Eight-path isolation RS-422 / RS-485 signal conversion device based on SiP packaging

Abstract

The invention relates to an eight-channel isolation RS-422 / RS-485 signal conversion device based on SiP packaging, according to the signal conversion device, an isolation power supply and a plurality of functional chips are integrated through SiP packaging and then packaged into a module, BGA packaging is adopted for replacing various discrete devices, the occupied area on a substrate is greatly reduced, and the eight-channel isolation RS-422 / RS-485 signal conversion device comprises a substrate 1 and an isolation power supply 2, an isolation signal converter 3 and a housing 12; the isolation power supply supplies power to the eight signal circuits and needs relatively high power; in order to reduce the size of the isolation power supply, the isolation power supply adopts push-pull topology and open-loop control, and output voltage is set through an LDO. According to the conversion module disclosed by the invention, the overall volume of the module is only about one third of the volume of a discrete device through design and centralized packaging by utilizing various high-integration-level bare cores, and the area occupied by components on a substrate can be greatly reduced in the field of multipath isolation RS-422 / RS-485 signal conversion.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor components, and in particular to an 8-way isolated RS-422 / RS-485 signal conversion device based on SiP packaging. Background Art

[0002] With the continuous improvement of integration, the requirements for communication modules are getting higher and higher. Miniaturization, multi-function and high integration are a trend. How to reduce the volume of hybrid circuit modules and ensure the stability of the circuit system is an urgent problem to be solved. In general, the structural dimensions of devices such as inductors, resistors, and capacitors are difficult to compress, and other technical approaches must be used to achieve ideal design. In the process of hybrid circuit micromodule integration, with the continuous improvement of integration, how to integrate more components in a limited space to achieve better working performance is particularly important. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides an 8-way isolated RS-422 / RS-485 signal conversion device based on SiP packaging. The signal conversion device uses SiP packaging to integrate an isolated power supply with multiple functional chips and then packages them into a module, and adopts BGA packaging to replace various discrete devices, which greatly reduces the area occupied on the substrate. The device includes a substrate 1, an isolated power supply 2, an isolated signal converter 3 and a shell 12; wherein the isolated signal converter 3 is provided with eight groups, and is distributed on both sides of the isolated power supply 2 in an array structure, and the isolated signal converter 3 also includes a coding and decoding chip 9, a signal transformer 10 and a signal transceiver 11, and at the same time, the power supply input end of the isolated power supply 2 and the coding and decoding chip 9 on the primary side is connected to the input power supply (V IN , GND),

[0004] The primary side of the signal conversion device is provided with eight single-ended input signal ports TxDn (n=1-8). When the single-ended signal is connected, it is first encoded by the encoder, then isolated and transmitted to the decoder by the signal transformer 10, and then processed by the signal transceiver 11 after decoding to obtain differential output signals YOn, ZOn (n=1-8).

[0005] At the same time, the isolated power supply 2 includes a resistor and capacitor device 4, a PWM chip 5, an isolation transformer 6, a diode 7, and an LDO 8. After the isolated power supply 2 is powered, the PWM chip 5 works to generate a set of complementary square wave signals, which pass through the isolation transformer 6 and the diode 7 to obtain a higher isolated output voltage, and then adjust to the voltage required for the secondary side encoding and decoding chip 9 to work through the LDO 8, so as to centrally power the secondary side circuit, and also realize the isolated power supply of the primary and secondary sides, and the resistor and capacitor device 4 is arranged on both sides of the input and output of the LDO 8 and the PWM chip 5 to protect and prevent overload voltage.

[0006] In one embodiment of the present invention, all functional units are electrically connected to the printed circuit on the substrate 1 by welding, bonding or gold wire bonding, and the housing 12 carries the assembled substrate 1 and all functional units.

[0007] In one embodiment of the present invention, the secondary side of the signal conversion device is provided with eight groups of differential input signal ports AIn, BIn (n=1~8). When the differential signal is connected, it is first processed by the signal transceiver 11, then encoded by the encoder, and then isolated by the signal transformer 10 and transmitted to the decoder for decoding to obtain a single-ended output signal RxDn (n=1~8).

[0008] In one embodiment of the present invention, the eight single-ended input signals and eight single-ended output signals of the primary side of the signal conversion device are all provided with enable terminals (DEn and REn, n=1 to 8). By configuring the enable terminals, full-duplex or half-duplex communication can be achieved, wherein the signals of the primary side and the secondary side can be isolated, and the isolation strength is ≥5000VDC.

