Switching power supply integrated circuit

Abstract

The invention provides a switching power supply integrated circuit integrated with a power grid voltage zero-cross detection function. The switching power supply integrated circuit comprises a zero-crossing detection circuit which is manufactured in a first wafer and is used for detecting a zero-crossing point of power grid voltage and outputting a zero-crossing detection signal through a zero-crossing signal output pin; the power switch tube is manufactured in the second wafer, and the output voltage of the switch power supply integrated circuit is controlled by controlling the switch-on and switch-off of the power switch tube; and the fly-wheel diode is manufactured in the third wafer, the fly-wheel diode is coupled with the power switch tube, a switch node pin is formed at a coupling point, and the switch node pin is used for being coupled with an inductor to form a buck type Buck circuit or a buck-boost type Buck-Boost circuit. The switching power supply integrated circuit provided by the invention has the advantages of high integration level, high zero-cross detection precision, low system cost, simplicity in use and the like.

Description

Technical Field

[0001] The present invention relates to the field of electronics, and in particular but not limited to a switching power supply integrated circuit. Background Art

[0002] In application fields such as kitchen appliances, environmental appliances, and nursing appliances, non-isolated ACDC power supplies are commonly used to provide auxiliary power for system boards. The non-isolated ACDC power supplies are usually Buck topology or Buck-Boost topology. Figure 1 A typical step-down (Buck) non-isolated ACDC power supply system is shown, which uses an integrated circuit 10 to form a Buck topology. The rectifier circuit 11 rectifies the grid AC voltage VAC into a DC voltage source. The power switch, rectifier tube D1, and inductor L in the integrated circuit 10 form a Buck circuit for converting the DC voltage source into a target output voltage Vo.

[0003] In such an ACDC power supply system, the zero-crossing detection of the grid AC voltage VAC can have important application value, including but not limited to thyristor on-off control, relay on-off control, grid voltage frequency detection, MCU timing, etc.

[0004] The grid voltage zero-crossing detection circuit can usually be completed using discrete devices. Figure 2 A zero-crossing detection circuit composed of discrete devices is shown. However, the use of discrete devices to build a zero-crossing detection circuit is affected by the errors of various components, and the accuracy of the zero-crossing detection signal is poor. The poor accuracy is mainly reflected in the large time delay between the level jump edge of the zero-crossing detection signal and the zero-crossing point of the grid voltage, such as Figure 3 As shown in the figure, the time delay Tzero_de l ay of the zero-crossing detection signal is usually greater than +-50us. In addition, due to the low integration of discrete devices, the material cost of the circuit and the processing costs such as patch are high. The integrated zero-crossing detection circuit also has the disadvantages of complex electrical isolation between high and low voltage areas, high cost, and more pins.

[0005] In view of this, it is necessary to provide a new structure or control method to solve at least part of the above problems. Summary of the invention

[0006] To address at least one or more problems in the background technology, the present invention provides a switching power supply integrated circuit.

[0007] The switching power supply integrated circuit includes: a zero-crossing detection circuit, which is made in the first chip, and is used to detect the zero-crossing point of the grid voltage and output a zero-crossing detection signal through a zero-crossing signal output pin; a power switch tube, which is made in the second chip, and controls the output voltage of the switching power supply integrated circuit by controlling the on and off of the power switch tube; and a freewheeling diode, which is made in the third chip, and is coupled to the power switch tube and forms a switch node pin at the coupling point, and the switch node pin is used to couple an inductor to form a buck-type Buck circuit or a buck-boost type Buck-Boost circuit.

[0008] Optionally, the zero-crossing detection circuit includes: a control signal generating circuit, used to obtain a signal representing the grid voltage value and generate a zero-crossing detection control signal; a pull-up resistor, a first end of which is coupled to a voltage source; and an open-circuit switch tube, a control end of which is coupled to the output end of the control signal generating circuit, a first end of the open-circuit switch tube is coupled to the second end of the pull-up resistor and the zero-crossing signal output pin, and a second end of the open-circuit switch tube is grounded.

[0009] Optionally, the open-circuit switch tube includes an N-type metal oxide semiconductor field effect transistor (MOSFET), a drain of the MOSFET is coupled to a pull-up resistor and outputs a zero-crossing detection signal, and a source of the MOSFET is grounded.

