Isolation power supply chip based on double-resonance topology and control method thereof

Abstract

The invention provides an isolated power supply chip based on double-resonant topology and a control method thereof. The isolated power supply chip comprises a first oscillator, a transformer, a second oscillator, a control circuit and a detection circuit, the transformer comprises a primary coil connected with the first oscillator and a secondary coil connected with the second oscillator, and the first oscillator is used for inverting a direct-current input voltage into a high-frequency oscillation power signal, so that the first oscillator works in a first oscillation state; the second oscillator works in a second oscillation state after receiving a high-frequency oscillation power signal which is coupled and transmitted to the secondary coil from the primary coil, and a direct-current output voltage is obtained; the control circuit is used for detecting the direct-current output voltage and regulating and controlling the second oscillation state; and the detection circuit is used for detecting the first oscillation state to determine the influence of the second oscillation state on the first oscillation state, and adjusting the first oscillation state in real time to realize stable work of the isolated power supply.

Description

Technical Field

[0001] The present disclosure relates to the technical field of isolated power supplies, and in particular to an isolated power supply chip based on a dual-resonance topology and a control method thereof. Background Art

[0002] Isolated power chips can be used to transmit energy between two electrically isolated systems, effectively eliminating noise and surge current between different voltage domains, ensuring that devices are not damaged in the event of a circuit failure, and preventing people from getting electric shock. Therefore, they are more widely used in automotive electronics, biomedicine, electric power and other fields. Traditional isolated power chips consist of three parts: an inverter circuit at the transmitting end, a power transmission isolation barrier using a transformer, and a rectifier circuit at the receiving end.

[0003] Conversion efficiency is one of the important technical indicators of power supply. Improving conversion efficiency can reduce energy loss and electricity cost, reduce the design burden of cooling system, extend the service life of equipment, and reduce maintenance requirements due to overheating. The AC-DC rectifier circuit at the receiving end of the traditional isolated power chip can be divided into active rectifier and passive rectifier. The active rectifier has excessive gate capacitance switching loss at high frequency and low efficiency, which is not suitable for small-size and low-cost isolated power chips. The passive devices used in the passive rectifier have high forward conduction voltage drop and large conduction loss, which limits the conversion efficiency of the isolated power chip. The traditional isolated power chip requires an additional digital isolator as a feedback circuit to adjust the output voltage, which increases the size and cost of the isolated power chip. Summary of the invention

[0004] In view of this, in order to at least partially solve at least one of the above-mentioned technical problems, the present disclosure provides an isolated power supply chip based on a dual resonance topology and a control method thereof.

[0005] In order to achieve the above purpose, the technical solution of the present invention is as follows:

[0006] According to an embodiment of one aspect of the present disclosure, there is provided an isolated power supply chip based on a dual-resonance topology, comprising a first oscillator, a transformer, a second oscillator, a control circuit, and a detection circuit; the transformer comprises a primary coil connected to the first oscillator and a secondary coil connected to the second oscillator, wherein: the first oscillator is used to invert a DC input voltage into a high-frequency oscillation power signal, so that the first oscillator operates in a first oscillation state; the second oscillator operates in a second oscillation state after receiving the high-frequency oscillation power signal coupled to the secondary coil by the primary coil, and obtains a DC output voltage; the control circuit is used to detect the DC output voltage and regulate the second oscillation state; the detection circuit is used to detect the first oscillation state to determine the influence of the second oscillation state on the first oscillation state, and to adjust the first oscillation state in real time, so as to achieve stable operation of the isolated power supply.

[0007] According to an embodiment of the present disclosure, the control circuit is also used to control the second oscillator to be turned on or short-circuited, and the detection circuit is also used to control the first oscillator to be turned on or off, thereby realizing the turning on or off of the isolated power supply through the cooperation between the control circuit and the detection circuit.

[0008] According to the embodiment of the present disclosure, when the isolated power supply chip changes from the on state to the off state, the control circuit controls the second oscillator to short-circuit, and the detection circuit controls the first oscillator to shut down by detecting the change in the oscillation frequency of the first oscillator, thereby realizing the shutdown of the isolated power supply.

[0009] According to the embodiment of the present disclosure, the isolated power supply chip changes from the off state to the on state, the control circuit controls the second oscillator to operate, and the detection circuit controls the first oscillator to start by detecting that the first oscillator is affected by the second oscillator to generate oscillations, thereby realizing the startup of the isolated power supply.

[0010] According to an embodiment of the present disclosure, the second oscillator is provided with a second switch; the control circuit includes a feedback network, a non-overlapping circuit, and a short-circuit switch, wherein: the feedback network is configured to detect a DC output voltage and generate a control signal; the non-overlapping circuit receives the control signal and controls the conduction and disconnection of the short-circuit switch and the second switch.

