JP2815744B2 - Integrated circuit for driving inductive load constant current - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated circuit for driving an inductive load with a constant current.

[0002]

2. Description of the Related Art FIG. 7 is a diagram showing a conventional inductive load constant current drive circuit, in which 8 is an inductive load, and 11 is a switch for flowing or stopping a current to the inductive load 8. Means 5 and 7 are a diode and a Zener diode connected to the cathode terminals so that the current flows only in one direction to both ends of the inductive load 8, 6 is a diode connected to both ends of the inductive load by the switch means 12, 100
Is a power supply terminal, 200 and 300 are switches 11 and 12
A signal input terminal for N / OFF, 400 is a ground terminal.

Next, the operation will be described. First, when the input terminals 200 and 300 are L, the switches 11 and
Reference numeral 12 denotes an OFF state, in which no voltage is applied to the inductive load 8 and no load current flows. Next, the input terminals 200, 30
When 0 is set to H, the switches 11 and 12 are turned on, a voltage is applied to both ends of the inductive load 8, and a load current starts to flow. However, since the load current is limited by the back electromotive force of the L component of the inductive load 8, the load current increases while having a slope determined by the L component of the inductive load 8 and the resistance of the switch 11 and the inductive load.

Next, when the input terminal 200 is set to L again,
The switch 11 is turned off, and the current of the inductive load 8 decreases. As a result, a back electromotive force is generated in the opposite direction, and the energy stored in the inductive load 8 is discharged.
A current flows through the inductive load 8 through the. This current also decreases while being limited by the L component and the resistance component of the inductive load 8, the resistance component of the switch 12, and the forward voltage of the diode 6.

As described above, when the switch 11 is ON and the switch 11 is appropriately turned ON / OFF, a constant current can be supplied to the inductive load 8 on average. In addition, by appropriately changing the ON / OFF duty ratio of the switch 11, the current of the inductive load 8 can be varied. Such a current control method is generally applied to a PWM (Pulse-Width- modulation).

When it is necessary to rapidly reduce the current flowing through the inductive load 8, the switch 11 is turned off.
As described above, the load current only decreases at a constant slope when the flip-flop is used, so that it takes time, and the object cannot be achieved. Then, when the switch 12 is turned off and the diode 6 is disconnected, a current flows from the ground terminal 400 through the diode 5 and the Zener diode 7. In this case, since the potential difference of the Zener diode 7 is large, the energy consumed by the Zener diode 7 increases, and the energy stored in the inductive load 8 is rapidly discharged, and the current rapidly increases. Decrease.

[0007]

As described above, the conventional inductive load constant current driving integrated circuit is composed of a combination of individual components, so that the number of components is large and the cost is disadvantageous. There are problems such as difficulty in reducing the size of the device. SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has an inductive load constant current drive capable of efficiently integrating a function realized by a combination of individual components without a defect. It is an object of the present invention to provide an integrated circuit.

[0008]

An integrated circuit for driving an inductive load constant current according to the present invention has an inductive load having a first terminal connected to a first potential and a second inductive load. A switch connected between a terminal and a second potential; an Nch (N-channel) MOS transistor having a source and a back gate connected to a second terminal of the inductive load; and the Nch MOS transistor A first diode having its cathode terminal connected to its drain terminal and its anode terminal connected to said first potential;
A resistor connected between the source terminal and the gate terminal of the ch-type MOS transistor, a Zener diode whose anode terminal is connected to the gate terminal of the N-channel MOS transistor, and a cathode terminal connected to the cathode terminal of the Zener diode A second diode having its anode terminal connected to the first potential, a source terminal and a back gate terminal connected to the second potential, and a drain terminal connected to a gate terminal of the Nch-type MOS transistor. A Pch (P-channel) MOS transistor and an input terminal connected to the gate terminal of the Pch MOS transistor.

