JP2009021289A - Solenoid control unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solenoid control unit which reduces footprint. <P>SOLUTION: A free-wheel diode (vertical diode 105) which was externally fitted in conventional way and a conventional linear solenoid driving IC 150 composed of a lateral power MOS 106 and a control circuit portion 107 are formed on the same (p) substrate to constitute a compound linear solenoid driving IC 102, thereby reducing the footprint of the solenoid control unit 100. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solenoid control device that controls a solenoid.

Conventionally, linear solenoids are used to drive valves that control oil pressure and air flow rate. The linear solenoid is a solenoid in which a movable iron core housed in the solenoid moves linearly in proportion to current.
FIG. 10 is a block diagram of a main part of a linear solenoid and a conventional solenoid control device that controls the linear solenoid. In this specification, the solenoid control device 200 includes a power supply 101, a lateral power MOSFET (lateral power MOS 106) and a linear solenoid driving IC 150 having a control circuit unit 107 for controlling the power MOSFET 101, a current detection resistor 104, and a free wheel diode ( It is composed of a vertical diode 105).
The operation of this solenoid control device will be described. The current flowing through the linear solenoid 103 is converted into a voltage by the current detection resistor 104 and taken into the linear solenoid driving IC 150. The control circuit unit 107 in the linear solenoid driving IC 150 compares the current command value (actually a voltage value) with the taken-in voltage value, performs pulse width modulation (PWM (Pulse Width Modulation)), and power switch Is driven (turned on / off).
When the horizontal power MOS 106 is turned on, a current flows from the power source 101 through the horizontal power MOS 106 to the ground 108 via the linear solenoid 103 and the current detection resistor 104.

Next, when the horizontal power MOS 106 is turned off, the current flowing through the linear solenoid 103 cannot be changed suddenly. Therefore, the linear solenoid 103, the current detection resistor 104, the ground 108, a free wheel diode (vertical type) A circulating current flows back to the linear solenoid 103 via the diode 105). A free wheel diode (vertical diode 105) functions to cause the circulating current to flow.
By the operation of the solenoid control device 200 described above, the same current as the current command value of the control circuit unit 107 flows through the linear solenoid 103.
FIG. 11 is a cross-sectional view of a main part of a linear solenoid driving IC in which a lateral power MOS is integrated on a p-substrate. The p substrate 20 is a silicon substrate in which a p region 2 is formed by epitaxial growth or the like on the following p ⁺ region 1 (usually a p ⁺ substrate). In the following description, p is indicated when the conductivity type is p-type, and n is indicated when the conductivity type is n-type.
An n-well region 3 is formed in the surface layer of the p-region 2 formed on the p ⁺ region 1, and a p-well region 4 and an n ⁺ drain region 5 are selectively formed in the surface layer of the n-well region 3, An n ⁺ source region 6 is formed on the surface of the p well region 4.
n ⁺ drain region 5 and the n ⁺ source region 6 sandwiched by p-well region 4 on the surface, through the gate oxide film 7, a gate electrode 8 of polysilicon is formed, the n ⁺ drain region 5 A drain electrode 9 is formed thereon, and a source electrode 10 is formed on the n ⁺ source region 6.

All drain electrodes 9 are connected to the drain terminal (terminal a), all source electrodes 10 are connected to the source terminal (terminal b), and a ground electrode 12 is provided under the p ⁺ region 1 (the back surface of the p substrate 20). Formed and connected to the ground 108.
Further, Patent Document 1 discloses that functions of a plurality of semiconductor elements are mounted on the same chip by an SOI process technology so that even if a circuit is thermally damaged, the control of a vehicle or the like is not adversely affected. Has been.
Patent Document 2 discloses that a plurality of semiconductor drivers having different withstand voltages can be integrated on the same chip to cope with various withstand voltages.
JP-A-11-251564 JP 2002-246551 A

In the conventional solenoid control device 200, the linear solenoid driving IC 150 formed in the p region 2 is composed of the horizontal power MOS 106 and the control circuit unit 107 and formed on the same p substrate 20. The other components, the linear solenoid 103, the current detection resistor 104, and the free wheel diode (vertical diode 105) are externally attached as individual components.
For example, when a large number of the solenoid control devices 200 to which the free wheel diode (vertical diode 105) and the current detection resistor 104 are externally used are used, for example, in an automobile electrical product, the solenoid control device 200 itself. It is strongly desired to reduce the occupied space.
Further, Patent Document 1 does not describe that a plurality of semiconductor elements are formed of horizontal elements and that vertical elements are combined.
In Patent Document 2, a horizontal element is formed in a semiconductor region surrounded by a buried insulating layer, and it is not described that a vertical element is combined as described above.
An object of the present invention is to provide a solenoid control device capable of solving the above-described problems and reducing the occupied space.

