JPS59123003A - Driving circuit - Google Patents

Abstract

PURPOSE:To prevent the runaway of a load owing to a fault of a driving circuit which is driven with a pulse signal by adding a monostable multivibrator to the driving circuit. CONSTITUTION:Both the output of an oscillating circuit 1 and the output of an injection quantity setter 2 are given to a data pulse converting circuit 3 and converted into the pulse proportional to the set data. This converted pulse signal is supplied to both a gate circuit 4 and a monostable multivibrator 5, and the output of the circuit 4 is sent to a driving circuit 6. The vibrator 5 works on the pulse signal and produces a pulse which is little longer than the time width of the pulse signal and applies the pulse to the circuit 4. In other words, the gate 4 is opened only while the vibrator 5 delivers an output, and the output of the converter 3 is led to the circuit 6 to actuate a load 7. In such a constitution, the runaway of the load due to a circuit fault can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a driving method for driving a load using a pulse signal, which enables safe driving even when the pulse signal becomes fixed at a certain voltage level due to some kind of circuit abnormality. This relates to a drive circuit.

Usually, the drive method involves driving the load at a constant frequency;
Alternatively, there are various methods for driving the load by varying the frequency according to a set value.A4 various methods are available, and a driving method often used for infusion pumps will be described below as an example.

Many of these types of pumps are configured so that the injection volume can be varied, and high injection accuracy is required. In particular, with microinjection pumps, medical solutions (e.g. nutrients, hepadan,
It is often used for the purpose of injecting insulin, etc.
Depending on the drug solution, it is necessary to completely prevent abnormal injection due to runaway of the injection pump for safety reasons. However, the drive method used in conventional infusion pumps is often to operate a motor drive circuit using a pulse signal and rotate the motor for a certain period of time (the time the pulse signal is output). If the motor is fixed at the "H" level (or "L" level) due to some kind of circuit abnormality, there is a concern that the motor will rotate continuously and cause excessive injection. (H1
:H1gk, "L" :Low) Therefore, the inventor of the present invention has studied various methods to improve the safety-related shortcomings of the conventional drive circuit, and as a result, has arrived at the present invention.

Therefore, it is an object of the present invention to add a monostable multi-by-break to a normal drive circuit driven by a pulse signal, thereby preventing the load from running out of control due to circuit abnormality and providing stable injection operation. It is an object of the present invention to provide a drive circuit that achieves the following. ) In order to achieve this objective, the drive circuit according to the present invention operates a motor drive circuit with a pulse signal, and uses a monostable multi-channel motor that outputs a pulse slightly longer than the time width of the emitted pulse in the circuit that rotates the motor for a certain period of time. The present invention is characterized in that a vibrator circuit is inserted, and the motor drive circuit is configured to be effective only while the vibrator circuit is outputting power.

With the above configuration, even if the pulse signal is fixed at the 1H level or 1L level due to a circuit abnormality, the motor will be stopped by the output of the monostable multivibrator.

Next, embodiments of the present invention will be described in detail with reference to the attached figures.

FIG. 1 shows a schematic diagram of a drive circuit according to the present invention.

The output of the oscillation circuit l and the injection amount setting device 2. The outputs of the data path/lz and path conversion circuits 3 are respectively converted into pulses having a frequency or a time width proportional to the set data. The pulse signal converted in this way is input to the gate circuit and the monostable multivibrator,
The output of gate circuit≠ is led to the next drive circuit B.

The monostable vibrator j is activated by a pulse signal, generates a pulse output slightly longer than the time width of the signal, and is configured to lead the output to the gate circuit≠. That is, the gate circuit G is opened only while the monostable multivibrator j is outputting, and the output of the data pulse converter is guided to the drive circuit B to operate the load 7 (the motor in this example).

Now, when the pulse signal input to the gate circuit≠ is fixed at the 'H' level (or 1L level) due to some circuit abnormality, if the monostable multi-node ibrator j is not set, the load 7 will be continuous. The drive circuit according to the present invention is in an operating state, that is, it goes out of control. However, in the drive circuit according to the present invention in which the monostable multivibrator j is installed, it does not operate after it operates with the last normal pulse signal, and the gate circuit ≠ becomes invalid. The pulse signal is not input to the drive circuit B and the load is not driven.In other words, even if there is a circuit abnormality, continuous operation can be prevented.

Although the present invention has been described above as a preferred example in which it is used in an infusion pump drive circuit, it is of course possible to make minor design changes without departing from the spirit of the present invention. be.

[Brief explanation of the drawing]

FIG. 7 is a block diagram according to the present invention. age 14

Claims (1)

[Claims] In a drive method that drives a load using an intermittent operation signal,
A monostable multivibrator activated by this signal is provided and set to output a pulse slightly longer than the signal, and when the pulse is output through the gate circuit, the load can be driven by the signal. A drive circuit characterized in that it is configured such that it is impossible to drive a load when there is no output.