JPS6158844B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive device for driving a proportional solenoid that is displaced in response to a supplied current, for example to control the flow rate of a gas-liquid fluid.

As an example of a proportional solenoid, a structure shown in FIG. 1 devised by the present inventors will be described below. 140 and 141 are housings that are fixed to each other with screws. 142a is a tubular support made of magnetic material, and the housing 1
40, and reference numeral 142b is a disk-shaped support made of a magnetic material, which is fixed to the housing 140, and is arc-shaped and faces each other and is magnetized with an N pole on the inside and an S pole on the outside. Two permanent magnets 143 and 144 are adhesively fixed to the housing using an adhesive. 145 is a cylindrical shaft 14 fixed to the housing 141 with a spool.
Move up and down on the outer circumference of 6. A coil 147 is wound around the spool 145. A spring 145 pushes the spool 145 downward. 14
9 is a lead wire at the beginning of winding of the coil 147;
Reference numeral 150 denotes lead wires at the end of winding of the coil 147, both of which are connected to the drive circuit. The cylindrical shaft 146 is provided with isosceles triangular slits 146a as shown on both sides, that is, at two locations. As the spool 145 moves on the shaft 146, the slit 14 is moved by the spool 145.
The opening degree of 6a changes to control the amount of gas-liquid fluid flowing from the inlet pipe 152 to the outlet pipe 153. The amount of displacement, that is, the amount of movement of the spool 145 is proportional to the square root of the opening area of the slit 146a.

To explain its operation with the above configuration, if the inside of the permanent magnets 143, 144, which have arcuate cross-sectional shapes, are the N poles and the outside of the magnets 143, 144 are the S poles, the magnetic path will shift from the inside N pole of the permanent magnet 143. 14
6, passes through the support 142b and the support 142a, and reaches the outer S pole of the permanent magnet 143. Similarly, the inside of the permanent magnet 144, the shaft 146, the support 1
42b, 142a, and a magnetic path is formed outside the permanent magnet 144. Therefore, permanent magnets 143, 14
A parallel magnetic field is applied from the inside of the shaft 146 toward the center of the shaft 146. When a current is passed through the coil 147 in this magnetic field, an electromagnetic force acts on the coil 147 in the downward direction in the figure due to Fleming's law. Therefore, the spool 145 moves downward and stops when the force of the spring 148 is balanced. In this case, the electromagnetic force is proportional to the product of the number of turns N of the coil 147 and the current i flowing through the coil.

The number of turns N is constant, and the electromagnetic force is proportional to the current flowing through the coil 147. On the other hand, the force of the spring 148 is the product of the amount of movement and the spring constant. Therefore, the current flowing through the lead wires 149, 150 and the amount of movement are proportional to the square root of the opening area of the slit of the shaft 146, that is, the supplied current is proportional to the square root of the opening area of the slit.

However, the problem here is that friction between the spool 145 and the shaft 146 prevents smooth operation. To reduce this friction, spool 1
45 and the shaft 146, but if this is done, there is a problem that leakage of gas-liquid fluid increases and accuracy deteriorates.

The present invention has been made in view of the above problem, and by changing the current that drives the proportional solenoid to a stepwise waveform current value that changes stepwise, it is possible to improve the movement of the spool and control the gas-liquid fluid with high precision. The purpose is to