In order to achieve the above object, a solenoid control device for controlling a solenoid, comprising:
A power source, a MOS transistor for controlling a current flowing from the power source to the soredoid, a control circuit unit for controlling on / off of the MOS transistor, a current detector for detecting a current flowing through the solenoid, and a current flowing through the solenoid A free wheel diode for refluxing,
The high potential side of the power supply and the drain of the MOS transistor are connected, the gate of the MOS transistor and the control circuit unit are connected, the source of the MOS transistor and one end of the solenoid are connected, and the other end of the solenoid The ground of the power source is connected, the current detector inserted between the solenoid and the ground of the power source, the other end of the solenoid is connected to the anode of the free wheel diode, and the cathode of the free wheel diode is In a solenoid control device that is connected to one end of the solenoid, the current detector and the control circuit unit are connected,
The solenoid driving IC composed of the MOS transistor and the control circuit section and the free wheel diode are formed on a silicon substrate having a p-type conductivity.
The current detector may be a current detection resistor.

The solenoid may be a linear solenoid.
The MOS transistor may be a lateral MOSFET, and the freewheel diode may be a vertical diode.
Further, an n well region formed on the surface layer of the p substrate, a p well region and an n ⁺ drain region selectively formed on the surface layer of the n well region, and formed on the surface of the p well region. An n ⁺ source region, a gate electrode formed on a surface of the p well region sandwiched between the n ⁺ drain region and the n ⁺ source region via a gate oxide film, and on the n ⁺ drain region The lateral MOSFET having a drain electrode formed and a source electrode formed on the n ⁺ source region;
An n region formed on the surface layer of the p substrate apart from the n well region, an n ⁺ cathode region formed on the surface layer of the n region, and a cathode electrode formed on the n ⁺ cathode region; The vertical diode comprising:
The control circuit unit formed on the surface layer of the p substrate apart from the lateral MOSFET and the vertical diode,
The back surface of the p substrate is connected to the ground of the power source, and the back surface layer of the p substrate is an anode region of the vertical diode.

The pad of the control circuit unit may be disposed on the cathode electrode through an insulating film.
In addition, it may be configured to have a p ⁺ region formed toward the back surface of the p substrate adjacent to the n region, and a ground electrode formed on the p ⁺ region.
The p ⁺ region may be formed so as to reach the back surface from the front surface of the p substrate.

According to the present invention, the space occupied by the solenoid control device can be reduced by using the composite linear solenoid drive IC in which the external free wheel diode and the linear solenoid drive IC are formed on the same p substrate.
Further, by allocating a part of the layout of the vertical diode to the pad of the control circuit unit, the p-board can be reduced in size, and the space occupied by the solenoid control device can be reduced.
Also, by forming all terminals connected to the external circuit in a concentrated manner on one surface of the p substrate, the p substrate can be resin-sealed by CSP (Chip Size Package), and SOP (Small Outline Package) The package can be further reduced in size as compared with the case of using. As a result, the space occupied by the solenoid control device can be reduced.

  Embodiments of the invention will be described in the following examples. The same parts as those in the conventional configuration are denoted by the same reference numerals.

1 to 4 are main part configuration diagrams of a solenoid control apparatus according to a first embodiment of the present invention. FIG. 1 is a circuit configuration diagram of a solenoid control device, FIG. 2 is a layout diagram of a composite linear solenoid drive IC of FIG. 1, and FIG. FIG. 4 is a schematic cross-sectional view of a main part of a composite linear solenoid driving IC in which the IC is formed on a silicon substrate, and FIG. 4 is a schematic view in which the composite linear solenoid driving IC of FIG. Here, the free wheel diode is a vertical diode 105 that allows a main current to flow in the vertical direction.
The reason why the p-type substrate 20 is used instead of the n-type substrate is that the back side of the substrate is set to the ground potential and the anode of the vertical diode 105 can be formed on the back side of the substrate.
In FIG. 1, a solenoid control apparatus 100 of the present invention is for driving a composite linear solenoid having a power source 101, a lateral power MOSFET (lateral power MOS 106), a control circuit unit 107 for controlling the power MOSFET, and a free wheel diode (vertical diode 105). An IC 102 and a current detection resistor 104 are included. This composite linear solenoid driving IC 102 is obtained by forming a linear solenoid driving IC 150 and a vertical diode 105 on the same p substrate 20.