[0010] Optionally, the open-circuit switch tube includes a PNP-type transistor, wherein the collector of the transistor is coupled to a pull-up resistor and outputs a zero-crossing detection signal, and the emitter of the transistor is grounded.

[0011] Optionally, the zero-crossing detection signal is a high-low level signal, and when it is detected that the grid voltage crosses zero, the level of the zero-crossing detection signal is switched.

[0012] Optionally, the zero-crossing detection signal is a pulse signal, and when it is detected that the grid voltage crosses zero, the zero-crossing detection signal outputs a high-level pulse or a low-level pulse.

[0013] Optionally, the switching power supply integrated circuit further includes a first rectifier diode, which is manufactured in a fourth chip, wherein an anode of the first rectifier diode is coupled to a grid input pin, and a cathode of the first rectifier diode is coupled to an input end of the zero-crossing detection circuit.

[0014] Optionally, the switching power supply integrated circuit further includes a second rectifier diode, which is fabricated in a fifth chip, wherein an anode of the second rectifier diode is coupled to a cathode of the first rectifier diode, and a cathode of the second rectifier diode is coupled to a bus pin.

[0015] Optionally, in a switching power supply integrated circuit, a bus pin is coupled to an input end of a power switch tube.

[0016] Optionally, a control circuit is further manufactured in the second chip to control the on and off of the power switch tube.

[0017] Optionally, the switching power supply integrated circuit further includes a power supply diode, an anode of the power supply diode is coupled to the output feedback pin, and a cathode of the power supply diode is coupled to the power supply pin.

[0018] Optionally, the output feedback pin is coupled to a power supply terminal of a zero-crossing detection circuit.

[0019] The switching power supply integrated circuit proposed by the present invention has the advantages of high integration, improved zero-crossing detection accuracy, low system cost, simple use, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present invention and are used together with the description to explain the embodiments of the present invention, but do not constitute a limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 A typical buck-type non-isolated ACDC power supply system is shown;

[0022] Figure 2 A zero-crossing detection circuit composed of discrete devices is shown;

[0023] Figure 3 The zero-crossing detection signal waveform diagram in the prior art is shown;

[0024] Figure 4 A switching power supply integrated circuit with a grid voltage zero-crossing detection function according to an embodiment of the present invention is shown;

[0025] Figure 5 A Buck switching power supply system according to an embodiment of the present invention is shown;

[0026] Figure 6 A Buck-Boost switching power supply system according to an embodiment of the present invention is shown;

[0027] Figure 7 shows a zero-crossing detection signal waveform diagram according to an embodiment of the present invention;

[0028] Figure 8 shows a zero-crossing detection signal waveform diagram according to another embodiment of the present invention;

[0029] Fig. 9 shows a zero-crossing detection signal waveform diagram according to another embodiment of the present invention;

[0030] Fig.10 A zero-crossing detection circuit according to an embodiment of the present invention is shown;

[0031] Fig.11 A zero-crossing detection circuit according to an embodiment of the present invention is shown;

[0032] Fig.12 A switching power supply integrated circuit according to another embodiment of the present invention is shown;

[0033] Fig.13 A schematic diagram of the internal structure of an electronic packaging device for a switching power supply integrated circuit according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0034] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0035] The description in this section is only for several typical embodiments, and the present invention is not limited to the scope of the embodiments. The combination of different embodiments, the mutual replacement of some technical features in different embodiments, and the mutual replacement of the same or similar prior art means with some technical features in the embodiments are also within the scope of the description and protection of the present invention.

[0036] "Coupled" or "connected" in the specification includes both direct connection and indirect connection. Indirect connection is a connection through an intermediate medium, such as a connection through an electrical conductive medium such as a conductor, wherein the electrical conductive medium may contain parasitic inductance or parasitic capacitance, or a connection through an intermediate circuit or component described in the embodiments of the specification; indirect connection may also include a connection through other active or passive devices on the basis of achieving the same or similar functions. "Multiple" or "many" means two or more.