Further, an inductive load constant current driving integrated circuit according to the present invention has an inductive load having a first terminal connected to a first potential, a second terminal of the inductive load and a second terminal. And a Pch type M having a drain terminal connected to a second terminal of the inductive load.
An OS transistor, a first diode connected to a source terminal and a back gate terminal of the Pch type MOS transistor, a cathode terminal connected to the terminal, and a first diode connected to an anode terminal to a first potential; MO
A resistor connected between the gate terminal of the S transistor and the first potential, a Zener diode whose anode terminal is connected to the drain terminal of the Pch type MOS transistor, and a cathode terminal connected to the cathode terminal of the Zener diode A second diode having its anode terminal connected to the gate terminal of the Pch MOS transistor, an Nch MOS transistor having its source terminal and back gate terminal connected to the drain terminal of the Pch MOS transistor, A third diode having its cathode terminal connected to the drain terminal of the P-type MOS transistor and its anode terminal connected to the gate terminal of the P-channel MOS transistor;
and an input terminal connected to the gate terminal of the ch-type MOS transistor.

Further, an inductive load constant current driving integrated circuit according to the present invention has an inductive load having a first terminal connected to a first potential, a second terminal of the inductive load and a second terminal. A first Nch-type MOS transistor having a source and a back gate terminal connected to a second terminal of the inductive load,
A first diode whose cathode terminal is connected to the drain terminal of the Nch-type MOS transistor, and whose anode terminal is connected to a first potential;
A resistor connected between the source terminal and the gate terminal of the S transistor, a Zener diode whose anode terminal is connected to the gate terminal of the first N-channel MOS transistor, and a cathode terminal connected to the cathode terminal of the Zener diode A second diode having its anode terminal connected to a first potential, a source terminal and a back gate terminal connected to a gate terminal of the first N-channel MOS transistor, and a drain terminal connected to the Zener diode. Nch connected to the cathode terminal of
A MOS transistor and an input terminal connected to the gate terminal of the second Nch MOS transistor.

Further, an inductive load driving integrated circuit according to the present invention includes an inductive load having a first terminal connected to a first potential, a second terminal of the inductive load and a second potential. And a switch means connected between the second terminal of the inductive load and its source and back gate terminals.
h (N-channel) type MOS transistor;
a diode having its cathode terminal connected to the drain terminal of the h-type MOS transistor and its anode terminal connected to the first potential, a resistor connected between a source terminal and a gate terminal of the Nch-type MOS transistor, A Zener diode having an anode terminal connected to the gate terminal of the N-channel MOS transistor and a cathode terminal connected to the cathode terminal of the diode; a source terminal and a back gate terminal connected to the second potential; Pch (P-channel) type M having a terminal connected to the gate terminal of the Nch-type MOS transistor
It has an OS transistor and an input terminal connected to the gate terminal of the Pch type MOS transistor.

Further, an inductive load constant current driving integrated circuit according to the present invention has an inductive load having a first terminal connected to a first potential, a second terminal of the inductive load and a second terminal. A first Nch-type MOS transistor having a source and a back gate terminal connected to a second terminal of the inductive load,
The cathode terminal is connected to the drain terminal of the Nch-type MOS transistor, and the anode terminal is connected to the first potential. The diode is connected between the source terminal and the gate terminal of the first Nch-type MOS transistor. A resistor, a Zener diode having its anode terminal connected to the gate terminal of the first N-channel MOS transistor, and its cathode terminal connected to the cathode terminal of the diode, and a gate terminal of the first N-channel MOS transistor. A second N-channel MOS transistor having its source terminal connected to the back-gate terminal and its drain terminal connected to the cathode terminal of the Zener diode; and an input terminal connected to the gate terminal of the second N-channel MOS transistor. It is provided with.

[0013]

Since the integrated circuit for driving an inductive load constant current according to the present invention has the above-described configuration, the function realized by the combination of the individual components in the conventional example can be performed without any trouble.
In addition, an integrated circuit can be efficiently formed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing an inductive load constant current driving integrated circuit according to a first embodiment of the present invention. In the figure,
8 is an inductive load, 1 is a current flowing through the inductive load 8,
Nch type MOS transistors 5 and 7 for stopping are respectively connected to both ends of the inductive load 8 by a diode and a zener diode connected so as to flow only in one direction;
6 is an Nch type MOS transistor 2 as a switch means
A diode connected across the inductive load,
3 is a Pch type MOS transistor for turning on / off the Nch type MOS transistor 2, 9 is an inverter for adjusting the polarity of the signal, 4 is a resistor, 100 is a power supply terminal, and 200 and 300 are Nch type MOS transistors 1 and 2, respectively. ON / OF the Pch type MOS transistor 3
F is a signal input terminal, and 400 is a ground terminal.

