Relay drive circuit with a current mirror circuit
AssigneeOnkyo Corporation
InventorNaofumi Murai
Life of this patent
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Abstract
The present invention is intended to provide constant drive conditions of a relay switch. A relay drive circuit includes a current mirror circuit, a current suppression circuit 26, and a transistor Q3. The current mirror circuit includes a transistor Q1, a first resistor element R1, a transistor Q2, and a second resistor element R2. A relay coil 18 is provided on a current supply path extending from a collector terminal of the transistor Q1 to an earth conductor. The current suppression circuit 26 includes a capacitor C1 as a current suppression element configured to suppress, after conduction between an emitter terminal and a collector terminal of the transistor Q2 has been made, the current flowing through the current suppression element itself as compared to that in such conduction.
Claims7
A relay drive circuit comprising:
- a current mirror circuit including a first semiconductor element and a second semiconductor element, the current mirror circuit being configured to adjust a current flowing through a first current path including the first semiconductor element according to a current flowing through a second current path including the second semiconductor element;
- a control switch provided on the second current path, and
- a current suppression circuit provided on the second current path and configured to suppress, after conduction of the second semiconductor element has been made, the current flowing through the second current path as compared to that in the conduction of the second semiconductor element,
- wherein the current suppression circuit includes
- a current suppression element configured to suppress, after the conduction of the second semiconductor element has been made, a current flowing through the current suppression element itself as compared to that in the conduction of the second semiconductor element, and
- a current determination element configured to divide the current flowing through the current suppression element and to determine the current flowing through the second current path,
- wherein a relay coil is provided on the first current path.
A relay drive circuit comprising:
- a current mirror circuit including a first semiconductor element and a second semiconductor element, the current mirror circuit being configured to adjust a current flowing through a first current path including the first semiconductor element according to a current flowing through a second current path including the second semiconductor element;
- a control switch provided on the second current path, and
- a current suppression circuit provided on the second current path and configured to suppress, after conduction of the second semiconductor element has been made, the current flowing through the second current path as compared to that in the conduction of the second semiconductor element,
- wherein the current suppression circuit includes
- a capacitor and
- a current determination element configured to divide a current flow for the capacitor and to determine the current flowing through the second current path,
- wherein a relay coil is provided on the first current path.
Dependencies are inferred from the claim text.