third controllable switch element are respectively connected to the negative voltage source, and connected to the positive voltage source through the third resistor;

[0023] One end of the third resistor is connected to the collector of the first transistor, and the other end is connected to the base of the first transistor;

[0024] Two ends of the fourth resistor are respectively connected to the collector and emitter of the first transistor.

[0025] In one embodiment, a fourth freewheeling diode is further included; the second controllable switch element is a PNP type transistor; the third controllable switch element is an NPN type transistor;

[0026] The cathode of the fourth freewheeling diode is connected to the base of the second controllable switch component, and the anode is connected to the emitter of the second controllable switch component and is grounded; the collector of the second controllable switch component is connected to the base of the third controllable switch component; the collector of the third controllable switch component is connected to the positive voltage source through the third resistor, and the emitter is connected to the negative voltage source.

[0027] In some embodiments, the compensation module includes a sampling resistor, a third amplifier, and a fourth amplifier;

[0028] The sampling resistor is connected in series with the load circuit and then grounded; the positive input terminal of the third amplifier is connected to the non-grounded end of the sampling resistor, and the negative input terminal is connected to the output terminal;

[0029] The second reference voltage is input to the positive input terminal of the fourth amplifier, the negative input terminal is connected to the output terminal of the third amplifier, and the output terminal is connected to the duty cycle adjustment module.

[0030] In some embodiments, a fifth resistor and a sixth resistor are further included; the output end of the first amplifier is connected to the positive input end of the fourth amplifier through the fifth resistor, and is grounded through the sixth resistor to output the second reference voltage.

[0031] A household appliance comprises the above-mentioned bidirectional constant current source circuit.

[0032] Compared with the prior art, the advantages and positive effects of the present invention are as follows: the bidirectional constant current source circuit and household appliances of the present invention generate positive and negative voltage sources through positive and negative voltage generation modules; the output positive voltage source or negative voltage source is controlled to be connected to the load circuit through the output module and the output control module, so that the inductive load that needs to operate forward and reverse can quickly and efficiently realize positive and reverse control, thereby improving the control efficiency; the compensation module is respectively connected to the load circuit and the duty cycle adjustment module, and the electrical signal of the load circuit is collected to realize feedback control of the load current, so that the positive and negative voltage sources provide constant current power supply for the load circuit, so that the current of the load circuit with constant voltage division remains constant, thereby ensuring constant voltage and constant current of the load circuit, and improving the stability and operation efficiency of the load operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 It is a functional block diagram of an embodiment of a bidirectional constant current source circuit proposed by the present invention;

[0035] Figure 2 The figure is a schematic diagram of the circuit principle of an embodiment of a bidirectional constant current source circuit proposed by the present invention.

[0036] In the figure,

[0037] 1. Chopper circuit module; 2. Positive and negative voltage generation module; 3. Output module; 4. Duty cycle adjustment module; 5. Output control module; 6. Compensation module; Lo, load circuit; P1, first controllable switch; Vi, input voltage; T, forward transformer; A1, primary winding; A2, secondary winding; C1, first capacitor; C2, second capacitor; C3, third capacitor; C4, fourth capacitor; D1, first freewheeling diode; D2, second freewheeling diode; D3, third freewheeling diode; D4, fourth freewheeling diode; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth Resistor; R5, fifth resistor; R6, sixth resistor; R7, seventh resistor; R8, eighth resistor; R9, ninth resistor; R10, tenth resistor; R11, eleventh resistor; R12, twelfth resistor; R13, thirteenth resistor; R14, fourteenth resistor; R15, fifteenth resistor; R16, sixteenth resistor; Ri, sampling resistor; U1, first amplifier; U2, second amplifier; U3, third amplifier; U4, fourth amplifier; Q1, first triode; Q2, second triode; Q3, second controllable switch element; Q4, third controllable switch element; Vo1, first voltage output terminal; Vo+ , positive voltage source; Vo - , negative voltage source; Vt, set voltage; VCC, first reference voltage; Vu1_out, first amplifier output terminal voltage; Vu2_out, second amplifier output terminal voltage; Vu3_out, third amplifier output terminal voltage; Vu4_out, fourth amplifier output terminal voltage. DETAILED DESCRIPTION

[0038] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0039] Reference Figure 1 The present invention discloses a bidirectional constant current source circuit and a household appliance including the same; the bidirectional constant current source circuit includes a chopper circuit module 1, a duty cycle adjustment module 4, a positive and negative voltage generation module 2, an output module 3, an output control module 5, and a compensation module 6.