Next, the operation will be described with reference to FIG. FIG. 2 shows changes in load current and load voltage in the circuit shown in FIG. First, input terminals 200 and 3
When 00 is L, the Nch type MOS transistor 1 is in the OFF state because the gate terminal voltage is L, and the output of the inverter 9 is H, so that the Pch type MOS transistor 3 is OFF.
Since no voltage is applied to the state, that is, no voltage is applied to the gate terminal of the Nch-type MOS transistor 2, the Nch-type MOS transistor 2 is turned off, no voltage is applied to the inductive load 8, and no load current flows.

Next, when the input terminals 200 and 300 are set to H, the Nch type MOS transistor 1 is turned on because its gate terminal voltage is H, and the Pch type MOS transistor 3 is turned on because the output of the inverter 9 is L. Therefore Nc
Since a voltage is applied to the gate terminal of the h-type MOS transistor 2, the Nch-type MOS transistor 2 is turned on, a voltage is applied to both ends of the inductive load 8, and a load current starts flowing. However, since the load current is limited by the back electromotive force of the L component of the inductive load 8, the slope determined by the L component of the inductive load 8, the ON resistance of the Nch type MOS transistor 1, and the resistance component of the inductive load 8. Increase while having.

Next, when the input terminal 200 is set to L again,
Since the gate voltage of the Nch-type MOS transistor 1 becomes L, the Nch-type MOS transistor 1 is turned off. As a result, the current of the inductive load 8 is reduced, so that a back electromotive force is generated in the opposite direction, and the energy stored in the inductive load 8 is discharged. A current flows to the inductive load 8 through the MOS transistor 2. This current is also the L component and the resistance component of the inductive load 8 and the O component of the Nch type MOS transistor 2.
It decreases while being limited by the N resistance and the forward voltage of the diode 6.

As described above, the Nch type MOS transistor 2
Is ON, a constant current flows through the inductive load 8 on average by repeating ON / OFF of the Nch type MOS transistor 1 appropriately. Also, by appropriately changing the duty ratio of ON / OFF of the Nch type MOS transistor 1, the current of the inductive load 8 is varied.
WM control becomes possible.

As described above, if the Nch-type MOS transistor 1 is simply turned off, the load current decreases only at a constant slope, and it takes time. Therefore, the current flowing through the inductive load 8 needs to be reduced rapidly. In this case, the input terminal 300 is set to L, and the Pch type MOS transistor 3 is turned off. Thereby, the Nch from the ground terminal 400
Voltage VT of type MOS transistor 2
When the sum of H, the forward voltage VF of the diode 5, and the Zener voltage VZ of the Zener diode 7 decreases, the Nch-type MOS transistor 2 is turned on, and current flows through the diode 6 and the Nch-type MOS transistor 2. In this case, since the potential difference of the Zener diode 7 is large, the energy consumed between the source and the drain of the Nch type MOS transistor 2 increases, and the energy stored in the inductive load 8 is rapidly discharged. And the current decreases rapidly.

FIG. 3 is a circuit diagram showing an inductive load constant current driving integrated circuit according to a second embodiment of the present invention. The Nch MOS transistor 2 of the first embodiment is replaced by a Pch MOS transistor 13 and the function of the Pch MOS transistor 3 is replaced by an Nch MOS transistor 15.

