Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
172 words
In a driving circuit of a solenoid actuated device of the type wherein a plunger is actuated by a solenoid coil, the driving circuit comprising a comparator having a first input supplied with an analog control signal representing an operating condition of a member to be controlled by the plunger, a second input, and an output; and a power amplifier circuit including an output amplifier in the form of an output transistor for supplying exciting current to the solenoid coil in response to the output of the comparator, the improvement comprising means coupled to said coil for detecting a voltage corresponding to said exciting current, positive feedback means, connected between said first input of said comparator and the output of one of said comparator and said output amplifier, and negative feedback means connected between said second comparator input and a junction between said detecting means and said coil, in order to provide ON-OFF control of said output transistor such that said exciting current comprises a current proportional to said analog control signal.
Claim 2
Dependent Claim
172 words
In a driving circuit of a solenoid actuated device of the type wherein a plunger is actuated by a solenoid coil, the driving circuit comprising a comparator having a first input supplied with an analog control signal representing an operating condition of a member to be controlled by the plunger, a second input, and an output; and a power amplifier circuit including an output amplifier in the form of an output transistor for supplying exciting current to the solenoid coil in response to the output of the comparator, the improvement comprising means coupled to said coil for detecting a voltage corresponding to said exciting current, positive feedback means, connected between said first input of said comparator and the output of one of said comparator and said output amplifier, and negative feedback means connected between said second comparator input and a junction between said detecting means and said coil, in order to provide ON-OFF control of said output transistor such that said exciting current comprises a current proportional to said analog control signal.
Claim 3
Dependent Claim
40 words
The driving circuit according to claim 1 wherein said solenoid actuated device controls operating fluid supplied to a power steering unit of a motor car and said analog control signal is proportional to the running speed of said motor car.
Claim 4
Dependent Claim
31 words
The driving circuit according to claim 1 wherein said positive feedback means is connected between the output terminal of said power amplifier circuit and said first input terminal of said comparator.
Claim 5
Dependent Claim
26 words
The driving circuit according to claim 1 wherein said positive feedback means is connected to said output terminal of said comparator and said input terminal thereof.
Claim 6
Dependent Claim
55 words
The driving circuit according to claim 1 wherein said positive feedback means comprises two serially connected resistors connected between the output of said amplifier circuit and said first input terminal of said comparator, and wherein a constant voltage element is connected between the junction between said serially connected resistors and a point of reference potential.