[0009] In one embodiment of the present invention, the PWM chip 5, diode 7, LDO 8, encoding and decoding chip 9, signal transformer 10 and signal transceiver 11 are all bare chips, and are connected to the substrate 1 by conductive adhesive bonding, and gold wire or aluminum wire bonding is used to achieve electrical connection between the bare chip surface Pad and the substrate 1.

[0010] The bare chip is bonded to the substrate with conductive adhesive. The bonding area can be designed with multi-layer, large-area thermal pads (usually the electrical network of the thermal pad is GND), which can achieve signal shielding and provide a large heat dissipation area. For bare chips with higher power, the back-gold process is used to reduce the thermal resistance between the chip and the substrate, further improve the heat dissipation capacity, and improve the overall reliability of the module.

[0011] In one embodiment of the present invention, the resistor and capacitor component 4 is directly soldered on the substrate 1 by soldering.

[0012] The above technical solution of the present invention has the following advantages over the prior art: the signal conversion device of the present invention adopts an advanced packaging concept, integrates more than 40 chips in the form of bare chips on a substrate, and has its own high-power isolated power supply to solve the problem of isolated power supply of SiP modules. Under this design, the volume of the entire SiP module is only 1 / 3 of the system built with discrete devices, realizing the miniaturization of the entire SiP module.

[0013] At the same time, designing a large area of ​​copper at the bottom of the chip during the circuit layout process can effectively reduce the heat accumulation of the chip itself and improve the reliability of the module. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0015] Figure 1 is a block diagram of the architecture of the signal transceiver in the present invention;

[0016] Figure 2 It is a principle block diagram of an 8-way isolated RS-422 / RS-485 signal conversion module of the present invention;

[0017] Figure 3 It is a bottom surface pin pad diagram of the substrate of the present invention;

[0018] Figure 4 It is a schematic diagram of the layout of each functional unit on the substrate in the embodiment of the present invention;

[0019] Figure 4-1 It is a structural block diagram of the isolated power supply described in the embodiment of the present invention;

[0020] Figure 4-2 It is a structural block diagram of the isolation signal converter described in the embodiment of the present invention;

[0021] Figure 5 It is a principle block diagram of the application scheme in the embodiment of the invention application.

[0022] As shown in the figure, 1. substrate, 2. isolation power supply, 3. isolation signal converter, 4. resistor and capacitor device, 5. PWM chip, 6. isolation transformer, 7. diode, 8. LDO, 9. encoding and decoding chip, 10. signal transformer, 11. signal transceiver, 12. casing. DETAILED DESCRIPTION

[0023] This embodiment provides an 8-way isolated RS-422 / RS-485 signal conversion module based on SiP packaging, and uses SiP technology to achieve system integration. Figure 1 As shown in the figure, a centralized isolated power supply + 8 groups of signal transceivers are used. Figure 4 As shown, it includes a substrate 1, an isolation power supply 2, an isolation signal converter 3 and a housing 12; wherein the isolation signal converter 3 is provided with eight groups, and is distributed on both sides of the isolation power supply 2 in an array structure, and the isolation signal converter 3 also includes a coding and decoding chip 9, a signal transformer 10 and a signal transceiver 11, and the isolation power supply 2 and the power supply input end of the primary side coding and decoding chip 9 are connected to the input power supply (V IN , GND),

[0024] Meanwhile, the isolated power supply 2 includes a resistor and capacitor device 4, a PWM chip 5, an isolation transformer 6, a diode 7, and an LDO 8;

[0025] The isolation capability is achieved by the internal isolation transformer 6 and the isolation signal converter 3, which electrically isolate the power part and the signal part respectively;

[0026] Furthermore, the isolation transformer 6 and the signal transformer 10 realize electrical isolation of the power supply and the signal respectively.

