Circuit board

Abstract

To solve the problem in which: it has been difficult to replace an IC with another IC replaceable with the IC.SOLUTION: A circuit board has an IC 1 and an IC 2 exclusively mounted thereon, and has: an attachment part ZIC; an attachment part Pren1 on which a resistance Rren1 is mounted when the IC 1 is mounted; attachment parts Z1-Z5 on which a voltage conversion part 801 is mounted when the IC 2 is mounted; a conductor pattern between a pad Pen of the attachment part ZIC and a pad of the attachment part Pren1; a conductor pattern between the pad Pen of the attachment part ZIC and a pad of the attachment part Z4; and a conductor pattern electrically connecting the other pad of the attachment Pren1 and a pad of the attachment part Z1.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a circuit board on which different integrated circuits can be exclusively mounted. [Background technology]

[0002] Some electrical appliances are equipped with multiple control circuit boards. Multiple electrical components are mounted on the control circuit boards, such as electrical components for performing logical operations, electrical components for drive control, and electrical components for generating power supply voltages. Each electrical component, together with surrounding electrical components, constitutes an electrical component component that realizes a specific function. For example, an electrical component component is made up of an integrated circuit (IC) and peripheral electrical components such as resistors, capacitors, and inductors that are connected to the input / output terminals of the IC.

[0003] Circuit boards are manufactured by procuring and mounting many electrical components. However, for various reasons, electrical components can become difficult to obtain. For example, a supply shortage of ICs has become a problem in recent years. To avoid such a situation, for each electrical component, replaceable parts with the same function and the same or similar shape and specifications are investigated in advance, and when a problem occurs in procuring parts, the replaceable parts are procured. The production of circuit boards continues using the replaceable parts.

[0004] In a control circuit board, the voltage value required may differ depending on the actuator connected. For this reason, electrical components for generating a plurality of voltages that generate different voltage values ​​are mounted on the circuit board. In such a configuration, power supply voltages of a plurality of different voltage values ​​are generated within the control circuit board. DC-DC converter ICs with low heat loss are widely used as electrical components for generating voltages (Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2021-164356 A Summary of the Invention [Problem to be solved by the invention]

[0006] For example, the electrical specifications of DC-DC converter ICs are often different for each IC. For this reason, even if you replace an IC with another IC, there is a high possibility that normal operation will not be guaranteed because the electrical specifications are different. In addition to DC-DC converters, if you replace an IC with a motor driver that drives a motor, there is also a high possibility that normal operation will not be guaranteed.

[0007] As described above, a circuit board for realizing a given function is mounted with electrical components consisting of an IC and peripheral parts (electrical parts) that complement the functions of the IC. In addition, the wiring (conductor pattern) on the circuit board is often specific to the IC. Therefore, when replacing an IC with another IC, peripheral parts and wiring (conductor pattern) corresponding to the IC to be replaced are required. In other words, when replacing an IC with another IC, it is necessary to start from the design of the circuit board, and there is a problem that it is not easy to replace an IC.

[0008] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a circuit board that enables an IC to be easily replaced with another IC that can replace the IC. [Means for solving the problem]

[0009] In order to solve the above problems, the circuit board of the present invention is a circuit board on which a first integrated circuit and a second integrated circuit having the same number of terminals as the first integrated circuit and a common arrangement of the terminals are exclusively mounted, the circuit board comprising a plurality of mounting parts on which the first integrated circuit and the second integrated circuit are exclusively mounted and to which the terminals of each integrated circuit are connected, a first mounting part to which a first electric component is attached when the first integrated circuit is mounted, a second mounting part to which a second electric component is attached when the second integrated circuit is mounted, and a predetermined mounting part included in the plurality of mounting parts and a second mounting part formed to electrically connect the first mounting part to each other. the first mounting portion is open so that the first conductor pattern and the third conductor pattern are not electrically connected to each other when the first electrical component is not mounted, and the second mounting portion is open so that the second conductor pattern and the third conductor pattern are not electrically connected to each other when the second electrical component is not mounted.