[0037] Figure 4 The switching power supply integrated circuit 100 with an integrated grid voltage zero-crossing detection function according to an embodiment of the present invention is shown. The switching power supply integrated circuit 100 includes: a rectifier circuit 41, a zero-crossing detection circuit 42, a power switch tube 43, a control circuit 44 and a freewheeling diode 45. The rectifier circuit 41 includes a first rectifier diode M1 and a second rectifier diode M2 ​​connected in series. The anode of the first rectifier diode M1 is coupled to the grid input pin L of the switching power supply integrated circuit 100 for receiving the AC mains voltage, the cathode of the first rectifier diode M1 is coupled to the anode of the second rectifier diode M2, and the cathode of the second rectifier diode M2 ​​is coupled to the bus pin BUS for providing the bus voltage. By using the structure of the rectifier circuit 41 in the illustrated embodiment, the bus voltage can be obtained more conveniently and zero-crossing detection can be performed. The zero-crossing detection circuit 42 is coupled to the cathode of the first rectifier diode M1 to detect the zero-crossing point of the grid AC voltage, and outputs a zero-crossing detection signal at the zero-crossing signal output pin Zero of the switching power supply integrated circuit 100. In other embodiments, the rectifier circuit may have other forms, such as Figure 1The rectifier circuit shown, or the rectifier circuit includes only one diode M1 without a second diode. In another embodiment, the switching power supply integrated circuit may not include a rectifier circuit, but the bus pin BUS and / or the zero-crossing detection pin are directly coupled to the external circuit. The input end of the power switch tube 43 is coupled to the bus pin BUS. The control circuit 44 obtains the output voltage Vout feedback signal of the switching circuit from the output feedback pin Vo of the switching power supply integrated circuit 100, and controls the conduction and shutdown of the power switch tube 43 based on the output voltage Vout. The cathode of the freewheeling diode is coupled to the source of the power switch tube 43 and forms the switch node pin ICG of the switching power supply integrated circuit 100 at the coupling point. The anode of the freewheeling diode is coupled to the reference ground pin GND of the switching power supply integrated circuit 100. Preferably, the rectifier circuit 41, the zero-crossing detection circuit 42, the power switch tube 43 and the freewheeling diode 45 are made on different semiconductor substrates, that is, made in different semiconductor chips, and multiple chips are made in the same electronic package through a multi-chip packaging process to form an electronic package device or an integrated circuit. This is beneficial to solving the problem of electrical isolation between the high voltage area and the low voltage area, and at the same time, the integrated circuit 100 has a higher integration and fewer external pins. The zero-crossing detection circuit 42 is made in the first chip, the power switch tube 43 is made in the second chip, and the freewheeling diode 45 is made in the third chip. The control circuit 44 can also be further made in the second chip to control the conduction and shutdown of the power switch tube 43.

[0038] Figure 5 FIG. 2 shows a Buck switching power supply system 200 according to an embodiment of the present invention. The switching power supply integrated circuit 50 in the switching power supply system 200 can be used as Figure 4 The switching power supply integrated circuit 100 with integrated grid voltage zero-crossing detection function shown can be configured as a Buck topology, which is used to convert the grid voltage VAC into a stable DC output voltage Vout. The DC output voltage can be controlled to 3.3V, 5V, 12V, 15V or 18V, etc. The switching power supply system 200 includes an input capacitor Cin, a switching power supply integrated circuit 50, an inductor L1 and an output capacitor Cout. The grid input pin L of the switching power supply integrated circuit 50 is coupled to the first input terminal L of the AC grid, the reference ground pin GND is coupled to the second input terminal N of the AC grid, and the AC input power VAC is connected between the grid input pin L and the reference ground pin GND. The bus pin is coupled to the input capacitor Cin for stabilizing the input voltage. The switch node pin ICG is coupled to the first end of the inductor L1, and the second end of the inductor L1 is the output end of the Buck circuit for providing the output voltage Vout and can be coupled to the output feedback pin Vo.