[0011] According to an embodiment of the present disclosure, the first oscillator is provided with a first switch; the detection circuit includes a level detection circuit, a frequency detection circuit, and a logic circuit, wherein: the level detection circuit is used to detect the level change of the oscillation power signal of the first oscillator, and transmit the level detection result to the logic circuit; the frequency detection circuit is used to detect the oscillation frequency of the oscillation power signal of the first oscillator, and transmit the frequency detection result to the logic circuit; the logic circuit is configured to control the conduction and disconnection of the first switch according to the level detection result and the frequency detection result, so as to control the opening and closing of the first oscillator.

[0012] According to an embodiment of the present disclosure, the first oscillator and / or the second oscillator adopts a cross-coupled LC oscillator topology structure, or adopts a switch full-bridge driver topology structure.

[0013] According to an embodiment of the present disclosure, the transformer includes a primary coil or includes a plurality of primary coils arranged in series, and correspondingly, the transformer includes a secondary coil or includes a plurality of secondary coils arranged in series.

[0014] According to an embodiment of the present disclosure, the coupling coefficient of the transformer is greater than 0.75.

[0015] Another aspect of the present disclosure provides a control method for an isolated power supply chip based on a dual resonance topology, and controls the isolated power supply chip described in any one of the above items. The control method includes: inverting a DC input voltage into a high-frequency oscillation power signal to enable a first oscillator to operate in a first oscillation state; coupling and transmitting the high-frequency oscillation power signal to a secondary coil through a primary coil of a transformer, so that the second oscillator operates in a second oscillation state and obtains a DC output voltage; detecting the DC output voltage and regulating the second oscillation state; and detecting the first oscillation state to determine the influence of the second oscillation state on the first oscillation state, and adjusting the first oscillation state in real time to achieve stable operation of the isolated power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0017] Figure 1 This is a system block diagram of a traditional full-bridge rectifier isolated power supply chip.

[0018] Figure 2 Schematic diagram of an isolated power supply chip based on a dual resonance topology according to an embodiment of the present disclosure.

[0019] Figure 3 It is a schematic diagram of an isolated power chip based on a dual resonance topology according to another embodiment of the present disclosure.

[0020] Figure 4 This is a schematic diagram of an isolated power chip based on a dual-resonance topology according to another embodiment of the present disclosure.

[0021] Figure 5 Schematic diagram of key waveforms of an isolated power supply chip based on a dual-resonance topology according to an embodiment of the present disclosure.

[0022] Figure 6 Schematic diagram of the key waveforms and working principle of the isolated power chip based on the dual resonance topology of the embodiment of the present disclosure.

[0023] Figure 7This is a flow chart of a control method for an isolated power supply chip based on a dual resonance topology according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0024] The present invention provides an isolated power chip based on a dual-resonance topology and a control method thereof, which transmits feedback signals to achieve voltage modulation by multiplexing power transformers, thereby saving the digital isolator circuit required by traditional isolated power chips, reducing chip size and reducing costs; at the same time, by introducing a class D LC oscillator into the receiving end to replace the traditional rectifier, the conversion efficiency of the isolated power system is improved. Compared with traditional rectifiers, class D LC oscillators have no gate capacitance switching loss, and the gate voltage of the MOS tube is higher when it is turned on, and the conduction loss is small, so higher efficiency can be achieved.

[0025] Isolation devices in isolated power supplies include linear optocouplers, capacitors, and transformers. Linear optocouplers have problems such as large size, high cost, and high loss, which limit their application in portable devices and high-speed digital isolators. Traditional capacitive isolators are limited by their dielectric breakdown voltage and are difficult to achieve high isolation. The use of transformers as isolation devices has become the mainstream in isolated power chips due to their high noise immunity, small size, and monolithic integration.

[0026] In isolated power supplies, the loss of AC-DC rectification limits the efficiency and cost of isolated power supplies. The loss of active rectifiers based on MOS tubes can be divided into conduction loss and gate capacitance switching loss. When the switching frequency is low, since the MOS tube can be fully turned on at a high gate-source voltage, a small conduction loss can be achieved at a certain size, and the gate capacitance switching loss is low, so that the active rectification of the MOS tube can achieve higher efficiency. Reference [D. Pan et al, "A2.1W 60%-Peak-Efficiency Isolated DC-DC Converter with Complementary Edge-Aligned and Adaptive Over-Compensation Techniques Meeting the CISPR-32 Class-B EMI Standard," IEEE European Solid-State Electronics Research Conference -(ESSERC), Bruges, Belgium, 2024]. However, when the switching frequency is high (generally above 25MHz), the gate capacitance switching loss is too large, making the active rectifier less efficient. Therefore, the use of active rectification circuits will increase the size of the transformer, which increases the size and cost of the chip.