[0010] In order to achieve the above object, another circuit board of the present invention is a circuit board on which a first integrated circuit and a second integrated circuit having the same number of terminals as the first integrated circuit and a common arrangement of the terminals are exclusively mounted, the circuit board comprising: a plurality of mounting sections on which the first integrated circuit and the second integrated circuit are exclusively mounted and to which each terminal of each integrated circuit is connected; a first mounting section to which a first electric component is attached when the first integrated circuit is mounted; a second mounting section to which a second electric component is attached when the second integrated circuit is mounted; a predetermined mounting section included in the plurality of mounting sections; a first conductor section to which a first terminal of the first electric component is connected in the first mounting section; and the second mounting portion electrically connecting a third conductor portion to which the second terminal of the first electrical component is connected in the first mounting portion and a fourth conductor portion to which the second terminal of the second electrical component is connected in the second mounting portion, wherein the first mounting portion is open so that the first conductor portion and the third conductor portion are not electrically connected when the first electrical component is not mounted, and the second mounting portion is open so that the second conductor portion and the fourth conductor portion are not electrically connected when the second electrical component is not mounted. Effect of the Invention

[0011] According to the present invention, an IC can be easily replaced with another IC that can replace the IC. [Brief description of the drawings]

[0012] [Figure 1] Schematic diagram of an image forming apparatus connected via a network. [Diagram 2] System block diagram of an image forming apparatus [Diagram 3] Functional block diagram of power supply control of an image forming apparatus [Figure 4] Circuit block diagram of a DC-DC converter with integrated circuits [Diagram 5] Voltage conversion circuit block diagram [Figure 6] Schematic diagram of the circuit board of the DCDC converter [Figure 7] Circuit block diagram of a high-side switch with an integrated circuit [Figure 8] A timing chart showing signals at each terminal of an integrated circuit. [Figure 9] Schematic diagram of a high-side switch circuit board DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The following description will be given using a circuit board provided in image forming apparatus 100 as an example, but the present invention can also be applied to circuit boards used in general information devices such as PCs and servers, and electrical devices such as air conditioners and refrigerators.

[0014] FIG. 1 is a schematic diagram of an image forming apparatus 100 connected to a plurality of PCs via a network. The image forming apparatus 100 is connected to a LAN 106 using a LAN cable 107. There is no problem if a plurality of image forming apparatuses are connected to the same LAN 106. The PCs 103, 104, and 105 are connected to the LAN 106 using LAN cables 108, 109, and 110, respectively. Although FIG. 1 illustrates a connection using a LAN cable, a connection using a wireless LAN may also be used. When a print job is sent from the PC 103, the print job is sent to the image forming apparatus 100. Also, when it is desired to turn off the power of the image forming apparatus 100 from the PC 104, a remote shutdown instruction is sent to the image forming apparatus 100 via the LAN 106.

[0015] FIG. 2 shows a system block diagram of the image forming apparatus 100. In the image forming apparatus 100, power is supplied to each block from a power supply unit 200. A power supply unit for power supply control 202 controls the power supply of the power supply unit 200 and the control unit 220 of the image forming apparatus 100. The power supply unit for power supply control 202 is implemented in the control unit 201, and is a block that controls whether to supply power to each block according to a user's instruction such as a power switch. Details will be described in FIG. 3. The control unit 220 has a CPU 203, which executes a software program that controls the entire image forming apparatus 100. The CPU 203 is connected to a ROM 204, a RAM 205, and a storage 206. The storage 206 is, for example, an HDD or SSD. The ROM 204 stores the start-up program and various setting values ​​of the image forming apparatus 100. The RAM 205 is used for temporary data storage when the image forming apparatus 100 is controlled. The storage 206 is connected to the CPU 203 via a serial ATA (hereinafter referred to as SATA). The CPU 203 may be configured to be connected to multiple storages. For example, control such as RAID0 (striping) or RAID1 (mirroring) may be performed, but detailed description will be omitted. Data is written to or read from the CPU 203 to the storage 206. The storage 206 temporarily stores image data and stores part of the software for operating the image forming apparatus 100.

[0016] The CPU 203 is connected to an image processing unit 207, which is connected to a reader 230 and a printer 240. The control of the image forming apparatus 100 may be performed directly by the CPU 203 or via the image processing unit 207. The image processing unit 207 performs image processing such as color space conversion on the data received from the reader 230, converts it for printing, and outputs it to the printer 240. The reader 230 has an ADF (Auto Document Feeder) and a scanner unit, reads an image of a document placed on a document tray or the ADF, generates image data, and transmits the data to the image processing unit 207. The data processing of the image data may be performed by a CPU (not shown) built into the reader 230 or may be performed by the image processing unit 207. The printer 240 prints the image data received from the image processing unit 207 on paper. A LAN controller (hereinafter described as LANC) is connected to the LAN 106 (network) using a LAN cable 107, and is used as an input control for a print job from a PC or the like. The operation unit 250 is an IF that accepts instructions from a user, such as to copy, scan, print, or switch to a power saving mode, etc. The operation unit 250 is composed of an LCD panel, a touch panel, or the like.