[0039] Figure 6FIG. 3 shows a Buck-Boost switching power supply system 300 according to an embodiment of the present invention. The switching power supply integrated circuit 60 in the switching power supply system 300 may also be Figure 4 The switching power supply integrated circuit 100 with integrated grid voltage zero-crossing detection function can be configured as a Buck-Boost topology to convert the grid voltage VAC into a stable DC output voltage Vout. The DC output voltage Vout can be less than the average value of the DC rectified voltage of VAC, or higher than the average value of the DC rectified voltage of VAC. Figure 5 In comparison, the output feedback pin Vo of the switching power supply integrated circuit 60 is coupled to the second input terminal N of the AC power grid, and the AC input power VAC is connected between the grid input pin L and the output feedback pin Vo. The input capacitor Cin is coupled between the bus pin BUS and the output feedback pin Vo for stabilizing the input voltage. The switch node pin ICG is coupled to the first end of the inductor L1, and the second end of the inductor L1 is the first output end of the Buck-Boost circuit. The reference ground pin GND is used as the second output end of the Buck-Boost circuit to provide the output voltage Vout. The zero-crossing signal output pin Zero provides a zero-crossing detection signal Vzero.

[0040] Figure 7 FIG. 2 shows a waveform diagram of a zero-crossing detection signal Vzero according to an embodiment of the present invention. When the grid voltage, ie, the AC input voltage VAC, crosses zero, the zero-crossing detection signal Vzero presents a high level pulse.

[0041] Figure 8 FIG. 2 shows a waveform diagram of a zero-crossing detection signal Vzero according to another embodiment of the present invention. When the AC input voltage VAC crosses zero, the zero-crossing detection signal Vzero presents a low-level pulse.

[0042] Fig. 9 FIG. 2 shows a waveform diagram of a zero-crossing detection signal Vzero according to another embodiment of the present invention. The zero-crossing detection signal Vzero is a high-low level signal. When the grid voltage VAC is detected to be zero-crossing, the level of the zero-crossing detection signal Vzero is switched.

[0043] Fig.10A zero-crossing detection circuit 400 according to an embodiment of the present invention is shown. The output end of the zero-crossing detection circuit 400 can be open-circuit controlled. The zero-crossing detection circuit 400 includes a control signal generating circuit 101 for performing zero-crossing detection, a pull-up resistor R1, and an open-circuit switch tube K1. The control signal generating circuit 101 is used to obtain a signal representing the voltage value of the power grid and generate a zero-crossing detection control signal Vzt. The first end of the pull-up resistor R1 is coupled to the voltage source Vcc, the control end of the open-circuit switch tube K1 is coupled to the output end of the control signal generating circuit 101, the first end of the open-circuit switch tube K1 is coupled to the second end of the pull-up resistor R1 and the zero-crossing signal output pin Zero, and the second end of the open-circuit switch tube K1 is grounded. Preferably, the open-circuit switch tube K1 includes an N-type metal oxide semiconductor field effect tube (MOSFET), the drain of the MOSFET is coupled to the pull-up resistor R1 and outputs the zero-crossing detection signal, and the source of the MOSFET is grounded.

[0044] Fig.11 FIG. 5 shows a zero-crossing detection circuit 500 according to an embodiment of the present invention. Fig.10 Compared with the zero-crossing detection circuit 400 shown in FIG. 1 , the open-circuit switch in the zero-crossing detection circuit 500 may be an NPN transistor K2 , wherein the collector of the transistor K2 is coupled to the pull-up resistor R2 and outputs a zero-crossing detection signal, and the emitter of the transistor K2 is grounded.

[0045] In one embodiment, the zero-crossing detection signal provided by the switching power supply integrated circuit of the present invention has high consistency and a delay time of less than 25 us, which greatly improves the accuracy.

[0046] Fig.12 FIG. 6 shows a switching power supply integrated circuit 600 according to another embodiment of the present invention. Figure 4 Compared with the switching power supply integrated circuit 100 in the embodiment of the present invention, the switching power supply integrated circuit 600 further has a power supply pin VDD and includes a power supply diode M3. The anode of the power supply diode M3 is coupled to the output feedback pin Vo, and the cathode of the power supply diode M3 is coupled to the power supply pin VDD. In this way, the switching power supply system can power the chip in the integrated circuit through the output voltage Vout.

