Fully integrated isolation power supply

Abstract

The invention provides a fully-integrated isolated power supply. The fully-integrated isolated power supply comprises an oscillator, an isolated transmission circuit and a rectifying circuit, the oscillator comprises an electric connection driving power tube module and a radio frequency choking coil module, the isolation transmission circuit comprises a transformer, a first capacitor module and a second capacitor module, a primary coil of the transformer is electrically connected with the oscillator through the first capacitor module, and a secondary coil of the transformer is electrically connected with the rectifying circuit through the second capacitor module. The oscillator is based on the driving power tube module and the radio frequency choking coil module, the output voltage swing is not limited by tail current, introduction of phase noise can be effectively reduced, isolation transmission of alternating current signals is completed through the transformer and the capacitor module, the isolation withstand voltage strength is increased, the secondary common-mode current of the transformer can be reduced, and the service life of the oscillator is prolonged. The electromagnetic compatibility characteristic is improved; and finally, the rectifying circuit rectifies and outputs a direct current signal, so that the overall stability of the power supply can be improved.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to a fully integrated isolated power supply. Background Art

[0002] The development of high-performance fully integrated isolated power supplies with miniaturization, high efficiency and low power consumption will meet the needs of many high-end applications, such as applications that require physical isolation, electrical isolation and anti-interference characteristics. The architecture of a fully integrated isolated power supply is generally as follows: Figure 1 As shown, it mainly includes a primary side circuit module and a secondary side circuit module. Among them, the power oscillator and the primary coil of the transformer mainly constitute the primary side circuit module, and the rectifier bridge filter and the secondary coil of the transformer mainly constitute the secondary side circuit module. The primary side completes the function of converting DC to AC, and the secondary side completes the function of converting AC to DC.

[0003] In the application circuit module of the fully integrated isolated power supply, the commonly used oscillator structure is as follows Figure 2 As shown, it is generally a Class B VCO voltage-controlled oscillator. The output voltage swing of this type of oscillator is limited by the tail current (or resistance). Therefore, the maximum output swing of this type of oscillator is 2Vdd-Vs, and the presence of the tail current will also introduce noise. In addition, since the oscillator output is a high-frequency AC signal, the common-mode voltage (or current) at the secondary end of the transformer is unstable during power transmission, which will cause strong electromagnetic radiation and affect the electromagnetic compatibility of the fully integrated isolated power supply. In related technologies, the improvement of isolation strength generally only depends on a single device type, such as an isolation capacitor or an isolation transformer; especially in the field of isolated power supply applications, the isolation withstand voltage strength of the on-chip isolation transformer is determined by the thickness of the dielectric layer. Due to the manufacturing process and dielectric characteristics, the improvement of isolation withstand voltage strength is limited. Summary of the invention

[0004] The main purpose of the present application is to provide a fully integrated isolated power supply, which can at least solve the problems of large phase noise, poor electromagnetic compatibility and low isolation withstand voltage strength of the isolated power supply in the related art.

[0005] To achieve the above-mentioned purpose, the present application provides a fully integrated isolated power supply, including: an oscillator, an isolated transmission circuit and a rectifier circuit; the oscillator includes an electrically connected driving power tube module and a radio frequency choke coil module, and the oscillator is used to convert an input DC signal into an AC signal; the isolated transmission circuit includes a transformer, a first capacitor module and a second capacitor module, the primary coil of the transformer is electrically connected to the oscillator through the first capacitor module, the secondary coil of the transformer is electrically connected to the rectifier circuit through the second capacitor module, and the isolated transmission circuit is used to transmit the AC signal transmitted by the oscillator to the rectifier circuit; the rectifier circuit is used to convert the AC signal transmitted by the isolated transmission circuit into a DC signal.

[0006] Furthermore, the oscillator also includes a first startup auxiliary circuit and a second startup auxiliary unit circuit, the first startup auxiliary circuit and the second startup auxiliary circuit both include a pulse signal generating circuit and a switch tube, the pulse signal generating circuit is electrically connected to the first end of the switch tube, and the second end and the third end of the switch tube are both electrically connected to the driving power tube module.

[0007] Furthermore, the fully integrated isolated power supply includes multiple rectifier circuits, the first ends of multiple rectifier circuits are electrically connected to the isolated transmission circuit, the second ends of multiple rectifier circuits are used to be electrically connected to an external load, the third end of the last rectifier circuit is grounded, and the third ends of the remaining rectifier circuits are respectively electrically connected to the second ends of the next rectifier circuit.