In FIG. 2, a drain pad 109, a source pad 110, a gate pad 111, a cathode pad 112, and a pad 113 of the control circuit unit 107 are connected to terminals a to e, respectively. 103, and connected to the ground 108 and the current detection resistor 104.
In FIG. 3, a method for forming the lateral power MOS 106 will be described first. However, the control circuit unit 107 is not shown.
An n well region 3 is formed in the surface layer of the p region 2 formed on the p ⁺ region 1, and a p well region 4 and an n ⁺ drain region 5 are selectively formed in the surface layer of the n well region 3.
An n ⁺ source region 6 is formed on the surface of the p well region 4, and a gate oxide film 7 is interposed on the surface of the p well region 4 sandwiched between the n ⁺ drain region 5 and the n ⁺ source region 6. A gate electrode 8 made of crystalline silicon is formed, a drain electrode 9 is formed on the n ⁺ drain region 5, and a source electrode 10 is formed on the n ⁺ source region 6.
All drain electrodes 9 are connected to a drain pad 109, all source electrodes 10 are connected to a source pad 110, the drain pad 109 is connected to a drain terminal (terminal a), and the source pad 110 is a source terminal (terminal b). Connected to.

A ground electrode 12 is formed under the p ⁺ region 1 and connected to the ground terminal (terminal c). Here, the case where the number of cells constituting the horizontal power MOS 106 is two is shown.
Next, a method for forming the vertical diode 105 will be described. An n region 13 is formed on the surface layer of the p region 2 apart from the n well region 3, an n ⁺ cathode region 14 is formed on the surface layer of the n region 13, and a cathode electrode 15 is formed on the n ⁺ cathode region 14. Then, the insulating film 16 is formed on the surfaces of the n ⁺ cathode region 14 and the n region 13, and finally, the cathode electrode 15 is connected to the source terminal (terminal b) via the cathode pad 112 and the source pad 110 (not shown). .
As a result, a composite linear solenoid driving IC 102 in which the horizontal power MOS 106 and the vertical diode 105 are integrated on the same p substrate 20 (p region 2) is obtained. As a result, the occupied space of the solenoid control device 100 can be reduced as compared with the conventional solenoid control device 200 to which the vertical diode 105 is externally attached.
In FIG. 4, an example in which the p substrate 20 is housed in a package of the SOP 21 is given. Since the terminal 22 (pin) of the package protrudes from the mold resin, the occupied area of the package is larger than the CSP described later. Although not shown, there is a DIP (Dual Inline Package) other than the SOP as a package. However, since the pins protrude from the mold resin, the area occupied by the package is larger than that of the CSP.

Since a parasitic npn transistor is formed between the drain region 5 and the cathode region 14, it is necessary to electrically isolate the n well region 3 and the n region 13 from each other. This isolation method includes increasing the interval between the n well region 3 and the n region 13 or forming an insulating isolation region between the n well region 3 and the n region 13.
In the description of the first embodiment, the linear solenoid 103 has been described as an example of the solenoid. However, the linear solenoid 103 is not necessarily required, and the relationship between the current flowing through the solenoid and the movement of the movable iron core can be grasped. If so, a normal solenoid may be used. In this case, as a solenoid driving IC, naturally, a normal solenoid driving IC is used instead of a linear solenoid driving IC.
In the first embodiment, the lateral power MOS 106 has been described as an example, but a lateral IGBT (insulated gate bipolar transistor) may be used. When a lateral IGBT is used, the n ⁺ source region 6 is an n ⁺ emitter region, and the n ⁺ drain region 5 is a p ⁺ collector region.
When the element breakdown voltage is as low as about 10 V, the n ⁺ source region 6 and the n ⁺ drain region 5 are formed on the surface layer of the p region 2 without forming the n well region 3 and the p well region 4 of the lateral power MOS 106. You may form directly.