[0027] When the frequency is high, the receiving module of the traditional isolated power supply adopts passive full-bridge rectification as the AC-DC rectification scheme. Specific implementation schemes include but are not limited to diode full-bridge rectification, MOS tube full-bridge rectification and other schemes. Reference [W. Qin et al., "An 800mW Fully Integrated Galvanic Isolated Power Transfer System Meeting CISPR 22 Class-B Emission Levels with 6dB Margin," 2019 IEEEInternational Solid- State Circuits Conference - (ISSCC), San Francisco, CA, USA, 2019].

[0028] like Figure 1 As shown, when the conventional isolated power chip is working, the LC oscillator 100 is connected to the primary inductance L of the transformer 200. P The AC signal is coupled to the secondary inductor L of the transformer 200. S The sinusoidal current I with alternating direction is generated LS . When I LS When the current direction is from a to b, diodes D1 and D4 are turned on. LS When the current direction is from b to a, diodes D2 and D3 are turned on. In this process, the current flowing through capacitor C O The current direction is always from the output voltage V ISO The output end of the current is directed to GND2, thus providing energy to the load. The two diodes that are turned on in the current path have V D The voltage drop of the rectifier can be expressed as:

[0029] ;

[0030] Although compared with active rectification, diode full-bridge rectification does not have gate capacitance switching loss, the forward voltage and on-resistance of the on-chip diodes in conventional BCD processes are relatively high, resulting in V D Larger, efficiency η RX Lower. Using Schottky diodes can use a larger area in exchange for a lower voltage drop V D However, it requires special processes and is relatively expensive. Since MOS tubes have threshold voltages, using diode-connected MOS tubes instead of rectifier diodes cannot significantly improve the efficiency of passive rectifiers.

[0031] On the other hand, since the transmitting end of the traditional isolated power supply chip is a DC-AC inverter circuit, such as an LC oscillator, and the receiving end is an AC-DC rectifier circuit, such as a diode full-bridge rectifier, the circuits of the transmitting and receiving ends are different and need to be designed and manufactured separately, which increases the design and development cost of the isolated power supply.

[0032] As can be seen from the above, the circuits of the transmitting end and the receiving end of the traditional isolated power supply chip are different, and need to be designed and manufactured separately, which increases the development cost. In the traditional isolated power supply chip, an additional digital isolator circuit is required to transmit the feedback signal to adjust the output power, which increases the size and cost of the isolated power supply chip. Therefore, the present disclosure proposes an isolated power supply chip based on a dual resonance topology and a control method thereof, which introduces a Class D LC oscillator into the receiving end to replace the traditional rectifier and improve the conversion efficiency of the isolated power supply system. The transmitting end and the receiving end circuits can be designed to be exactly the same, so the transmitting end circuit and the receiving end circuit can be reused, reducing the design and development cost of the isolated power supply. By reusing the power control method of the power transformer to transmit the feedback signal, the digital isolator circuit required for the traditional isolated power supply chip is saved, the chip size is reduced, and the cost is reduced.

[0033] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0034] In an embodiment of the present disclosure, an isolated power supply chip based on a dual resonance topology is provided. Figure 2 As shown, the isolated power supply chip includes a first oscillator 100 arranged at the transmitting end, a transformer 200, a second oscillator 300 arranged at the receiving end, a control circuit, and a detection circuit; the transformer 200 includes a primary coil L connected to the first oscillator P and a secondary coil L connected to the second oscillator S ,in:

[0035] The first oscillator 100 is used to invert the DC input voltage into a high-frequency oscillation power signal, so that the first oscillator works in a first oscillation state;

[0036] The second oscillator 300 operates in a second oscillation state after receiving the high-frequency oscillation power signal coupled and transmitted from the primary coil to the secondary coil, and obtains a DC output voltage;

[0037] The control circuit 400 is used to detect the DC output voltage and regulate the second oscillation state;

[0038] The detection circuit 500 is used to detect the first oscillation state to determine the influence of the second oscillation state on the first oscillation state, and to adjust the first oscillation state in real time to achieve stable operation of the isolated power supply.

[0039] Specifically, combined Figure 2 As shown, the first oscillator 100 is used to convert the DC input voltage V IN Inverted into a differential high-frequency oscillation power signal V PP and V PN And output to the primary coil L of the transformer 200 P ; Transformer 200, used as an isolation device for transmitting AC power, consists of a primary coil L P and the secondary coil L S The high frequency oscillation power signal V in the first oscillator 100 is PP and V PN The primary coil L of the transformer 200 is connected to the voltage node P Both ends of TX P and TX N The high frequency oscillation power signal V of the second oscillator 300 SP and V SN The secondary coil L of the transformer 200 is connected via a voltage node S Both ends of RX P and RX N . The primary coil L P The high frequency oscillation power signal V PP and V PN Coupled to the secondary coil L S , so that the second oscillator 300 has a high oscillation power signal V SP and V SN With V PP and V PN Oscillate together, and with V SP and V SN The high frequency oscillation power signal forms a DC common mode point at the center point of the transformer 200, from which a DC output voltage V ISO ; The receiving end control circuit 400 detects the output voltage V ISO , and controls the state of the second oscillator; when the second oscillator oscillates, it affects the oscillation state of the first oscillator. The transmitting end detection circuit 500 detects the working state of the first oscillator, thereby controlling the working state of the first oscillator to achieve voltage modulation.