The following is an example in which the present invention is applied to an exhaust gas purification device that adjusts the amount of secondary air supplied to the exhaust system of an internal combustion engine according to the output signal of an air-fuel ratio detector and purifies exhaust gas using a three-way catalyst. state FIG. 2 shows the first embodiment. In FIG. 2, 1 is an internal combustion engine, 2 is an intake pipe, and 3 is an exhaust pipe. A carburetor 4 is provided in the intake pipe 2 and is configured to supply air-fuel mixture to the engine 1. This carburetor 4 has a bench lily 6 and a throttle valve 7. Further, 5 is an air cleaner, which cleans the air taken into the engine 1. A known air-fuel ratio detector 9 is installed in the exhaust pipe 3, detects the air-fuel ratio based on the oxygen concentration in the exhaust gas, and outputs an output according to the air-fuel ratio as shown in FIG. Further, a three-way catalyst 8 is provided downstream of the air-fuel ratio detector 9. As is well known, the three-way catalyst 8 converts CO in the exhaust gas flowing into it,
Promotes oxidation and reduction of HC and NOx and purifies these harmful components. Especially when the air-fuel ratio of the engine exhaust system is around the predetermined (theoretical) air-fuel ratio (147), CO,
Purifies both HC and NOx with high purification performance. Reference numeral 10 denotes an air pump driven by the engine 1, which serves as air supply means. Reference numeral 11 denotes a relief valve which serves as a pressure regulating means, and the air discharged from the air pump 10 is transferred to a proportional solenoid 14 which serves as an air control valve.
It is provided in the middle of the supply pipe 12 leading to the inlet of the
It is for adjusting the pressure within this supply pipe line 12. One diaphragm chamber 1 of this relief valve 11
14 is connected to the conduit 12 through the conduit 13. The other diaphragm chamber 113 is connected to the pipe 15.
It is connected to a conduit 15 downstream of the air control valve 14 via a. This relief valve 11 functions to keep the pressure difference between the output of the conduit 12 and the conduit 15 constant.
The air control valve 14 has an inlet side connected to the pipe line 12 as described above.
The outlet side is connected to one end of the conduit 15, and is connected to a discrimination circuit 16 and a drive circuit 17, which will be described later.
This is a proportional electromagnetic actuation type in which the spool is continuously displaced in proportion to the control signal, and the amount of secondary air is controlled in proportion to this control signal. The other end of the pipe line 15 is connected to the exhaust pipe 3. The determination circuit 16 determines whether the air-fuel ratio is larger or smaller than a predetermined (theoretical) air-fuel ratio based on the output signal of the air-fuel ratio detector 9 at predetermined intervals, and outputs the result to the drive circuit 17. In response to this discrimination signal, a control signal in which a predetermined value is added or subtracted from the previous value is output, and the opening degree, that is, the displacement amount of the air control valve 14 is controlled by this control signal.

The detailed structure and function of the relief valve 11 will be explained. In the relief valve 11, the pressure in the pipe line 12 and the pressure in the pipe line 15 are introduced into both diaphragm chambers 114 and 113, and the pressure difference between the two pressures causes the pressure in the diaphragm 111 to
The valve body 117 and the valve seat 119 release the air in the pipe line 12 to the atmosphere by swinging the valve body 117 and the valve seat 119. In the figure, 110 is a housing 112 is a spring, 1
15 is bellow frame, 116 is shaft, 120
is a pressure chamber open to the atmosphere. Spring 1
12 exerts a force to press the diaphragm 111 to the left side in the figure, that is, to close the valve body 117.
The shaft 116 includes the diaphragm 111 and the valve body 11
Connect 7. Here, the first diaphragm chamber 11
3 and the second diaphragm chamber 114 have the same pressure receiving area. The absolute value of the positive pressure acting on the first diaphragm chamber 113 is P ₂ , the absolute value of the positive pressure acting on the second diaphragm chamber 114 is P ₁ , and the second diaphragm chamber 1
13 and 114 is A, the force W acting in the right direction of the diaphragm 111, that is, in the direction of opening the valve body 117, is expressed as W=(P ₁ -P ₂ )×A. If the pressure P ₁ in the air pump side pipe line 12 increases now, the diaphragm 111 moves to the right. Therefore, the valve body 117 moves in the direction in which it is opened. Then, the opening area between the valve body 117 and the valve seat 119 increases, and the air in the pipe line 12 flows into the pressure chamber 12.
0 to the atmosphere increases, the pressure in the pipe line 12, that is, the pressure _P1 in the second diaphragm chamber 114 decreases, and the force W and the force F of the spring 112 decrease.
The pressure difference between the two pressures P ₁ and P ₂ is eventually maintained at a constant value. Even when the pressure P ₁ decreases, the pressure difference is maintained at a constant value in the same way.

A detailed explanation of the proportional solenoid 14 is omitted in FIG. 1, but if the difference between the pressure in the pipe line 12 and the pressure in the pipe line 15 is constant, the air flow rate at the outlet of the proportional solenoid 14 is determined as an experimental value by the opening of the slit. It has been observed that it is approximately proportional to the square root of the area.
Since this pressure difference is controlled to be constant by the relief valve 11 as described above, the proportional solenoid 1
The air flow rate can be controlled in proportion to the current input to 4.