[0017] FIG. 3 shows a functional block diagram of the power supply control of the image forming apparatus 100. A power supply 330 input from 300 is supplied to the first power supply unit 301 and the second power supply unit 302 of the image forming apparatus 100. The first power supply unit 301 supplies power to the power supply control unit 202 and each power supply block as a power supply 331, and the power supply control unit 202 controls the ON / OFF of each power supply block. At this time, the first power supply unit 301 converts the voltage according to the power supply control unit 202 and supplies the power. The power supply units used in the following explanation do not indicate a single power supply, but convert the voltage according to the supply destination and output according to the instruction of the power supply control unit. Details of the output voltage of each power supply and the power supply sequence are omitted. The power supply control unit 202 outputs power supply control signals (340 to 344) so ​​that each block can be turned ON / OFF individually. The first power supply unit 301 supplies power to each block from the power supply blocks (310 to 314). When each power supply is turned off, not only are each power supply block (340-344) turned off, but also the regulation for each block is observed by signals (350-354) that control each charge discharge circuit (320-324). At this time, the charge discharge circuit is illustrated as a simplified diagram of only transistors, but in order to observe the regulation for each block, a resistor is used to adjust the current value that flows. Also, in order to reduce power consumption, for blocks with a large power load such as the printer 240 and the reader 230, a separate second power supply unit 302 supplies power as a power supply 332 only when necessary under the control of the power supply control unit 202. The second power supply unit 302 supplies power to each block from the power supply blocks (315, 316). When each power supply is turned off, not only are each power supply block (345, 346) turned off, but also the regulation for each block is observed by signals (355, 356) that control each charge discharge circuit (325, 326). As shown in FIG. 3, power supply circuits are often used in electronic devices. Its purpose is to generate power according to the specifications of the electronic device being used and to switch the power on and off. Although the power blocks are described as being independent, they may be shared with other power blocks.

[0018] (First embodiment) As the circuit board of the first embodiment, the following describes a circuit board of a DC-DC converter that can exclusively implement integrated circuits having the same number of terminal pins, the same pin arrangement, and the same functions, but different threshold values ​​to be compared with the input voltage of the enable terminal.

[0019] Figure 4(A) is a circuit block diagram of a DCDC converter when IC1 is implemented as an integrated circuit. Figure 4(B) is a circuit block diagram of a DCDC converter when IC2 is implemented as an integrated circuit. As shown in Table 1, IC1 and IC2 have different input thresholds for the EN terminal. Note that other terminals are arranged so that they are shared, including the surrounding board patterns.

[0020] [Table 1]

[0021] As shown in Figure 4(A) and Figure 4(B), the integrated circuit (IC) implemented in the DC-DC converter has an input terminal (VIN terminal), an output terminal (SW terminal), a GND terminal, and a feedback terminal (FB). It is important that these terminals have the same layout and electrical specifications. The VIN terminal and SW terminal, which have a large current flow, require a thicker conductor pattern than the conductor patterns for other terminals. Furthermore, a capacitor is required near the VIN terminal and SW terminal to reduce switching noise. In addition, since the feedback terminal compares the reference voltage with the input voltage and switches the SW terminal ON / OFF based on the result, it is necessary to use wiring (conductor pattern) that is not affected by noise in order to maintain output accuracy. Therefore, in order to make the conductor pattern thickness and the layout of peripheral components (electrical components) common, these terminals have the same layout and electrical specifications.

[0022] In addition to the above, IC1 or IC2 has a capacitor terminal for bootstrap (VBST terminal), a capacitor terminal for the power supply that drives the internal logic (VREG terminal), an EN terminal for output control, and a PG terminal for the power good function. The power good function is a function that notifies that a specified voltage has been output. In some cases, it also has a terminal for detecting abnormalities in the output voltage and a terminal for controlling the switching frequency. An 8-pin integrated circuit (IC1 or IC2) with GND as the bottom electrode is mounted on the circuit board with the DC-DC converter function shown in Figure 4(A) and Figure 4(B).