[0040] According to the embodiments of the present disclosure, the first oscillator and / or the second oscillator may adopt a cross-coupled LC oscillator topology, or a switch full-bridge driver topology. It should be noted that the two oscillators may also adopt other topologies such as a Class D oscillator or other types of oscillators, as long as the oscillator function can be realized.

[0041] According to the embodiment of the present disclosure, the control circuit 400 is also used to control the second oscillator 300 to be turned on or short-circuited, and the detection circuit 500 is also used to control the first oscillator 100 to be turned on or off, thereby realizing the turning on or off of the isolated power supply through the cooperation between the control circuit and the detection circuit.

[0042] For example, from the on state to the off state, the control circuit controls the second oscillator to be short-circuited, and the detection circuit controls the first oscillator to be turned off by detecting the change in the oscillation frequency of the first oscillator, thereby realizing the shutdown of the isolated power supply. Specifically, after the receiving end control circuit 400 detects the output voltage and generates a shutdown signal, the second oscillator 300 is short-circuited. The short circuit of the second oscillator 300 will change the oscillation frequency of the first oscillator 100. At this time, the transmitting end detection circuit 500 detects the change in the oscillation frequency of the first oscillator 100, controls the first oscillator 100 to be turned off, and realizes the shutdown of the entire isolated power supply system.

[0043] From the off state to the on state, the control circuit controls the second oscillator to work, and the detection circuit controls the first oscillator to start by detecting that the first oscillator is affected by the second oscillator to oscillate, thereby realizing the start of the isolated power supply. Specifically, when the receiving end control circuit 400 detects the DC output voltage and generates a start signal, the second oscillator 300 starts to oscillate, and the secondary coil L S The high frequency oscillation power signal V SP and V SN Will be coupled to the primary coil L P , so that the high oscillation power signal V PP and V PN With V SP and V SN The two oscillators oscillate together, and after the oscillating voltage signal is detected by the control circuit 500, the first oscillator 100 is turned on, thereby realizing the start-up of the entire isolated power supply system.

[0044] According to the embodiment of the present disclosure, Figure 2 , Figure 3 , Figure 4 As shown, the transformer may include one primary coil or multiple primary coils arranged in series, and correspondingly, the transformer may include one secondary coil or multiple secondary coils arranged in series.

[0045] According to the embodiment of the present disclosure, Figure 3As shown, the transformer 200 includes two primary coils arranged in series and two secondary coils arranged in series, forming a transformer group including two transformers. The first oscillator 100 and the second oscillator 300 adopt a cross-coupled LC oscillator topology. The second oscillator is provided with a second switch 301; the control circuit 400 includes a feedback network 401, a non-overlapping circuit 402, and a short-circuit switch 403; the feedback network 401 is configured to detect a DC output voltage and generate a control signal; the non-overlapping circuit 402 is configured to receive the control signal and control the conduction and disconnection of the short-circuit switch 403 and the second switch 301.

[0046] Specifically, Figure 3 As shown, the first oscillator 100 converts the DC input voltage V IN Inverted into a differential high-frequency oscillation power signal V PP and V PN And output to the primary coil L of the transformer group 200 P1 and L P2 The transformer group 200 with symmetric primary and secondary windings is used as an isolation device for transmitting AC power. The primary winding and the secondary winding are composed of two identical windings. The identical windings are for the convenience of analysis, but are not limited to this. The coupling coefficient of the transformer is greater than 0.75. The first transformer is composed of a primary winding L P1 and the secondary coil L S1 In this example, L P1 With L S1 The same is for the convenience of analysis, but is not limited to this. The second transformer consists of a primary coil L P2 and the secondary coil L S2 In this example, L P2 With L S2 The same is for the convenience of analysis, but is not limited to this. P1 The high frequency oscillation power signal V PP Coupled to the secondary coil L S1 , so that V SP Follow V PP Oscillation, the second transformer will convert the primary coil L P2 The high frequency oscillation power signal V PN Coupled to the secondary coil L S2 , so that V SN Follow V PN Oscillation, so that the second oscillator 300 has a high oscillation power signal V SP and V SN With V PP and V PN oscillates together, and by virtue of port V SP and V SNThe high frequency oscillation power signal forms a DC common mode point at the center point of the transformer group 200, from which a DC output voltage is output. It should be noted that the second oscillator 300 is the same as the first oscillator circuit. The second oscillator 300 is the same as the first oscillator 100 for the convenience of analysis, and is not limited to being the same as the transmitting end circuit 100. The receiving end control circuit 400 detects the output voltage V ISO , and controls the state of the second oscillator; when the second oscillator oscillates, it affects the oscillation state of the first oscillator, and the transmitting end detection circuit 500 detects the working state of the first oscillator, thereby controlling the working state of the first oscillator to achieve voltage modulation.