  Moreover, you may use a current probe (CT: Current Transformer) instead of the said current detection resistor 104 as a current detector.

5 and 6 are main part configuration diagrams of a solenoid control apparatus according to a second embodiment of the present invention. FIG. 5 is a layout diagram of a composite linear solenoid driving IC. FIG. 6 is a composite linear solenoid driving IC of FIG. It is principal part sectional drawing of IC.
In FIG. 5, the layout of the composite linear solenoid driving IC 120 includes three layouts of a horizontal power MOS 106, a vertical diode 105, and a control circuit unit 107. The difference from the first embodiment is that the cathode pad 112 (cathode electrode 15) of the vertical diode 105 is formed close to one side of the vertical diode 105, and the pad 113 of the control circuit unit 107 is formed in the vacant space. Is a point.
6, the vertical cathode electrode 15 of the diode 106 is formed on one side of the surface layer of the n ⁺ cathode region 14, the open space n ⁺ pad 113 of the control circuit section 107 on the insulating film 7 on the cathode region 14 Form. By using this composite linear solenoid drive IC 120, the occupied space of the solenoid control device 100 can be further reduced as compared with the case of the first embodiment.

FIGS. 7 to 9 are main part configuration diagrams of a solenoid control apparatus according to a third embodiment of the present invention. FIG. 7 is a layout diagram of a composite linear solenoid driving IC, and FIG. 8 is a composite linear solenoid driving IC of FIG. FIG. 9 is a schematic view in which the p substrate of FIG. 8 is housed in a package.
In the composite linear solenoid driving IC 130, since the p substrate 20 is resin-sealed with the CSP 23, all the terminals a to e are formed on the surface of the p substrate 20.
In FIG. 7, terminals a to e connected to the pads are formed on the pads 109 to 113.
In FIG. 8, an n well region 3 is formed in the surface layer of p region 2 formed on p ⁺ region 1, and p well region 4 and n ⁺ drain region 5 are selectively formed on the surface layer of n well region 3. N ⁺ source region 6 is formed on the surface of p well region 4, and gate oxide film 7 is formed on the surface of p well region 4 sandwiched between n ⁺ drain region 5 and n ⁺ source region 6. through it, the gate electrode 8 of polysilicon is formed, a drain electrode 9 is formed on the n ⁺ drain region, a source electrode 10 on the n ⁺ source region 6.
All the drain electrodes 9 are connected to the drain pad 109, and all the source electrodes 10 are connected to the source pad 110. The drain pad 109 is connected to the drain terminal (terminal a), and the source pad 110 is connected to the source terminal (terminal b).

The p ⁺ region 17 is formed from a p ⁺ region 1 to the surface of the p-type substrate 20, a ground electrode 18 formed on the surface of the p ⁺ region 17, to connect the ground electrode 18 and the ground terminal (terminal c). Note that the p ⁺ region 17 may be formed on the surface layer of the p substrate 20 (p region 2). In this case, as described above, since the p ⁺ region 17 does not reach the p ⁺ region 1, the forward voltage drop of the vertical diode, which is good in the above case, is somewhat increased. Further, when the p substrate 20 is formed of a low impurity layer, the p ⁺ region 17 is preferably formed so as to reach the back surface from the front surface of the p substrate 20.
With the above configuration, since all the terminals a to e are formed on one surface of the p substrate 20, it is possible to perform resin sealing with the CSP 23 shown in FIG. By storing the p substrate 20 in the CSP 23, the occupied space of the solenoid control device 100 can be reduced.
Further, when applied to the first embodiment, the composite linear solenoid drive IC can be further reduced in size compared to the first embodiment, and the occupied space of the solenoid control device 100 can be further reduced.
In the vertical diode 105 shown in FIG. 8, although a minute current flows in the horizontal direction, the current flowing in the vertical direction is overwhelmingly large, so it is treated as a vertical diode here.