[0023] Here, the EN pin is also used for controls such as adjusting the timing when configuring the power supply sequence. For this reason, multiple power supply voltages must be input to multiple control targets, and when multiple types of DCDC converters are mounted on a common board pattern, each IC must comply with the regulations of each EN pin.

[0024] In this way, the number of pins, pin arrangement, and terminal functions are exactly the same, but by exclusively mounting ICs for DCDC converters (IC1 or IC2) with some different pin characteristics on a common circuit board, it is possible to flexibly respond to changes in procurement situations.

[0025] As shown in Figure 4(A) and Figure 4(B), the power supply voltage of the DCDC converter is supplied to the VIN terminal. In this circuit diagram, a 12V power supply is input. Capacitors for noise reduction (Cin1 and Cin2) are placed in the input power supply. Capacitor Cvbst and resistor Rvbst for noise reduction are connected to the VBST terminal. Inductor L and output smoothing capacitors Cout1 to 3 are connected to the SW terminal, and an output voltage of 5V is output. The output voltage is not limited to 5V, and can be appropriately determined according to the electronic components used, such as 3.3V or 1.8V. The constant of inductor L is selected according to the DCDC converter to be implemented, and in order to realize it as a common board, it is necessary to select an inductor of approximately the same size that allows for a shared pattern. The GND terminal and the GND of the bottom electrode are directly connected to GND. The output voltage is supplied to the FB terminal. Since the reference voltage that controls the OFF / ON of the SW terminal is specified for the connection method, resistors Rfb1 and Rfb2 are connected to divide the voltage according to the DCDC converter. The resistance values ​​of resistors Rfb1 and Rfb2 can be designed according to the desired output voltage. A capacitor Cvreg is connected to the VREG terminal.

[0026] The PG terminal is an open drain output terminal. By connecting it to a 5V power supply voltage via resistor Rpu, it notifies the power good to other control units other than IC1 and IC2. The resistor Rpu is a pull-up resistor.

[0027] Here, it is assumed that the CPU 203 (FIG. 3) inputs a 1.8V enable signal (EN_Sig) to the EN terminal. The enable signal (EN_Sig) is an example of an electrical signal. When IC1 is implemented as shown in FIG. 4(A), a pull-up resistor Ren1 is connected to the EN terminal. In IC1 in FIG. 4(A), a 1.8V enable signal (EN_Sig) is input to the EN terminal via the pull-up resistor Ren1. As shown in Table 1 above, when a 1.8V enable signal (EN_Sig) is input to the EN terminal of IC1, the input voltage is equal to or higher than VIHmin, so an output voltage of 5V is output from the SW terminal of IC1.

[0028] On the other hand, when IC2 is mounted as shown in FIG. 4B, an electric component called a voltage conversion unit 801 is connected to the EN terminal. In IC2 in FIG. 4B, the voltage value of the enable signal of 1.8V is converted to, for example, 3.3V by the voltage conversion unit 801 and input to the EN terminal. As shown in Table 1, since the input voltage of the EN terminal of IC2 does not reach VIHmin or higher, an output voltage of 5V cannot be output from the SW terminal of IC2. Therefore, the DC-DC converter shown in FIG. 4B has a voltage conversion unit 801 that adjusts the voltage value of the enable signal from CPU203 (FIG. 3) to a value equal to or higher than VIHmin in order to enable a predetermined function based on the enable signal from CPU203 (FIG. 3).

[0029] 5 is a circuit block diagram of the voltage conversion unit 801. When the 1.8V enable signal (EN_Sig) becomes High (1.8V), the NPN transistor 901 turns ON, and the gate terminal of the P-channel FET 902, which has been pulled up by the resistor 903, changes to Low. When the P-channel FET 902 turns ON, a voltage of VIHmin or more is input to the EN terminal of IC2, and the function of IC2 generating 5V from 12V is enabled. Resistors 904 and 905 are used to adjust the voltage to a range that can be input to the EN terminal of IC2. Note that this circuit block diagram is merely an example of a circuit configuration that realizes the voltage conversion unit 801, and the voltage conversion unit 801 is not limited to the above-mentioned configuration.