[0008] Furthermore, the fully integrated isolated power supply includes a first oscillator, a second oscillator, a first isolated transmission circuit, a second isolated transmission circuit, a first rectifier circuit and a second rectifier circuit; the first isolated transmission circuit is electrically connected to the first oscillator and the first rectifier circuit respectively, the second isolated transmission circuit is electrically connected to the second oscillator and the second rectifier circuit respectively, the primary coil of the first isolated transmission circuit is coupled to the secondary coil of the second isolated transmission circuit, and the primary coil of the second isolated transmission circuit is coupled to the secondary coil of the first isolated transmission circuit.

[0009] From the above description, it can be seen that the oscillator of the present application is based on a driving power tube module and an RF choke coil module, and the output voltage swing is not limited by the tail current, which can effectively reduce the introduction of phase noise and increase the power on the primary side, thereby improving the load driving capacity of the isolated power supply; the transformer and the capacitor module are then used to complete the isolated transmission of the AC signal, so that the isolation withstand voltage strength is increased, and by connecting the capacitor module and the primary coil of the transformer to the output end of the oscillator, the common mode current can be reduced and the electromagnetic compatibility characteristics can be improved; finally, the secondary coil of the transformer transmits the AC signal to the rectifier circuit through the capacitor module, so that the rectifier circuit rectifies and outputs a DC signal. The capacitor module can also isolate the noise signal between the ground and the signal, thereby improving the overall stability of the isolated power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0011] Figure 1 It is a structural schematic diagram of a fully integrated isolated power supply of the related technology; Figure 2 It is a circuit schematic diagram of a Class B oscillator in the related art; Figure 3 It is a structural schematic diagram of a fully integrated isolated power supply according to an embodiment of the present application; Figure 4 It is a circuit schematic diagram of a class E power amplifier of the related technology; Figure 5 is a circuit schematic diagram of an oscillator according to an embodiment of the present application; Figure 6 is a circuit schematic diagram of a startup auxiliary circuit according to an embodiment of the present application; Figure 7 It is a schematic diagram of principle analysis of a startup auxiliary circuit according to an embodiment of the present application; Figure 8 It is a circuit schematic diagram of the first fully integrated isolated power supply of the embodiment of the present application; Fig. 9 is a schematic diagram of the structure of a transformer subjected to electromagnetic compatibility optimization processing according to an embodiment of the present application; Fig.10 is a circuit schematic diagram of a rectifier circuit according to an embodiment of the present application; Fig.11 It is a schematic diagram of principle analysis of a rectifier circuit according to an embodiment of the present application; Fig.12is a circuit schematic diagram of a second fully integrated isolated power supply according to an embodiment of the present application; Fig.13 is a circuit schematic diagram of a third fully integrated isolated power supply according to an embodiment of the present application; Fig.14 It is a structural schematic diagram of a cross-coupled isolation transformer according to an embodiment of the present application. DETAILED DESCRIPTION

[0012] In order to make the purpose, features, and advantages of the invention of this application more obvious and easy to understand, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0013] In the related art, since there are problems of large phase noise, poor electromagnetic compatibility and low isolation withstand voltage strength of the isolated power supply, an embodiment of the present application provides a fully integrated isolated power supply.

[0014] like Figure 3 The figure shows a schematic diagram of the structure of a fully integrated isolated power supply provided by an embodiment of the present application, wherein the fully integrated isolated power supply includes: an oscillator 100, an isolated transmission circuit 200 and a rectifier circuit 300; the oscillator 100 includes an electrically connected driving power tube module 110 and a radio frequency choke coil module 120, and the oscillator 100 is used to convert an input DC signal into an AC signal; the isolated transmission circuit 200 includes a transformer 210, a first capacitor module 220 and a second capacitor module 230, the primary coil of the transformer 210 is electrically connected to the oscillator 100 through the first capacitor module 220, the secondary coil of the transformer 210 is electrically connected to the rectifier circuit 300 through the second capacitor module 230, the isolated transmission circuit 200 is used to transmit the AC signal transmitted by the oscillator 100 to the rectifier circuit 300; the rectifier circuit 300 is used to convert the AC signal transmitted by the isolated transmission circuit 200 into a DC signal.