[0047] According to the embodiment of the present disclosure, the first oscillator 100 includes a pair of NMOS transistors, the NMOS transistors including a first NMOS transistor M N1 and the second NMOS tube M N2 The first NMOS tube M N1 The gate of the second NMOS tube M N2 The drain stage of the second NMOS tube M N2 Connected to the first NMOS tube M N1 The drain of the first NMOS tube M N1 and the second NMOS tube M N2 The source of the first NMOS tube M is connected to one end of the switch, and the other end of the switch is grounded. N1 The drain of the transformer group 200 is connected to the TX port P , the second NMOS tube M N2 The drain of the transformer group 200 is connected to the TX port N .

[0048] According to the embodiment of the present disclosure, the second oscillator 300 includes a pair of NMOS transistors, the NMOS transistors including a third NMOS transistor M N3 and the fourth NMOS tube M N4 The third NMOS tube M N3 The gate of the fourth NMOS tube M N4 The drain stage of the fourth NMOS tube M N4 The gate of the third NMOS tube M N3 The third NMOS tube M N3 and the fourth NMOS tube M N4 The source of the third NMOS tube M is connected to one end of the switch, and the other end of the switch is grounded. N3 The drain of the transformer bank 200 is connected to the RX port P , the fourth NMOS tube M N4 The drain of the transformer bank 200 is connected to the RX port N .

[0049] According to the embodiment of the present disclosure, the receiving end control circuit 400 is composed of a feedback network 401, a non-overlapping circuit 402 and an oscillator short-circuit switch 403. The feedback network is used to detect the output voltage V ISO A control signal is generated and transmitted to the non-overlapping circuit 402. The function of the non-overlapping circuit 402 is to control the conduction and disconnection of the second switch 301 and the short-circuit switch 403, and to avoid the second switch 301 and the short-circuit switch 403 being turned on at the same time to cause a power short circuit.

[0050] According to an embodiment of the present disclosure, the first oscillator is provided with a first switch 101; the detection circuit 500 includes a level detection circuit 501, a frequency detection circuit 502, and a logic circuit 503, wherein: the level detection circuit 501 is used to detect the level change of the oscillation power signal of the first oscillator, and transmit the level detection result to the logic circuit 503; the frequency detection circuit 502 is used to detect the oscillation frequency of the oscillation power signal of the first oscillator, and transmit the frequency detection result to the logic circuit 503; the logic circuit 503 is configured to control the conduction and disconnection of the first switch 101 according to the level detection result and the frequency detection result, so as to control the opening and closing of the first oscillator 100.

[0051] According to the embodiment of the present disclosure, the level detection result is a high-low level signal transmitted to the logic circuit 503; the frequency detection result is a high-low level signal transmitted to the logic circuit 503. The level detection circuit 501 and the frequency detection circuit 502 can select to detect V in the two paths of the first oscillator. PP or V PN One of them, or you can choose to detect both at the same time.

[0052] According to the embodiment of the present disclosure, Figure 3 As shown, the transformer group 200 is composed of two transformers, wherein the primary coil L of the first transformer P1 The first port, TX P Connected to the first NMOS transistor M in the first oscillator 100 N1 The drain of the first transformer secondary coil L S1 The first port, RX P The third NMOS transistor M connected to the second oscillator 300 N3 The drain of the first transformer primary coil L P1 The second port is connected to the primary of the second transformer L P2 The first port of the transformer is connected to the DC common mode point port TX of the primary side of the transformer group. M , and the DC input voltage V of the isolated power chip IN The secondary coil L of the first transformer is connected. S1 The second port is connected to the second transformer secondary coil LS2 The first port is connected to the DC common mode point port RX of the secondary side of the transformer group. M , and the DC output voltage V of the isolated power chip ISO The second transformer primary coil L P2 The second port TX N The second NMOS transistor M connected to the first oscillator 100 N2 The drain of the second transformer secondary coil L S2 The second port RX N The fourth NMOS transistor M connected to the second oscillator 300 N4 The drain level.

[0053] Further, such as Figure 4 As shown, the first NMOS transistor M of the first oscillator 100 N1 The gate of the C1 Connected to the second NMOS tube M N2 The drain stage of the second NMOS tube M N2 The gate of the C2 Connected to the first NMOS tube M N1 The bias voltage V BN1 The first bias resistor R B1 Connected to the first NMOS tube M N1 The gate of the B2 Connected to the second NMOS tube M N2 The first coupling capacitor C C1 and the second coupling capacitor C C2 The two coupling capacitors respectively convert the differential signal V generated by the oscillator into PP and V PN Coupled to the second NMOS tube M N2 , the first NMOS tube M N1 The gate of the MOS tube has a coupling capacitance value equal to the parasitic capacitance C GG The ratio of determines the swing of the MOS tube gate voltage signal. Bias DC voltage V BN1 Through the feedback resistor R B1 , R B2 Set the gate common mode voltage of the NMOS in the oscillator to V BN1 .