In the drawing, reference numeral 8 denotes an inductive load, 1 denotes an Nch type MOS transistor for flowing and stopping a current to the inductive load 8, and 5 and 7 denote Pch type MO transistors, respectively.
A diode connected to clamp the gate-drain voltage of the S transistor 13 and a Zener diode. A diode 6 is connected between the gate and the drain of the Pch-type MOS transistor 13 by an Nch-type MOS transistor 15 as a switch. , 14 is P
a diode for preventing reverse current when the ch-type MOS transistor 13 is OFF; 4 a resistor; 100 a power supply terminal;
0, 300 are Nch type MOS transistors 1,
A signal input terminal for turning on / off the Pch-type MOS transistor 15 and a ground terminal 400 are shown.

Hereinafter, the operation will be described with reference to FIG. First, when the input terminals 200 and 300 are L, Nc
Since the gate terminal voltage of the h-type MOS transistor 1 is L, the transistor is OFF, the gate terminal voltage of the N-channel MOS transistor 15 is L, the N-channel MOS transistor 15 is OFF, and the gate terminal of the P-channel MOS transistor 13 is a resistor 4. Pch type MOS for ground terminal potential
The transistor 13 is turned off, no voltage is applied to the inductive load 8, and no load current flows.

Next, when the input terminals 200 and 300 are set to H, the gate terminal voltage of the Nch-type MOS transistor 1 is H, so that the N-channel MOS transistor 15 is ON. Is turned on, a voltage is applied to both ends of the inductive load 8, and a load current starts to flow. However, since the load current is limited by the back electromotive force of the L component of the inductive load 8,
L component of inductive load 8 and Nch type MOS transistor 1
While having a slope determined by the ON resistance and the resistance component of the inductive load.

Next, when the input terminal 200 is set to L again,
When the Nch-type MOS transistor 1 is turned off, the current of the inductive load 8 decreases, so that the back electromotive force is generated in the opposite direction, and the forward voltage VF of the diodes 6 and 14 and the Pch-type MOS transistor 13 Threshold voltage VTH and Nch type MOS transistor 15
When the sum voltage becomes equal to the source-drain voltage, a current flows from the ground terminal 400 to the inductive load 8 through the diode 14 and the Pch-type MOS transistor 13 in order to discharge the energy stored in the inductive load 8. This current is also the L component and the resistance component of the inductive load 8 and the Pch type MO.
It decreases while being limited by the source-drain voltage of the S transistor 2 and the forward voltage of the diode 14.

As described above, the Pch type MOS transistor 1
When the Nch type MOS transistor 1 is appropriately turned ON / OFF while the switch 3 is ON, a constant current flows through the inductive load 8 on average. Also, by appropriately changing the ON / OFF duty ratio of the Nch type MOS transistor 1, the current of the inductive load 8 is varied.
WM control becomes possible.

As described above, if the Nch type MOS transistor 1 is simply turned off, the load current decreases only at a constant gradient, and it takes time. Therefore, it is necessary to rapidly reduce the current flowing through the inductive load 8. In this case, the input terminal 300 is set to L, and the Nch type MOS transistor 15
Is turned off and the diode 6 is disconnected. As a result, the forward voltage VF and P
When the sum voltage of the threshold voltage VTH of the ch-type MOS transistor 13, the forward voltage VF of the diode 5, and the Zener voltage VZ of the Zener diode 7 decreases, P
The channel MOS transistor 13 is turned on, and a current flows through the diode 14 and the channel MOS transistor 13. In this case, since the potential difference of the Zener diode 7 is large, the energy consumed between the source and the drain of the Pch type MOS transistor 13 increases, and the energy stored in the inductive load 8 is rapidly discharged. And the current decreases rapidly.

FIG. 4 is a circuit diagram showing an inductive load constant current driving integrated circuit according to a third embodiment of the present invention. In the figure, reference numeral 8 denotes an inductive load, 1 denotes an Nch-type MOS transistor for flowing and stopping a current to the inductive load 8, and 5 and 7 denote Nch-type MOS transistors 2 respectively.
, A diode and a zener diode connected so as to flow only in one direction between the gate and the source of the IGBT, 6 is a diode connected to both ends of the inductive load by an Nch type MOS transistor 2 serving as a switch means, and 16 is a diode of a zener diode 7. Nch type MOS to short both ends
Transistors 16 and 4 are resistors, 100 is a power supply terminal, 20
0, 300 are Nch type MOS transistors 1,
A signal input terminal for turning on / off the Nch type MOS transistor 16 is shown, and 400 is a ground terminal.