[0015] Specifically, in order to solve the problems of low conversion efficiency and poor electromagnetic compatibility caused by the use of a Class B oscillator in the related art, the oscillator 100 in this embodiment designs a low electromagnetic radiation LC oscillator by referring to the structure of a Class E power amplifier. The structure of the Class E power amplifier is as follows: Figure 4 As shown, the amplifier is in the two working states of the switch of the active switch device. When the switch SW is in the closed state, the current flows through the switch SW, and the voltage on the switch SW and the capacitor C1 (the switch SW and the capacitor C1 are equivalent to the switch device and the parasitic capacitance of the switch device respectively) is zero. S and CS The frequency modulation effect makes the sinusoidal current signal fully transmitted to the load. S The inductance value should be large enough so that it can provide a DC path from the power supply to the load and is approximately an open circuit at high frequencies. In the loop, the difference between the current in the DC path and the switch current is the load current. When the switch SW is in the open state, the current on the switch SW is zero. However, the DC path on the DC inductor still provides the same current, and the current flowing through the load through the LC matching network remains unchanged. Therefore, the current that originally flowed through the switch SW now flows into the capacitor C1, which generates a dynamic voltage on the switch SW and the capacitor C1. When the switch SW is closed again, if the voltage on the capacitor C1 still exists, the capacitor C1 will discharge. In this process, the switch SW and the non-ideal resistor are both energy-consuming devices. This switching loss can be reduced by using a soft-open method, which is equivalent to reducing the voltage across the switch SW before the switch SW is closed next time. Assume that the voltage across the switch SW is zero before the closed state, as a zero-voltage switching technology. According to the relationship of capacitance I=cdv / dt, theoretically, zero-voltage switching can be achieved as long as the switch voltage or slope is zero when the switch is turned on. This state can provide sufficient freedom to change the switch voltage waveform through different value combinations of components in the circuit, thereby reducing switching losses and achieving 100% efficiency in theory.

[0016] The oscillator 100 proposed in this embodiment based on the working principle of the Class E amplifier includes a driving power tube module 110 and a radio frequency choke coil module 120, and the primary coil of the transformer 210 and the first capacitor module 220 can be used as a matching network of the oscillator 100. The oscillator 100 is used as the primary side of the isolated power supply, which can effectively improve the conversion efficiency of DC input to AC output; and, the primary coil of the transformer 210 and the first capacitor module 220 are used as the matching network of the oscillator 100, which can overcome the disadvantage that the traditional isolated power supply is susceptible to electromagnetic radiation interference; and the isolation channel formed by the two capacitor modules and the transformer 210 can increase the isolation withstand voltage of the on-chip isolation transformer 210; finally, the rectifier circuit 300 converts the isolated transmitted AC signal into a DC signal for output to the external load, providing the load with an efficient and stable power supply.

[0017] like Figure 5 The circuit diagram of an oscillator provided in the embodiment of the present application is shown in FIG. Figure 5 The driving power tube module 110 includes a first power tube M1, a second power tube M2, a first AC coupling capacitor C shift1 And the second AC coupling capacitor C shift2 The first end of the first power tube M1 is coupled to the second AC coupling capacitor Cshift2 The first end of the first power tube M1 is electrically connected to the first end of the second power tube M2, and the second end of the first power tube M1 is connected to the first AC coupling capacitor C shift1 The first power tube M1 and the second power tube M2 are electrically connected to the second end of the second power tube M2. The third ends of the first power tube M1 and the second power tube M2 are grounded.

[0018] Specifically, in a fully integrated isolated power supply, the design requirements of the oscillator 100 mainly include conversion efficiency, voltage amplitude, frequency stability and phase noise. Negative resistance oscillators are widely used because of their simple structure and strong robustness. In this embodiment, the driving power tube module 110 includes a differential input power tube and an AC coupling capacitor, such as Figure 5 The gate and drain of the power tubes M1 and M2 are connected to each other, forming a negative resistance characteristic in the positive feedback loop, so that the output of the oscillator 100 is a periodic high voltage waveform; wherein, in one cycle, the two power tubes are each turned on for half a cycle. The driving power tube module 110 is combined with the LC loop, and after the circuit resistance is offset, a frequency of oscillator; the AC coupling capacitor can form a capacitor voltage divider with the parasitic capacitance of the power tube, so that the high-voltage output waveform acts on the gate of the power tube in the form of voltage division, thereby avoiding the difficulties and cost problems caused by the selection of high-voltage tubes, that is, the AC coupling capacitor can make the gate voltage acting on the power tube meet the withstand voltage requirements of the process under a certain proportion specification, without the need to use high-voltage metal oxide transistors, such as the power tube in the Class B oscillator, which brings the problems of high process manufacturing cost and large device area occupation.

[0019] For further information, see Figure 5 The RF choke coil module 120 includes a first RF choke coil L RF_Choke-1 and the second RF choke coil L RF_Choke-2 , the first RF choke coil L RF_Choke-1 and the second RF choke coil L RF_Choke-2 One end of each of the first RF choke coil L is electrically connected to a DC power supply. RF_Choke-1 The other end of the second RF choke coil L is electrically connected to the second end of the first power tube M1 and serves as the first output end of the oscillator 100. RF_Choke-2 The other end of is electrically connected to the first end of the second power tube M2 and serves as the second output end of the oscillator 100.