[0027] Specifically, Figure 2 The principle block diagram shown (Note: n = 1 to 8 in the figure, representing channel 1 to channel 8; m = 1 to 2, representing VOUT1 and VOUT2):

[0028] That is, the isolated power supply 2 (internal structure see Figure 4-1 ) after power is supplied, the PWM chip 5 works to generate a set of complementary square wave signals, and a higher isolated output voltage is obtained after passing through the isolation transformer 6 and the diode 7, and then adjusted to the voltage required for the operation of the secondary encoding and decoding chip 9 through the LDO8, so as to centrally power the secondary circuit, and also realize the isolated power supply of the primary and secondary sides, and the resistor and capacitor device 4 is arranged on both sides of the input and output of the LDO8 and the PWM chip 5 to protect and prevent overload voltage.

[0029] The primary side has 8 single-ended input signal ports TxDn (n=1~8). When the single-ended signal is connected, it is first encoded by the encoder, then isolated and transmitted to the decoder through the signal transformer 10, and then processed by the signal transceiver 11 after decoding to obtain differential output signals YOn, ZOn (n=1~8).

[0030] The secondary side has 8 groups of differential input signal ports AIn, BIn (n=1~8). When the differential signal is connected, it is first processed by the signal transceiver 11, then encoded by the encoder, and then isolated by the signal transformer 10 and transmitted to the decoder for decoding to obtain a single-ended output signal RxDn (n=1~8).

[0031] The 8 single-ended input signals and 8 single-ended output signals on the primary side all have enable terminals (DEn and REn, n=1~8). Full-duplex or half-duplex communication can be achieved by configuring the enable terminals.

[0032] exist Figure 4 , Figure 4-2 In the application scheme shown in , after connecting to the power supply, DEn (n=1~8) is configured to be high (directly connected to the input power supply) and REn (n=1~8) is configured to be low (directly connected to the input ground), and full-duplex communication can be achieved.

[0033] The 8-channel isolated RS-422 / RS-485 signal conversion device described in this embodiment utilizes advanced packaging concepts, multi-layer substrate design and reasonable component layout to develop a signal transmission module with isolation function. This module not only contains a high-power isolated power supply internally, but also can relatively reduce the total area of ​​components.

[0034] At the same time, the present application also provides a process design for a signal conversion device, including the following steps:

[0035] Step S1: SiP module designs a multilayer wiring substrate 1, on which a transformer 6 and a resistor and capacitor device 4 are soldered by reflow soldering using lead-free solder paste;

[0036] Step S2: All bare chips (PWM chip 6, diode 7, LDO 8, encoding and decoding chip 9, signal transformer 10 and signal transceiver 11) on the substrate of the SiP module are bonded by conductive adhesive;

[0037] Step S3: All bare chips are bonded to the substrate 1 through gold wires (or aluminum wires) to achieve electrical connection;

[0038] Step S4: After all the devices are assembled, the SiP module is packaged (plastic or ceramic 12);

[0039] Step S5: perform bottom ball planting on the packaged SiP module, and all assembly is completed.

[0040] Design idea: Select a variety of bare chips designed and produced independently, use advanced SiP packaging concepts, combine circuit blocks with the same functions, and distribute them symmetrically to form functional modules. In SiP modules, many types and quantities of bare chips are used. All bare chips are bonded to the substrate with conductive glue and then bonded with gold wire (aluminum wire). Because the bare chip does not have a plastic package, its size is greatly reduced, which also greatly reduces the area occupied by components on the substrate, providing a new design idea for higher integration; this design method is mainly based on the limited substrate space, Figure 1 The conventional model shown is designed without affecting the basic performance parameters of the internal circuit, and the substrate design and internal layout are determined according to the number of chips, functional division and plastic package size.

[0041] The 8-way isolated RS-422 / RS-485 signal conversion module based on SiP packaging includes a main control substrate 1, an isolated power supply 2 (see Figure 3 , including PWM chip 5, isolation transformer 6, diode 7, LDO 8 and resistor and capacitor device 4), isolation signal converter 3 (see Figure 3, including a coding and decoding chip 9, a signal transformer 10 and a signal transceiver 11). The resistor and capacitor device 4 and the isolation transformer 6 are connected to the substrate by welding; the bare chip is connected to the substrate by bonding, and the bare chip surface Pad is electrically connected to the substrate by bonding. Because the bare chip is connected to the copper on the substrate, the heat dissipation capacity of the chip can be improved, thereby improving the reliability of the module.