[0040] The chopper circuit module 1 comprises a first voltage output terminal Vo1, which can output a first output voltage different from the input voltage Vi.

[0041] The duty cycle adjustment module 4 is connected to the chopper circuit module 1 ; the duty cycle adjustment module 4 can output a control wave with adjustable duty cycle, which is output to the chopper circuit module 1 for adjusting the magnitude of the first output voltage.

[0042] The positive and negative voltage generation module 2 is connected to the first voltage output terminal Vo1 and is used to generate positive and negative voltage sources Vo. - The output module 3 is connected to the positive and negative voltage generation module 2 and the load circuit Lo respectively, and is used to select the positive voltage source Vo + Or negative voltage source Vo - Connected with the load circuit Lo to provide a positive voltage source Vo to the load circuit Lo + Or negative voltage source Vo - .

[0043] The output control module 5 is connected to the output module 3 and is used to control the output module 3 to select the positive voltage source Vo. + Or negative voltage source Vo - Output.

[0044] The compensation module 6 is connected to the duty cycle adjustment module 4 and the load circuit Lo respectively, and collects the voltage signal or current signal of the load circuit Lo to be used as the feedback signal of the load circuit Lo to adjust the duty cycle of the control wave, thereby finally adjusting the positive voltage source Vo. + Or negative voltage source Vo- The voltage value is set to ensure that the current of the load circuit Lo is constant, thus realizing a bidirectional constant current power supply.

[0045] The bidirectional constant current source circuit and the household appliance of the present invention generate positive and negative voltage sources Vo through the positive and negative voltage generation module 2. - ; Through the output module 3 and the output control module 5 to control the output positive voltage source Vo + Or negative voltage source Vo - Connected with the load circuit Lo, the inductive load that needs to be operated forward and reverse can realize forward and reverse control quickly and efficiently, thereby improving the control efficiency; the compensation module 6 is respectively connected with the load circuit Lo and the duty cycle adjustment module 4, and collects the electrical signal of the load circuit Lo to realize the feedback control of the load current and realize the positive and negative voltage source Vo. - Provide a constant current power supply for the load circuit Lo, so that the current of the load circuit Lo with constant voltage division remains constant, ensuring constant voltage and constant current of the load circuit Lo, and improving the stability and efficiency of load operation.

[0046] In one embodiment, referring to Figure 1 The chopper circuit is a BUCK chopper circuit, which includes a first controllable switch element P1; the control end of the first controllable switch element P1 is connected to the duty cycle adjustment module 4.

[0047] Preferably, the control wave output by the duty cycle adjustment module 4 is a sawtooth wave, and its duty cycle is adjustable. The first controllable switch is a MOS tube.

[0048] Of course, the chopper circuit may also be a Boost chopper circuit or a BUCK-Boost chopper circuit, both of which can adjust the value of the first output voltage when a fixed voltage is input.

[0049] In one embodiment, referring to Figure 1 and Figure 2 The positive and negative voltage generating module 2 includes a forward transformer T, which includes a primary winding A1 and a secondary winding A2; the primary winding A1 is connected to the chopper circuit module 1 as a load of the chopper circuit module 1; the middle tap of the secondary winding A2 is grounded; a positive voltage source Vo is generated at both ends of the secondary winding A2. + , negative voltage source Vo - .

[0050] The positive and negative voltage generating module 2 further includes a first freewheeling diode D1, a second freewheeling diode D2, a third freewheeling diode D3, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a first resistor R1, and a second resistor R2.

[0051] A series circuit formed by the first capacitor C1 and the primary winding A1 is connected in series with the first freewheeling diode D1 in parallel, and the anode of the first freewheeling diode D1 is grounded.