[0030] Fig. 6 is a schematic diagram of a main part of a circuit board on which IC1 and resistor Ren1, and IC2 and electrical component components constituting voltage conversion unit 801 can be exclusively mounted. The circuit board shown in Fig. 6 is described as a double-sided board.

[0031] 6(A) is a schematic diagram showing the main part of the mounting surface (first surface) of the circuit board. The mounting surface (first surface) of the circuit board has a mounting portion ZIC on which an integrated circuit (IC1 or IC2) is exclusively mounted, and a mounting portion ZL on which an inductor L, which is a common electrical component, is mounted. The mounting surface has an input portion for inputting a 12V power supply voltage, and an output portion for outputting a 5V output voltage.

[0032] A plurality of terminals of the integrated circuit mounted on the mounting portion ZIC are connected to pads as conductors formed on the mounting surface. The pads for the terminals of the integrated circuit have a pad Pvin as a conductor to which the VIN terminal is connected, and a pad Pen as a conductor to which the EN terminal is connected.

[0033] 6(B) is a schematic diagram showing the main part of the solder side (second side) of the circuit board. The solder side (second side) of the circuit board has an input part to which an enable signal (EN_Sig) is input, and a mounting part Pren1 on which a resistor Ren1 is mounted. The solder side (second side) of the circuit board further has a mounting part Z1 on which an NPN transistor 901 is mounted, a mounting part Z2 on which a P-channel FET 902 is mounted, and mounting parts Z3, Z4, and Z5 on which resistors 903, 904, and 905 are mounted.

[0034] In addition, a plurality of vias are formed on the circuit board to electrically connect the mounting surface and the solder surface. The pad Pen for the EN terminal is electrically connected to the via Via1 through a conductor pattern. On the solder surface, the via Via1 is electrically connected to one of the pads to which the resistor Ren1 is connected, one of the pads to which the resistor 904 is connected, and one of the pads to which the resistor 905 is connected through conductor patterns extending in three directions.

[0035] 6(B), the solder surface is electrically connected to the other pad to which resistor 904 is connected and one of the three pads of P-channel FET 902 via a conductor pattern. The other two of the three pads of P-channel FET 902 and the two pads to which resistor 903 is connected are electrically connected via conductor patterns. In addition, one of the two pads to which resistor 903 is connected is electrically connected to via Via2 via a conductor pattern, and is electrically connected to the VIN terminal on the mounting surface.

[0036] One of the three pads of the NPN transistor 901 is electrically connected to one of the three pads of the P-channel FET 902. The input portion of the enable signal (EN_Sig) is electrically connected to one of the other two pads of the NPN transistor 901 and the other pad to which the resistor Ren1 is connected via a conductor pattern. Therefore, the conductor pattern that is electrically connected to the input portion of the enable signal (EN_Sig) has one end connected to the pad of the NPN transistor 901 and the other end connected to the pad of the resistor Ren1.

[0037] 6(B), when IC1 is mounted on the circuit board, resistor Ren1 is mounted, and NPN transistor 901, P-channel FET 902, resistors 903, 904, and 905 are not mounted. On the other hand, when IC2 is mounted on the circuit board, NPN transistor 901, P-channel FET 902, resistors 903, 904, and 905 are mounted, and resistor Ren1 is not mounted.

[0038] When resistor Ren1 is not mounted, the mounting portion Pren1 of the solder side is open so that the conductor patterns electrically connected to each pad are not conductive. Similarly, when resistor 904 is not mounted, the mounting portion Z4 of the solder side is open so that the conductor patterns electrically connected to each pad are not conductive. Similarly, when other electrical components are not mounted, each pad is open.

[0039] In this way, the circuit board described in this embodiment can be mounted by switching electrical components according to the characteristics of the DC-DC converter, so IC1 can be easily replaced with IC2 (or IC2 can be replaced with IC1). Furthermore, the circuit board of this embodiment is configured such that electrical components are exclusively mounted on the solder side different from the mounting side on which the integrated circuit is mounted, so that space saving of the circuit board can be achieved.

[0040] Second embodiment As the circuit board of the second embodiment, a circuit board of an input side switch (hereinafter referred to as a high side SW) capable of exclusively mounting integrated circuits having the same number of terminal pins, the same pin arrangement, and the same functions, but different output characteristics of the overcurrent terminal, will be described below. The high side SW is provided in a USB interface to control the power supply to an optional device connected to the USB, for example. The optional device is, for example, an expansion memory or a card reader.