Next, the operation will be described with reference to FIG. First, when the input terminals 200 and 300 are L, Nc
The h-type MOS transistor 1 is turned off because its gate terminal voltage is L, the N-channel MOS transistor 16 is turned off because its gate voltage is L, and no voltage is applied between the gate and source terminals of the N-channel MOS transistor 2. Therefore, the state is turned off, no voltage is applied to the inductive load 8, and no load current flows.

Next, when the input terminals 200 and 300 are set to H, the Nch type MOS transistor 1 is turned on because the gate terminal voltage is H, and the Nch type MOS transistor 1 is turned on.
Reference numeral 6 denotes an ON state, and since no voltage is applied to the gate terminal of the Nch-type MOS transistor 2, the Nch-type MOS transistor 2 is turned off, a voltage is applied to both ends of the inductive load 8, and a load current starts to flow. However, the load current is
Since it is limited by the back electromotive force of the L component of the inductive load 8, it increases while having a slope determined by the L component of the inductive load 8, the ON resistance of the Nch type MOS transistor 1, and the resistance component of the inductive load.

Next, when the input terminal 200 is set to L again,
Since the current of the inductive load 8 decreases, a back electromotive force is generated in the opposite direction, and the voltage across the inductive load 8 is reduced by the forward voltage VF of the diode 5 and the Nch type MOS transistor 1.
6 and the threshold voltage VTH of the Nch-type MOS transistor 2, when the sum voltage becomes equal to the sum voltage of the inductive load 8, the diode 6 and the Nch-type M
A current flows to the inductive load 8 through the OS transistor 2. This current is also the L component, the resistive component and N
The voltage decreases while being limited by the source-drain voltage of the ch-type MOS transistor 2 and the forward voltage of the diode 6.

As described above, the Nch type MOS transistor 1
When the Nch-type MOS transistor 1 is appropriately turned ON / OFF while the switch 6 is ON, a constant current flows through the inductive load 8 on average. Also, by appropriately changing the ON / OFF duty ratio of the Nch type MOS transistor 1, the current of the inductive load 8 is varied.
WM control becomes possible.

As described above, if the Nch type MOS transistor 1 is simply turned off, the load current decreases only at a constant gradient, so that it takes time. Therefore, it is necessary to rapidly reduce the current flowing through the inductive load 8. In this case, the input terminal 300 is set to L, and the Nch-type MOS transistor 16
Is turned off. As a result, the Nc
Threshold voltage V of h-type MOS transistor 2
When the sum voltage of TH, the forward voltage VF of the diode 5 and the Zener voltage VZ of the Zener diode 7 decreases, Nch
The MOS transistor 2 is turned ON, and a current flows through the diode 6 and the Nch MOS transistor 2. In this case, since the potential difference of the Zener diode 7 is large, the energy consumed between the source and the drain of the Nch type MOS transistor 2 increases, and the energy stored in the inductive load 8 is rapidly discharged. And the current decreases rapidly.

FIG. 5 is a circuit diagram showing an inductive load constant current driving integrated circuit according to a fourth embodiment of the present invention. Book 4
The embodiment of the present invention differs from the circuit of the first embodiment in that
In this case, the diodes 5 and 6, which have the same function of preventing the reverse current and the clamp voltage at the time of the discharge and at the time of the rapid discharge, are shared, and have the same effects as the first embodiment. In the third embodiment as well, the diodes 5 and 6 can be shared, and the same effects can be obtained.

FIG. 6 shows an integrated circuit for driving an inductive load constant current which is integrated in a structure in which an N-type epitaxial layer is stacked on a P-type substrate in the first, third and fourth embodiments of the present invention. It is a part of structure sectional drawing. Since the anode of the diode can be constituted by the P-type substrate 27 and the cathode can be constituted by the N-type epitaxial layer 26, the P-type diffusion layer 25 (back gate), the N-type diffusion layer 23 (source), and the N-type diffusion layer 24 (drain) Nch type MO composed of polysilicon wirings (gates) of oxide film layers 21 and 22 and aluminum wiring 20
It can be formed in the same structure as the S transistor.