[0054] According to the embodiment of the present disclosure, Figure 4 As shown, the third NMOS transistor M of the second oscillator 300 N3 The gate of the C3 Connected to the fourth NMOS tube M N4The drain stage of the fourth NMOS tube M N4 The gate of the C4 Connected to the third NMOS tube M N3 The bias voltage V BN2 The third bias resistor R B3 Connected to the third NMOS tube M N3 The gate of the B4 Connected to the fourth NMOS tube M N4 The third coupling capacitor C C3 and the fourth coupling capacitor C C4 The differential signal V generated by the oscillator is SP and V SN Coupled to the fourth NMOS tube M N4 , the third NMOS tube M N3 The gate of the MOS tube has a coupling capacitance value equal to the parasitic capacitance C GG The ratio of determines the swing of the MOS tube gate voltage signal. Bias DC voltage V BN2 Through the feedback resistor R B3 , R B4 Set the gate common mode voltage of the NMOS in the oscillator to V BN2 .

[0055] According to the embodiment of the present disclosure, Figure 5 As shown in the figure, when the isolated power chip starts working, the working principle of the isolated power system is divided into two phases for description, and each phase includes 5 states:

[0056] In the first phase:

[0057] State ①: The first NMOS tube M N1 And the third NMOS tube M N3 The first transformer primary L is turned on. P1 Current I LP1 is a positive value, that is, V IN Flows to GND1 and gradually increases; the secondary of the first transformer L S1 Current I LS1 is negative, that is, it flows from GND2 to V ISO The second NMOS tube M N2 With the fourth NMOS tube M N4 Turn off, the second transformer primary L P2 Current I LP2 is a positive value, that is, V IN flows to GND1 and gradually increases, V PN Less than V IN And gradually increases. The second transformer secondary L S2Current I LS2 is a positive value, that is, V ISO flows to GND2 and gradually increases, V SN Less than V ISO And gradually increase.

[0058] State ②: First NMOS tube M N1 And the third NMOS tube M N3 The first transformer primary L is turned on. P1 Current I LP1 is a positive value, that is, V IN Flows to GND1 and gradually increases; the secondary of the first transformer L S1 Current I LS1 is negative, that is, it flows from GND2 to V ISO The second NMOS tube M N2 With the fourth NMOS tube M N4 Turn off, the second transformer primary L P2 Current I LP2 is a positive value, that is, V IN flows to GND1 and gradually decreases, V PN Greater than V IN And gradually increases. The second transformer secondary L S2 Current I LS2 is a positive value, that is, V ISO flows to GND2 and decreases first and then increases, V SN Greater than V ISO And gradually increase.

[0059] State ③: The first NMOS tube M N1 And the third NMOS tube M N3 The first transformer primary L is turned on. P1 Current I LP1 is a positive value, that is, V IN Flows to GND1 and gradually increases; the secondary of the first transformer L S1 Current I LS1 is negative, that is, it flows from GND2 to V ISO The second NMOS tube M N2 With the fourth NMOS tube M N4 Turn off, the second transformer primary L P2 Current I LP2 is a positive value, that is, V IN flows to GND1 and gradually decreases, V PN Greater than V IN And gradually increases. The second transformer secondary L S2 Current I LS2 is negative, that is, it flows from GND2 to V ISO And gradually increases, VSN Greater than V ISO And gradually decreases.

[0060] State ④: First NMOS tube M N1 And the third NMOS tube M N3 The first transformer primary L is turned on. P1 Current I LP1 is a positive value, that is, V IN Flows to GND1 and gradually increases; the secondary of the first transformer L S1 Current I LS1 is negative, that is, it flows from GND2 to V ISO The second NMOS tube M N2 With the fourth NMOS tube M N4 Turn off, the second transformer primary L P2 Current I LP2 is negative, that is, it flows from GND1 to V IN And gradually increases, V PN Greater than V IN And gradually decreases. The second transformer secondary L S2 Current I LS2 is negative, that is, it flows from GND2 to V ISO And it increases first and then decreases, V SN Greater than V ISO And gradually decreases.

[0061] State ⑤: First NMOS tube M N1 And the third NMOS tube M N3 The first transformer primary L is turned on. P1 Current I LP1 is a positive value, that is, V IN Flows to GND1 and gradually increases; the secondary of the first transformer L S1 Current I LS1 is negative, that is, it flows from GND2 to V ISO The second NMOS tube M N2 With the fourth NMOS tube M N4 Turn off, the second transformer primary L P2 Current I LP2 is negative, that is, it flows from GND1 to V IN And gradually increases, V PN Less than V IN And gradually decreases. The second transformer secondary L S2 Current I LS2 is negative, that is, it flows from GND2 to V ISO And gradually increases, V SN Less than V ISO And gradually decreases.