[0052] Preferably, one end of the first capacitor C1 is connected to the anode of the first freewheeling diode D1.

[0053] The two ends of the secondary winding are respectively connected to the positive electrode of the second freewheeling diode D2 and the negative electrode of the third freewheeling diode D3; the second capacitor C2 is connected in parallel with the first resistor R1 to form a first parallel circuit; the third capacitor C3 is connected in parallel with the second resistor R2 to form a second parallel circuit; the negative electrode of the second freewheeling diode D2 is connected to one end of the first parallel circuit and one end of the fourth capacitor C4; the middle tap of the secondary winding A2 is connected to the other end of the first parallel circuit and one end of the second parallel circuit; the other end of the first parallel circuit is connected to one end of the second parallel circuit; the positive electrode of the third freewheeling diode D3 is connected to the other end of the second parallel circuit and the other end of the fourth capacitor C4.

[0054] The bidirectional constant current source circuit of this embodiment eliminates voltage ripples through the first resistor R1 and the second resistor R2 as dummy load resistors of the positive and negative voltage generating module 2 and the second capacitor C2, the third capacitor C3, and the fourth capacitor C4, thereby providing a bidirectional power supply with low ripple rate and stable voltage.

[0055] In one embodiment, referring to Figure 1 and Figure 2 , output module 3 is a push-pull circuit.

[0056] The output module 3 is preferably a transistor push-pull circuit, which includes a first transistor Q1 and a second transistor Q2; the first transistor Q1 is an NPN transistor; the second transistor Q2 is a PNP transistor; the collector of the first transistor Q1 is connected to the positive voltage source Vo + Connection: The collector of the second transistor Q2 is connected to the negative voltage source Vo - Connection; the base of the first transistor Q1 is connected to the base of the second transistor Q2, which is the input end of the positive and negative voltage power supply; the emitter of the first transistor Q1 is connected to the emitter of the second transistor Q2, and is connected to the load circuit Lo, which is the output end of the positive and negative voltage power supply.

[0057] The bidirectional constant current source circuit of this embodiment can control the load circuit Lo to be connected to the positive voltage source Vo by controlling the first transistor Q1 or the second transistor Q2 to be connected. + Or negative voltage source Vo - , realizing bidirectional power supply switching with high efficiency.

[0058] In one embodiment, referring to Figure 1 and Figure 2 The output control module 5 includes a first amplifier U1, a second amplifier U2, a second controllable switch element Q3, a third controllable switch element Q4, a third resistor R3, and a fourth resistor R4.

[0059] The first amplifier U1 is used as a comparator, and a set voltage Vt is input to its positive input terminal through an input resistor, and a first reference voltage VCC is input to its negative input terminal through an amplifying resistor.

[0060] The input resistors include a seventh resistor R7 and an eighth resistor R8; the amplifying resistor is a ninth resistor R9; and the first amplifier U1 is further provided with a tenth resistor R10 as an amplifying resistor.

[0061] The seventh resistor R7 is connected in series with the eighth resistor R8; the eighth resistor R8 is grounded; the common end of the seventh resistor R7 and the eighth resistor R8 is connected to the positive input end of the first amplifier U1; the seventh resistor R7 is the input end of the set voltage Vt.

[0062] The ninth resistor R9 is connected in series with the tenth resistor R10; the ninth resistor R9 end is used to input the first standard voltage; the tenth resistor R10 end is connected to the output end of the first amplifier U1; the common end of the ninth resistor R9 and the tenth resistor R10 is connected to the negative input end of the first amplifier U1.