[0035]

As described above, according to the integrated circuit for driving an inductive load constant current according to the present invention, the first terminal of the inductive load is connected to the first potential, and the first terminal of the inductive load is connected to the first potential. Switch means is connected between the second terminal and the second potential, and Nch
The source and back gate terminals of the (N-channel) type MOS transistor are connected to a second terminal of the inductive load, and the cathode terminal of a first diode is connected to the drain terminal of the Nch type MOS transistor. The anode terminal of the first diode to the potential of
A resistor is connected between the source terminal and the gate terminal of the Nch-type MOS transistor, the anode terminal of the Zener diode is connected to the gate terminal of the Nch-type MOS transistor, and the cathode of the second diode is connected to the cathode terminal of the Zener diode. Connecting the anode terminal of the second diode to the first potential;
a source terminal and a back gate terminal of the channel MOS transistor are connected to the second potential, and a drain terminal is connected to a gate terminal of the N channel MOS transistor;
Since the input terminal is connected to the gate terminal of the type MOS transistor, the function conventionally realized by the combination of individual components can be integrated into an integrated circuit, which is advantageous in cost and can reduce the mounting area. This has the effect.

According to the integrated circuit for driving an inductive load constant current according to the present invention, the first terminal of the inductive load is connected to the first terminal.
And a switch means is connected between a second terminal of the inductive load and a second potential, and a drain terminal of a Pch-type MOS transistor is connected to a second terminal of the inductive load. Connecting the source terminal and the back gate terminal of the Pch-type MOS transistor, connecting the cathode terminal of the first diode to the terminal thereof, connecting the anode terminal of the first diode to a first potential, A resistor is connected between the gate terminal of the type MOS transistor and the first potential, an anode terminal of the Zener diode is connected to a drain terminal of the Pch type MOS transistor, and a cathode terminal of the second diode is connected to the Zener diode. Connect the anode terminal to the Pch
Connected to the gate terminal of the N-type MOS transistor, the source terminal and the back gate terminal of the N-channel MOS transistor are connected to the drain terminal of the P-channel MOS transistor, and the cathode terminal of the third diode is connected to the N-channel MOS transistor.
Connecting the drain terminal of the OS transistor and the anode terminal to the gate terminal of the Pch type MOS transistor;
Since the input terminal is connected to the gate terminal of the Nch type MOS transistor, the same effect as described above can be obtained.

According to the integrated circuit for driving an inductive load constant current according to the present invention, the first terminal of the inductive load is connected to the first terminal.
And a switch means is connected between a second terminal of the inductive load and a second potential. A source of the first N-channel MOS transistor is connected to a second terminal of the inductive load. A back gate terminal is connected, a cathode terminal of the first diode is connected to a drain terminal of the first N-channel MOS transistor, an anode terminal is connected to a first potential, and a source terminal of the first N-channel MOS transistor is connected. A resistor is connected between the first Nch and the gate terminal.
The anode terminal of the Zener diode is connected to the gate terminal of the MOS transistor, the cathode terminal of the second diode is connected to the cathode terminal of the Zener diode, and the anode terminal is connected to the first potential.
The source terminal and the back gate terminal of the S transistor are connected to the gate terminal of the first N-channel MOS transistor, the drain terminal is connected to the cathode terminal of the Zener diode, and the input terminal is connected to the gate terminal of the second N-channel MOS transistor. Are connected, so that the same effect as above can be obtained.