[0062] In the first phase, the first transformer secondary winding L S1 Current I LS1 is negative, that is, it flows from GND2 to V ISO , so it can be V ISO Transmit energy.

[0063] In the second phase, the first NMOS tube M N1 And the third NMOS tube M N3 Turn off, the second NMOS tube M N2 and the fourth NMOS tube M N4 The working states ①-⑤ are similar to those of the first phase. In the second phase, the second transformer secondary coil L S2 Current I LS2 is negative, that is, it flows from GND2 to V ISO , so it can be V ISO Transmit energy.

[0064] The working principle of the receiving end control circuit 400 and the transmitting end detection circuit 500 is as follows: Figure 6 As shown:

[0065] The isolated power system is turned on and off: When the feedback network 401 detects the voltage and generates a shutdown signal, the non-overlapping circuit 402 receives the shutdown signal and first turns on the signal EN. RX From high to low, the second switch 301 is disconnected, and then the short-circuit switch 403 is turned on to short-circuit the second oscillator 300, which will change the oscillation frequency of the first oscillator 100. At this time, the transmitter frequency detection circuit 502 detects the change in the oscillation frequency of the first oscillator 100 and outputs the signal EN of the logic circuit 503. TX From high to low, the first oscillator first switch 301 is disconnected, thereby shutting down the entire isolated power supply chip.

[0066] The isolated power system switches from off to on: When the receiving end control circuit 400 detects the voltage and generates an on signal, the non-overlapping circuit 402 first disconnects the short-circuit switch 403 after receiving the on signal, and then turns on the signal EN. RX From low to high, the second switch 301 is turned on, and the second oscillator 300 starts to oscillate. S The high frequency oscillation power signal V SP and V SN Coupled to the primary coil L P , so that V PP and V PN Oscillation, the oscillating voltage signal is detected by the level detection circuit 501, and the output signal EN of the logic circuit 503 is TX The signal changes from low to high, turning on the first switch 301 of the first oscillator, thereby turning on the entire isolated power supply chip.

[0067] Another aspect of the present disclosure also provides a control method for an isolated power supply chip based on a dual resonance topology, which controls the above-mentioned isolated power supply chip, such as Figure 7 As shown, the control method includes:

[0068] Operation S1: inverting the DC input voltage into a high-frequency oscillation power signal to enable the first oscillator to operate in a first oscillation state;

[0069] Operation S2: coupling and transmitting the high-frequency oscillation power signal to the secondary coil through the primary coil of the transformer, so that the second oscillator operates in a second oscillation state and obtains a DC output voltage;

[0070] Operation S3: detecting the DC output voltage and regulating the second oscillation state;

[0071] Operation S4: detecting the first oscillation state to determine the influence of the second oscillation state on the first oscillation state, and adjusting the first oscillation state in real time to achieve stable operation of the isolated power supply.

[0072] So far, the embodiments of the present disclosure have been described in detail in conjunction with the accompanying drawings. It should be noted that the implementation methods not shown or described in the drawings or the body of the specification are all forms known to ordinary technicians in the relevant technical field and are not described in detail. In addition, the above definitions of each element and method are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and ordinary technicians in the field can simply change or replace them.

[0073] Based on the above description, those skilled in the art should have a clear understanding of the isolated power supply chip based on the dual resonance topology and the control method thereof disclosed in the present invention.

[0074] In summary, the present disclosure provides an isolated power supply chip based on a dual-resonance topology and a control method thereof, which effectively improves the conversion efficiency of the isolated power supply system by introducing a more efficient Class D oscillator at the receiving end to replace the traditional inefficient AC-DC rectifier to receive energy. Moreover, compared with the traditional isolated power supply chip in which the transmitting and receiving circuits need to be developed separately, the transmitting and receiving circuits of the isolated power supply chip based on this architecture can be reused, reducing the design and development cost of the isolated power supply. In combination with the power control method proposed by the system architecture of the isolated power supply chip based on the dual-resonance topology to transmit the feedback signal by reusing the power transformer, compared with the traditional isolated power supply chip, the digital isolator circuit is saved, the chip size is reduced, and the cost is reduced.

[0075] It should be noted that, in this document, unless otherwise specified, “a” element is not limited to a single element, but may include one or more elements.

[0076] In addition, in this document, unless otherwise specified, ordinal numbers such as "first" and "second" are only used to distinguish multiple components with the same name, and do not indicate that there is a hierarchy, level, execution order, or process order between them. A "first" component and a "second" component may appear together in the same component, or appear in different components. The presence of a component with a larger ordinal number does not necessarily indicate the presence of another component with a smaller ordinal number.