[0063] The voltage Vu1_out at the output of the first amplifier is calculated according to the principle of virtual short and virtual disconnection of the amplifier as follows:

[0064]

[0065] The positive input terminal of the second amplifier U2 is grounded; the negative input terminal is connected to the output terminal of the first amplifier U1 through the eleventh resistor R11, and is connected to its output terminal through the twelfth resistor R12; the voltage Vu2_out at the output terminal of the second amplifier is calculated according to the principle of virtual short and virtual disconnection of the amplifier as follows:

[0066] Vu2_out=Vu1_out·R 12 / R 11 (2)

[0067] Combining equation (1) and equation (2), we can get:

[0068]

[0069] The second controllable switch element Q3 is a PNP type transistor, whose emitter is grounded and the base is connected to the output end of the second amplifier U2; when the voltage Vu2_out at the output end of the second amplifier is less than -0.7V, the second controllable switch element Q3 is turned on; when the voltage Vu2_out at the output end of the second amplifier is not less than -0.7V, the second controllable switch element Q3 is turned off.

[0070] The third controllable switch element Q4 is an NPN type transistor, the base of which is connected to the collector of the second controllable switch element Q3 through the thirteenth resistor R13, and the emitter is connected to the negative voltage source Vo. -The collector is connected to the base of the first transistor Q1 and the second transistor Q2, and is connected to the positive voltage source Vo through the third resistor R3. + The two ends of the fourth resistor R4 are respectively connected to the collector and emitter of the first transistor Q1.

[0071] When the second controllable switch Q3 is turned on, the third controllable switch Q4 is turned on, and the third resistor R3 is large enough to turn on the second transistor Q2 and turn off the first transistor Q1, so that the output terminal is connected to the negative voltage source Vo. - , output negative voltage source Vo - To the load circuit Lo.

[0072] The base current I of the third controllable switch element Q4 Q4_b for:

[0073] I Q4_b =(Vo-+0.7V) / R13

[0074] At this time, the voltage drop across R3 is V R3 =β*I Q4_b *R3, where β is the gain of the third controllable switch element Q4. When a sufficiently large value of R3 is selected, the collector voltage of the third controllable switch element Q4 can be guaranteed to be (Vo-)+0.3V, where 0.3V is the voltage between the collector and the emitter of the third controllable switch element Q4.

[0075] When the second controllable switch Q3 is turned off, the third controllable switch Q4 is turned off, the first transistor Q1 is turned on, and the second transistor Q2 is turned off. The collector voltage of the third controllable switch Q4 is the positive voltage source Vo. + The collector voltage of the third controllable switch Q4 is also the base voltage of the first transistor Q1 and the second transistor Q2. The output terminal is connected to the positive voltage source Vo. + , output positive voltage source Vo + .

[0076] According to the base voltage range of the first transistor Q1 and the second transistor Q2, the output voltage Vo is V o+ -0.7V or V o- +1V voltage.

[0077] The bidirectional constant current source circuit of this embodiment sets a first reference voltage VCC and an input setting voltage Vt, and controls the positive voltage source Vo by comparing the setting voltage Vt with the first reference voltage VCC through the first amplifier circuit. + Or negative voltage source Vo - Output, ingenious design and high control efficiency.

[0078] In some embodiments, reference Figure 2The output control module 5 further includes a fourth freewheeling diode D4 , an anode of which is connected to the emitter of the second controllable switch element Q3 , and a cathode of which is connected to the base of the second controllable switch element Q3 .

[0079] The fourth freewheeling diode D4 of this embodiment protects the second controllable switch Q3 when the voltage Vu2_out at the output end of the second amplifier is small, thereby preventing the second controllable switch Q3 from being damaged due to insufficient withstand voltage, thereby improving the stability and reliability of the output control module 5, and further improving the stability and reliability of the bidirectional constant current source circuit.

[0080] In some embodiments, reference Figure 2 The compensation module 6 includes a sampling resistor Ri, a third amplifier U3, and a fourth amplifier U4.

[0081] The sampling resistor Ri is connected in series with the load circuit Lo and then grounded; the positive input terminal of the third amplifier U3 is connected to the non-grounded end of the sampling resistor Ri to collect the voltage signal representing the current signal of the load circuit Lo, and the negative input terminal is connected to its output terminal.

[0082] Preferably, the positive input terminal of the third amplifier U3 is connected to the non-grounded terminal of the sampling resistor Ri through a fourteenth resistor R14 for current limiting.