According to the inductive load constant current driving integrated circuit of the present invention, the first terminal of the inductive load is connected to the first terminal.
And a switch means is connected between a second terminal of the inductive load and a second potential, and a source of an Nch (N-channel) MOS transistor is connected to the second terminal of the inductive load. And a back gate terminal, a cathode terminal of the diode is connected to a drain terminal of the Nch-type MOS transistor, an anode terminal is connected to the first potential, and a resistor is provided between a source terminal and a gate terminal of the Nch-type MOS transistor. The anode terminal of the Zener diode is connected to the gate terminal of the Nch-type MOS transistor, the cathode terminal is connected to the cathode terminal of the diode, and the source terminal and the back gate terminal of the Pch (P-channel) MOS transistor are connected to the first terminal. 2 and the drain terminal is connected to the gate terminal of the N-channel MOS transistor. Since so as to connect the input terminal to the gate terminal of the Pch-MOS transistors, the same effects as described above.

According to the inductive load driving integrated circuit of the present invention, the first terminal of the inductive load is connected to the first potential, and the second terminal of the inductive load is connected to the second potential. , A switch means is connected between the inductive load, a source and a back gate terminal of a first N-channel MOS transistor are connected to a second terminal of the inductive load, and a cathode terminal of the diode is connected to the first N-channel MOS transistor. And the anode terminal is connected to a first potential, and the first N
A resistor is connected between the source terminal and the gate terminal of the ch-type MOS transistor, the anode terminal of the Zener diode is connected to the gate terminal of the first N-channel MOS transistor, and the cathode terminal is connected to the cathode terminal of the diode. A source terminal and a back gate terminal of the second N-channel MOS transistor are connected to a gate terminal of the first N-channel MOS transistor, a drain terminal is connected to a cathode terminal of the Zener diode, and a gate of the second N-channel MOS transistor is connected. Since the input terminal is connected to the terminal, the same effect as described above can be obtained.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an inductive load constant current driving integrated circuit according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the integrated circuit for driving an inductive load constant current according to the first to fourth embodiments of the present invention;

FIG. 3 is a circuit diagram showing an inductive load constant current driving integrated circuit according to a second embodiment of the present invention.

FIG. 4 is a circuit diagram showing an inductive load constant current driving integrated circuit according to a third embodiment of the present invention.

FIG. 5 is a circuit diagram showing an inductive load constant current driving integrated circuit according to a fourth embodiment of the present invention.

FIG. 6 is a cross-sectional view of an inductive load constant current driving integrated circuit integrated in a structure in which an N-type epitaxial layer is stacked on a P-type substrate in the first, third, and fourth embodiments of the present invention. It is a figure which shows a part of.

FIG. 7 is a circuit diagram showing an integrated circuit for driving an inductive load constant current according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nch type MOS transistor 2 Nch type MOS transistor 3 Pch type MOS transistor 4 Resistance 5 Diode 6 Diode 7 Zener diode 8 Inductive load 9 Inverter 11 Switch 12 Switch 13 Pch type MOS transistor 14 Diode 15 Nch type MOS transistor 16 Nch type MOS Transistor 20 Aluminum wiring 21 Oxide film 22 Polysilicon wiring (gate) 23 N-type diffusion layer (source) 24 N-type diffusion layer (drain) 25 P-type diffusion layer (back gate) 26 N-type epitaxial layer 27 P-type substrate 28 Parasitic diode

Claims (6)