Next, the detailed configuration and functions of the discrimination circuit 16 will be explained with reference to FIG. In Figure 4, input terminal 1
60 is connected to the output terminal of the air-fuel ratio detector 9, and the other input terminal 161 is connected to the ground terminal of the air-fuel ratio detector 9. Note that the lead wire from the air-fuel ratio detector 9 uses a shielded wire. Input terminal 160 is connected to a non-inverting input of buffer amplifier 164 via resistor 162. A noise absorbing capacitor 163 is inserted between the non-inverting input and the ground terminal. Input terminal 161 is grounded. The buffer amplifier 164 uses an IC product number CA3130 manufactured by RCA. The inverting input terminal of the buffer amplifier 164 is connected to the output terminal. Further, the output terminal is connected to the non-inverting input terminal of the comparator 165. The output terminal of the comparator 165 is connected to the output terminal 167 of the discrimination circuit 16.

Next, to explain the operation of the discrimination circuit 16, when the output voltage Vx of the air-fuel ratio detector 9 is higher than the set voltage Vr, that is, when the air-fuel ratio of the exhaust system is lower than the predetermined air-fuel ratio, the output of the comparator 165 is 1. Therefore, when the output voltage Vx is smaller than the set voltage Vr, that is, when the air-fuel ratio of the exhaust system is larger than the predetermined air-fuel ratio, the output of the comparator 165 becomes C.

Next, the detailed configuration and functions of the drive circuit 17 will be explained with reference to FIG. The drive circuit 17 is composed of a staircase wave generation circuit 18 and a current amplification circuit 19. First, the staircase wave generation circuit 18 will be explained. The output 167 of the discrimination circuit 16 is connected to the input 170 of the drive circuit 17. Output 1 of the drive circuit 17
96 is connected to one end of the proportional solenoid 14. Further, the terminal 197 is connected to the negative terminal of the power source. The input 170 is connected to the U/D input of an up-down counter 174. 17
1 is an astable multivibrator, which uses RCA's IC part number CD4047. A constant voltage Vc is applied to terminals 4, 5, 6, and 14 of the IC terminals, and terminals 7, 8, 9, and 12 are grounded to operate as an astable multivibrator. The oscillation frequency is determined by the time constant of the capacitor 172 and resistor 173. The outputs of the astable multivibrators 171 are connected to one input of an AND gate 179, respectively. The up-down counter 174 uses two RCA IC part number 4029 and is a binary up-down counter. The clock input measurement CL is connected to the output terminal of the AND gate 180, and each output terminal Q ₁ , Q ₂ , Q ₄ , Q ₅ is connected to R-
They are connected to the 2R ladder network circuit 181 in order from the bottom row. Each input terminal of the 5-input AND gate 175 is connected to the up-down counter 1.
74 output terminals Q ₁ , Q ₂ , Q ₃ , Q ₄ , and Q ₅ , respectively. Each input terminal of the 5-input OR gate 176 is connected to each output terminal of the up-down counter 174.
They are connected to Q ₁ , Q ₂ , Q ₃ , Q ₄ , and Q ₅ respectively.
One input terminal of the NAND gate 177 is the terminal 1
70, the other input terminal is the AND gate 175
It is connected to the output terminal of. The NAND gate 177
The output terminal of is connected to the other input terminal of AND gate 179. One input terminal of the OR gate 178 is connected to the input 170 of the drive circuit 17, and the other input terminal is connected to the OR gate 176. The output of the OR gate 178 is connected to one terminal of an AND gate 180. The output terminal of AND gate 179 is connected to the other input terminal of AND gate 180. The output of the AND gate 180 is connected to the clock input CL of the up-down counter 174 as described above. The output of R-2R ladder network 181 is connected to the non-inverting input of buffer amplifier 182. The buffer amplifier 18
The inverting input terminal of No. 2 is connected to the output terminal. The output terminal of the buffer amplifier 182 is connected to one fixed terminal of a variable resistor 183. The variable resistor 1
The other fixed terminal 83 is grounded, and the variable terminal 184 is connected to the input terminal 190 of the current amplification circuit 19. The input terminal is connected to a non-inverting input of an amplifier 192 via a resistor 191. The amplifier 1
The output of 92 is connected to the base of transistor 194, and the inverting input is connected to the transistor 1 through resistor 193.
It is connected to the emitter of 94. The emitter of the transistor 194 is also connected to one end of a resistor 195. The other end of the resistor 195 is grounded. A capacitor 199 is inserted between the base and collector of the transistor 194. The transistor 1
The collector of 94 is the output terminal 196 of the drive circuit 17.
It is connected to. Output terminal 196 of drive circuit 17
is connected to one end of the coil of the proportional solenoid 14, and the other end of the coil of the proportional solenoid 14 is connected to the positive terminal of the battery Ba via the key switch Ks. Further, the power terminal 172 is connected to the negative electrode of the battery Ba.