[0083] The second reference voltage is input to the positive input terminal of the fourth amplifier U4, and the negative input terminal is connected to the output terminal of the first amplifier U1 through the fifteenth resistor R15 and to its output terminal through the sixteenth resistor R16; the output terminal of the fourth amplifier U4 is connected to the duty cycle adjustment module 4.

[0084] In the bidirectional constant current source circuit of this embodiment, the sampling voltage of the sampling resistor Ri is transmitted to the fourth amplifier U4 through the voltage follower function of the third amplifier U3; the fourth amplifier U4 is actually a comparator, which compares the sampling voltage with the second reference voltage; the sampling voltage reflects the load current; specifically, the output voltage Vu4_out of the fourth amplifier is calculated as follows:

[0085]

[0086] Vu3_out is the output voltage of the third amplifier.

[0087] The output end of the fourth amplifier U4 is connected to the duty cycle adjustment module 4, and the duty cycle of the sawtooth wave is adjusted by the voltage at the output end of the fourth amplifier U4, thereby adjusting the positive and negative voltage sources Vo. - The voltage of the load circuit Lo keeps the working current, realizing the positive and negative voltage source Vo - of constant current.

[0088] In some embodiments, reference Figure 2, further comprising a fifth resistor R5 and a sixth resistor R6; the output end of the first amplifier U1 is connected to the positive input end of the fourth amplifier U4 through the fifth resistor R5, and is grounded through the sixth resistor R6.

[0089] The voltage Vu4_out at the output terminal of the fourth amplifier of the bidirectional constant current source circuit of this embodiment is specifically calculated according to the virtual short and virtual break principle of the amplifier as follows:

[0090]

[0091] Vu3_out=V Ri (6)

[0092] Combining equation (1), equation (5) and equation (6), we get:

[0093]

[0094] In this embodiment, the second reference voltage is determined by the input first reference voltage VCC and the set voltage Vt.

[0095] In one embodiment, referring to Figure 2 The power supplies of the first amplifier U1, the second amplifier U2, the third amplifier U3, and the fourth amplifier U4 must all be connected to positive and negative power supplies so that they can output positive and negative voltages.

[0096] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "front", "back", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0097] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0098] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0099] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0100] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0101] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A bidirectional constant current source circuit, used to provide a bidirectional constant current power supply for a load circuit, characterized in that: include: A chopper circuit module, comprising a first voltage output terminal; A duty cycle adjustment module, which outputs a control wave with an adjustable duty cycle and is connected to the chopper circuit module to control the output voltage of the first voltage output terminal; A positive and negative voltage generating module, connected to the first voltage output terminal, for generating positive and negative voltage sources; an output module, which is connected to the positive and negative voltage generating modules and the load circuit respectively, and is used to select a positive voltage source or a negative voltage source to be connected to the load circuit; An output control module is connected to the output module and is used to control the output module to select the positive voltage source or the negative voltage source for output; the output control module includes a first amplifier, a second amplifier, a second controllable switch, a third controllable switch, a third resistor, and a fourth resistor; the first amplifier is used as a comparator, and its positive input terminal inputs a set voltage through an input resistor, and its negative input terminal inputs a first reference voltage through a ninth resistor; the output terminal of the first amplifier is connected to the negative input terminal of the second amplifier; the positive input terminal of the second amplifier is grounded, and the output terminal is connected to the control terminal of the second controllable switch; the switch ends of the second controllable switch are respectively connected to the control terminal and ground of the third controllable switch; the switch ends of the third controllable switch are respectively connected to the control terminal and ground of the third controllable switch; The first amplifier is connected to the negative voltage source and the positive voltage source through the third resistor; the input resistor includes a seventh resistor and an eighth resistor; the amplifying resistor is the ninth resistor and the tenth resistor; the seventh resistor is connected in series with the eighth resistor; the non-common end of the eighth resistor is grounded; the common end of the seventh resistor and the eighth resistor is connected to the positive input end of the first amplifier; the non-common end of the seventh resistor is the input end of the set voltage; the ninth resistor is connected in series with the tenth resistor; the non-common end of the ninth resistor is used to input the first reference voltage; the non-common end of the tenth resistor is connected to the output end of the first amplifier; the common end of the ninth resistor and the tenth resistor is connected to the negative input end of the first amplifier; A compensation module is connected to the duty cycle adjustment module and the load circuit respectively, and collects the electrical signal of the load circuit for adjusting the duty cycle of the control wave; the compensation module includes a sampling resistor, a third amplifier, and a fourth amplifier; the load circuit is connected in series with the sampling resistor and then grounded; the positive input end of the third amplifier is connected to the non-grounded end of the sampling resistor through a fourteenth resistor, and the voltage signal representing the current signal of the load circuit is collected, and the negative input end is connected to its output end; the positive input end of the fourth amplifier inputs a second reference voltage, and the negative input end is connected to the output end of the third amplifier through a fifteenth resistor, and is connected to its output end through a sixteenth resistor; the output end of the fourth amplifier is connected to the duty cycle adjustment module.