[0041] Figure 7(A) is a circuit block diagram of a high-side switch when IC4 is implemented as an integrated circuit. Figure 7(B) is a circuit block diagram of a high-side switch when IC5 is implemented as an integrated circuit. The integrated circuit IC4 (or IC5) implemented in the high-side switch has the input terminal (VIN), output terminal (VOUT), and GND terminal as its main terminals. It is important that these terminals are in the same position. The reason for this is that the VIN and VOUT terminals, which have large currents flowing through them, need to be made into thick patterns, unlike other controls.

[0042] The integrated circuit IC4 (or IC5) further has a resistor terminal for current limiting (ILIM terminal), an EN terminal for output control, and an overcurrent terminal (OC terminal) for error notification when the current limiter is activated. In this explanation, the 6-pin IC4 (or IC5) is used as the integrated circuit implemented in the high-side switch.

[0043] A 5V power supply is input to the VIN terminal. Furthermore, the VIN terminal is electrically connected to a capacitor (Cin4) for noise reduction. An output capacitor Cout4 is electrically connected to the VOUT terminal. A 5V voltage (hereinafter referred to as 5V_B for ease of explanation) output from the VOUT terminal is supplied to an IC of an optional device connected to the USB interface. Note that the high-side SW in this embodiment is just an example, and the input and output voltages may be 3.3V or 1.8V, and may be designed appropriately according to the electrical components to which the voltage output from the VOUT terminal is supplied.

[0044] The GND terminal is directly connected to GND. When power supply timing control is required, a power supply control signal is input to the EN terminal. When outputting a free-running output voltage in accordance with the input power supply, a pull-up (PU) connection to the power supply voltage via a resistor can also be used. The ILIM terminal is connected to GND via resistor RILIM. The current limit resistance value differs for each high-side switch, so the resistor can simply be selected to match the desired current value.

[0045] The integrated circuit mounted on the high-side SW has an overcurrent protection function. The open current signal (OC_sig2) from the OC terminal indicates a high level if the current flowing through the ILIM terminal is below the threshold, and indicates a low level if the current flowing through the ILIM terminal is above the threshold. The open current signal (OC_sig2) is an example of an electrical signal. Note that when IC4 is mounted, a short resistor 1301 is also mounted.

[0046] The open current signal (OC_sig2) is input to the CPU 203 (FIG. 3) functioning as a signal processor, for example. When the open current signal (OC_sig2) changes from high level (first state) to low level (second state), the CPU 203 (FIG. 3) stops the power supply to the optional device connected downstream of the high-side switch. As a result, even if the IC of the optional device is shorted and an overcurrent flows, the power supply to the optional device is stopped, thereby reducing the impact on other devices.

[0047] Here, because the OC terminal of IC4 is an open-drain output, it is electrically connected via resistor Rpu2 to the power supply voltage V_rec supplied to the optional device in the downstream stage, and outputs an open current signal (OC_sig2).On the other hand, there is also an integrated circuit (IC5) that pulls up the OC terminal using the power supply voltage (5V) of the high-side switch IC, rather than pulling up with the power supply voltage supplied to the optional device in the downstream stage as with open-drain output.

[0048] FIG. 8(A) is a timing chart showing the signals at each terminal of IC4. As shown in FIG. 8(A), when the power supply voltage V_rec is input at timing t1, the voltage at the OC terminal of IC4 rises to the same value as the power supply voltage V_rec. On the other hand, FIG. 8(B) is a timing chart showing the signals at each terminal of IC5. As shown in FIG. 8(B), from timing t1 when the power supply voltage V_rec is input to timing t2 when 5V is input to the VIN terminal, the voltage at the OC terminal of IC5 becomes an intermediate potential. This is because IC5 pulls up the OC terminal using the power supply voltage (5V) of the high-side switch IC. If the overcurrent signal (OC_Sig2) is an intermediate potential, the power supply to the IC of the downstream optional device may stop, or the overcurrent protection function may not be properly realized.