[0077] In this document, unless otherwise specified, the so-called feature A "or" or "and / or" (and / or) feature B means that A exists alone, B exists alone, or A and B exist at the same time; the so-called feature A "and" (and) or "and" (and) or "and" (and) feature B means that A and B exist at the same time; the so-called "include", "comprise", "have" and "contain" mean including but not limited to these.

[0078] In addition, in this document, the terms "upper", "lower", "left", "right", "front", "back", or "between" are only used to describe the relative positions between multiple elements, and can be extended to include translation, rotation, or mirroring. In addition, in this document, unless otherwise specified, "an element is on another element" or similar descriptions do not necessarily mean that the element contacts the other element.

[0079] In addition, unless the steps are specifically described or must occur in sequence, the order of the above steps is not limited to the above list, and can be changed or rearranged according to the required design. And the above embodiments can be mixed and matched with each other or with other embodiments based on design and reliability considerations, that is, the technical features in different embodiments can be freely combined to form more embodiments.

[0080] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above description is only a specific embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. An isolated power supply chip based on a dual-resonance topology, comprising a first oscillator, a transformer, a second oscillator, a control circuit, and a detection circuit; the transformer comprises a primary coil connected to the first oscillator and a secondary coil connected to the second oscillator, wherein: The first oscillator is used to invert the DC input voltage into a high-frequency oscillation power signal, so that the first oscillator works in a first oscillation state; The second oscillator operates in a second oscillation state after receiving the high-frequency oscillation power signal coupled and transmitted from the primary coil to the secondary coil, and obtains a DC output voltage; The control circuit is used to detect the DC output voltage and regulate the second oscillation state; The detection circuit is used to detect the first oscillation state to determine the influence of the second oscillation state on the first oscillation state, and to adjust the first oscillation state in real time to achieve stable operation of the isolated power supply.

2. According to the isolated power supply chip based on dual resonance topology described in claim 1, the control circuit is also used to control the second oscillator to be turned on or short-circuited, and the detection circuit is also used to control the first oscillator to be turned on or off, so that the isolated power supply can be turned on or off by cooperating with the control circuit and the detection circuit.

3. According to the isolated power supply chip based on dual resonance topology as described in claim 2, from the on state to the off state, the control circuit controls the second oscillator to short-circuit, and the detection circuit controls the first oscillator to shut down by detecting the change in the oscillation frequency of the first oscillator, thereby realizing the shutdown of the isolated power supply.

4. According to the isolated power supply chip based on dual resonance topology described in claim 2, from the off state to the on state, the control circuit controls the second oscillator to work, and the detection circuit controls the first oscillator to start by detecting that the first oscillator is affected by the second oscillator to generate oscillation, thereby realizing the start-up of the isolated power supply.

5. According to any one of claims 1 to 4, the isolated power supply chip based on dual resonance topology is provided with a second switch; the control circuit comprises a feedback network, a non-overlapping circuit, and a short-circuit switch, wherein: a feedback network configured to detect a DC output voltage and generate a control signal; The non-overlapping circuit receives the control signal and controls the on and off of the short-circuit switch and the second switch.

6. According to any one of claims 1 to 4, the isolated power supply chip based on the dual resonance topology is provided with a first switch; the detection circuit comprises a level detection circuit, a frequency detection circuit, and a logic circuit, wherein: The level detection circuit is used to detect the level change of the oscillation power signal of the first oscillator and transmit the level detection result to the logic circuit; The frequency detection circuit is used to detect the oscillation frequency of the oscillation power signal of the first oscillator and transmit the frequency detection result to the logic circuit; The logic circuit is configured to control the on and off of the first switch according to the level detection result and the frequency detection result, so as to control the on and off of the first oscillator.

7. According to the isolated power supply chip based on dual resonance topology according to any one of claims 1 to 4, the first oscillator and / or the second oscillator adopts a cross-coupled LC oscillator topology structure, or adopts a switch full-bridge driver topology structure.

8. According to the isolated power supply chip based on dual resonance topology according to any one of claims 1-4, the transformer includes a primary coil or includes multiple primary coils arranged in series, and correspondingly, the transformer includes a secondary coil or includes multiple secondary coils arranged in series.

9. According to the isolated power chip based on dual resonance topology according to any one of claims 1 to 4, the coupling coefficient of the transformer is greater than 0.

75.

10. A control method for an isolated power chip based on a dual resonance topology, controlling the isolated power chip according to any one of claims 1 to 9, the control method comprising: Inverting the DC input voltage into a high-frequency oscillation power signal to enable the first oscillator to operate in a first oscillation state; The high-frequency oscillation power signal is coupled and transmitted to the secondary coil through the primary coil of the transformer, so that the second oscillator operates in a second oscillation state and obtains a DC output voltage; Detecting the DC output voltage and regulating the second oscillation state; as well as The first oscillation state is detected to determine the influence of the second oscillation state on the first oscillation state, and the first oscillation state is adjusted in real time to achieve stable operation of the isolated power supply.

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