(57) [Claims] An inductive load having a first terminal connected to a first potential; a switch connected between a second terminal of the inductive load and a second potential; An Nch (N-channel) MOS transistor having a source and a back gate connected to a second terminal of the load; a cathode connected to a drain of the Nch MOS transistor; and an anode connected to the first potential A first diode having a terminal connected thereto; a resistor connected between a source terminal and a gate terminal of the Nch-type MOS transistor; a Zener diode having an anode terminal connected to the gate terminal of the Nch-type MOS transistor; A second diode having its cathode terminal connected to the cathode terminal of the diode and its anode terminal connected to the first potential. Pch (P channel) having its source terminal and back gate terminal connected to the second potential and its drain terminal connected to the gate terminal of the Nch type MOS transistor.
An inductive load constant current integrated circuit, comprising: a MOS transistor; and an input terminal connected to a gate terminal of the Pch MOS transistor. 2. An inductive load having its first terminal connected to a first potential; switch means connected between a second terminal of the inductive load and a second potential; A Pch-type MOS transistor having a drain terminal connected to a second terminal of the load, a source terminal and a back gate terminal of the Pch-type MOS transistor connected, a cathode terminal connected to the terminal, and a first potential A first diode connected to the anode terminal, a resistor connected between the gate terminal of the Pch-type MOS transistor and the first potential, and a Zener connected to the anode terminal to a drain terminal of the Pch-type MOS transistor A diode, a cathode terminal of which is connected to a cathode terminal of the Zener diode, and a gate terminal of the Pch-type MOS transistor. A second diode connected to the anode terminal, Nch-type MO connected to its source terminal and the back gate terminal to the drain terminal of the Pch-MOS transistor
An S transistor; a third diode having its cathode terminal connected to the drain terminal of the Nch-type MOS transistor and its anode terminal connected to the gate terminal of the Pch-type MOS transistor; and a gate terminal of the Nch-type MOS transistor. An inductive load constant current driving integrated circuit, comprising: an input terminal connected thereto. 3. An inductive load having its first terminal connected to a first potential; switch means connected between a second terminal of the inductive load and a second potential; A first Nch-type MOS transistor having a source and a back gate terminal connected to a second terminal of the load; a cathode terminal connected to a drain terminal of the first Nch-type MOS transistor; A first diode connected to an anode terminal, a resistor connected between a source terminal and a gate terminal of the first N-channel MOS transistor, and an anode terminal connected to a gate terminal of the first N-channel MOS transistor And a second diode having its cathode terminal connected to the cathode terminal of the Zener diode and its anode terminal connected to a first potential. A second N-channel MOS transistor having a source terminal and a back-gate terminal connected to a gate terminal of the first N-channel MOS transistor, and a drain terminal connected to a cathode terminal of the Zener diode; 2. An inductive load constant current driving integrated circuit, comprising: an input terminal connected to a gate terminal of two Nch-type MOS transistors. 4. An inductive load having its first terminal connected to a first potential; switch means connected between a second terminal of the inductive load and a second potential; An Nch (N-channel) MOS transistor having a source and a back gate connected to a second terminal of the load; a cathode connected to a drain of the Nch MOS transistor; and an anode connected to the first potential A diode connected to a terminal; a resistor connected between a source terminal and a gate terminal of the Nch-type MOS transistor; an anode terminal connected to a gate terminal of the Nch-type MOS transistor; and a cathode connected to a cathode terminal of the diode. Connecting a source terminal and a back gate terminal to the second potential and connecting the source terminal and the back gate terminal to the second potential; Pch (P channel) with a rain terminal connected to the gate terminal of the Nch MOS transistor
An inductive load constant current integrated circuit, comprising: a MOS transistor; and an input terminal connected to a gate terminal of the Pch MOS transistor. 5. An inductive load having its first terminal connected to a first potential; switch means connected between a second terminal of the inductive load and a second potential; A first Nch-type MOS transistor having a source and a back gate terminal connected to a second terminal of the load; a cathode terminal connected to a drain terminal of the first Nch-type MOS transistor; A diode connected to an anode terminal, a resistor connected between a source terminal and a gate terminal of the first N-channel MOS transistor, and an anode terminal connected to a gate terminal of the first N-channel MOS transistor; A Zener diode having a cathode terminal connected to the cathode terminal of the diode, and a source connected to a gate terminal of the first N-channel MOS transistor. A second Nch-type MOS transistor having a terminal connected to the back gate terminal and a drain terminal connected to the cathode terminal of the Zener diode; and an input terminal connected to the gate terminal of the second Nch-type MOS transistor. An integrated circuit for driving an inductive load and a constant current. 6. An integrated circuit for driving an inductive load and a constant current, which is integrated in a structure in which an N-type epitaxial layer is stacked on a P-type substrate, wherein the N-type epitaxial layer is a back gate.
And a diode having an anode formed of a P-type substrate and a cathode formed of an N-type epitaxial layer serving as a back gate of the Nch-type MOS transistor. Item 6. An integrated circuit for driving an inductive load constant current according to any one of Items 3 to 5.