Note that the power supply circuit that generates the constant voltage Vc to be supplied to the power supply terminal of the IC is well known and is therefore omitted.

To explain the operation of the drive circuit 17 having the above configuration, when the input 170 of the drive circuit 17 is "1", the up/down counter 174 becomes an up count;
When it is “0”, it becomes a down count. 5 input AND
The gate 175 is for preventing the up-down counter 174 from overflowing, and when all the outputs of the up-down counter 174 are "1".
The output of AND gate 175 becomes "1". And when the U/D input is “1”, the NAND gate 17
Since the output of 7 is “0”, AND gate 179
The output of oscillator 171 becomes "0" and the clock signal from oscillator 171 is stopped. On the other hand, 5 input OR gate 176
This is to prevent further down-counting after all the outputs of the up-down counter 174 have become "0". When all the outputs of the up-down counter 174 become "0", the output of the 5-input OR gate 176 becomes "0". Since the U/D input is "0", the output of the OR gate 178 is "0" and
The clock signal from gate 179 is stopped by AND gate 180. In other words, when the U/D input is 1 and the outputs of the up-down counter 174 are all 1, and when the U/D input is 0 and the outputs of the up-down counter 174 are all 0, no clock is input to the clock input terminal CL. It is prohibited. Otherwise, a clock signal is applied to the clock input. Note that the oscillation frequency of the oscillator 171, that is, the frequency of the clock signal, is approximately 100 Hz. When the air-fuel ratio is currently less than the predetermined air-fuel ratio and the output of the discrimination circuit 16 is "1", the up-down counter 174 counts up by one for each clock from the oscillator 171, and when the air-fuel ratio is greater than the predetermined air-fuel ratio When the output of the discrimination circuit 16 reaches "0", it counts down every clock. The ladder network 181 is an R-2R type converter that converts the binary output value of the up-down counter 174 into a staircase voltage. The buffer amplifier 182 amplifies the output of the ladder network 181, and operates in the same manner as the buffer amplifier 165 of the discrimination circuit 16, converting a high input impedance to a low impedance. Variable resistor 18
The output voltage Vr of the buffer amplifier 182 is divided by 3 to obtain the voltage KVr. Next, the current amplification circuit 19 will be explained. Resistance 191, 193, 195,
An amplifier 192 and a transistor 194 constitute a current amplification circuit, and an output constant current corresponding to the input voltage KVr is obtained as the collector current of the transistor 194. The operation is well known and will therefore be omitted. The capacitor 191 is used to prevent oscillation since the collector load of the transistor 194 is an electromagnetic coil.

Next, to explain the operation of the above-mentioned device as a whole, when the output voltage Vr of the air-fuel ratio detector 9 is higher than the output voltage Vr, that is, when the air-fuel ratio of the exhaust system is lower than the predetermined air-fuel ratio, the output of the discrimination circuit 16 becomes "1". Since the count value of the up-down counter 174 increases every period of the oscillator 171, that is, every 0.01 seconds (100 Hz), the output voltage Vr of the buffer amplifier 182 increases in a corresponding step. Therefore, the voltage at the non-inverting input of the amplifier 192 of the current amplifier circuit 19
Since KVr also increases stepwise, the current flowing through the coil 147 of the proportional solenoid 14 increases accordingly. Therefore, spool 145 and shaft 1
Even if there is some friction at 46, there is almost no problem and the opening area of the slit increases proportionally. On the other hand, since the pressure difference between the input and output of the proportional solenoid 14 is always constant due to the relief valve 11, the amount of secondary air flowing through the proportional solenoid 14 is proportional to the opening area. As the amount of air increases, the air-fuel ratio increases and approaches the predetermined air-fuel ratio. Then, the output voltage of the air-fuel ratio detector 9 becomes smaller and finally becomes smaller than the set voltage Vr. Then, the up-down counter 170 counts down and the output value decreases by 1 count every 0.1 seconds. Therefore, the amount of secondary air flowing through the air control valve 14 becomes smaller, and the air-fuel ratio becomes smaller. In this way, the air-fuel ratio of the exhaust system is controlled to converge to a predetermined (theoretical) air-fuel ratio.

