Title:
ELECTROMAGNETIC VALVE DRIVE CIRCUIT
Document Type and Number:
Japanese Patent JPS57179486
Kind Code:
A
Abstract:
PURPOSE:To enable an electromagnetic valve to control current such that valve opening current can be changed over to valve holding one even under the lowered voltage condition of a battery by setting the valve opening current for completely opening the electromagnetic valve in response to current applied to an electromagnetic coil. CONSTITUTION:Electromagnetic coil current is gradually decreased by reverse electromotive force produced in an electromagnetic coil 1. When voltage across both ends of resistance R1 is lowered lower than a predetermined voltage Vb, a holding current comparating circuit 3 stops generation of second current increasing pulse. Thus, the output of a switching control circuit 5 reaches again high level to turn on a transistor Q1. Next, when the electromagnetic coil current increases so that the voltage across both ends of the resistance R1 reaches a predetermined voltage Va, the holding current comparing circuit 3 generates again the second current increasing pulse so that control from the valve opening current to the holding one can be carried out.
Inventors:
TOMIZAWA NAOMI
Application Number:
JP6367981A
Publication Date:
November 05, 1982
Filing Date:
April 27, 1981
Export Citation:
Assignee:
JAPAN ELECTRONIC CONTROL SYST
International Classes:
F16K31/06; H01F7/18; (IPC1-7): F16K31/02