[0020] Specifically, the RF choke coil (ie, DC feed-through inductor) in this embodiment is an S-shaped on-chip inductor, and the inductance value can be adjusted according to the frequency requirement of the oscillator 100; and the RF choke coil L RF_CHOKE1 and L RF_CHOKE2In the oscillator 100 , since it is on-chip, the required inductance value can be made relatively small, thereby increasing the operating frequency of the fully integrated isolated power supply.

[0021] For further information, see Figure 5 The oscillator 100 also includes a first startup auxiliary circuit 130 and a second startup auxiliary circuit 140. The first startup auxiliary circuit 130 and the second startup auxiliary circuit 140 both include a pulse signal generating circuit 131 / 141 and a switch tube M3 / M4. The pulse signal generating circuit 131 / 141 is electrically connected to a first end of the switch tube M3 / M4. The second end and the third end of the switch tube M3 / M4 are both electrically connected to the driving power tube module 110.

[0022] For details, see Figure 6 As shown in the circuit schematic diagram of the start-up auxiliary circuit, the pulse signal generating circuit 131 / 141 includes a trigger Q1, a first NOT gate I1 and a delay unit. The first end of the trigger Q1 is used to be electrically connected to an external control signal generator, and the second end of the trigger Q1 is electrically connected to the third end of the trigger Q1 and the delay unit through the first NOT gate I1. Among them, the delay unit includes a second NOT gate I2, a third NOT gate I3, a fourth NOT gate I4, a fifth NOT gate I5, a sixth NOT gate I6, a seventh NOT gate I7, an eighth NOT gate I8, a ninth NOT gate I9 and a NAND gate I10; the second NOT gate I2 is electrically connected to the trigger Q1 and the third NOT gate I3 respectively, the fourth NOT gate I4 is electrically connected to the third NOT gate I3 and the fifth NOT gate I5 respectively, the sixth NOT gate I6 is electrically connected to the fifth NOT gate I5 and the NAND gate I10 respectively, the seventh NOT gate I7 ​​is electrically connected to the third NOT gate I3 and the eighth NOT gate I8 respectively, the eighth NOT gate I8 is also electrically connected to the NAND gate I10, and the ninth NOT gate I9 is ​​electrically connected to the NAND gate I10 and the first switch tube M3 / M4 respectively.

[0023] In this embodiment, the startup auxiliary circuit is connected to two power tubes respectively, and each startup auxiliary unit includes a pulse signal generating circuit based on a digital logic circuit and a switch tube, which can solve the problem that the oscillator 100 cannot start itself under DC due to the existence of AC coupling capacitors, thereby affecting the conversion efficiency. Figure 6 As shown, at the falling edge of the control signal, the startup auxiliary circuit will generate a delay through the digital logic circuit. The narrow pulse signal K1 is used as the starting signal of the oscillator 100. When the narrow pulse is at a low level, the switch tube M3 / M4 is turned on, thereby starting the oscillator 100. The core of the startup auxiliary unit is the width t5 of the narrow pulse signal K1 and the size of the switch tube M3 / M4. The width t5 of the narrow pulse signal K1 determines whether the switch tube M3 / M4 can be fully turned on. The size of the switch tube M3 / M4 determines the speed at which M3 / M4 is turned on, thereby determining the amount of energy (i.e., voltage) stored on the inductor in the LC oscillator 100. The principle analysis diagram of the startup auxiliary unit is shown in the figure below. Figure 7 As shown, the falling edge slope t6 and pulse width t5 of the narrow pulse signal K1 driving the switch tube M3 / M4 both affect the normal oscillation effect of the oscillator 100, wherein the slope t6 determines the voltage drop on the inductor. The larger the slope t6, the greater the voltage drop on the inductor, the higher the initial oscillation voltage, the greater the gate voltage division, and the easier it is to oscillate; the larger the pulse width t5, the lower the duty cycle utilization rate, and the lower the efficiency. Because the role of the inductor is to generate an induced voltage that hinders the change of current, the current on the inductor cannot change suddenly in an instant. When the current does not change, there is no induced voltage because the magnetic field does not change, and the voltage remains constant.

[0024] like Figure 8 The circuit diagram of the first fully integrated isolated power supply provided by the present application is shown in FIG. Figure 8 , the transformer 210 includes a first primary coil L P1 , the second primary coil L P2 , first secondary coil L S1 And the second secondary coil L S2 The first capacitor module 220 includes a first capacitor C ISP1 , the second capacitor C ISP2 The second capacitor module 230 includes a third capacitor C ISS1 And the fourth capacitor C ISS2 ; The first primary coil L P1 One end of the first capacitor C ISP1 The second primary coil L is electrically connected to an output terminal of the oscillator 100. P2 One end of the second capacitor C ISP2 The first primary coil L is electrically connected to the other output terminal of the oscillator 100. P1 and the second primary coil L P2 The other end of the first secondary coil L S1 One end of the third capacitor C ISS1 The second secondary coil L is electrically connected to an input terminal of the rectifier circuit 300. S2 One end of the fourth capacitor C ISS2 The first secondary coil L is electrically connected to the other input terminal of the rectifier circuit 300.S1 And the second secondary coil L S2 The other ends of the transformer 210 are interconnected. The primary coil of the transformer 210 is coupled to the secondary coil.