[0042] The 8-way isolated RS-422 / RS-485 signal conversion module based on SiP packaging realizes the primary and secondary side isolation power supply through the isolation transformer 6, and realizes the primary and secondary side isolation communication of the signal through the signal transformer 10. After the signal is isolated, mutual interference of the signals can be avoided, the stability and consistency of the signals can be ensured, thereby providing the reliability of the system. At the same time, the distance between the primary and secondary sides (isolation zone) is controlled during the design of the substrate, so that the SiP module has a certain isolation strength.

[0043] After analyzing the circuit principle and dividing the functional blocks, the following Figure 4 The scheme shown is laid out, and each internal chip is bonded to the substrate in the form of a bare core, which can reduce the size of the required substrate and improve the efficiency of substrate use.

[0044] like Figure 2 , Figure 3 As shown, the transformer 6 and the resistor and capacitor device 4 can be reflow soldered using lead-free solder paste, and the PWM chip 6, the diode 7, the LDO 8, the encoding and decoding chip 9, the signal transformer 10 and the signal transceiver 11 need to be bonded by conductive adhesive. After bonding, multiple process steps such as chip bonding are performed, and finally the entire module is plastic-sealed.

[0045] Due to the large number of bare chips contained inside, during the packaging process of the SiP-packaged isolation signal conversion module, it is necessary to strictly follow the relevant quality levels and processes to avoid delamination, bubbles and other phenomena after the module is packaged.

[0046] When designing the power supply circuit, the power (power supply) loop area should be minimized to reduce the impact on various module parameters.

[0047] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. An 8-way isolated RS-422 / RS-485 signal conversion device based on SiP packaging, wherein the signal conversion device uses SiP packaging to integrate an isolated power supply with multiple functional chips and then packages them into a module, and adopts BGA packaging, characterized in that: The invention comprises a substrate (1), an isolation power supply (2), an isolation signal converter (3) and a housing (12); wherein the isolation signal converter (3) is provided with eight groups and is distributed in an array structure on both sides of the isolation power supply (2); the isolation signal converter (3) also comprises a coding and decoding chip (9), a signal transformer (10) and a signal transceiver (11); and the power supply input end of the isolation power supply (2) and the primary coding and decoding chip (9) is connected to the input power of the substrate (1). The primary side of the signal conversion device is provided with eight single-ended input signal ports TxDn. When the single-ended signal is connected, it is first encoded by the encoder, then isolated and transmitted to the decoder through the signal transformer (10), and then processed by the signal transceiver (11) after decoding to obtain differential output signals YOn and ZOn. At the same time, the isolated power supply (2) comprises a resistor and capacitor device (4), a PWM chip (5), an isolation transformer (6), a diode (7), and an LDO (8). After the isolated power supply (2) is powered, the PWM chip (5) works to generate a set of complementary square wave signals, which are passed through the isolation transformer (6) and the diode (7) to obtain a higher isolated output voltage, which is then adjusted to the voltage required for the operation of the secondary encoding and decoding chip (9) through the LDO (8), and the secondary circuit is centrally powered. At the same time, isolated power supply of the primary and secondary sides is also realized. The resistor and capacitor device (4) is arranged on both sides of the input and output of the LDO (8) and the PWM chip (5) to protect and prevent overload voltage.

2. The signal conversion device according to claim 1, characterized in that: All functional units are electrically connected to the printed circuit on the substrate (1) by welding, bonding or gold wire bonding, and the housing (12) carries the assembled substrate (1) and all functional units.

3. The signal conversion device according to claim 1, characterized in that: The secondary side of the signal conversion device is provided with eight groups of differential input signal ports AIn and BIn. When the differential signal is connected, it is first processed by a signal transceiver (11), then encoded by an encoder, and then isolated by a signal transformer (10) and transmitted to a decoder for decoding, thereby obtaining a single-ended output signal RxDn.

4. The signal conversion device according to claim 1, characterized in that: The eight single-ended input signals and eight single-ended output signals of the primary side of the signal conversion device all have enable terminals, through the configuration of the enable terminals.

5. The signal conversion device according to claim 1, characterized in that: The PWM chip (5), diode (7), LDO (8), encoding and decoding chip (9), signal transformer (10) and signal transceiver (11) are all bare chips, and are connected to the substrate (1) by means of conductive adhesive bonding, and are bonded by gold wire or aluminum wire to achieve electrical connection between the bare chip surface Pad and the substrate (1).

6. The signal conversion device according to claim 1, characterized in that: The resistor and capacitor component (4) is directly soldered on the substrate (1) by soldering.

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