2. The bidirectional constant current source circuit according to claim 1, characterized in that: The chopper circuit module is a BUCK chopper circuit, a Boost chopper circuit or a BUCK-Boost chopper circuit, which includes a first controllable switch element; The first controllable switch element includes a control terminal connected to the duty cycle adjustment module.

3. The bidirectional constant current source circuit according to claim 1 or 2, characterized in that: The positive and negative voltage generating module comprises a forward transformer, which comprises a primary winding and a secondary winding; a middle tap of the secondary winding is grounded; and two ends of the secondary winding respectively generate the positive voltage source and the negative voltage source.

4. The bidirectional constant current source circuit according to claim 3, characterized in that: The positive and negative voltage generation module also includes a first freewheeling diode, a second freewheeling diode, a third freewheeling diode, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first resistor, and a second resistor; The first capacitor is connected in series with the primary winding and then connected in parallel with the first freewheeling diode; the positive electrode of the first freewheeling diode is grounded; The two ends of the secondary winding are respectively connected to the positive electrode of the second freewheeling diode and the negative electrode of the third freewheeling diode; the second capacitor is connected in parallel with the first resistor to generate a first parallel circuit; the third capacitor is connected in parallel with the second resistor to generate a second parallel circuit; the negative electrode of the second freewheeling diode is connected to one end of the first parallel circuit and one end of the fourth capacitor; the middle tap of the secondary winding is connected to the other end of the first parallel circuit and one end of the second parallel circuit; the positive electrode of the third freewheeling diode is connected to the other end of the second parallel circuit and the other end of the fourth capacitor.

5. The bidirectional constant current source circuit according to claim 1, characterized in that: The output module is a triode push-pull circuit, which includes a first triode and a second triode; The first transistor is an NPN transistor; the second transistor is a PNP transistor; the base of the first transistor is connected to the base of the second transistor; the emitter of the first transistor is connected to the emitter of the second transistor and then connected to the load circuit; the collector of the first transistor is connected to the positive voltage source; and the collector of the second transistor is connected to the negative voltage source.

6. The bidirectional constant current source circuit according to claim 5, characterized in that: One end of the third resistor is connected to the collector of the first transistor, and the other end is connected to the base of the first transistor; Two ends of the fourth resistor are respectively connected to the collector and emitter of the first transistor.

7. The bidirectional constant current source circuit according to claim 6, characterized in that: It also includes a fourth freewheeling diode; the second controllable switch element is a PNP type transistor; the third controllable switch element is an NPN type transistor; The cathode of the fourth freewheeling diode is connected to the base of the second controllable switch component, and the anode is connected to the emitter of the second controllable switch component and is grounded; the collector of the second controllable switch component is connected to the base of the third controllable switch component; the collector of the third controllable switch component is connected to the positive voltage source through the third resistor, and the emitter is connected to the negative voltage source.

8. The bidirectional constant current source circuit according to claim 6 or 7, characterized in that: It also includes a fifth resistor and a sixth resistor; the output end of the first amplifier is connected to the positive input end of the fourth amplifier through the fifth resistor, and is grounded through the sixth resistor to output the second reference voltage.

9. A household appliance, characterized in that: A bidirectional constant current source circuit comprising any one of claims 1 to 8.

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