[0025] Specifically, in this embodiment, the transformer 210 is an on-chip isolation transformer, and in order to enhance the isolation and integration, the primary coil of the transformer 210 and the first capacitor module 220 are used as the capacitive and inductive loads of the oscillator 100, wherein the primary coil of the transformer 210 can be equivalent to the inductive load of the oscillator 100, and the two primary coils of the transformer 210 can be centrally grounded to reduce the path of the common mode current, thereby benefiting electromagnetic compatibility; in addition, the first capacitor module 220 and the primary coil of the transformer 210 can form a matching network of the oscillator 100, and then AC-coupled to the secondary end of the transformer 210. The isolated transmission circuit 200 in this embodiment includes the load capacitor of the matching network of the oscillator 100 (that is, the first capacitor module), the on-chip isolation transformer 210 and the coupling capacitor of the rectifier circuit 300 (that is, the second capacitor module). Compared with the isolation brought by relying only on the on-chip isolation transformer medium, the isolated transmission circuit 200 in this embodiment combines the on-chip capacitors of the primary and secondary of the transformer 210, which can enhance the isolation withstand voltage of the overall isolated power supply. Furthermore, in this embodiment, a second capacitor module 230 is added between the rectifier circuit 300 and the transformer 210. On the one hand, it can enhance the isolation strength. On the other hand, the capacitor module can also isolate the noise signal between the ground and the signal.

[0026] In addition, a ferrite shielding layer may be provided on two adjacent sides of the isolation transformer 210, for example Fig. 9 As shown, a ferrite shielding layer 2 is provided on the upper and lower sides of the isolation transformer (also known as the on-chip isolation transformer) 1, wherein the design concept and selection of the shielding layer material technology are mainly derived from the core material of the core transformer and the EMI performance optimization based on the packaging level. Ferrite is a ceramic ferromagnetic material with a crystalline structure, generally composed of a mixture of iron oxide and manganese or zinc oxide. The eddy current loss of ferrite can be basically ignored, which is due to its own high resistivity characteristics. For the isolation transformer, the high resistivity characteristics of ferrite can be used as a reference, so that the coil of the isolation transformer is wrapped by the ferrite material, thereby effectively reducing the radiated magnetic field, which is mainly used in occasions with strict electromagnetic compatibility requirements. If electromagnetic radiation mitigation technology is used at the packaging level, the need for additional substrate-level filtering can be reduced, and while meeting the electromagnetic compatibility standards, the design can be simplified and the cost can be reduced.

[0027] like Fig.10 The circuit diagram of a rectifier circuit provided by the present application is shown in FIG. Fig.10 The rectifier circuit 300 includes a CMOS full-wave rectifier bridge, which includes a first PMOS tube Mp1 , the second PMOS tube M p2 , the first NMOS tube M n1 And the second NMOS tube M n2 ; The first PMOS tube M p1 The gate of the second PMOS tube M p2 The drain of the second NMOS tube M n1 The drain of the second PMOS tube M is electrically connected to the first input terminal of the rectifier circuit 300. p2 The gate of the first PMOS tube M p1 The drain of the first NMOS tube M p1 The drain of the first PMOS tube M is electrically connected to the second input terminal of the rectifier circuit 300. p1 And the second PMOS tube M p2 The source of the first NMOS tube M is used to be electrically connected to an external load. n1 And the second NMOS tube M n2 The gate and source of the first PMOS tube M are grounded. p1 And the second PMOS tube M p2 The drain terminals are grounded.

[0028] It should be noted that in the related art, the rectifier circuit 300 of the fully integrated isolated power supply generally uses an integrated on-chip Schottky diode rectifier bridge, which has a large reverse leakage current, resulting in a low conversion efficiency of the isolated power supply. In order to drive heavy loads, it is necessary to reduce the forward conduction voltage drop, and the number of Schottky diodes used will also increase, thereby causing the problem of uneven diode conduction, affecting the overall performance of the isolated power supply. In addition, the practical Schottky diode rectifier bridge under the standard CMOS process requires an additional mask process, which is costly.