[0049] Therefore, when IC5 is implemented, a resistor-integrated PNP transistor 1302 and a resistor-integrated NPN transistor 1303 are implemented so that the overcurrent signal (OC_Sig2) is adjusted to a predetermined voltage value. The power supply voltage (5V) of IC5 is supplied to the resistor-integrated PNP transistor 1302. As a result, in the high-side switch in which IC5 is implemented, the output of the OC terminal of IC5 is pulled up by the power supply voltage (5V) of IC5, and the resistor-integrated NPN transistor 1303 outputs an open drain. Therefore, a normal overcurrent signal (OC_sig2) can be input to the CPU 203 (FIG. 3). Note that when IC5 is implemented, the short resistor 1301 is not implemented. On the other hand, when IC4 is implemented, the resistor-integrated PNP transistor 1302 and the resistor-integrated NPN transistor 1303 are not implemented.

[0050] Fig. 9 is a schematic diagram of a main part of a circuit board on which IC4 and a short resistor 1301, and IC5 and a resistor-built-in PNP transistor 1302 and a resistor-built-in NPN transistor 1303 can be mounted exclusively. As shown in Fig. 9, only one side of the circuit board is shown, but the circuit board of this embodiment may be a single-sided board, a double-sided board, or a multi-layer board.

[0051] The mounting surface of the circuit board has a mounting portion Z2IC on which an integrated circuit (IC4 or IC5) is exclusively mounted, a mounting portion Z11 on which a short resistor 1301 is mounted, and a plurality of vias. The mounting surface further has a mounting portion Z12 on which a resistor-integrated PNP transistor 1302 is mounted, and a mounting portion Z13 on which a resistor-integrated NPN transistor 1303 is mounted.

[0052] A plurality of terminals of the integrated circuit attached to the attachment portion Z2IC are connected to pads serving as conductors formed on the mounting surface. The pads for the terminals of the integrated circuit have a pad Pvin2 serving as a conductor to which the VIN terminal is connected, a pad Pvout2 serving as a conductor to which the VOUT terminal is connected, and a pad Poc2 serving as a conductor to which the OC terminal is connected.

[0053] The mounting portion Z11 on which the short resistor 1301 is mounted is provided with two pads as conductors to which the terminals of the short resistor 1301 are connected. The mounting portion Z12 on which the resistor-built-in PNP transistor 1302 is mounted is provided with three pads as conductors to which the terminals of the resistor-built-in PNP transistor 1302 are connected. Similarly, the mounting portion Z13 on which the resistor-built-in NPN transistor 1303 is mounted is provided with three pads as conductors to which the terminals of the resistor-built-in NPN transistor 1303 are connected.

[0054] 9, the pad Poc2 for the OC terminal and one of the pads for the terminal of the resistor-integrated PNP transistor 1302 are electrically connected via a conductor pattern. Furthermore, the conductor pattern extends to one of the pads of the short resistor 1301. As a result, the pad Poc2 for the OC terminal and one of the pads of the short resistor 1301 are also electrically connected. Note that when the short resistor 1301 is not mounted, the space between the two pads of the short resistor 1301 is open so as not to be conductive.

[0055] In addition, another pad for the terminal of the resistor-built-in PNP transistor 1302 is electrically connected to one of the pads for the terminal of the resistor-built-in NPN transistor 1303 via a conductor pattern. The other pad for the terminal of the resistor-built-in NPN transistor 1303 is also electrically connected to the other pad of the short resistor 1301 via a conductor pattern. When the resistor-built-in PNP transistor 1302 is not mounted, the three pads of the resistor-built-in PNP transistor 1302 are open so as not to be conductive. Similarly, when the resistor-built-in NPN transistor 1303 is not mounted, the three pads of the resistor-built-in NPN transistor 1303 are open so as not to be conductive.

[0056] Also, the other pad of the short resistor 1301 is connected to the CPU 203 (FIG. 3) via a conductor pattern. The circuit board has a via Via3 for inputting an overcurrent signal (OC_Sig2) to the CPU 203 (FIG. 3). The overcurrent signal (OC_Sig2) outputted via the via Via3 is inputted to the CPU 203 (FIG. 3) via a conductor pattern (not shown). The via Via3 functions as an output conductor section for outputting the overcurrent signal (OC_Sig2). The conductor pattern electrically connecting the via Via3 and the other pad of the short resistor 1301 is referred to as an output conductor pattern.

[0057] 9, when IC4 is mounted on the circuit board, short resistor 1301 is mounted, and resistor-integrated PNP transistor 1302 and resistor-integrated NPN transistor 1303 are not mounted. On the other hand, when IC5 is mounted on the circuit board, resistor-integrated PNP transistor 1302 and resistor-integrated NPN transistor 1303 are mounted, and short resistor 1303 is not mounted.