[0047] Fig.13The internal structure schematic diagram of an electronic package device 700 for a switching power supply integrated circuit according to an embodiment of the present invention is shown. The electronic package device 700 includes six chips 71-76 and five base islands 701-705, and has seven pins. The pins are used to connect to the outside, including a power grid input pin L, a bus pin BUS, a reference ground pin GND, a switch node pin ICG, a zero-crossing signal output pin Zero, an output feedback pin Vo and a power supply pin VDD. The first chip 71 includes a zero-crossing detection circuit, the first chip 71 is arranged on the first base island 701, and a part of the first base island 701 extends outward to expose the electronic package device to form a reference ground pin GND. The zero-crossing signal output pin Zero and the first chip 71 are bonded and coupled by conductive electrical leads to output a zero-crossing detection signal; a power switch tube is made on the second chip 72, and a freewheeling diode is made on the third chip 73. The second chip 72 and the third chip 73 are arranged on the second base island 702, and a part of the second base island 702 extends outward to expose the electronic package device to form a switch node pin ICG. The anode of the freewheeling diode on the third chip 73 is coupled to the first base island 702 through a conductive lead for coupling to the reference ground pin GND, and the cathode of the freewheeling diode is located on the back of the third chip 73, and is coupled to the switch node pin ICG by bonding the second base island 702. In the illustrated embodiment, the second chip 72 includes a power switch tube and a control circuit for controlling the power switch tube, and the output end of the power switch tube is coupled to the second base island through a conductive lead. The fourth chip 74 is made with a first rectifier diode and is arranged on the third base island 703. A portion of the third base island extends outward to expose the electronic packaging device to form a grid input pin L. The anode of the first rectifier diode (the back of the fourth chip 74 shown in the figure) is bonded and coupled to the third base island 703 for coupling to the grid input pin L, receiving the AC grid input signal, and the cathode of the first rectifier diode is coupled to the input end of the zero-crossing detection circuit in the first chip 71 through a conductive lead. A second rectifier diode is made on the fifth chip 75 and is arranged on the fourth base island 704. A portion of the fourth base island 704 extends outward to expose the electronic packaging device to form a bus pin BUS. The anode of the second rectifier diode is coupled to the cathode of the first rectifier diode through a conductive lead, and the cathode of the second rectifier diode is attached to and coupled to the fourth base island 704 for coupling to the bus pin BUS.

[0048] In another embodiment, the power switch tube is made in the seventh chip and placed on the fourth base island 704. The seventh chip is used to couple the bus pin BUS by bonding the fourth base island 704, and is respectively coupled to the second chip 72 containing the control circuit for obtaining the control signal and the second base island 702 for coupling the switch node pin ICG through conductive leads. The fourth base island 704 is coupled to the input end of the power switch tube on the second chip 72 through conductive leads. In another embodiment, the electronic packaging device does not include the fifth chip 75, and the cathode of the first rectifier diode in the fourth chip 74 is coupled to the fourth base island 704 through conductive leads for direct coupling to the bus pin BUS.

[0049] A power supply diode is fabricated on the sixth chip 76 and is disposed on the fifth base island 705, wherein a portion of the fifth base island extends outward to expose the electronic package device to form an output feedback pin Vo, the anode of the power supply diode is attached and coupled to the fifth base island for coupling to the output end of the switching power supply system through the output feedback pin Vo to obtain the output voltage, and the cathode of the power supply diode on the sixth chip 76 is coupled to the power supply pin VDD through a conductive lead to provide power supply for the chip in the electronic package device 700. In one embodiment, the power supply pin VDD is externally connected to a capacitor. In another embodiment, the capacitor is built into the electronic package device, and the electronic package device may not have a power supply pin. The power supply pin VDD is coupled to the second chip 72 through a conductive lead to power the second chip 72. The fifth base island 705 is further coupled to the power supply end of the first chip 71 through a conductive lead, and the output voltage is used to directly power the zero-crossing detection chip. In another embodiment, the power supply pin VDD is further coupled to the first chip 71 through a conductive lead to power the first chip.

[0050] In another embodiment, the electronic package device includes only four chips 71 - 73 and 76 and three base islands 701 , 702 and 705 , but does not include the first rectifying diode and the second rectifying diode, and the bus pin BUS directly obtains the bus voltage from the external circuit.