[0029] The rectifier circuit 300 of this embodiment includes a cross-coupled high-voltage PMOS tube, the gate of which is connected to the drain of the symmetrical PMOS tube. Since the rectifier circuit 300 processes an AC signal, a CMOS tube with an isolation ring can be used to isolate noise; two NMOS tubes M n1 、M n2 The parallel body diode is an independent intrinsic body diode. This embodiment uses a body diode with a low voltage drop formed by a CMOS transistor to replace the Schottky diode, which can overcome the problems of reverse leakage and turn-on unevenness of the Schottky diode, and can improve the overall conversion efficiency of the circuit while improving the rectification efficiency, and reduce the additional process masks and process applications, thereby reducing the cost caused by process complexity.

[0030] The working principle of the rectifier circuit 300 in this embodiment is as follows: First, define Vin=Vacs1-Vacs2; When the input of the rectifier circuit 300 is in the positive half-cycle working time (Vin≥0), Vin is less than the conduction threshold of the PMOS tube, M p1 and M p2 Tube off; 0 <Vacs2<Vacs1<Viso_out,M n1 and M n2 The transistors are all turned off and no current flows to the output terminal Viso_out. Once Vin reaches the threshold voltage of the PMOS transistor, M p1 The tube is gradually turned on, and the entire rectifier circuit 300 enters the state as follows Fig.11 The state shown; when Vacs2>0, M n2 Although the tube is in the off state, Viso_out gradually approaches Vin. Therefore, once Viso_out increases to a value exceeding the body diode (M n2 The conduction voltage of the tube) will cause the current to flow from M n2 The tube flows out and charges the capacitor Co; when Vin increases to the peak value and then starts to decrease, at this time, the Mp1 tube is kept turned on, and the M n1 The tube is closed and the current flows through M n2 The transistor flows out and charges the capacitor Co; when Vin is less than the conduction threshold of the PMOS, M p1 and M p2 When the input of the rectifier circuit 300 is in the negative half-cycle working time (Vin<0), the principle is the same as the positive half-cycle process, and the path of the current flowing to Viso_out changes from M n1 To M p2 .

[0031] like Fig.12 The circuit schematic diagram of the second fully integrated isolated power supply provided by the present application is shown in FIG. Fig.12 The fully integrated isolated power supply includes multiple rectifier circuits 300, the first ends of the multiple rectifier circuits 300 are electrically connected to the isolated transmission circuit 200, the second ends of the multiple rectifier circuits 300 are used to be electrically connected to an external load, the third end of the last rectifier circuit 300 is grounded, and the third ends of the remaining rectifier circuits 300 are respectively electrically connected to the second ends of the next rectifier circuit 300.

[0032] Specifically, taking two rectifier circuits 300 as an example, this embodiment designs the fully integrated isolated power supply as a stacked dual CMOS full-wave rectifier bridge architecture, and the VISO_OUT output of the second-layer rectifier circuit 300 is equivalent to the ground line of the first-layer rectifier circuit 300. This architecture not only maintains the advantages of a fully integrated isolated power supply including a single rectifier circuit 300, but also can output twice the voltage without any other external devices or parameter changes (such as the number of turns), for example, the input is 3.3V or 5V, and the output is 6.6V or 10V, which can meet the conversion requirements from low-voltage domain input to high-voltage domain output, and a coupling capacitor is added between the transformer 210 and the rectifier circuit 300, which can achieve enhanced isolation strength and noise isolation.

[0033] like Fig.13 The circuit schematic diagram of the third fully integrated isolated power supply provided by the present application is shown in FIG. Fig.13 The fully integrated isolated power supply includes a first oscillator, a second oscillator, a first isolated transmission circuit, a second isolated transmission circuit, a first rectifier circuit and a second rectifier circuit; the first isolated transmission circuit is electrically connected to the first oscillator and the first rectifier circuit respectively, the second isolated transmission circuit is electrically connected to the second oscillator and the second rectifier circuit respectively, the primary coil of the first isolated transmission circuit is coupled to the secondary coil of the second isolated transmission circuit, and the primary coil of the second isolated transmission circuit is coupled to the secondary coil of the first isolated transmission circuit.