[0058] In this way, the circuit board described in this embodiment allows electrical components to be switched and mounted according to the characteristics of the high-side switch, so IC4 can be easily replaced with IC5 (or IC5 can be replaced with IC4). Furthermore, the circuit board of this embodiment is configured to mount integrated circuits on a common mounting portion Z2IC, so there is no need to provide a separate mounting portion for mounting the integrated circuits, and space saving of the circuit board can be achieved. [Explanation of symbols]

[0059] ZIC mounting part Pren1 mounting part Z1~Z5 Mounting part

Claims

1. A circuit board on which a first set including at least a first integrated circuit and a first electrical component, or a second set including at least a second integrated circuit and a second electrical component, is exclusively mounted, an IC mounting portion on which the first integrated circuit or the second integrated circuit is mounted; a first mounting portion configured to allow a first electrical component to be mounted thereon and including at least a first pad and a second pad; a second mounting portion configured to be mountable to a second electrical component and including at least a third pad and a fourth pad; a first conductor pattern electrically connecting the IC mounting portion and the first pad of the first mounting portion; a second conductor pattern electrically connecting the IC mounting portion and the third pad of the second mounting portion; a third conductor pattern electrically connecting the second pad of the first mounting portion and the fourth pad of the second mounting portion, When the first electric component is not mounted, the first pad and the second pad of the first mounting portion are open so as not to be electrically connected to each other, A circuit board characterized in that, when the second electrical component is not mounted, the third pad and the fourth pad of the second mounting portion are open so as not to be electrically connected to each other.

2. the IC mounting portion is formed on a first surface of the circuit board; 2. The circuit board according to claim 1, wherein the first mounting portion and the second mounting portion are formed on a second surface of the circuit board opposite to the first surface.

3. 2. The circuit board according to claim 1, wherein the IC mounting portion, the first mounting portion, and the second mounting portion are formed on a mounting surface of the circuit board.

4. 2. The circuit board according to claim 1, wherein an input portion for inputting an electrical signal is formed between one end of the third conductor pattern and the other end of the third conductor pattern.

5. 5. The circuit board according to claim 4, wherein the electrical signal is an enable signal for switching whether or not a predetermined function is enabled.

6. an enable signal for switching whether a predetermined function is enabled is input to the first integrated circuit or the second integrated circuit; If the first integrated circuit is implemented, a voltage of the enable signal is compared to a first threshold voltage; 2. The circuit board according to claim 1, wherein, when the second integrated circuit is mounted, the voltage of the enable signal is compared with a second threshold voltage different from the first threshold voltage.

7. A circuit board on which a first set including at least a first integrated circuit and a first electrical component, or a second set including at least a second integrated circuit and a second electrical component, is exclusively mounted, an IC mounting portion on which the first integrated circuit or the second integrated circuit is mounted; a first mounting portion configured to allow a first electrical component to be mounted thereon and including at least a first pad and a second pad; a second mounting portion configured to be mountable to a second electrical component and including at least a third pad and a fourth pad; a first conductor pattern electrically connecting the IC mounting portion, the first pad of the first mounting portion, and the third pad of the second mounting portion; a second conductor pattern that electrically connects the second pad of the first mounting portion and the fourth pad of the second mounting portion, When the first electric component is not mounted, the first pad and the second pad of the first mounting portion are open so as not to be electrically connected to each other, A circuit board characterized in that the third pad and the fourth pad of the second mounting portion are open so that they are not electrically connected to each other when the second electrical component is not mounted.

8. an output unit that outputs the electrical signal output from the IC attachment unit to another signal processing unit; 8. The circuit board according to claim 7, further comprising a third conductor pattern that electrically connects the output portion, the second pad of the first mounting portion, and the fourth pad of the second mounting portion.

9. 9. The circuit board according to claim 8, wherein the electrical signal is an overcurrent signal that changes from a first state to a second state when an overcurrent is detected.

10. When the first integrated circuit is mounted, a voltage value of an overcurrent signal output from the IC mounting portion when no overcurrent is detected is a first voltage value; 8. The circuit board according to claim 7, wherein when the second integrated circuit is mounted, the voltage value of the overcurrent signal output from the IC mounting portion when no overcurrent is detected is a second voltage value different from the first voltage value.

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