[0051] The description and application of the present invention here are illustrative, and it is not intended to limit the scope of the present invention to the above-mentioned embodiments. The effects or advantages involved in the specification may not be reflected in the actual experimental examples due to the uncertainty of specific condition parameters or other factors, and the effects or advantages are not used to limit the scope of the invention. The deformation and change of the embodiments disclosed here are possible, and the replacement of the embodiments and the various equivalent parts are well known to those of ordinary skill in the art. It should be clear to those skilled in the art that the present invention can be implemented in other forms, structures, arrangements, proportions, and with other components, materials and parts without departing from the spirit or essential features of the present invention. Other deformations and changes can be made to the embodiments disclosed here without departing from the scope and spirit of the present invention.

Claims

1. A switching power supply integrated circuit with an integrated grid voltage zero-crossing detection function, comprising: A zero-crossing detection circuit is manufactured in the first chip, and is used to detect the zero-crossing point of the grid voltage and output a zero-crossing detection signal through a zero-crossing signal output pin; A power switch tube is manufactured in the second wafer, and controls the output voltage of the switching power supply integrated circuit by controlling the on and off of the power switch tube; as well as A freewheeling diode is manufactured in the third chip. The freewheeling diode is coupled to the power switch tube and forms a switch node pin at the coupling point. The switch node pin is used to couple the inductor to form a step-down Buck circuit or a step-up / step-down Buck-Boost circuit.

2. The switching power supply integrated circuit as claimed in claim 1 further comprises a first rectifier diode, which is fabricated in a fourth chip, wherein an anode of the first rectifier diode is coupled to a grid input pin, and a cathode of the first rectifier diode is coupled to an input end of the zero-crossing detection circuit.

3. The switching power supply integrated circuit as described in claim 2 further includes a second rectifier diode, which is fabricated in the fifth chip, wherein the anode of the second rectifier diode is coupled to the cathode of the first rectifier diode, and the cathode of the second rectifier diode is coupled to the bus pin. 4 . The switching power supply integrated circuit as claimed in claim 3 , wherein the bus pin is coupled to the input end of the power switch tube.

5. The switching power supply integrated circuit as claimed in claim 1, wherein the zero-crossing detection circuit comprises: A control signal generating circuit is used to obtain a signal representing a grid voltage value and generate a zero-crossing detection control signal; A pull-up resistor, a first end of which is coupled to a voltage source; as well as The open-circuit switch tube has a control end coupled to the output end of the control signal generating circuit, a first end of the open-circuit switch tube coupled to the second end of the pull-up resistor and the zero-crossing signal output pin, and a second end of the open-circuit switch tube grounded.

6. The switching power supply integrated circuit as claimed in claim 5, wherein the open-circuit switch tube comprises an N-type metal oxide semiconductor field effect transistor (MOSFET), a drain of the MOSFET is coupled to a pull-up resistor and outputs a zero-crossing detection signal, and a source of the MOSFET is grounded.

7. The switching power supply integrated circuit as claimed in claim 5, wherein the open-circuit switch tube comprises a PNP-type transistor, wherein the collector of the transistor is coupled to a pull-up resistor and outputs a zero-crossing detection signal, and the emitter of the transistor is grounded.

8. The switching power supply integrated circuit as claimed in claim 1, wherein the zero-crossing detection signal is a high-low level signal, and when it is detected that the grid voltage crosses zero, the level of the zero-crossing detection signal switches.

9. The switching power supply integrated circuit as claimed in claim 1, wherein the zero-crossing detection signal is a pulse signal, and when it is detected that the grid voltage crosses zero, the zero-crossing detection signal outputs a high-level pulse or a low-level pulse.

10. The switching power supply integrated circuit as claimed in claim 1, wherein a control circuit is further manufactured in the second chip to control the on and off of the power switch tube. 11 . The switching power supply integrated circuit as claimed in claim 1 , further comprising a power supply diode, an anode of the power supply diode is coupled to the output feedback pin, and a cathode of the power supply diode is coupled to the power supply pin. 12 . The switching power supply integrated circuit as claimed in claim 11 , wherein the output feedback pin is coupled to a power supply terminal of the zero-crossing detection circuit.

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