[0034] Specifically, the Class B oscillator used in the isolated power supply in the related art may not meet the phase noise index requirements in low-voltage processes or high-power transmission applications, or requires large external / internal inductance and capacitance values ​​to ensure its performance. Therefore, in order to better reduce phase noise, this embodiment uses multiple groups, such as two groups of oscillators, isolated transmission circuits, and rectifier circuits to form a fully integrated isolated power supply. The structure of the dual differential oscillator can effectively reduce phase noise. For example, the phase noise of the dual differential oscillator in this embodiment can be reduced by 3dB, and the output voltage amplitude and frequency do not change. The windings of the two transformers in this embodiment are cross-coupled, for example Fig.14As shown, the primary coils LP1 and LP2 of the first transformer are coupled with the secondary coils LS3 and LS4 of the second transformer, and the magnetic core is set between LP1 / LP2 and LS3 / LS4. The primary coils LP3 and LP4 of the second transformer are coupled with the secondary coils LS1 and LS2 of the first transformer, and the magnetic core is set between LS1 / LS2 and LP3 / LP4. Insulating materials are used between the first transformer and the second transformer to ensure the withstand voltage characteristics; the energy transmitted by the two transformers is from the primary coils LP1 and LP2 of the first transformer to the secondary coils LS3 and LS4 of the second transformer; the other is from the primary coils LP3 and LP4 of the second transformer to the secondary coils LS1 and LS2 of the first transformer; the coupling between the two is externally manifested as the mutual cancellation effect of magnetic flux. Therefore, the two sets of cross-coupled isolation transmission circuits cancel each other out due to the opposite directions of adjacent magnetic fluxes, which improves the anti-interference ability and thus increases the electromagnetic compatibility of the isolated power supply as a whole. In addition, it should also be understood that the dual differential cross-coupling structure is equivalent to a common centroid matching structure in space, so that it can meet the high-precision requirements of the overall circuit, such as linearity, frequency response and stability. In addition, if there is an application requirement, the rectifier circuit in the common centroid matching structure can also be set to multiple outputs, thereby outputting double voltage while meeting high-precision design requirements.

[0035] The fully integrated isolated power supply provided in the embodiment of the present application includes an oscillator, an isolated transmission circuit and a rectifier circuit. Among them, the oscillator can be set to a dual differential structure, that is, it includes two oscillators with a theoretical conversion efficiency of 100%, which can effectively reduce phase noise; and due to the application of the Class E oscillator, the power at the input end can be effectively increased, thereby improving the overall conversion efficiency and driving load capacity of the fully integrated isolated power supply; the introduction of the startup auxiliary circuit can solve the problem that the Class E amplifier is expanded into an oscillator and applied to the primary side of the isolated power supply and cannot start automatically; the application of the dual differential oscillator and the cross-coupled isolated transmission circuit causes the adjacent electromagnetic radiation effects to cancel each other, which can effectively reduce the impact of electromagnetic interference; the rectifier circuit can use a CMOS full-wave rectifier bridge, which can achieve high-efficiency AC signal to DC signal rectification, and can avoid the manufacturing cost and performance risks brought by special devices (such as Schottky diodes); and the application of the stacked CMOS full-wave rectifier bridge structure can achieve the application requirements of low-voltage domain to high-voltage domain while coupling the noise isolation capacitor to enhance the overall isolation strength. Therefore, the fully integrated isolated power supply provided in the embodiment of the present application has the advantages of low manufacturing cost, fast startup speed, high conversion efficiency, heavy driving load, enhanced isolation, strong anti-interference ability, and high linearity in the circuit, which can better meet the needs of high-end application scenarios.

[0036] It should be noted that the various embodiments in the present application are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0037] It should also be noted that, in the content of the present application, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first" and "second" can expressly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements that are not clearly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "include one..." do not exclude the presence of other identical elements in the process, method, article or equipment including the elements.

[0038] The above description of the disclosed embodiments enables professionals and technicians in the field to implement or use the present application. Various modifications to these embodiments will be apparent to professionals and technicians in the field, and the general principles defined in the present application can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown in the present application, but will conform to the widest range consistent with the principles and novel features disclosed in the present application.

Claims

1. A fully integrated isolated power supply, characterized in that: include: Oscillator, isolated transmission circuit and rectifier circuit; The oscillator includes an electrically connected driving power tube module and a radio frequency choke coil module, and the oscillator is used to convert an input DC signal into an AC signal; The isolated transmission circuit includes a transformer, a first capacitor module and a second capacitor module, the primary coil of the transformer is electrically connected to the oscillator through the first capacitor module, the secondary coil of the transformer is electrically connected to the rectifier circuit through the second capacitor module, and the isolated transmission circuit is used to transmit the AC signal transmitted by the oscillator to the rectifier circuit; The rectifier circuit is used to convert the AC signal transmitted by the isolation transmission circuit into a DC signal.

2. The fully integrated isolated power supply according to claim 1, characterized in that: The driving power tube module includes a first power tube, a second power tube, a first AC coupling capacitor and a second AC coupling capacitor; The first end of the first power tube is electrically connected to the first end of the second power tube through the second AC coupling capacitor, the second end of the first power tube is electrically connected to the second end of the second power tube through the first AC coupling capacitor, and the third ends of the first power tube and the second power tube are grounded.