The control amount of the proportional solenoid 14 in FIG. 5 is determined by the number of bits in the up-down counter 174.
In the embodiment, since there are 5 bits, a staircase wave of 32 steps can be obtained. However, in addition, the control amount, that is, the up-down counter and the R-2R type ladder circuit network 18
As the number of 1 bits increases, the amount of change in voltage per step of the output of the staircase wave generation circuit 17 decreases, so naturally the spool 14 of the proportional solenoid 14 decreases.
The friction between the shaft 146 and the shaft 146 affects the movement of the shaft 146. As a countermeasure against this problem, a drive circuit 17A of the second embodiment as shown in FIG. 6 is effective.

To explain the drive circuit 17A shown in FIG. 6, in the drive circuit 17A, the oscillation frequency of the oscillator 171 is set to twice that in the first embodiment shown in FIG. 5, that is, 200 Hz. By connecting the input of the frequency dividing circuit 171a to the output of the oscillator 171, and connecting the output of the frequency dividing circuit 171a to one terminal of the AND gate 179,
The clock frequency input to the AND gate 179 is 100Hz, and the operation of the staircase wave generation circuit 18 is the first.
It is the same as the example. In this second embodiment, the portion added to the first embodiment is the trigger circuit 2.
0, so only this circuit 20 will be explained.

One input of the AND gate 201 is connected to the output of the oscillator 171, and the other input of the AND gate 201 is connected to the output of the frequency dividing circuit 171a. The output of the AND gate 201 is connected to one fixed terminal of a variable resistor 202. The other fixed terminal of the variable resistor 202 is grounded, and the variable terminal is connected to the analog switch 2 via a resistor 203.
It is connected to the 05 and 206 inputs. The input of the inverter 204 is connected to the output of the discrimination circuit 16, that is, the input 170 of the drive circuit 17A. The input of the inverter 204 is an analog switch 205.
Control input, output is analog switch 2
06 control inputs, respectively. The output of the analog switch 206 is sent to the amplifier 20.
The output of analog switch 205 is connected to the inverting input of amplifier 207 and the non-inverting input of amplifier 207, respectively. Analog switches 205 and 206 are RCA
One end of the resistor 208 is connected to the variable terminal of the variable resistor 183, and the other end is connected to the non-inverting input of the amplifier 207. A resistor 209 is inserted between the inverting input of amplifier 207. A resistor 210 is inserted between the inverting input of amplifier 207 and ground. amplifier 2
The output of 07 is connected to the input 190 of the current amplification circuit 19 instead of the output terminal of the staircase wave generation circuit 18 in the first embodiment.

The operation of the main components of the second embodiment described above will be explained with reference to the waveform diagram of FIG. 7. The output waveform of the oscillator 171 is shown in FIG. 7A. The frequency dividing circuit 171a is 1/
Since the frequency is divided by 2, the waveform shown in FIG. 7B is obtained. If the output waveform of the discrimination circuit 16 is C, then the waveform of the variable terminal of the variable resistor 183 in FIG. 6 is as shown in FIG.
become that way. On the other hand, since the output waveform of the AND gate 201 is ANDed between A and B in FIG. 7, it becomes the waveform in FIG. 7E. When the output signal of the discrimination circuit 16 is "1", the analog switch 205 is conductive, and when it is "0", it is inverted by the inverter 204, so that the analog switch 206 is conductive. On the other hand, the amplifier 207 and resistors 209 and 210 constitute a non-inverting amplification circuit. Now, if the AND gate 201 is “1”, that is, the high level voltage is Vc,
When the division ratio of the variable resistor 202 is K ₁ , the voltage at the variable terminal of the variable resistor 202 is K ₁ Vc. Therefore, when the output of the discrimination circuit 16 is "1", that is, at a high level, the analog switch 206 is cut off and the analog switch 205 is conductive, so that the output voltage of the amplifier 207 is set to the voltage at the variable terminal of the variable resistor 183 by KVr. Then, it becomes KVr + K ₁ Vc. Further, when the output of the discrimination circuit 16 is "0", that is, at a low level, the analog switch 206 is conductive, and the analog switch 205 is cut off, so the amplifier 207
The output voltage of is KVr−K ₁ Vc. Therefore, the output voltage waveform of amplifier 207 becomes the waveform shown in FIG. 7F.
In other words, when the staircase waveform goes up, a 2.5ms trigger pulse is added with a voltage of K ₁ Vc, and when it goes down, a 2.5ms trigger pulse is subtracted with a voltage of K ₁ Vc, so when the staircase waveform changes, the trigger pulse is Since the amount of change in the voltage applied to the proportional solenoid increases accordingly, malfunctions caused by mechanical friction can be significantly reduced.