The circuit block diagram of the solenoid control apparatus of 1st Example of this invention Layout diagram of composite linear solenoid driving IC 102 of FIG. Sectional drawing of the principal part of IC102 for composite linear solenoid drive of FIG. The figure which stored p substrate of Drawing 3 in the package Layout diagram of composite linear solenoid drive IC 120 constituting the solenoid control device of the second embodiment of the present invention. Sectional drawing of the principal part of IC 120 for composite linear solenoid drive of FIG. Layout diagram of composite linear solenoid driving IC 130 constituting the solenoid control device of the second embodiment of the present invention. Sectional drawing of the principal part of IC 130 for composite linear solenoid drive of FIG. The figure which stored p board of Drawing 8 in the package Configuration diagram of the main parts of a linear solenoid and a conventional solenoid control device that controls the linear solenoid Cross-sectional view of the main part of a conventional linear solenoid drive IC in which a lateral power MOS is integrated on a p-substrate

Explanation of symbols

1 p ⁺ region 2 p region 3 n well region 4 p well region 5 n ⁺ drain region 6 n ⁺ source region 7 gate oxide film 8 gate electrode 9 drain electrode 10 source electrode 12 ground electrode 13 n region 14 n ⁺ cathode region 15 Cathode electrode 16 Insulating film 17 p ⁺ region 18 Ground electrode 20 p substrate 21 SOP
22 pin 23 CSP
100 Solenoid Control Device 101 Power Supply 102 Compound Linear Solenoid Drive IC
103 Linear solenoid 104 Current detection resistor 105 Vertical diode (freewheel diode)
106 Horizontal power MOS
107 control circuit section 108 ground 109 drain pad 110 source pad 111 gate pad 112 cathode pad 113 pad (control circuit section)
120 Compound Linear Solenoid Drive IC
130 Compound Linear Solenoid Drive IC
150 Linear solenoid drive IC (conventional)
200 Solenoid control device (conventional)
a to e terminals

Claims (8)

A solenoid control device for controlling a solenoid,
A power source, a MOS transistor for controlling a current flowing from the power source to the solenoid, a control circuit unit for controlling on / off of the MOS transistor, a current detector for detecting a current flowing through the solenoid, and a current flowing through the solenoid A free wheel diode for refluxing,
The high potential side of the power supply and the drain of the MOS transistor are connected, the gate of the MOS transistor and the control circuit unit are connected, the source of the MOS transistor and one end of the solenoid are connected, and the other end of the solenoid The ground of the power supply is connected, the current detector inserted between the solenoid and the ground of the power supply, the other end of the solenoid is connected to the anode of the freewheel diode, and the cathode of the freewheel diode is connected In the solenoid control device connected to one end of the solenoid, the current detector and the control circuit unit are connected.
A solenoid control device comprising: a solenoid driving IC comprising the MOS transistor and the control circuit portion; and the free wheel diode formed on a silicon substrate having a p-type conductivity. The solenoid control device according to claim 1, wherein the current detector is a current detection resistor. The solenoid control device according to claim 1, wherein the solenoid is a linear solenoid. 2. The solenoid control device according to claim 1, wherein the MOS transistor is a lateral MOSFET, and the freewheel diode is a vertical diode. An n-well region formed in the surface layer of the p-substrate, a p-well region and an n ⁺ drain region selectively formed in the surface layer of the n-well region, and an n-type formed on the surface of the p-well region ^{A +} source region, a gate electrode formed on the surface of the p well region sandwiched between the n ⁺ drain region and the n ⁺ source region via a gate oxide film, and formed on the n ⁺ drain region The lateral MOSFET having a drain electrode and a source electrode formed on the n ⁺ source region;
An n region formed on the surface layer of the p substrate apart from the n well region, an n ⁺ cathode region formed on the surface layer of the n region, and a cathode electrode formed on the n ⁺ cathode region; The vertical diode comprising:
The control circuit unit formed on the surface layer of the p substrate apart from the lateral MOSFET and the vertical diode,
5. The solenoid control device according to claim 4, wherein a back surface of the p substrate is connected to a ground of the power source, and a back surface layer of the p substrate is an anode region of the vertical diode. The solenoid control device according to claim 5, wherein a pad of the control circuit unit is disposed on the cathode electrode through an insulating film. 7. The semiconductor device according to claim 5, further comprising a p ⁺ region formed toward the back surface of the p substrate adjacent to the n region, and a ground electrode formed on the p ⁺ region. Solenoid control device. The solenoid control device according to claim 7, wherein the p ⁺ region is formed so as to reach the back surface from the front surface of the p substrate.

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