3. The fully integrated isolated power supply according to claim 2, characterized in that: The RF choke coil module includes a first RF choke coil and a second RF choke coil, one end of the first RF choke coil and the second RF choke coil are both electrically connected to a DC power supply, the other end of the first RF choke coil is electrically connected to the second end of the first power tube and serves as the first output end of the oscillator, and the other end of the second RF choke coil is electrically connected to the first end of the second power tube and serves as the second output end of the oscillator.

4. The fully integrated isolated power supply according to claim 1, characterized in that: The oscillator also includes a first startup auxiliary circuit and a second startup auxiliary circuit, each of which includes a pulse signal generating circuit and a switch tube, the pulse signal generating circuit is electrically connected to the first end of the switch tube, and the second end and the third end of the switch tube are both electrically connected to the driving power tube module.

5. The fully integrated isolated power supply according to claim 4, characterized in that: The pulse signal generating circuit includes a trigger, a first NOT gate and a delay unit. The first end of the trigger is used to be electrically connected to an external control signal generator, and the second end of the trigger is electrically connected to the third end of the trigger and the delay unit through the first NOT gate.

6. The fully integrated isolated power supply according to claim 5, characterized in that: The delay unit includes a second NOT gate, a third NOT gate, a fourth NOT gate, a fifth NOT gate, a sixth NOT gate, a seventh NOT gate, an eighth NOT gate, a ninth NOT gate and a NAND gate; The second NOT gate is electrically connected to the trigger and the third NOT gate respectively, the fourth NOT gate is electrically connected to the third NOT gate and the fifth NOT gate respectively, the sixth NOT gate is electrically connected to the fifth NOT gate and the NAND gate respectively, the seventh NOT gate is electrically connected to the third NOT gate and the eighth NOT gate respectively, the eighth NOT gate is also electrically connected to the NAND gate, and the ninth NOT gate is electrically connected to the NAND gate and the first switch tube respectively.

7. The fully integrated isolated power supply according to claim 1, characterized in that: The transformer includes a first primary coil, a second primary coil, a first secondary coil and a second secondary coil, the first capacitor module includes a first capacitor and a second capacitor, and the second capacitor module includes a third capacitor and a fourth capacitor; One end of the first primary coil is electrically connected to an output end of the oscillator through the first capacitor, one end of the second primary coil is electrically connected to the other output end of the oscillator through the second capacitor, the other ends of the first primary coil and the second primary coil are both grounded, one end of the first secondary coil is electrically connected to an input end of the rectifier circuit through the third capacitor, one end of the second secondary coil is electrically connected to the other input end of the rectifier circuit through the fourth capacitor, and the other ends of the first secondary coil and the second secondary coil are interconnected.

8. The fully integrated isolated power supply according to claim 1, characterized in that: The rectifier circuit includes a CMOS full-wave rectifier bridge.

9. The fully integrated isolated power supply according to claim 8, characterized in that: The CMOS full-wave rectifier bridge comprises a first PMOS tube, a second PMOS tube, a first NMOS tube and a second NMOS tube; The gate of the first PMOS tube is electrically connected to the drain of the second PMOS tube and the drain of the second NMOS tube respectively and serves as the first input end of the rectifier circuit; the gate of the second PMOS tube is electrically connected to the drain of the first PMOS tube and the drain of the first NMOS tube respectively and serves as the second input end of the rectifier circuit; the source of the first PMOS tube and the second PMOS tube are both used to be electrically connected to an external load; the gate and source of the first NMOS tube and the second NMOS tube are both grounded; and the drain of the first PMOS tube and the second PMOS tube are both grounded.

10. The fully integrated isolated power supply according to any one of claims 1 to 9, characterized in that: It comprises a plurality of rectifier circuits, wherein the first ends of the plurality of rectifier circuits are electrically connected to the isolation transmission circuit, the second ends of the plurality of rectifier circuits are electrically connected to an external load, the third end of the last rectifier circuit is grounded, and the third ends of the remaining rectifier circuits are respectively electrically connected to the second ends of the next rectifier circuit.

11. The fully integrated isolated power supply according to claim 1, characterized in that: It includes a first oscillator, a second oscillator, a first isolated transmission circuit, a second isolated transmission circuit, a first rectifier circuit and a second rectifier circuit; The first isolated transmission circuit is electrically connected to the first oscillator and the first rectifier circuit respectively, the second isolated transmission circuit is electrically connected to the second oscillator and the second rectifier circuit respectively, the primary coil of the first isolated transmission circuit is coupled to the secondary coil of the second isolated transmission circuit, and the primary coil of the second isolated transmission circuit is coupled to the secondary coil of the first isolated transmission circuit.

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