Note that in each of the above embodiments, the switching period of the control output signal of the drive circuit 17 is determined by the constant oscillation period of the oscillator 171, but the speed of the secondary air passing through the proportional solenoid 14, that is, the above-mentioned delay time is determined by the internal combustion engine. Focusing on the fact that it depends on the rotation speed, the oscillator 1 generates a signal with a period corresponding to the engine rotation, for example, a signal synchronized with the ignition signal of a distributor, etc.
It can be used in place of the oscillation signal of 71. In addition to the above-mentioned embodiments, a staircase wave generation circuit using a microcomputer can also be used as the staircase wave generation circuit based on the same technical idea. In addition, the proportional solenoid 14 was used as an air control valve to control the secondary air of an internal combustion engine, but it can also be used to control air that bypasses a throttle valve if the solenoid is used for an internal combustion engine. However, it goes without saying that the present invention can also be applied to various other types of displacement control.

As described above, the device of the present invention calculates the control amount at each predetermined clock, holds or stores this calculated value until the next calculation, and outputs a step-wave voltage of a value corresponding to this calculated value. The configuration includes a staircase wave generation circuit consisting of a circuit, and a current amplification circuit that outputs a current value corresponding to the output voltage of the staircase wave generation circuit to a proportional solenoid, and drives the proportional solenoid with a step-shaped staircase waveform current. Therefore, the sliding part of the proportional solenoid can have a good start of movement and the static friction can be reduced, so the hysteresis of the displacement amount of the proportional solenoid can be significantly reduced.
It also has the excellent effect of preventing malfunctions caused by deposits such as dust.

Further, in the present invention, a pulse voltage having a time width smaller than the time width of the cycle of the clock is generated in synchronization with the predetermined clock, and this pulse voltage is applied when the output value of the staircase wave generation circuit tends to increase. is additionally equipped with a trigger circuit that subtracts and outputs the result when the addition tends to decrease, which has the excellent effect of improving the operation of the proportional solenoid and reducing hysteresis.

[Brief explanation of the drawing]

Figure 1 is a structural diagram of an example of a proportional solenoid used in the present invention, Figure 2 is a configuration diagram showing the first embodiment of the present invention, and Figure 3 is an output characteristic diagram of the air-fuel ratio detector shown in Figure 2. , FIG. 4 is an electric circuit diagram of the discrimination circuit shown in FIG. 2, FIG. 5 is an electric circuit diagram of the drive circuit shown in FIG. 2, and FIG. 6 is an electric circuit diagram of the drive circuit in the second embodiment of the present invention. 7 are explanatory diagrams of the operation of the drive circuit shown in FIG. 6. 17... Drive circuit, 18... Staircase wave generation circuit,
19... Current amplification circuit, 20... Trigger circuit.

Claims (1)

[Scope of Claims] 1. A device for driving a proportional solenoid that is displaced in accordance with a supplied current, which calculates a control amount at every predetermined cycle and generates a step-wave voltage of a value corresponding to the calculated value. A proportional solenoid drive device comprising: a wave generation circuit; and a current amplification circuit that outputs a current having a value corresponding to the output voltage of the staircase wave generation circuit to the proportional solenoid. 2. A device for driving a proportional solenoid that is displaced in accordance with a supplied current, which includes a staircase wave generation circuit that calculates a control amount at predetermined intervals and generates a step wave voltage of a value corresponding to the calculated value; When the output voltage of this staircase wave generation circuit decreases from the previous calculation value, a pulse voltage with a time width smaller than the time width of the operation cycle of this staircase wave generation circuit is subtracted from the output voltage of the wave generation circuit, and the pulse voltage is increased. 1. A proportional solenoid drive device comprising: a trigger circuit that generates an added output voltage when the trigger circuit generates an added output voltage; and a current amplification circuit that supplies the proportional solenoid with a current having a value corresponding to the output voltage of the trigger circuit.